Beat-less Control of Electrolytic Capacitor-less Air Conditioning Motor Drive System

There is ripples in the DC bus voltage of the electrolytic capacitor-less air condition motor system because the film capacitor is not big enough to store plenty of energy, which will cause a motor voltage offset and go further causing beat phenomenon in the motor current and the torque. Firstly, the reason of the beat phenomenon in the current and the torque is analyzed mathematically. Furthermore, a novel beat-less control strategy is proposed, which is realized by moving the modulation wave of space vector pulse width modulation up or down. The proposed method realizes the modulation wave moving by the different value between the feedback and the reference currents, which can lead to an offset in the inverter output voltage that can be used to neutralize the offset mentioned above. At last, the proposed beat-less control strategy was validated through simulation by the MATLAB/Simulink and experiment on a 1.0kW IPMSM air condition drive system.