Ac-dc generating system

Claim 2

A power transfer system for providing a-c and/or d-c voltages, comprising: an induction machine having a mechanical input shaft, a plurality of output conductors for supplying an a-c output voltage, and means for enabling the induction machine to build up during start-up; a capacitor; a switching system, including a plurality of output connections coupled to the induction machine output conductors, and a plurality of additional connections coupled to said capacitor, said system including a plurality of switches connected to receive actuating signals to control the switching frequency; and means, including an oscillator-and-logic circuit, connected to regulate the actuating times of the switches in the switching system, to thus regulate the frequency or the amplitude of output a-c energy provided by the power transfer system.

Claim 3

A power transfer system as claimed in claim 1, in which the oscillator in the oscillator-and-logic circuit is connected to operate at a fixed frequency, thus maintaining a fixed frequency output a-c energy from the power transfer system.

Claim 4

A power transfer system as claimed in claim 1, in which the oscillator in the oscillator-and-logic circuit is connected to operate at a variable frequency as a functiOn of variations in the speed of the mechanical input shaft of the induction machine, thus maintaining a constant amplitude of the output a-c energy from the power transfer system.

Claim 5

A generating system for providing a-c and/or d-c voltages, comprising: an induction machine having a mechanical input shaft, a plurality of output conductors for supplying an a-c output voltage, and means for enabling the induction machine to build up during start-up; a capacitor; a switching system, including a plurality of output connections coupled to the induction machine output conductors, a pair of additional connections coupled to said capacitor, from which additional connections a d-c output voltage can be supplied, and a plurality of semiconductor switches connected to receive gating signals to control the frequency of circuit switching; and means, including an oscillator-and-logic circuit, connected to regulate the turn-on times of the semiconductor switches in the switching system to thus regulate the frequency or the amplitude of output a-c energy provided by the generating system.

Claim 6

A generating system for providing a-c and/or d-c voltages, comprising: an induction machine having a mechanical input shaft, a plurality of output conductors for supplying an a-c output voltage, and means for enabling the induction machine to build up during start-up; a capacitor; a switching system, including a plurality of output connections coupled to the induction machine output conductors, a pair of additional connections coupled to said capacitor, from which additional connections a d-c output voltage can be supplied, and a plurality of semiconductor switches connected to receive gating signals to control the frequency of circuit switching; and means, including an oscillator-and-logic circuit, connected to regulate the turn-on times of the semiconductor switches in the switching system to thus regulate the frequency or the amplitude of output a-c energy provided by the generating system.

Claim 9

A generating system for providing a-c and/or d-c voltages, comprising: an induction generator, having a mechanical input shaft, a plurality of output conductors for supplying an a-c output voltage, and means for applying an excitation voltage, of a level approximately an order of magnitude less than the normal rated voltage level of the induction generator, to the induction generator only during start-up; a capacitor; a switching system, including a pair of bus conductors coupled to the capacitor, a plurality of output connections individually coupled to the respective induction generator output conductors, and a plurality of controlled rectifiers individually connected to receive gating signals for controlling the rectifier conduction times; means, including an oscillator-and-logic circuit, connected to regulate the application of the gating signals to the controlled rectifiers to regulate the amplitude or frequency of the system output voltage; and means for rotating the input shaft of the induction generator.

Claim 10

A generating system for providing a-c and/or d-c voltages, comprising: an induction generator, having a mechanical input shaft, a plurality of output conductors for supplying an a-c output voltage, and means for applying an excitation voltage, of a level approximately an order of magnitude less than the normal rated voltage level of the induction generator, to the induction generator only during start-up; a capacitor; a switching system, including a pair of bus conductors coupled to the capacitor, a plurality of output connections individually coupled to the respective induction generator output conductors, and a plurality of controlled rectifiers individually connected to receive gating signals for controlling the rectifier conduction times; means, including an oscillator-and-logic circuit, connected to regulate the application of the gating signals to the controlled rectifiers to regulate the amplitude or frequency of the system output voltage; and means for rotating the input shaft of the induction generator.

Claim 11

A generating system as claimed in claim 6 and further comprising a voltage comparator stage, having input connections coupled both to the induction generator output conductors and to a reference voltage unit, connected to regulate operation of the oscillator-and-logic circuit to govern the timing of the gating signals in the proper sense to maintain constant the amplitude of the system output voltage.

