Event-Based Control System Suitable for High-Precision Pulsed Current Source Applications With Improved Switching Behavior

Abstract

This work presents a control system suitable for high-precision pulsed current sources. The proposed control system is based on the detection of events so as to define changes in the power converter state in order to produce the required current waveform with a good dynamic response.Additionally, this control system is designed to regulate the flattop current with a well-defined precision. In order to mitigate the effect of the measurement noise, an estimation algorithm for the controlled current is incorporated. This algorithm generates a filtered version of the controlled variable without affecting the control dynamics. The use of the estimated current allows to improve the detection of the events and to avoid an increase in the number of commutations due to possible erratic comparisons. Then, the estimator gains are tuned by using genetic algorithm techniques to optimize the RMS value for a typical pulse.Furthermore, in order to independently perform the required set of tasks, the proposed control system is implemented by using a FPGA-based platform. Additionally, due to the demanding precision in these applications, different considerations regarding its implementation, such as the digital wordlength, binary point position, rounding method, and overflow behavior, have been taken into account. Experimental results obtained from the application of the proposed control system to a laboratory prototype are presented.

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“…A model predictive current control scheme with phase-shifted pulse-width modulation is introduced in [12], which has the advantages of small tracking error and high steady-state performance. What's more, reference [13] proposed a high-precision pulse current source control system can get good dynamic response by improving switching characteristics, and the flat top current can be regulated with precisely defined precision. A converter based on switched-capacitor units with high voltage gain and high efficiency was proposed in [14], the proposed topology can generate repetitive high-voltage pulses.…”

“…A converter based on switched-capacitor units with high voltage gain and high efficiency was proposed in [14], the proposed topology can generate repetitive high-voltage pulses. The literature [13] proposed a pulse current source control system with high-precision and fast dynamic response through the improvement of control strategy and algorithm.…”