Hysteresis controller and delta modulator- a two viable scheme for current controlled voltage source inverter

Current-controlled pulse width modulated voltage source inverters are most widely used in high performance AC drive systems, because they provides high dynamic response. This paper presents a comparative study between the hysteresis and delta modulated current controllers for three-phase voltage source inverter. The hysteresis controller provides excellent dynamic performance because it acts quickly. The integrator in the delta modulated PWM inverters acts as a low-pass filter for harmonics. Delta modulation technique have ability to optimize (harmonic minimization) pulse width modulated (PWM) inverter waveforms on-line without conventional optimization processes, like selective harmonic elimination or harmonic weighting techniques. A comparison has been made in terms of THD level at the three-phase load current, current error minimization and switching frequency. The simulation study has been carried out with the help of MATLAB Simulink environment and the performance of such controllers has been observed during load variations.