A switched-capacitor bidirectional dc–dc converter with a high step-up/step-down voltage gain is proposed for electric vehicles with a hybrid energy source system. The converter presented has the advantages of being a simple circuit, a reduced number of components, a wide voltage-gain range, a low voltage stress, and a common ground. In addition, the synchronous rectifiers allow zero voltage switching turn-on and turn-off without requiring any extra hardware, and the efficiency of the converter is improved. A 300 W prototype has been developed, which validates the wide voltage-gain range of this converter using a variable low-voltage side (40–100 V) and to give a constant high-voltage side (300 V). The maximum efficiency of the converter is 94.45% in step-down mode and 94.39% in step-up mode. The experimental results also validate the feasibility and the effectiveness of the proposed topology.

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A Switched-Capacitor Bidirectional DC–DC Converter With Wide Voltage Gain Range for Electric Vehicles With Hybrid Energy Sources

A PWM plus phase-shift control bidirectional DC/DC converter is proposed. In this converter, PWM control and phase-shift control are combined to reduce current stress and both conducting and switching loss, to expand ZVS range. The operation principle and analysis of the converter are explained, and ZVS condition is derived. A prototype of PWM plus phase-shift bidirectional DC/DC converter is built to verify analysis.

A pwm plus phase-shift control bidirectional dc/dc converter

In this paper, an interleaved switched-capacitor bidirectional dc-dc converter with a high step-up/step-down voltage gain is proposed. The interleaved structure is adopted in the low-voltage side of this converter to reduce the ripple of the current through the low-voltage side, and the series-connected structure is adopted in the high-voltage side to achieve the high step-up/step-down voltage gain. In addition, the bidirectional synchronous rectification operations are carried out without requiring any extra hardware, and the efficiency of the converter is improved. Furthermore, the operating principles, voltage and current stresses, and current ripple characteristics of the converter are analyzed. Finally, a 1 kW prototype has been developed which verifies a wide voltage-gain range of this converter between the variable low-voltage side (50–120 V) and the constant high-voltage side (400 V). The maximum efficiency of the converter is 95.21% in the step-up mode and 95.30% in the step-down mode. The experimental results also validate the feasibility and the effectiveness of the proposed topology.

/pdf/interleaved-switched-capacitor-bidirectional-dc-dc-converter-tyjarlpmox.pdf

Interleaved Switched-Capacitor Bidirectional DC-DC Converter With Wide Voltage-Gain Range for Energy Storage Systems

In this paper, a hybrid switched-capacitor/switched-quasi-Z-source bidirectional dc–dc converter is proposed for electric vehicles (EVs) with hybrid energy sources, which has a wide voltage gain range in the bidirectional energy flows. Compared with the traditional quasi-Z-source bidirectional dc–dc converter, the proposed converter only changes the position of the main power switch and employs a switched-capacitor cell at the output of the high-voltage side. Therefore, the advantages of the wide voltage gain range and the lower voltage stresses across the power switches can be achieved. The operating principle, the voltage and current stresses across the power switches, and the comparisons with other converters are analyzed in detail. Furthermore, the parameter design of the main components, the dynamic modeling analysis, and the voltage control scheme are also presented. Finally, the experimental results obtained from a 400 W prototype validate the characteristics and the theoretical analysis of the proposed converter.

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Hybrid Switched-Capacitor/Switched-Quasi-Z-Source Bidirectional DC–DC Converter With a Wide Voltage Gain Range for Hybrid Energy Sources EVs

High step-up DC/DC converter and maximum power point tracking (MPPT) control are essential components in photovoltaic (PV) systems. For the purpose of utilizing PV module in power generation, this manuscript proposes 1-new high step-up DC/DC converter 2-model predictive control based maximum power point tracking (MPC-MPPT) algorithm with optimum number of sensors. The suggested topology is able to provide a voltage gain up to 10 times of input-voltage and its measured efficiency is around 93%. MPC is a prevalent control technique with superior transient and steady-state performances in PV systems. However, in PV DC/DC converters, conventional MPC based MPPT technique typically requires two voltage-sensors and one current-sensor. For the purpose of reducing system cost, this manuscript presents MPC based MPPT technique with two-sensors. The algorithm is designed to operate with both fixed and adaptive step-size. Different scenarios and operating conditions are evaluated both in Simulink and with hardware set-up. Results obtained from the simulation and experimental work are consistent and verify the analytical analysis of the system.

/pdf/a-new-high-gain-dc-dc-converter-with-model-predictive-37z3t3jv9d.pdf

A new high gain DC-DC converter with model-predictive-control based MPPT technique for photovoltaic systems

In order to match the voltages between high voltage battery stacks and low voltage super-capacitors with a high conversion efficiency in hybrid energy sources electric vehicles (HESEVs), a high ratio bidirectional DC-DC converter with a synchronous rectification H-Bridge is proposed in this paper. The principles of high ratio step down and step-up operations are analyzed. In terms of the bidirectional characteristic of the H-Bridge, the bidirectional synchronous rectification (SR) operation is presented without any extra hardware. Then the SR power switches can achieve zero voltage switching (ZVS) turn-on and turn-off during dead time, and the power conversion efficiency is improved compared to that of the diode rectification (DR) operation, as well as the utilization of power switches. Experimental results show that the proposed converter can operate bidirectionally in the wide ratio range of 3~10, when the low voltage continuously varies between 15V and 50V. The maximum efficiencies are 94.1% in the Buck mode, and 93.6% in the Boost mode. In addition, the corresponding largest efficiency variations between SR and DR operations are 4.8% and 3.4%. This converter is suitable for use as a power interface between the battery stacks and super-capacitors in HESEVs.

/pdf/high-ratio-bidirectional-dc-dc-converter-with-a-synchronous-18g2yxiclw.pdf

High ratio bidirectional DC-DC converter with a synchronous rectification H-Bridge for hybrid energy sources electric vehicles

/pdf/a-bidirectional-three-level-dc-dc-converter-with-a-wide-2w10v4rgl7.pdf

Yongping Gao

Papers

A Switched-Capacitor Bidirectional DC–DC Converter With Wide Voltage Gain Range for Electric Vehicles With Hybrid Energy Sources

Interleaved Switched-Capacitor Bidirectional DC-DC Converter With Wide Voltage-Gain Range for Energy Storage Systems

Hybrid Switched-Capacitor/Switched-Quasi-Z-Source Bidirectional DC–DC Converter With a Wide Voltage Gain Range for Hybrid Energy Sources EVs

High ratio bidirectional DC-DC converter with a synchronous rectification H-Bridge for hybrid energy sources electric vehicles

A Bidirectional Three-level DC-DC Converter with a Wide Voltage Conversion Range for Hybrid Energy Source Electric Vehicles