Design And Implementation Of An ASIC For Three-phase Thyristor Rectifier Controller

As the basic converter circuit in power electronics technology, rectifier circuit is widely used in the fields of DC-motor speed control, electrolytic plating, medium frequency induction heating, etc. With the advantages of small voltage ripple and easy to filter, the three-phase full-controlled bridge rectifier circuit gains the most popularity. As the core component of the rectifier circuit, the control circuit, also known as the trigger circuit, is used to control rectifier’s output voltage by phase. Its stability and reliability will directly affect the performance of the rectifier circuit.This thesis analyzed the operating principle of the three-phase full-controlled bridge rectifier circuit in depth and designed an ASIC for three-phase thyristor rectifier’s control according to the users’actual requirement, aimed at resolving problems like sensitivity to process fluctuation, weak anti-interference ability and difficulty in debugging and maintenance, which commonly exist in the available trigger circuits in the market. This thesis focused on the stability and reliability of the circuit while realized the basic function of the trigger circuit. The main work and innovation include:1. The operating principle of the three-phase full-controlled bridge rectifier circuit was analyzed in detail and a system solution for trigger circuit was proposed according to the requirement of the rectifier circuit.2. A novel digital de-jitter solution was presented. All kinds of interference and noise are widespread in practical industry applications. The employment of hysteresis comparator in conventional ways can eliminate noise effectively but will introduce phase delay simultaneously. The proposed digital de-jitter solution can not only remove noise reliably but also guarantee the precision of the phase shift.3. A self-calibration technique for on-chip precise clock generator was proposed. The voltage-controlled oscillator is the determinant of the characteristic of the chip’s phase shift control, however, the on-chip oscillator was sensitive to the CMOS fabrication process fluctuation. Concerning this issue, the operating frequency of the power grid is employed as the frequency reference to eliminate the frequency variation in this technique, which solved the output frequency variation of the voltage controlled oscillator effectively. Moreover, this technique also improved the temperature stability of the oscillator.4. The rectifier control chip was implemented in CSMC0.5-μm CMOS process. The entire system including the main circuits and the sub circuits is designed and simulated by Cadence. The chip was successfully taped out by MPW, test results show that the desired goals have been achieved.