Starting control scheme for rectifier-inverter systems

Claim 2

For starting an electric power converter comprising a plurality of electric current conducting valves connected in a bridge configuration and arranged to commence conducting in a predetermined normal sequence, the comBination of: a. control means for cyclically generating a succession of relatively short gate pulses for the respective valves of the converter and for applying said pulses to corresponding valves so as to fire the valves in said normal sequence; b. said control means including means initially operative to cause said control means to idle, in which state the timing of said gate pulses is determinable but no gate pulses are actually applied to said valves; c. means for producing a starting signal; and d. disabling means connected to said control means and operative to disable said initially operative means in response to the coincidence of said starting signal being produced and one of said gate pulses being due; e. said control means being arranged upon operation of said disabling means to apply said one gate pulse to the corresponding valve and simultaneously to apply a gate pulse to the preceding valve in said normal sequence, thereby starting the converter.

Claim 3

For starting an electric power converter comprising a plurality of electric current conducting valves connected in a bridge configuration and arranged to commence conducting in a predetermined normal sequence, the combination of: a. control means for cyclically generating a succession of relatively short gate pulses for the respective valves of the converter and for applying said pulses to corresponding valves so as to fire the valves in said normal sequence; b. said control means including means initially operative to cause said control means to idle, in which state the timing of said gate pulses is determinable but no gate pulses are actually applied to said valves; c. additional means initially operative to precondition said control means for generating gate pulses characterized by a firing angle within predetermined limits; d. means for producing a starting signal; and e. disabling means connected to said control means and operative in response to said starting signal to disable the initially operative means which is identified in the above paragraph (b) when one of said gate pulses is due; f. said control means being arranged upon operation of said disabling means to apply said one gate pulse to the corresponding valve and simultaneously to apply a gate pulse to the preceding valve in said normal sequence, thereby starting the converter.

Claim 4

For starting an electric power converter comprising a plurality of electric current conducting valves connected in a bridge configuration and arranged to commence conducting in a predetermined normal sequence, the combination of: a. control means for cyclically generating a succession of relatively short gate pulses for the respective valves of the converter and for applying said pulses to corresponding valves so as to fire the valves in said normal sequence; b. said control means including means initially operative to cause said control means to idle, in which state the timing of said gate pulses is determinable but no gate pulses are actually applied to said valves; c. additional means initially operative to precondition said control means for generating gate pulses characterized by a firing angle within predetermined limits; d. means for producing a starting signal; and e. disabling means connected to said control means and operative in response to said starting signal to disable the initially operative means which is identified in the above paragraph (b) when one of said gate pulses is due; f. said control means being arranged upon operation of said disabling means to apply said one gate pulse to the corresponding valve and simultaneously to apply a gate pulse to the preceding valve in said normal sequence, thereby starting the converter.

Claim 5

The combination set forth in claim 2 in which said firing angle is no greater than 60 electrical degrees on an operating basis.

Claim 6

The combination set forth in claim 2 in which said additional means includes means for disabling the same in response to starting the converter.

Claim 7

The combination set forth in claim 4 in which said additional means is arranged to progressively change its preconditioning effect in response to starting the converter.

Claim 8

The combination set forth in claim 2 in which said additional means includes means for disabling the same in response to operation of the disabling means identified in paragraph (e).

Claim 9

For starting a first electric power converter comprising a plurality of electric current conducting valves connected in a bridge configuration and arranged to commence conducting in a predetermined normal sequence, which converter is adapted to be used in conjunction with another converter connected thereto via a DC link, the combination of: a. control means for cyclically generating a succession of relatively short gate pulses for the respective valves of said first converter and for applying said pulses to corresponding valves so as to fire the valves in said normal sequence; b. said control means including means initially operative to cause said control means to idle, in which state the timing of said gate pulses is determinable but no gate pulses are actually applied to said valves; c. means for producing a starting signal; and d. disabling means connected to said control means and to said starting signal producing means and also adapted to be connected to similar control means associated with said other converter, said disabling means being operative to disable said initially operative means in response to the coincidence of i. said starting signal, ii. a gate pulse being due at said first converter, and iii. a gate pulse being due at said other converter; e. the control means for said first converter being arranged upon operation of said disabling means to apply said one gate pulse to the corresponding valve and simultaneously to apply a gate pulse to the preceding valve in said normal sequence, thereby starting said first converter.

