Guidong Zhang

An Impedance Network Boost Converter With a High-Voltage Gain

An impedance network dc–dc boost converter is developed in this letter. Compared to the conventional boost converter, it can reach a higher voltage gain with fewer diodes and a small duty cycle (smaller than 33%) and, meanwhile, avoid instability caused by saturation of its inductors, whereas the conventional boost converters realize high-voltage gains at rather large duty cycles (normally exceeding 50%) resulting in saturation of inductors. Furthermore, it can well fulfill the stringent industrial requirements, particularly of renewable power systems. The proposed converter with continuous conduction modes is analyzed for different states of its components. Then, it is shown how to determine its various parameters. Finally, simulations and a 250-W prototype are conducted to verify the converters effectiveness.

A Novel Single-Input–Dual-Output Impedance Network Converter

A novel single-input–dual-output (SIDO) impedance network converter with only three switches is proposed in this paper. Due to the special features of impedance network, an artful design and some improvements are conducted on two Z-source half-bridge converters to form the proposed converter, the new designed converter can not only obtain all the advantages of Z-source half-bridge converters, but also realize dual outputs by reducing one fourth of components. The SIDO converter is potential for dual-outputs applications like electric vehicle systems for both driving the car and saving energy back. Therein, a detailed analysis of the proposed converter is conducted and the corresponding simulations are presented. Finally, the experimental results of a 100 W of implemented prototype can verify the effectiveness of the proposed converter.

A Single-Switch Quadratic Buck–Boost Converter With Continuous Input Port Current and Continuous Output Port Current

A single-switch quadratic buck–boost converter with continuous input port current and continuous output port current is proposed in this paper. Compared with the traditional buck-boost converter, the proposed converter can obtain a wider range of the voltage conversion ratio with the same duty cycle. Moreover, the proposed converter can operate with continuous input port current and continuous output port current compared to the existing counterparts with inherently discontinuous input port current and discontinuous output port current. The operating principle and steady-state performance of the proposed converter under continuous inductor current mode is analyzed in detail. Then, the comparison between the proposed converter and the existing quadratic buck–boost converters has been conducted to demonstrate the unique features of the proposed one. Finally, experimental results from a prototype built in the lab are recorded to verify the effectiveness and validity of the proposed quadratic buck–boost converter.

Impedance Source Converters: State-of-the-Art

This chapter presents the-stat-of-the-art of impedance source converters to understand their respective features and application scenarios [1, 2].

A Brief History of Power Electronics Converters

This chapter is to retrospect the development of power electronics converters, point out the challenges faced especially in renewable energy applications, and introduce a promising novel Z-source converter.

Voltage-, Current-, and Z-source Converters

Some fundamental concepts are to be introduced in this chapter, such as voltage sources, current sources, impedance networks, Z-source, two-port network, impedance source converters, impedance networks converters.

Design Methodology of Impedance Networks Converters

In terms of the impedance networks matching, a systematic design methodology of impedance networks converters is presented in this chapter.

Impedance Networks and Their Matching

Impedance networks matching involves input impedance matching, output impedance matching, and load phase matching, which should be considered together as designing an impedance networks converter.

A Δ-Y Hybrid Impedance Network Boost Converter With Reduced Input Current Ripple

This letter is to present a Δ-Y hybrid impedance network based boost converter with reduced input current ripple. Comparing to the existing impedance network based boost converters to enhance the output port characteristic, i.e., voltage conversion ratio, of the traditional boost converter (TBC), the proposed converter applies the impedance network to improve its input port performance, i.e., the input current ripple issue. The proposed Δ-Y hybrid impedance network consists of the TBCs main inductor, an additional coupled inductor, and an additional resonant inductor and capacitor pair. Although the peak currents flowing through the diode and the switch are higher in comparison to the TBC, the proposed converter can remain TBCs voltage conversion feature and effectively reduce the input current ripple and the average current of the main inductor with the application of the Δ-Y hybrid impedance network. The operating principle of the proposed converter is explained and the principle of current ripple reduction is analyzed in detail. Experimental results from a prototype are carried out to validate the effectiveness of the proposed converter.

Unique Modular Structure of Multicell High-Boost Converters With Reduced Component Currents

The traditional switched-inductor technique for high-step-up conversion is widely utilized in industrial applications, especially multicell technique is combined to realize ultra-high voltage. However, the component currents are accordingly increasing with the increasing number of cells, which results in high cost, low efficiency, and low stability. In order to solve these problems, an improved multicell structure of switched inductor is devised, which can be utilized to replace traditional switched-inductor cells for higher actual boost ratio and lower diode currents. An example of the proposed structure-based boost converter is demonstrated for a detailed analysis, and it is followed with a comparison to verify its features. Finally, simulations and experiments are conducted to validate the effectiveness.