Inverter control apparatus for elevator motor
First Claim
1. An apparatus for controlling a three-phase inverter supplying the a.c. motor of an elevator;
- said inverter having a power stage implemented using semiconductor switches; and
said apparatus comprisingelectronic control means (1) for producing a velocity reference value (v*);
tachometer generator means (11) for producing an actual velocity value (v);
voltage measuring means (9a-9c) for measuring phase voltages at the inverter output;
pulse width modulator means (6a-6c) and controller means for controlling semiconductor switches in said inverter power stage by control signals (A1,A2,B1,B2,C1,C2) obtained from said pulse width modulator means (6a-6c);
speed regulator means for forming the frequency (fr) of the rotor current and the frequency (fs) of the reference input voltages from said actual velocity value (v) and from said velocity reference value (v*);
curve calculator means for forming the amplitude of the reference voltages from said rotor current frequency (fr) and from the frequency (fs) of said reference input voltages;
three-phase oscillator (4) means for forming additional reference voltages (Va*,Vb*,Vc*) from the frequency (fs) and the amplitude (As) of said reference input voltages; and
voltage regulator means (5a-5c) for producing control voltages (Va'"'"',Vb'"'"',Vc'"'"') for controlling said pulse width modulator means (6a-6c) from said additional reference voltages (Va*,Vb*Vc*) and from the actual value voltages (Va,Vb,Vc) obtained from the output of said inverter.
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Accused Products
Abstract
An apparatus for controlling a three-phase inverter supplying the a.c. motor of an elevator, the inverter having a power stage implemented with semiconductor switches, and the apparatus comprising an electronic control unit for producing a velocity reference value and a tachometer generator for producing an actual velocity value, voltage measuring elements for measuring a.c. voltages at the inverter output, and pulse width modulators and drivers for controlling the semiconductor switches in the inverter'"'"'s power stage with control signals derived from the pulse width modulators. With the apparatus of the invention, fast control of the control voltage is achieved. Moreover, simpler voltage measuring elements may be used instead of current measuring elements. The apparatus of the invention comprises a speed regulator for producing a rotor current frequency and the frequencies of first reference voltages from the actual velocity value and the velocity reference value, a curve calculator for producing the amplitude of the reference voltages from the rotor current frequency and the frequency of the reference voltages, a three-phase oscillator for producing second reference voltages from the frequency and amplitude of the first reference voltages, and voltage regulators for producing control voltages for the pulse width modulators from additional reference voltages obtained from the second reference voltages and the actual value voltages obtained at the inverter output.
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Citations
10 Claims
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1. An apparatus for controlling a three-phase inverter supplying the a.c. motor of an elevator;
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said inverter having a power stage implemented using semiconductor switches; and said apparatus comprising electronic control means (1) for producing a velocity reference value (v*); tachometer generator means (11) for producing an actual velocity value (v); voltage measuring means (9a-9c) for measuring phase voltages at the inverter output; pulse width modulator means (6a-6c) and controller means for controlling semiconductor switches in said inverter power stage by control signals (A1,A2,B1,B2,C1,C2) obtained from said pulse width modulator means (6a-6c); speed regulator means for forming the frequency (fr) of the rotor current and the frequency (fs) of the reference input voltages from said actual velocity value (v) and from said velocity reference value (v*); curve calculator means for forming the amplitude of the reference voltages from said rotor current frequency (fr) and from the frequency (fs) of said reference input voltages; three-phase oscillator (4) means for forming additional reference voltages (Va*,Vb*,Vc*) from the frequency (fs) and the amplitude (As) of said reference input voltages; and voltage regulator means (5a-5c) for producing control voltages (Va'"'"',Vb'"'"',Vc'"'"') for controlling said pulse width modulator means (6a-6c) from said additional reference voltages (Va*,Vb*Vc*) and from the actual value voltages (Va,Vb,Vc) obtained from the output of said inverter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification