Design And Implementation Of Multiple Output Arbitrary Waveform Power Signal Source

In recent years,with the rapid development of China's power electronics industry,coupled with the initial formation of national grid interconnection and regional grid structure,the stability and security of the whole grid system has become the top priority.The stable and safe operation of the power grid benefits from the presence of relay protection equipment.At the same time,how to test these new relay protection devices can accurately and quickly identify fault signals in the power grid,cut off the fault part of the power grid,ensure the normal operation of the rest of the power grid.The design of an instrument which is portable,and can be field programmed and remotely controlled,and able to simulate the test of various fault signals in the power grid has become a necessary condition to ensure the safe and stable operation of the relay protection device.A multi-output arbitrary waveform power signal source and a programmable signal generator composed of FPGA controller and ARM controller are designed.DC/DC boost chopper circuit,single-phase full bridge inverter circuit,K-type filter circuit,error correction circuit,high-speed comparison circuit,bootstrap drive circuit and a combination of several auxiliary power supply circuits are also designed.In the first part,the programmable signal generator generates the reference signal according to the field demand.The upper computer controls the FPGA controller,invokes each waveform CORDIC algorithm module inside the FPGA to generate the reference waveform,and can adjust the amplitude and frequency of the reference signal.Finally,the digital signal is converted into the analog signal through the DAC circuit and connected to the power amplification part;In the second part,the amplified part can amplify the three reference signals and output them synchronously.The boost circuit provides the bus voltage required by the inverter circuit.The AC reference signal is compared with the output sampling signal to obtain the error signal,and then compared with the carrier signal to generate the PWM control signal.The opening and closing of MOS tube is controlled by the drive circuit.Finally,the power amplification waveform is obtained through LC filter.At the same time,in order to reduce the complexity of the PWM control circuit design and reduce the PWM duty cycle regulation range,the boost circuit and the inverter circuit are designed to form a correlation regulation.While adjusting the AC reference signal amplitude,the DC reference of the DC/DC boost circuit changes together,which changes the duty cycle of the boost circuit PWM,so that the bus voltage of the full bridge inverter also changes.Through parameter design and system simulation verification,the feasibility of the design scheme is proved,and a prototype is built and welded to test the system to realize the power amplification of sine wave,triangle wave and rectangular wave.Its efficiency is more than 82%,and its synchronization error and response time are less than 10?s.The system has successfully achieved the expected goal,and it is stable,reliable and easy to operate.