Characteristics of a current-fed inverter with auxiliary commutation applied through load neutral point
Abstract
A current-fed inverter which is commutated by an auxiliary commutating circuit acting through the load neutral point is investigated. The properties of the inverter and its variations are considered for the case of an ac machine load, although the results are general and can easily be applied to cases where the inverter is interconnected with an ac power system. A voltage behind subtransient reactance model for either a synchronous machine or an induction machine is shown to result in good prediction of the inverter operating modes. It's shown that if a delayed gating scheme is used for the thyristors, the peak commutating capacitor voltage is actively controlled, and thus, commutation for various inverter conditions is maintained. A scheme of parallel commutation circuits is introduced which allows the value of commutating capacitance to be actively selected as a function of load condition. In this manner, the troublesome case of high-speed, light-load condition can be met, simply by reducing the value of commutating capacitance through thyristor control.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1978
- Bibcode:
- 1978PhDT.......136S
- Keywords:
-
- Commutation;
- Electric Current;
- Inverted Converters (Dc To Ac);
- Alternating Current;
- Capacitance;
- Circuits;
- Thyristors;
- Electronics and Electrical Engineering