The Design Of The Hybrid Digital Control Active Power Filter

As the rapid development of the national economy and power industry, the contradictions between Power supply and demand have been resolved gradually. However, because of the complication and diversification of the power load, some application devices that contain nonlinear,impulsive,unbalanced load and abundant harmonics, for example the power equipments like semiconductor rectifier, inversion device's and frequency conversion speeder, can affect power supply network respectively. Today, customers have raised higher demand on power supply quality, so effectively handling power network harmonic pollution has an important significance.There are tow methods Active Power Filter and Passive Power Filter to handle harmonic pollution. Passive Power Filter can eliminate the main harmonic power current, while Active Power Filter can improve the overall effect. In the design, based on these advantages of Active Power Filter and Passive Power Filter, we present the Hybrid Active Power Filter. We established the mathematical model with objective function of which is the total capacity of the Hybrid Active Power Filter. Based on minimizing objective function, Consider need of filtering and Reactive Power Compensation, meanwhile, consider that in the real application, the capacity of the Active Power Filter can't be too large and the maximum filtering rate of passive can't be too low. Furthermore, optimizing the entire configuration by the means of Instantaneous Reactive Power.In the design, we use MCU to measure the DC capacitor voltage in digital method, and then use the High-Speed Serial port to transmit it into DSP for processing via Photoelectric Isolation, which simplify the circuit design and improve the system reliability. The DSP chip is High-Speed 32 bit TMS320F2810, which increase the calculation speed of the compensation current greatly. Furthermore, use fully digital mode to achieve Hysteresis-band Current Tracking, that is, output the Digital Signal directly through the PWM output port in DSP chip to control the IPM module.