Claim 10

For starting a first electric power converter comprising a plurality of electric current conducting valves connected in a bridge configuration and arranged to commence conducting in a predetermined normal sequence, which converter is adapted to be used in conjunction with another converter connected thereto via a DC link, the combination of: a. control means for cyclically generating a succession of relatively short gate pulses for the respective valves of said first converter and for applying said pulses to corresponding valves so as to fire the valves in said normal sequence; b. said control means including means initially operative to cause said control means to idle, in which state the timing of said gate pulses is determinable but no gate pulses are actually applied to said valves; c. means for producing a starting signal; and d. disabling means connected to said control means and to said starting signal producing means and also adapted to be connected to similar control means associated with said other converter, said disabling means being operative to disable said initially operative means in response to the coincidence of i. said starting signal, ii. a gate pulse being due at said first converter, and iii. a gate pulse being due at said other converter; e. the control means for said first converter being arranged upon operation of said disabling means to apply said one gate pulse to the corresponding valve and simultaneously to apply a gate pulse to the preceding valve in said normal sequence, thereby starting said first converter.

Claim 11

For starting an electric power converter in response to a starting or recycling command, said converter comprising N electric valves connected in at least one bridge configuration between a DC link and a polyphase system whose voltage alternates at a frequency of f hertz, an improved control circuit comprising: a. first means associated with the converter for cyclically generating a family of N control signals for effecting turn on of the respective valves of that converter in a predetermined sequence, each of said control signals subsisting appreciably longer than 1/Nf; b. a valve-firing system comprising N second means respectively operative when activated to transmit relatively short turn-on pulses to each valve in turn; c. third means connected to said first means and to said firing system for respectively activating each of said second means in response to the existence of a corresponding control signal; and d. blocking means connected to said third means for initially preventing activation of any second means until disabled in response to the coincidence of i. said command and ii. the leading edge of one of said control signals.

Claim 12

For starting an electric power converter in response to a starting or recycling command, said converter comprising N electric valves connected in at least one bridge configuration between a DC link and a polyphase system whose voltage alternates at a frequency of f hertz, an improved control circuit comprising: a. first means associated with the converter for cyclically generating a family of N control signals for effecting turn on of the respective valves of that converter in a predetermined sequence, each of said control signals subsisting appreciably longer than 1/Nf; b. a valve-firing system comprising N second means respectively operative when activated to transmit relatively short turn-on pulses to each valve in turn; c. third means connected to said first means and to said firing system for respectively activating each of said second means in response to the existence of a corresponding control signal; and d. blocking means connected to said third means for initially preventing activation of any second means until disabled in response to the coincidence of i. said command and ii. the leading edge of one of said control signals.

Claim 13

The improved control circuit of claim 8 in which said first means is arranged to generate said control signals in timed relation to the alternating voltage and in which starting bias means is connected to said first means for establishing the initial firing angle of said control signals within predetermined limits.

Claim 14

The improved control circuit of claim 9 in which means is provided for disabling said starting bias means in response to said blocking means being disabled.

