Two-level and Five-level Inverter Fed Bldc Motor Drives

In high power high voltage application BLDC motor are widely used because of higher efficiency, simple in construction, lower cost, less in maintenance and higher torque or high output power per unit volume. For driving the BLDC motor an electrical commutator (inverter) is required. PWM inverter gives good performance. In two level inverter there are problems of harmonics distortions, low electromagnetic interference, higher DC link voltage required, higher dV/dt, heating of rotor (rotor shaft) etc. The increase in the number of steps in voltage is one of the solutions for the above problems. This can be possible by using multilevel inverters. In this paper PWM control, Variable DC link control, Hysteresis control techniques are discussed and finally five level cascade H bridge inverter fed BLDC motor drive is proposed. The phase shift PWM, design of the inverter topology and other methods are presented in this paper. Simulation is carried out using matlab / Simulink, validating the steady state and dynamic performance of the drive.