Design and Simulation of H-Bridge Converter with Additional Switch Legs Using Different Control Techniques

This paper presents the design and implementation of H-bridge converter with additional switch legs (HA converter) which acts as AC-DC rectifier as well as DC-AC inverter. In this topology a solid connection is provided between the grounds of the input and output terminals, which reduces common mode noise and makes the converter suitable for PV PCS in dc distribution system or stand-alone power system. This paper presents the comparative evaluation of the performance of the two main control techniques for H-bridge converter with additional switch legs for reducing THD by reducing the common mode noise. Common-mode noise signals are high frequency signals which are created as a result of different voltage levels of input and output terminal with respect to ground terminal. SPWM voltage controller and average current controller are considered here. Harmonic analysis of these two control techniques is performed using FFT analysis of Simulink in MATLAB. Lower order harmonics are reduced using sinusoidal PWM technique. EMI filtering circuits are also used to get better results. As unwanted EMI is at much higher frequencies than normal signals, the EMI filter blocks or shunts unwanted higher frequencies. The main objective of this scheme is to reduce total harmonic distortion at the input side of the rectifier and output side of the inverter. The simulation results of both the techniques have been demonstrated. Keywords—H-bridge converter, average current control, Sinusoidal pulse width modulation (SPWM), common mode current, Total harmonic distortion (THD)