Claim 15

For cold starting an electric power converter comprising 6 electric valves connected in a double-way bridge configuration between a set of polyphase AC conductors and a pair of DC terminals, the combination of: a. first means for cyclically generating a set of six control signals for effecting turn on of the respective valves in a predetermined sequence, said control signals commencing at intervals of approximately one-sixth cycle and each subsisting for appreciably longer than one-sixth of a cycle; b. starting bias means for preconditioning said first means so that the initial firing angle of said control signals can not exceed 60 electrical degrees; c. a valve-firing system comprising six means respectively operative when activated to apply relatively short gate pulses to each valve in turn; d. means interconnecting said first means and said valve-firing system for respectively activating each of said six means in response to the existence of a corresponding control signal; e. said interconnecting means including blocking means for initially preventing activation of any one of said six means; f. means operative while two of said control signals coexist for disabling said blocking means and thereby permitting the converter to start; and g. means responsive to the converter starting for disabling said starting bias means.

Claim 16

For cold starting an electric power converter comprising 6 electric valves connected in a double-way bridge configuration between a set of polyphase AC conductors and a pair of DC terminals, the combination of: a. first means for cyclically generating a set of six control signals for effecting turn on of the respective valves in a predetermined sequence, said control signals commencing at intervals of approximately one-sixth cycle and each subsisting for appreciably longer than one-sixth of a cycle; b. starting bias means for preconditioning said first means so that the initial firing angle of said control signals can not exceed 60 electrical degrees; c. a valve-firing system comprising six means respectively operative when activated to apply relatively short gate pulses to each valve in turn; d. means interconnecting said first means and said valve-firing system for respectively activating each of said six means in response to the existence of a corresponding control signal; e. said interconnecting means including blocking means for initially preventing activation of any one of said six means; f. means operative while two of said control signals coexist for disabling said blocking means and thereby permitting the converter to start; and g. means responsive to the converter starting for disabling said starting bias means.

Claim 17

For starting an electric power system comprising at least first and second converters respectively connected to opposite ends of a DC link, the first converter comprising N electric valves connected in at least one bridge configuration between one end of said DC link and polyphase conductors the voltages across which aLternate at a frequency of f hertz, and the second converter comprising N'' electric valves connected in at least one bridge configuration between the other end of said DC link and polyphase conductors the voltages across which alternate at a frequency of f'' hertz, an improved control circuit comprising: a. first means associated with each of said converters for cyclically generating a series of control signals for effecting turn on of the respective valves of that converter in a predetermined sequence, the control signals generated by the first means at said first converter subsisting for appreciably longer than 1Nf and the control signals generated by the first means at said second converter subsisting appreciably longer than 1/N''f''; b. second means connected to each of said first means and operative in response to the existence of the control signals respectively generated thereby for sequentially transmitting relatively short turn-on pulses to the respective valves of the associated converter; and c. third means at each converter for initially blocking operation of the second means until disabled, said third means including means for disabling the same in response to the coincidence of; i. the coexistence of at least two control signals generated by the first means associated with the first converter and ii. the coexistence of at least two control signals generated by the first means associated with the second converter.

Claim 18

For starting an electric power system comprising at least first and second converters respectively connected to opposite ends of a DC link, the first converter comprising N electric valves connected in at least one bridge configuration between one end of said DC link and polyphase conductors the voltages across which aLternate at a frequency of f hertz, and the second converter comprising N'' electric valves connected in at least one bridge configuration between the other end of said DC link and polyphase conductors the voltages across which alternate at a frequency of f'' hertz, an improved control circuit comprising: a. first means associated with each of said converters for cyclically generating a series of control signals for effecting turn on of the respective valves of that converter in a predetermined sequence, the control signals generated by the first means at said first converter subsisting for appreciably longer than 1Nf and the control signals generated by the first means at said second converter subsisting appreciably longer than 1/N''f''; b. second means connected to each of said first means and operative in response to the existence of the control signals respectively generated thereby for sequentially transmitting relatively short turn-on pulses to the respective valves of the associated converter; and c. third means at each converter for initially blocking operation of the second means until disabled, said third means including means for disabling the same in response to the coincidence of; i. the coexistence of at least two control signals generated by the first means associated with the first converter and ii. the coexistence of at least two control signals generated by the first means associated with the second converter.

