Research on Composite Control Strategy of Quasi-Z-Source DC–DC Converter for Fuel Cell Vehicles

Abstract

The DC–DC converter for fuel cell vehicles requires high gain and wide voltage input range to boost the voltage of the fuel cell. However, with the traditional boost converter, it is difficult to meet the requirements of the fuel cell vehicle power system. Based on a quasi-Z-source network DC–DC converter, this paper proposes a composite controller, which includes a feedforward compensation network and feedback control to meet the control robustness requirement of the fuel cell vehicle power system. The dynamic model of the converter is obtained by using the state space averaging method and the small-signal dynamic modeling method. The input voltage and load disturbance experiments are performed on the DC–DC converter. Moreover, the converter is tested under the worldwide harmonised light vehicle test procedure (WLTP) to validate the effectiveness of the proposed composite controller. The simulation and experiment results show that the proposed composite controller effectively enhances the converter’s ability to resist input and load disturbance, and improves the dynamic response performance of the DC–DC converter for fuel cell vehicles.

Review of DC-DC Converter Topologies Based on Impedance Network with Wide Input Voltage Range and High Gain for Fuel Cell Vehicles

“…[3], a PI controller of the quasi-Z-source structure that combined composite feedforward and feedback controls was proposed in Ref. [82]. The quasi-Z-source converter was subsequently tested under the worldwide harmonized light-duty test cycle.…”

Power Quality Phenomena, Standards, and Proposed Metrics for DC Grids

“…Figure 11 illustrates three cases showing (a) voltage transients, (b) periodic oscillations with superposed higher frequency ringing, and (c) deterministic and random modulations for three different applications of a DC/DC converter. Figure 11a demonstrates the voltage transients at fuel cell terminals for an almost 100% load step; with an optimized control [138], the transient amplitude and duration amounts to 2.5-5% and less than 10 ms, thus polluting up to some tens of Hz. Figure 11b reports the behavior of the output of a full-bridge resonant LLC converter suitable for server supply in a data center [139].…”

ADC Quantization Effects in Two-Loop Digital Current Controlled DC-DC Power Converters: Analysis and Design Guidelines

“…Condition (8) indicates that the minimum output voltage variation, due to the minimum output current step change provoked by a variation in the output voltage, must be smaller than the quantization level of the output voltage. In this condition (8), the gain G is defined as 1/C o . The no-limit-cycling condition involving the integral gain is q v TK iv < q i .…”

“…Therefore, the digital closed-loop configuration is increasingly being used in dc-dc converters [4][5][6]. Digital control depicts an important element of power converters for renewable energy systems [7], automobile industry [8], and industrial applications [9]. However, many works report disadvantageous quantization effects related to the existence of limit cycles in digitally controlled pulse width modulation (DPWM) converters.…”