Real-Time Sampling Transmission Unit Isolated By Fiber For Power Electronics System

High dv/dt and di/dt are produced at the switching process in power electronics systems. They introduce noises through the capacitance and inductance parasitized in the trace. It is much difficult in designing the sampling circuits where the environment is electrically noisy. In traditional converters, sensors are commonly connected to the control unit directly by copper wire. The control algorithm is implemented by the digital signal processor (DSP) depends on the sampling signals transmitted by the sensors. In addition, a fault of the sampling results may destroy the whole system.A new structure of sampling and communication unit is introduced in this paper. It includes four function blocks, which are transmitting unit, receiving unit, high-isolated power supply, and the communication media. The receiver, linked with the transmitter by plastic optical fiber (POF), is a terminal node of the sensor. Analog signal is sampled by the transmitter first. Then the data is converted into specific format according to a customized protocol before transferred to the receiver. In the next time, the original signal is restored in the receiving unit and be read by other block. Multi-channel sampling and high-speed data transmission bus are supported by each transmitting unit. Each receiving unit can support several fiber decoding simultaneously too. The new intelligential sensor takes the outstanding advantages of high transmission speed, noise immunity, and high efficiency.It is point out that in complicate power electronic system, application of this unit has practical value for their excellent performance in insulation and transient characteristics. Finally, waveforms and propagation delay between two modes are presented by experimental result. According to capacity calculation, the feasibility of the system design is proved.