DEVELOPMENT OF SWITCHING-MODE RECTIFIERS WITH SOFT-SWITCHING

• Main Authors: Chien Heng Lin, 林見恒
• Other Authors: Chang-Ming Liaw
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/05062748551174756193

碩士 === 國立清華大學 === 電機工程學系 === 88 === The performance of battery and the steering capability of electric vehicle is significantly influenced by the battery charger. The battery in the electric vehicle can be charged by the on-board slow charger or the off-board fast charger. Conventionally, the chargers are constructed using SCR controlled rectifiers, which draw highly- distorted current with low power factor. Thus, the purpose of this thesis is to develop a boost-type soft-switching mode rectifier (SSMR) having high power quality. The developed SSMR can be employed as a DC power supply providing well-regulated DC source, or as an adjustable-voltage source to charge the battery. In the meantime, the researches are also made on multi-module parallel operation and the construction of three-phase SSMRs using the developed single-phase SSMR. First, the specifications and the battery charging/discharging characteristics of some existing electric vehicles are investigated. According to the typical input and output voltages of charger, a single-phase boost-type SSMR is designed and implemented. The proposed SSMR is formed from the conventional SMR by simply adding an auxiliary resonant branch, and the zero voltage transition soft-switching is achieved by applying PWM switching signals with suitable time delay for the main and auxiliary switches. After the detailed derivation and analysis of the operating principle, equivalent circuit and governing equation for each mode, the quantitative design procedure of the proposed SSMR circuit components are presented. As to the design of controllers, the SSMR dynamic model is derived first and hence the current controller is designed accordingly. On the other hand, the parameters of the voltage controller are systematically and quantitatively obtained according to the dynamic model estimated at a nominal case and the given control specifications. The simulated and measured results show that the operating performances of the proposed SSMR are very close to the expected ones. The input current is regulated to be sinusoidal and kept almost in phase with the input voltage. In addition, the charging control of the series-connected batteries using the developed SSMR and the strategy for deciding the charging status are also studied. Finally, based on the proposed single-phase SSMR, the following studies about multi-module operations are performed: (i) Parallel operation control of multi-module single-phase SSMRs, good current sharing control under output voltage regulation can be obtained; and (ii) Single-phase SSMRs are connected to form three-phase SSMRs, which can be used as off-board fast battery chargers.