Claim 19

For starting an electric power system comprising at least first and second converters respectively connected to opposite ends of a DC link, each converter comprising a plurality of electric valves connected in a bridge configuration, an improved control circuit comprising: a. means 19, 20 associated with each of said converters for producing a first set of control signals; b. means 42 for deriving a series of short pulses from the control signals of each first set; c. means 44, 45 for detecting when individual pulses at both converters are in substantially simultaneous existence; and d. means 27, 28'', 31-36 responsive to the simultaneous existence of said individual pulses for deriving from said control signals at each converter a set of gate pulses for the valves of the associated converter.

Claim 20

For starting an electric power system comprising at least first and second converters respectively connected to opposite ends of a DC link, each converter comprising a plurality of electric valves connected in a bridge configuration, an improved control circuit comprising: a. means 19, 20 associated with each of said converters for producing a first set of control signals; b. means 42 for deriving a series of short pulses from the control signals of each first set; c. means 44, 45 for detecting when individual pulses at both converters are in substantially simultaneous existence; and d. means 27, 28'', 31-36 responsive to the simultaneous existence of said individual pulses for deriving from said control signals at each converter a set of gate pulses for the valves of the associated converter.

Claim 21

A cold starting process for a multivalve, double-way electric power converting bridge including the steps of a. cyclically generating a family of staggered, relatively long control signals adapted to activate a valve-firing system for turning on the respective valves of the bridge in a predetermined normal sequence in timed relation to the voltages across the AC terminals of the bridge; b. preadjusting the timing of said control signals to establish an initial firing angle for said valves within predetermined limits; c. detecting the leading edges of successive control signals; d. applying one of said control signals to said valve-firing system at an instant of time determined by the detection of its leading edge, thereby turning on a corresponding valve; e. simultaneously applying an earlier control signal to said valve-firing system to turn on the valve that precedes said corresponding valve in said normal sequence; and f. thereafter applying said control signals in turn to said valve-firing system.

Claim 22

A cold starting process for a multivalve, double-way electric power converting bridge including the steps of a. cyclically generating a family of staggered, relatively long control signals adapted to activate a valve-firing system for turning on the respective valves of the bridge in a predetermined normal sequence in timed relation to the voltages across the AC terminals of the bridge; b. preadjusting the timing of said control signals to establish an initial firing angle for said valves within predetermined limits; c. detecting the leading edges of successive control signals; d. applying one of said control signals to said valve-firing system at an instant of time determined by the detection of its leading edge, thereby turning on a corresponding valve; e. simultaneously applying an earlier control signal to said valve-firing system to turn on the valve that precedes said corresponding valve in said normal sequence; and f. thereafter applying said control signals in turn to said valve-firing system.

Claim 23

The process set forth in claim 14 including an additional step of changing the effect of said preadjusting step when the bridge starts.

Claim 24

The combination set forth in claim 2 in which said additional means is arranged initially to precondition said control means for generating gate pulses characterized by a firing angle which varies with time between predetermined maximum and minimum values.

Claim 25

The combination set forth in claim 2 in which said additional means is temporarily operative in response to starting the converter to cause said control means to generate gate pulses characterized by a progressiVely increasing firing angle.

Claim 26

The combination of claim 7 in which additional means is provided initially to precondition the control means associated with said other converter for generating gate pulses characterized by a firing angle which varies with time between predetermined maximum and minimum values.

Claim 27

The improved control circuit of claim 9 in which said starting bias means is arranged temporarily to effect a progressively increasing firing angle in response to said blocking means being disabled.

