Common Grounded H-Type Bidirectional DC-DC Converter with a Wide Voltage Conversion Ratio for a Hybrid Energy Storage System

• Main Authors: Huakun Bi, Ping Wang, Zhishuang Wang
• Format: Article
• Language: English
• Published: MDPI AG 2018-02-01
• Series: Energies
• Subjects: H-type bidirectional DC-DC converter; good dynamic response; hybrid energy storage system; wide voltage conversion ratio
• Online Access: http://www.mdpi.com/1996-1073/11/2/349

Hybrid energy storage systems (HESS) play an important role in maintaining the power balance of a direct current (DC) micro-grid. A HESS is mainly composed of high power density super-capacitors (SCs) and high energy density batteries. According to the operational requirements of an SC, a bidirectional DC-DC converter with the characteristics of a good dynamic response and a wide voltage conversion ratio is needed to interface the SC and a high-voltage DC bus. In this paper, a novel common grounded H-type bidirectional converter characterized by a good dynamic response, a low inductor current ripple, and a wide voltage conversion ratio is proposed. In addition, it can avoid the narrow pulse of pulse width modulation (PWM) voltage waveforms when a high voltage conversion ratio is achieved. All of these features are beneficial to the operation of the SC connected to a DC bus. The operating principle and characteristics of the proposed converter are presented in this paper. A 320 W prototype with a wide voltage conversion ranging from 3.3 to 8 in step-up mode and 1/8 to 1/3 in step-down mode has been constructed to validate the feasibility and effectiveness of the proposed converter.