Abstract
For the voltage source type inverters of comparably small capacity, in order to control the feed back power from the load, the discharge resistance which is parallel-connected to dc link circuit is commonly used.
For such application as feeding back power repeatedly, or for the comparably large capacity, however, the discharge resistance method can not be applied. Instead of its method, it is well known that the line commutated inverter method is often applied. However, this method has the demerit of providing the identical two bridges of thyristors, and largely lowering the power factor as the regenerative power varies.
For the next type of regeneration control, the PWM converter has often reported, but is slightly different in contrast of the view of this paper. But, this converter has excellent characteristics. For the larger power capacity, however, the cost of the converter would be high. In the case that aims principally the regeneration control and does not care the improvement of the output waveforms, its application would be restricted. Under such circumstances, the first purpose of this paper, apart from the improvement of the output waveforms, is the proposal of a few regeneration method which can be realized at lower cost. From such viewpoints, the authors have investigated to accomplish the purpose. In the proposed equipments, the rectifier bridge can be also used for inversion through the medium of the dc reactor or the capacitor. The second purpose, in order to analyze the output current waveforms, is to propose a new frequency analysis method by using the switching function. The appropriateness of its theory has been experimentally confirmed.