Claim 28

For starting an electric power converter comprising N electric current conducting valves connected in at least one bridge configuration and arranged to commence conducting in a predetermined normal sequence, the combination of: a. control means for cyclically generating a succession of relatively short gate pulses for the respective valves of the converter and for applying said pulses to corresponding valves so as to fire the valves in said normal sequence; b. said control means including means initially operative to cause said control means to idle, in which state the timing of said gate pulses is determinable but no gate pulses are actually applied to said valves; c. additional means initially operative to precondition said control means for generating gate pulses characterized by a firing angle within predetermined limits; d. disabling means connected to said control means and operative in immediate response to receipt of a starting command to disable the initially operative means which is identified in the above paragraph (b); e. said control means being arranged upon operation of said disabling means to generate and apply simultaneous gate pulses for and to the N/3 valves which, in said normal sequence, in turn precede the one valve that is due to be fired by the gate pulse next generated after the incidence of said starting command; and f. means for supplying said starting command to said disabling means when starting is desired.

Claim 29

For starting an electric power converter comprising N electric current conducting valves connected in at least one bridge configuration and arranged to commence conducting in a predetermined normal sequence, the combination of: a. control means for cyclically generating a succession of relatively short gate pulses for the respective valves of the converter and for applying said pulses to corresponding valves so as to fire the valves in said normal sequence; b. said control means including means initially operative to cause said control means to idle, in which state the timing of said gate pulses is determinable but no gate pulses are actually applied to said valves; c. additional means initially operative to precondition said control means for generating gate pulses characterized by a firing angle within predetermined limits; d. disabling means connected to said control means and operative in immediate response to receipt of a starting command to disable the initially operative means which is identified in the above paragraph (b); e. said control means being arranged upon operation of said disabling means to generate and apply simultaneous gate pulses for and to the N/3 valves which, in said normal sequence, in turn precede the one valve that is due to be fired by the gate pulse next generated after the incidence of said starting command; and f. means for supplying said starting command to said disabling means when starting is desired.

Claim 30

The combination of claim 20 in which said additional means is arranged initially to precondition said control means for generating gate pulses characterized by a firing angle which is no greater than a predetermined maximum permissible initial firing angle minus 360/N degrees.

Claim 31

The combination of claim 20 in which said additional means is temporarily operative in response to starting the converter to cause said control means to generate gate pulses characterized by a progressively increasing firing angle.

Claim 32

For starting an electric power converter in response to a starting or recycling command, said converter comprising N electric valves connected in at least one bridge configuration between a DC link and a polyphase system whose voltage alternates at a frequency of f hertz, an improved control circuit comprising: a. first means associated with the converter for cyclically generating a family of N control signals for effecting turn on of the respective valves of that converter in a predetermined sequence in timed relation to the alternating voltage, each of said control signals subsisting appreciably longer than 1/Nf; b. starting bias means connected to said first means for establishing an initial firing angle of said control signals no greater than a predetermined maximum permissible initial firing angle minus 360/N degrees; c. a valve-firing system comprising N second means respectively operative when activated to transmit relatively short turn-on pulses to each valve in turn; d. third means connected to said first means and to said firing system for respectively activating each of said second means in response to the existence of a corresponding control signal; and e. blocking means connected to said third means for initially preventing activation of any second means until disabled in response to said command.

Claim 33

For starting an electric power converter in response to a starting or recycling command, said converter comprising N electric valves connected in at least one bridge configuration between a DC link and a polyphase system whose voltage alternates at a frequency of f hertz, an improved control circuit comprising: a. first means associated with the converter for cyclically generating a family of N control signals for effecting turn on of the respective valves of that converter in a predetermined sequence in timed relation to the alternating voltage, each of said control signals subsisting appreciably longer than 1/Nf; b. starting bias means connected to said first means for establishing an initial firing angle of said control signals no greater than a predetermined maximum permissible initial firing angle minus 360/N degrees; c. a valve-firing system comprising N second means respectively operative when activated to transmit relatively short turn-on pulses to each valve in turn; d. third means connected to said first means and to said firing system for respectively activating each of said second means in response to the existence of a corresponding control signal; and e. blocking means connected to said third means for initially preventing activation of any second means until disabled in response to said command.

