Zhejiang University

Silergy Semiconductor Technology (hangzhou) Ltd

Huawei Digital Power Technologies Co., Ltd.

Wuhua Li

Xiangning He

Chushan Li

Lei Shi

Wei Li

Huan Yang

Fangcheng Liu

Youtong Fang

Wenxi Yao

Min Chen

Heya Yang

Xin Xiang

Shengdao Ren

Xiaowei Gu

Haoze Luo

Lin Zhu

Huiqiang Yan

Jing Sheng

Yuxiang Wang

Ye Yan

Chengmin Li

Wanyuan Qu

Saizhen Chen

Qinghui Huang

A method for a direct current (DC) islanding detection based on positive feedback of a bus voltage at a specific frequency, essentially including three steps: extraction of a specific frequency component of the bus voltage, injection of a disturbance component of the specific frequency, and determination of DC islanding. The extraction of the specific frequency component of the bus voltage and the injection of the disturbance component of the specific frequency constitute a positive feedback mechanism in a power management unit control loop. In a grid-connected mode of a DC grid, the positive feedback mechanism fails due to a control action of a voltage management unit on a bus, and the bus voltage remains stable. In an islanding mode of the DC grid, under an action of the positive feedback mechanism, the power management unit allows the bus voltage to generate a self-excited oscillation at the specific frequency.

Method for DC islanding detection based on positive feedback of bus voltage at specific frequency

A resonance control method for differentiated phase correction under asymmetric positive and negative bilateral frequency domains includes a differentiated phase correction resonance control link with an independent phase correction angle at each resonance point, a decoupling link and a delay compensation link. As a high power converter has the characteristic of asymmetric positive and negative bilateral frequency domains under resonance control with decoupling, stability margin of a control link is enhanced while a negative-sequence current suppression capability is realized by means of differentiated phase correction at positive and negative resonance poles.

Resonance control method for differentiated phase correction

The present invention discloses a high step-down modular DC power supply, belonging to the field of power electronics technology, and the high step-down modular DC power supply includes an upper modular cascade circuit string, a lower modular cascade circuit string, a load, and an input source, where the upper modular cascade circuit string includes i upper sub-module circuits, and the lower modular cascade circuit string includes j lower sub-module circuits. A combination manner of module circuits includes: upper module string cascading, lower module string cascading, and hybrid cascading of the upper module string and the lower module string. The power supply is formed to be a high voltage step-down ratio power supply with high voltage direct current input and low voltage direct current output through modular cascading. No synchronous control signal is needed between sub-modules of the power supply, voltage equalization of power supply input series capacitors may be realized without a central controller, and therefore, a control strategy of each sub-module is very simple. The power supply may be flexibly expanded in voltage and power classes, and is suitable for auxiliary power supply applications in medium voltage or high voltage DC input occasions.

High step-down modular DC power supply

A voltage conversion circuit includes: an inductor, a first switch module, N second switch modules connected in series, N third switch modules connected in series, and N&#x2212;1 flying capacitors. One terminal of the first switch module is separately connected to one terminal of the N second switch modules connected in series and one terminal of the N third switch modules connected in series. The other terminal of the N third switch modules connected in series is connected to a positive electrode of a high-voltage power supply. The other terminal of the first switch module and the other terminal of the N second switch modules connected in series are connected to a negative electrode of the high-voltage power supply. A low-voltage power supply is connected to the two terminals of the first switch module through the inductor.

Voltage conversion circuit and power supply system

A gate voltage magnitude compensation equalization method and circuit for series operation of power switch transistors are provided. A dynamic voltage equalization of series-connected power switch transistors is implemented by using sampling principles where voltages of the power switch transistors are controlled by gate voltage magnitude and unbalanced voltage differentials are converted into unbalanced current differentials of buffer currents. The gate voltage magnitude compensation equalization method and circuit relates to differential control and works in a dynamic voltage change process of the series-connected power switch transistors, without having a negative effect on operation of the power switch transistors under normal operating conditions. Only adopting passive devices, the gate voltage magnitude compensation equalization circuit has a simple structure, is easy to integrate on a device drive board, implements response tracking of unbalanced voltage and voltage equalization of the series-connected power switch transistors, and improve speedability and stability of voltage equalization control.

Gate voltage magnitude compensation equalization method and circuit for series operation of power switch transistors

Methods, circuits, apparatus, and systems related to a hybrid driving and controlling circuit are disclosed. In one embodiment, a hybrid driving and controlling circuit in a double power supply system includes first and second power supplies and at least one load, and the circuit can include: (i) a controller coupled to a hybrid switcher that enables energy transfer from the first and second power supplies; (ii) when a determined energy of the first power supply is sufficient, the controller can control the hybrid switcher to transfer energy from the first power supply to the second power supply; and (iii) when the determined energy of the first power supply is insufficient, the controller can control the hybrid switcher to transfer energy from the second power supply to the at least one load.

Hybrid controlling and driving circuit and method thereof

Growing community of inventors

Hangzhou, China

Wuhua Li