Claim 12

A bi-directional power transfer system for transferring power in a first direction during start-up of a mechanical unit having a drive shaft and thereafter reversing the direction of power transfer from the mechanical unit to an electrical load, comprising: a switching system, having a pair of bus conductors, a plurality of output connections, and a plurality of semiconductor switches connected to receive gating signaLs for regulating turn-on of the semiconductor switches; a capacitor coupled to the bus conductors; an induction machine, having a mechanical shaft and a plurality of output conductors coupled to the plurality of switching system output connections; means for coupling the drive shaft of the mechanical unit to the mechanical shaft of the induction machine; means, including a first switch, for transferring d-c energy to the switching system bus conductors during system start-up, to provide an a-c output voltage from the switching system which energizes the induction machine as a motor and transfers mechanical drive to the mechanical unit to drive it up to rated speed; and means, including a second switch, for completing an electrical circuit to transfer d-c energy from the switching system bus conductors to the electrical load as the induction machine is driven by the mechanical unit to operate as a generator which passes energy through the switching system to supply the electrical load.

Claim 13

A bi-directional power transfer system for transferring power in a first direction during start-up of a mechanical unit having a drive shaft and thereafter reversing the direction of power transfer from the mechanical unit to an electrical load, comprising: a switching system, having a pair of bus conductors, a plurality of output connections, and a plurality of semiconductor switches connected to receive gating signaLs for regulating turn-on of the semiconductor switches; a capacitor coupled to the bus conductors; an induction machine, having a mechanical shaft and a plurality of output conductors coupled to the plurality of switching system output connections; means for coupling the drive shaft of the mechanical unit to the mechanical shaft of the induction machine; means, including a first switch, for transferring d-c energy to the switching system bus conductors during system start-up, to provide an a-c output voltage from the switching system which energizes the induction machine as a motor and transfers mechanical drive to the mechanical unit to drive it up to rated speed; and means, including a second switch, for completing an electrical circuit to transfer d-c energy from the switching system bus conductors to the electrical load as the induction machine is driven by the mechanical unit to operate as a generator which passes energy through the switching system to supply the electrical load.

Claim 14

A power transfer system as claimed in claim 8, and further comprising: an oscillator-and-logic circuit connected to provide the gating signals for the semiconductor switches in the switching system; a comparator stage, having a first input connection connected to receive a signal which varies as a function of the amplitude of the voltage at the induction machine output connections, a second input connection connected to receive a reference signal, and an output connection for supplying a control signal which varies as a function of amplitude variations of the induction machine output a-c voltage; and means for coupling the comparator output connection to the oscillator-and-logic circuit, to regulate the frequency of the gating signals and thus maintain constant the amplitude of the voltage at the induction machine output connections.

Claim 15

A power transfer system as claimed in claim 8, and further comprising: an oscillator-and-logic circuit connected to provide the gating signals for the semiconductor switches in the switching system; a comparator stage, having a first input connection connected to receive a signal which varies as a function of the amplitude of the switching system bus current, a second input connection connected to receive a reference signal, and an output connection for supplying a control signal which varies as a function of amplitude variations of the switching system bus current; and means for coupling the comparator output connection to the oscillator-and-logic circuit, to regulate the frequency of the gating signals as a function of the switching system bus current.

Claim 16

A power transfer system for providing a-c and/or d-c voltages, comprising: an induction machine having a mechanical input shaft, a plurality of output conductors for supplying a multi-phase a-c output voltage, and means for enabling the induction machine to build up during start-up; a switching system, including a plurality of output connections coupled to the induction machine output conductors, said system including a plurality of semiconductor switches connected to receive gating signals to control the switching frequency and periodically direct the flow of reactive energy from one phase circuit of the induction machine to another phase circuit of the machine; and means, including an oscillator-and-logic circuit, connected to regulate the turn-on times of the semiconductor switches in the switching system, to thus regulate the frequency or the amplitude of output a-c energy provided by the power transfer system.

Claim 17

A power transfer system for providing a-c and/or d-c voltages, comprising: an induction machine having a mechanical input shaft, a plurality of output conductors for supplying a multi-phase a-c output voltage, and means for enabling the induction machine to build up during start-up; a switching system, including a plurality of output connections coupled to the induction machine output conductors, said system including a plurality of semiconductor switches connected to receive gating signals to control the switching frequency and periodically direct the flow of reactive energy from one phase circuit of the induction machine to another phase circuit of the machine; and means, including an oscillator-and-logic circuit, connected to regulate the turn-on times of the semiconductor switches in the switching system, to thus regulate the frequency or the amplitude of output a-c energy provided by the power transfer system.