Study And Circuit Design On Continuously Adjustable Inductance Based On PWM Control Mode

In this thesis, a new type of continuously adjustable inductance circuit, composed of power transformer, power reactor and IGBT (insulated gated bipolar transistor), is brought forward based on PWM (pulse width modulation) control mode, considering that the demand for continuously adjustable inductance in power industry and the disadvantages to present inductance changing method.The restricted relationship of equivalent inductance with other circuit parameters is verified according as the circuit configuration in detail. The circuit parameters are decided by use of theoretical calculation. It is shown from the simulated experiments using the software of Matlab version 7.1 that the test results are in accorded with theoretical calculation. Moreover, the EXB841 of driven chip is selected as well as design and manufacturing of driven and protective circuits according to the principle and protection requirements of IGBT. In virtue of EDA (electronic design automation) technology, a pulse generator circuit is designed and realized on the CPLD (complicated programming logic device) programmed by use of hardware description language. A group of experiments is accomplished by setting up test circuit with suitable inductors and capacitors, which employs electrical isolated transducer as current transformer. Test data is basically accord with results of theoretical calculation. The rationality of circuit design and feasibility of circuit realization are testified with the experimental results.The continuously and extensively adjustable inductance can be carried out using the circuit put forward in this thesis with the right sine wave of inductive current in power grid side and without harmonic pollution basically. In contrast to past apparatus of adjustable inductance with slow response, discontinuous regulation, low range of adjustment, distorted sine wave in grid side, harmonic pollution and complexity in equipment, requirements of continuously and extensively adjustable inductance can be satisfied in power industry with the simple configuration, rapid response and wide range of inductance change.