Drive And Control Of Permanent Magnet Synchronous Motor For Electric Bus

Permanent Magnet Synchronous Motor is widely used in servo systems,new energy vehicles and household appliances benefit from its high power density,high power factor,simple structure,small size and reliability.Among them,Interior Permanent Magnet Synchronous Motor(IPMSM)has higher torque-current ratio,wider speed range and stronger flux-weakening control ability compared with Surface Permanent Magnet Synchronous Motor(SPMSM),but its q-axis inductance and d-axis inductance are asymmetric,and the motor parameters change dramatically under different working condition,which lead to more complicated controls and make it difficult to achieve.In this paper,the vector control based on the rotor field orientation of IPMSM is studied and the optimal control of the stator current in the full speed range is analyzed.Maximum Torque per Ampere(MTPA)is a better choice until the voltage is satrated,then field-weakening control is needed.In the depth field-weakening region,we can use Maximum Torque per Voltage to make full use of voltage.The paper designed the driver of electric bus,which include the main power circuit and the control circuit.The power circuit design need to consider the power level and the parasitic parameters of the circuit to prevent damage to the device.Control circuit design for vector control need to consider the corresponding signal sampling,protection,control and drive.Voltage feedback field-weakening control takes the difference between the output of current regulator and the voltage limit as the feedback quantity to modify the current given value.This strategy is independent of motor parameters,so the system is more robust.This paper improved the traditional negative id compensation voltage feedback field-weakening control strategy to realize MTPV control,besides,another strategy based on compensating iq is proposed.In order to verify the performance of those control scheme,simulations were built,and experiments are carried out.