Search Results

This paper proposes a simplified method to make the flux table considering the magnetic flux variation of the IPMSM (Interior Permanent Magnet Synchronous Machine) caused by temperature change in vehicle traction applications. Nowadays, normally an IPMSM with a rare-earth magnet is used for HEV traction applications. But because the flux density of the magnet varies with temperature, the optimal operating points, such as MTPA (Maximum Torque Per Ampere) and MTPV (Maximum Torque Per Voltage) of the motor drift according to temperature change. Those operating points can be expressed in a lookup table, that is, a flux table obtained by off-line experiment, which produces the DQ-axis current command with respect to the torque and flux reference. To reflect this temperature dependence in control, usually flux tables are generated at high, medium and low temperatures. Conventionally, all the three tables are constructed by experiment, which takes a great deal of time.

This paper proposes a method to reduce the DC link capacitor of the ISG (Integrated Starter Generator) inverter for the micro-hybrid system of which ESS (Energy Storage System) is composed of a 12V battery, a 48V super-capacitor and a bidirectional DC-DC converter. Firstly, analysis is performed to calculate the required dc link capacitance according to the allowable ripple voltages and some inverter switching frequencies. And then, a method to reduce the ripple voltage is presented in which increased is the switching frequency, namely decreasing the switching period smaller than the current control period. Thirdly, the other method is presented to compensate the ripple voltage with a bidirectional dc-dc converter which is controlled much faster than the inverter. Finally, several simulations are done to verify the effectiveness of the proposed method. Using the proposed method, the required capacitance can be reduced to about a half of that of the initial design.