Research On Two-amplitude Control Technique For Actively Clamped Resonant Dc-link Inverter

The Two-Amplitude Resonant DC-Link technique offers a good solution to the "bottleneck" problem of the traditional Actively Clamped Resonant DC-Link, that is, the high operation current and losses on the resonant loop. By this way, the Resonant DC-Link technique can be widely used in higher power application. The research work focuses on the proposed Two-Amplitude Resonant DC-Link technique. Four typical Actively ClampedResonant DC-Link Inverter (ACRDCLI) applications------Full-bridge Voltage Source Inverter (VSI), Half-bridgeVSI, Full-bridge Current Source Inverter, as well as Three-phase VSI, are selected as models.In the first chapter, the soft-switching technology is classified into three groups, in which the Resonant DC-Link Inverter leads to the author's keen interest because of its simplicity and effectiveness. The state-of-arts are described and the control techniques are discussed. The main ideas of the thesis and the contributions to the Resonant DC-Link area are also listed in this chapter.A novel control strategy for the Two-Amplitude Actively Clamped Resonant DC-Link is proposed in Chapter II. It neglects the bus short circuit time adjuster and stabilizes the clamping voltage by a PI regulator so that the obtained link frequency is improved and the link losses are greatly reduced. A numerical analysis method is introduced to guide the low loss design for the inverter system, according which lead to a satisfied experiment results for a 3KW prototype circuit.Half-bridge application for the Two-amplitude Actively Clamped Resonant DC-Link Inverter, with resonant frequency high up to 500kHz, is discussed in Chapter III. High operation frequency is attained by low time delay design for the controller and driver, bringing low distortion to the output waveform.Series Resonant DC-Link is the dual of the parallel one. The Two-Amplitude control technique is imported into the series topology. Comparison research verifies its effectiveness on reducing the de-link losses and improving the output performance.The three topologies mentioned above are all presented with detailed theoretical analysis, parameters design, simulation and experimental verifications.A 6KW three-phase inverter system is accomplished in order to verify that the Two-Amplitude control technique is fit for high power application. An HCC-SVM scheme is brought forward to get uni-polarity modulation output with no state feed-back. High speed and reliability of the control design is achieved by the use of CPLD. Simulation and experiment results show its feasibility.The further research aspects are given in Chapter VI.The research of this paper is supported by Natural Science Foundation of China (No. 59977021) and Natural Science Foundation of Zhejiang Province (No. 599074)...