Control of Variable Frequency Drive PWM to Mitigate Motor Overvoltage Due to Double Pulsing in Reflected Wave Phenomenon

摘要: It is well understood that variable frequency drives (VFDs) can cause overvoltage up to twice the DC bus voltage (2 pu, where 1 per unit voltage) at machine winding terminals, especially if long power cables are used and/or fast rise and fall times implemented. If oscillation not fully decayed when next pulse arrives, double pulsing occurs go 4 pu in one switching event. To prevent damage of electric insulation system, filters commonly between VFD machine. The filters, however, add significant cost size system. higher dv/dt associated with increasingly popular wide-bandgap devices requires even larger more expensive be installed. This paper proposes a new PWM control method, offset technique (DPOT), restrain peak-to-peaks within 2 regardless or dV/dt semiconductor devices. need install therefore, potentially eliminated implementation DPOT. scheme was validated using an accurate reflected wave phenomenon simulation model finite element analysis (FEA). also implemented online offline DSP SiC-MOSFET -based inverter. experimental results various operating conditions inverter presented analyzed. show DPOT successful eliminating harsh such as high dV/dt, cable length, frequent polarity reversals.