Development Design Construction and Testing of a Single- Phase ACAC Matrix Converter with Passive Loads

Abstract

This research concerns the principle of a single-phase PWM ac-ac matrix converter, using 4-units of bi-directional, Power MOSFET-Diode as main power switching devices. The converter can directly convert the utility, 1-phase, sinusoidal supply voltage and frequency into a variable frequency and variable voltage of variable pulse PWM pattern by adjusting the frequency and modulation index of the PWM control signal of the converter. The principle of design for the output of variable voltage and variable frequency will be first described for the cases of 5- pulses, 10-pulses and 20-pulses. These output voltage pattern together with the ac line-to-line input voltage can then be used to design the corresponding gating signals, and they are actually used to operate the proposed converts for the specified ac output voltage. The theoretical principle of matrix converter will be also described in terms of mathematics and then implemented in terms of theoretical waveform in order to verify the theoretical concept of this converts. Moreover, the matrix converter is actually designed, constructed and operated the in our laboratory to generate the 3-phase PWM ac output voltage of various patterns. These experimental results are also compared with the theoretical simulation results under various changing circuit parameters to confirm the actual circuit operation. All these PWM patterns are also analyzed in various harmonic spectra which can be further used to calculated the PWM output voltage in terms of RMS voltage and tested for the characteristics of this circuit. The matrix converts can be varied the variable pulse, the variable frequency and the variable voltage.