This digest proposes a cooperative control method of power factor correction circuit and inverter to reduce the heatsink of the electric drivetrain in air conditioning systems. Reducing total semiconductor losses in the rated power condition is critical for minimizing the heatsink in the hardware design. The six-step operation effectively reduces semiconductor losses at the rated power. When the DC-link voltage is constant, flux enhancement should be performed at a low speed with the six-step operation. In this case, large conduction losses of power devices occur and the motor efficiency degrades. Therefore, an algorithm that takes advantage of variable dc-link voltage, maintains the existing space vector pulse width modulation method at low/medium speed, and operates in six-step at high speed in fluid load applications. This digest proposes a control method for motor current vector control during six-step operation using variable DC-link voltage when the converter and motor-driven inverter share the same DC link. The experimental results show that the proposed method can reduce inverter loss significantly.
