Ballard Power Systems Corporation

Fengtai Huang

Bing Cheng

Duo Deng

Circuits and methods for use with an integrated circuit chip having internal back EMF estimation to control a permanent magnet synchronous motor includes an AC current feedback circuit, a scaling circuit, and a current regulator. Additionally, a speed regulator may be employed. In one embodiment, during operation at very low speed, the speed regulator is in an open loop control mode due to a back EMF detection limitation of the IC chip, and only the current regulator is active. A feedback current signal, together with a user-defined command current signal, serves the input of the current regulator, which controls the AC motor current and drives the motor speed from standstill. Once the motor speed reaches a certain level, the measured back EMF from the IC chip is sufficient to estimate the motor speed, which is compared with a user-defined command speed, and an error of the these two signals provides the input of a speed regulator.

Circuit configuration for permanent magnet synchronous motor control

A multilevel inverter control system having logic configured to substantially minimize and area between a target waveform and a step signal of a multilevel inverter.

Multilevel inverter control schemes

A start-up circuit for converters with controller power supply connected at output side. With this start-up circuit, all the control and supporting circuitries are connected at the converter output low voltage side and protected from high input DC voltage. After the converter is started and the controller starts generating normal switching pulses, the start-up circuit may be disabled.

Start-up circuit for power converters with controller power supply connected at output side

In one embodiment, a harmonic feedback system is characterized by: a three-phase to two-phase transformer configured to convert an output fundamental frequency current from a distributed power system and to convert the output fundamental frequency current from a three-phase current to a two-phase stationary reference current; a harmonic frequency transformer configured to convert the two-phase stationary reference current to a synchronous reference current, said harmonic frequency transformer having a target synchronous reference frame frequency based upon a reference harmonic current of the output fundamental frequency current; at least one filter device configured to remove predetermined components from the synchronous reference current to output a harmonic feedback current; a summation component to compare the harmonic feedback current with the reference harmonic current and to output a harmonic error current for driving the distributed power system to produce the output current.

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Windsor, CA, United States of America

Fengtai Huang