In this paper, the problem of designing a fractional order PID-type controller is considered for a boost converter. By using the output capacitance and input inductance values this paper characterizes integer order PID-type control gains which will make the closed-loop system transfer function approximately equal to a first order system with a unit DC gain and prescribed time constant τ . Next, a procedure to compute the design parameters of a fractional order PID-type controller is given together with a descritized control algorithm for DSP implementation. By using a floating-point DSP, the proposed control algorithm is implemented in real time. Finally, experimental results are given to show the practical feasibility and effectiveness of the proposed fractional order PID-type control system under several operating conditions. The results illuminate that the proposed controller can be better than a conventional integer order PID-type controller.

In this paper, a high-efficiency DC/DC converter with low voltage stress is designed for green power applications. The proposed non-isolated high step-up DC/DC converter combines the advantages of switched capacitors, coupling inductors, and voltage multiplier techniques. Adding the cells of the switched capacitor not only increases the voltage gain but reduces the voltage stress of the semiconductor devices. High voltage gain can be achieved by adding a coupled inductor method to adjust the turns ratio. When these are combined with a voltage multiplier circuit, the leakage energy of the coupled inductor is recirculated to the output terminal with lossless passive clamping performance. The leakage inductance of the coupled inductor controls the current dropping rate of the output diode turn OFF so that the reverse-recovery problem is mitigated. The proposed converter integrates these three techniques to achieve high voltage gain without operating at maximum duty cycle. In addition, switching loss reduction is realized through zero current switching turn ON soft switching performance with low voltage stress of semiconductor devices. Finally, this paper verifies the performance of the proposed converter for theoretical analysis by using a 35~45V input, 380V output, and 1kW power prototype circuit. INDEX TERMS Boost converter, high step-up, coupled inductor, switched capacitor, voltage multiplier cell.

In this paper, a non-isolated high step-up interleaved DC-DC converter for distributed generation applications such as solar cells and fuel cells. The proposed converter mixes the benefits of magnetic coupling, voltage multiplier, and voltage lift techniques to conventional interleaved schemes. The proposed converter's voltage lift technique can increase the voltage gain while guaranteeing low voltage stress of the switches. And the magnetic coupling method can combine the switched capacitor of the voltage multiplier technique with the lossless clamp circuit to achieve high voltage gain and reuse the leakage inductance energy to the output terminal. In addition, this leakage inductance energy can achieve zero current switching turn on soft switching performance and mitigate the output diode reverse recovery problem. The proposed converter avoids the extreme duty cycles that cause conduction losses in power devices and can give very low voltage stresses. Therefore, the use of low voltage rated MOSFETs and diodes not only reduces switching losses and costs, but also improves efficiency. INDEX TERMS High voltage gain, magnetic coupling, non-isolated, voltage lift (VL) technique, zero current switching (ZCS).

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