Current sensorless control for half‐bridge based AC/DC PFC converter with consideration of conduction losses

Abstract

The focus of this paper is on a simple half-bridge converter that performs power factor correction (PFC) using current sensorless control. Current sensors increase cost, auxiliary power required, conduction losses, and volume of the PFC converter. Moreover, measurement of high frequency current is demanding, especially in cost-sensitive applications. The PFC converter proposed combines simple half-bridge topology and improved current sensorless-control algorithm that takes into account conduction losses. These losses influence volt-second balance in the input inductor and result in distorted grid current shape. Their effect is especially evident in half-bridge converter, where input inductor operates with high voltage swing. The current sensorless control method proposed compensates this influence and allows achieving sinusoidal current shape. First, the phenomenon of current distortion was shown with numerical simulation in PSIM package. Experimental prototype rated for 350 W power was built to verify theoretical and simulation results. Experimental results are in good agreement with those obtained with simulation and theoretically. The PFC converter proposed features low cost of realization and can be used in consumer equipment for connection to the grid. accordance with real transistor parameters (Table II), the difference is only 24 ns that is 0.06% of switching period that is less than precision of the PWM module utilized in the experiments and thus can be neglected. The diode reverse recovery losses are not influencing volt-second balance of the inductor, but are a matter of capacitor discharge currents, and consequently can be neglected. Figure 7. Simulation results considering conduction losses: (a) light load condition-IM = 0.3 A; THD(Ic) = 91.2%; THD(Ig) = 2.9%; and (b) high load condition-IM =;4 A; THD(Ic) = 12.2%; THD(Ig) = 0.6%.Figure 8. Simulation results without consideration of conduction losses: (a) light load condition-IM = 0.3 A; THD(Ic) = 93.2%; THD(Ig) = 3.2%; and (b) high load condition-IM = 4 A; THD(Ic) = 48.5%; THD(Ig) = 37.4%.

Improved low-cost sliding mode control of 4-leg inverter for isolated microgrid applications

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Cost‐effective multi‐pulse AC‐DC converter with lower than 3% current THD

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Transfer function‐matched capacitor‐current sensing and its circuit implementation for high‐frequency power converters

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