Optimum sequence control of resonant converter with quantum transformation and characterization of matrix converter with circuit dq transformation

Abstract

In this thesis, resonant converter and matrix converters are modeled and analyzed with quantum transformation and circuit DQ transformation, respectively. To reduce weight and volume of the power converter, operating frequency is increased. In DC to DC converter, the PWM converters have been used predominantly stress and but the switching frequency is limited because of their switching stress and switching loss of the switching devices. Quantum resonant converters have been introduced to increase the switching frequency. In chapter II, new control scheme named optimum quantum sequence(OQS) control which minimizes the output voltage ripple of the quantum series resonant converter(QSRC) is proposed. This control scheme is so general that it is irrelevant to the magnitudes of circuit elements as well as to the input/output voltages so far as it is operating in the continuous conduction mode(CCM). This feature is verfied by appropriate simulations. In chapter III, new modified output voltage control scheme for the series resonant converter (SRC) is proposed. In this scheme, quantized output voltage is obtained by quantum duty control and one last unit voltage is continuously adjusted by phase angle control during a half resonant cycle period. Therefore the proposed control method offers a clue to get rid of the stepped discontinuity problem in the output voltage of quantum control without degrading the performance. Based on the steady state analysis, optimum quantum sequence having greatly reduced output voltage ripple is given. And in AC to AC converter, the nine switch matrix converter are modeled and analyzed. Matrix converter is very simple in structure and has powerful controllability. But the practical matrix converter is far beyond the ideal matrix converter because of its complexity due to the non ideal source such as L and C reactive components. In this thesis, the analytic expressions for the voltage gain, input power factor and so on are obtained easily ...