EP0466673A1
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EP
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Inverter
Assignee: Oerlikon Textile GmbH and Co KG
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Filing: 1991-07-11
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Granted: —
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Expires: 2011-07-11
Abstract
Abstract Method by a drive system for a DC-motor comprising an inverter and a multiple phase synchronous machine with a permanent magnet rotor and provided with a rotor position detecting means for detecting in order to generate a rotation dependent logic position signal or signals. Digital technique is used to displace the commutation points individually to an intended angle referred to said rotation dependent logic position signal or signals (POS 1,POS 2, POS 3). In a first step said position signal is supplied to a pulse detector (101) which creates a pulse train (T₀ - T₅) corresponding to the commutation reference points of time. In a second step every pulse in said pulse train gives a counting of a number of reference clock pulses (N₁,N₂,..N₆) in a counter (108) and in a third step corresponding binary numbers are stored in a register to be transmitted to a multiplier (111) in which multiplication takes place with a digital constant (k₁) from a constant memory (110).
Inventors
- 👤 Björn Lind
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 10:08
CPC Classifications
H; H02; H02P; H02P6/00; H02P6/14; H02P6/15
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
172 words
Method by a drive system for a DC-motor comprising an inverter and a multiple phase synchronous machine with a permanent magnet rotor and provided with a rotor position detecting means for detecting in order to generate a rotation dependent logic position signal or signals, characterized therein , that digital technique is used to displace the commutation points individually to an intended angle referred to said rotation dependent logic position signal or signals (POS 1,POS 2, POS 3), that in a first step said position signal is supplied to a pulse detector (101) which creates a pulse train (T₀ - T₅) corresponding to the commutation reference points of time and that in a second step every pulse in said pulse train gives a counting of a number of reference clock pulses (N₁,N₂,.. N₆) in a counter (108) and that in a third step corresponding binary numbers are stored in a register to be transmitted to a multiplier (111) in which multiplication takes place with a digital constant (k₁) from a constant memory (110).
Claim 2
Dependent Claim
130 words
Method according to claim 1, characterized therein , that a modification of a reference commutation time formed as the difference between two adjacent commutation points of time (eg. T₄ - T₃ ) corresponding to a certain number of reference clock pulses (N₁ pulses) occurs during the subsequent commutation interval (T₅ - T₄ = dT₅) whereby the result N₁′ of the multiplication in said multiplier (111) is stored in a register (112) the contents of which at the start of the interval (T₅), which follows that at which said multiplication occurs, is counted down with the clock frequency from the clock generator (100) in the counter (113) so that at the value zero of the counter (113) is obtained a pulse corresponding to the new commutation point of time (T₀′) .
Claim 3
Dependent Claim
105 words
Method according to claim 1 or 2, characterized therein , that an optimization function is used, which is based on the rotation dependent logical signals (POS 1, POS 2; POS 3) from the Back-EMF detector (5) by means of which the commutation points each are displaced individually such, that at said optimization function maximum driving shaft output power is detected to eliminate defects caused by unsymmetries in the motor iron or the windings as well as unsymmetries of the rotor magnet and by means of said function optimize motor performance with respect to e.g. efficiency at present velocity and load, maximum acceleration and motor vibrations.
Claim 4
Dependent Claim
52 words
Method according to claim 1 - 3, characterized therein , that at least one phase output (R,S,T) of the inverter is disconnected during a time period (δT) at a preselected rotation angle to make possible detection of the voltages which are generated in the stator windings (31,32,33) by rotation of the rotor.
Claim 5
Dependent Claim
108 words
Method according to claim 1 - 4, characterized therein , that rotation start for said rotor is created by a short first current pulse in a stator winding, which current pulse gives an arbitrary magnetic field whereby if no rotation is detected a second current pulse is supplied which generates a magnetic field the direction of which does not coincide with the first and if rotation thereby is detected, a third current pulse is supplied which maintains the rotation direction if it is the intended or shifts said direction so that further detected rotation signals directly or indirectly controls the drive system to reach the intended rotation speed.
Claim 6
Dependent Claim
146 words
Motor drive system to carry out a method according to claim 1-5, comprising a control unit (2) and a supervising unit (4) for controlling an inverter (1) the outputs (R,S,T) of which emit three phase square waves with 180° commutating angle which drive a synchronous machine (3) with phase windings (31,32,33) and a permanent magnet rotor (30) whereby the inverter (1) is supplied from a pulse width modulated constant voltage source (10), characterized therein , that the back-EMF detecting circuit (5) is connected between the supply lines (51,52,53) to said synchronous machine (3) and the inputs (r,s,t) of the control unit (2) and that said circuit detects the voltage (back-EMF) induced by the rotor (30) in the stator windings during a time section (δT) which is generated in the control unit (2) in response to the output signals (POS1, POS2, POS3) from the detecting circuit (5).
Claim 7
Dependent Claim
81 words
Motor drive system according to claim 6, characterized therein that the stator of the synchronous machine contains two sets of phase windings (31,32,33) and (31′,32′,33′) which are driven from an inverter (1′) the outputs (R,S,T) and (R′,S′,T′) of which emit first and second three phase square waves with 180° commutating angle and a phase displacement of 60° between first and second sets of voltage waves in order to suppress fifth and seventh harmonics in the stator (3) of the synchronous machine.
Claim 8
Dependent Claim
74 words
Motor drive system according to claims 6 or 7 , characterized therein , that the control unit comprises means for detecting speed (91) and position (90) of the rotor (30) in order to emit information signals (ACTUAL DIRECTION;ACTUAL SPEED) to the supervising unit (4) at start of rotation in response to a start impulse (DRIVER MODE, START) and direction command (DRIVER MODE, DIRECTION) given from the supervising unit (4) to the timing logic (93).
Claim 9
Dependent Claim
130 words
Motor drive system according to any of claims 6 - 8 characterized therein , that the control unit comprises an angle modifying block (94) for displacing the commutation times (T₀,..T₅) in which angle modifying block (94) a first counter (108) is contained which counts clock pulses (N₁,..N₆) from a reference oscillator (100) between time intervals (dT₀,..dT₅) obtained from the pulse detector (101) which time intervals correspond to successive zero crossings detected through the back-EMF detector (5) whereby after a multiplication with a constant stored in a constant memory (110) the result (N₁′,..N₆′) is counted down with the clock frequency reference oscillator (100) in a second counter (113) which gives modified time intervals (dT₀′,.. dT₅′) for activation of a logic block (119,.. 124) för creation of modified control signals (A′+, ..C′-).
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