| Title |
Analysis of Motor Winding Impact by Inverter Switching Voltage Waveforms |
| Abstract |
In this paper the problems associated with the switching surge of PWM inverter devices were analysed. As the application of ASD for efficient speed control of AC motors is increased so is the motor and ASD-related failure increased. In the industrial motor applications, the introduction of PWM drives can sometimes cause insulation breakdown between the phase windings due to high transient voltage peak. The motor cable length combined with the high switching frequency becomes more sensitive issue for proper drive operation. Effects of the cable length and high switching frequency influence both on motor and inverter. When the insulation level of motor winding is low, the failure probability caused by high peak voltage and fast voltage rise times(dv/dt) is high. Voltage reflections are simulated for motor capacities, ASD and rise times and are presented graphically. The filtering techniques are discussed to reduce the motor terminal overvoltage and dv/dt in inverter fed AC motor drive systems. We confirmed that the lower motor capacity and motor insulation level, the shorter switching time and cable length and the higher the probability of insulation breakdown. |