Claim 34

For starting an electric power system comprising at least first and second Converters respectively connected to opposite ends of a DC link, each converter comprising a plurality of electric valves connected in a bridge configuration, an improved control circuit comprising: a. means associated with each of said converters for producing a first set of control signals; b. means for deriving a series of short pulses from the control signals of the first set produced at said first converter; c. means associated with said first converter and responsive to the coexistence of a starting command and one of said short pulses for deriving from the control signals at said first converter a set of gate pulses for the valves of that converter, thereby starting said first converter; d. starting bias means associated with said second converter and initially operative to establish a predetermined firing angle of the control signals of the first set produced at said second converter; and e. means associated with said second converter and responsive to starting of said first converter for deriving from the control signals at said second converter a set of gate pulses for the valves of the latter converter, thereby starting said second converter.

Claim 35

For starting an electric power system comprising at least first and second Converters respectively connected to opposite ends of a DC link, each converter comprising a plurality of electric valves connected in a bridge configuration, an improved control circuit comprising: a. means associated with each of said converters for producing a first set of control signals; b. means for deriving a series of short pulses from the control signals of the first set produced at said first converter; c. means associated with said first converter and responsive to the coexistence of a starting command and one of said short pulses for deriving from the control signals at said first converter a set of gate pulses for the valves of that converter, thereby starting said first converter; d. starting bias means associated with said second converter and initially operative to establish a predetermined firing angle of the control signals of the first set produced at said second converter; and e. means associated with said second converter and responsive to starting of said first converter for deriving from the control signals at said second converter a set of gate pulses for the valves of the latter converter, thereby starting said second converter.

Claim 36

The improved control circuit of claim 24 in which said starting bias means is initially operative to establish a firing angle which is no greater than a predetermined maximum permissible initial firing angle minus the electrical degrees between successive gate pulses for the valves of said second converter.

Claim 37

The improved control circuit of claim 24 in which said starting bias means is arranged temporarily to effect a progressively increasing firing angle of the control signals produced at said second converter in response to starting of said second converter.

Claim 38

For starting an electric power converter in response to a starting or recycling command, said converter comprising N electric valves connected in at least one bridge configuration between a DC link and a polyphase system whose voltage alternates at a frequency of f hertz, an improved control circuit comprising: a. first means associated with the converter for cyclically generating a family of N control signals for effecting turn on of the respective valves of that converter in a predetermined sequence and at a predetermined firing angle, each of said control signals subsisting appreciably longer than 1/Nf; b. a valve-firing system comprising N second means respectively operative when activated to transmit relatively short turn-on pulses to each valve in turn; c. third means connected to said first means and to said firing system for respectively activating each of said second means in response to the existence of a corresponding control signal; d. said third means including blocking means for initially preventing activation of any second means until disabled; e. means for disabling said blocking means in response to said command, thereby starting the converter; and f. bias means connected to said first means for temporarily effecting a progressively increasing firing angle in response to starting the converter.

Claim 39

For starting an electric power converter in response to a starting or recycling command, said converter comprising N electric valves connected in at least one bridge configuration between a DC link and a polyphase system whose voltage alternates at a frequency of f hertz, an improved control circuit comprising: a. first means associated with the converter for cyclically generating a family of N control signals for effecting turn on of the respective valves of that converter in a predetermined sequence and at a predetermined firing angle, each of said control signals subsisting appreciably longer than 1/Nf; b. a valve-firing system comprising N second means respectively operative when activated to transmit relatively short turn-on pulses to each valve in turn; c. third means connected to said first means and to said firing system for respectively activating each of said second means in response to the existence of a corresponding control signal; d. said third means including blocking means for initially preventing activation of any second means until disabled; e. means for disabling said blocking means in response to said command, thereby starting the converter; and f. bias means connected to said first means for temporarily effecting a progressively increasing firing angle in response to starting the converter.