On the leading angle control of natural commutating invefter using DC excitation of inverter transformer

摘要

Because natural commutating inverter builts up AC output voltage following to circuit condition and valve action of inverter, AC output voltage and leading angle of inverter vary widely with change of load and disturbance. In order to operate this inverter stably, AC output voltage and leading angle of inverter must be controlled at constant value even if load changes. Then several steps have been taken for these purposes. But these can be done by controlling of DC excitation of inverter transformer. Constant control of AC output voltage by this method has been reported, so we discuss the constant control of leading angle by adjusting DC excitation of inverter transformer in this paper. It is proved theoretically in chapter 2 that the leading angle is controlled by DC excitation of inverter transformer. And this fact is proved experimentally by 6KW inverter in chapter 4. In chapter 4 we expressed the leading angle control system of invetter with block diagram also, and obitained the transient response of the system to reference input, load resistance and capacitance changes. From these steady state and transient responses, it has been pointed out that： (1) controllable domain of leading angle is determined by construction of inverter circuit, (2) the response speed of leading angle is determined by the time constant of DC source circuit of inverter, and (3) construction of the control system discussed here is easier than others.