3ph Converter with LCL Filter

In this simulation, I create a full bridge inverter with an 800 DC voltage source to make 300 V AC. When AC is manufactured using only an inverter, there are many harmonics due to technical problems. Harmonic current causes many problems in using machines such as motors and optical cables to use the supply power. We can replace the element in an electrical circuit with a pure inductor. If the current fluctuation (di/dt) is very large, the voltage drop on the inductor is also large. That is, the power loss is also significant (Q = U_L^2/Z_L). As a result, the machine and cables are heated and the machine and supply system are disturbed. So we have to manage the harmonic current and voltage.

 

For inverter control, a reference signal must be created from the output voltage and current. During normal operation, the 3ph voltage is 120° phase shift. The transfer abc to dq0 block allows you to recognize that the voltage remains in normal operation. If the phase between V_Q and V_D is not 90°, there is a slight phase change in our electricity supply. Therefore, the signal can be taken from the output voltage to the dq0 change and the signal must be controlled.

so we can design a control system to manage V_D / V_Q and I_D / I_Q. That controlled voltage can be used for reference voltage to making PWM-signal.