초록 ▼

A multi-motor drive in which the resonance existing between one or more output filter capacitors of a current source inverter and an a.c. induction motor is reduced. The inverter features a switching pattern generator which controls the power switches of the inverter based on a reference current. A

A multi-motor drive in which the resonance existing between one or more output filter capacitors of a current source inverter and an a.c. induction motor is reduced. The inverter features a switching pattern generator which controls the power switches of the inverter based on a reference current. A control loop, connected to the switching pattern generator, measures the load current or voltage and generates a nominal reference current based on an error therein; determines a damping current based on the voltage at the terminal; and determines the reference current supplied to the switching pattern generator by subtracting the damping current from the nominal reference current. The invention essentially simulates the use of a physical damping resistor connected in parallel with each output filter capacitor, but without the corresponding energy loss. This form of active damping control is also applied to a resonance mode existing between the input filter capacitors of a PWM-based rectifier and the system inductance of a power source.

대표청구항 ▼

[ We claim:] [16.] An a.c. induction motor drive, comprising:a three-phase inverter comprising a first three-phase switching bridge, a first switching pattern generator for the control thereof based on a first reference current, and three output filter capacitors connected to the bridge and being co

[ We claim:] [16.] An a.c. induction motor drive, comprising:a three-phase inverter comprising a first three-phase switching bridge, a first switching pattern generator for the control thereof based on a first reference current, and three output filter capacitors connected to the bridge and being connectable to a three-terminal, three-phase, motor having a per phase inductance;a three-phase rectifier comprising a second three-phase switching bridge, a second switching pattern generator for the control thereof based on a second reference current, and three input filter capacitors connected to the second bridge and being connectable to a three-phase power source having a per phase system inductance;a d.c. link choke connected between the rectifier and inverter;an inverter controller, connected to the first switching pattern generator, for(i) measuring the motor current or voltage and generating a first nominal reference current based on an error therein;(ii) determining a first damping current based on the voltages across the three output capacitors; and(iii) determining the first reference current supplied to the first switching pattern generator by subtracting the first damping current from the first nominal reference current;a rectifier controller, connected to the second switching pattern generator and the inverter controller, for(i) measuring the current flowing through the d.c. link choke and generating a second nominal reference current based on an error therein;(ii) determining a second damping current based on the voltages across the input filter capacitors; and(iii) determining the second reference current supplied to the second switching pattern generator by subtracting the second damping current from the second nominal reference current.