Nr Electric Co., Ltd

Nr Engineering Co., Ltd

Haier Group Corporation

Qingdao Haier Electronics Co., Ltd.

Nr Electric Engineering Co., Ltd.

Wenqiang Zhao

Yongping Wang

Nannan Wang

Yu Lu

Jiang Lu

Yunlong Dong

Jie Tian

Hongtao Qi

Yilong Chen

Yong Liu

Jianwei Guo

Haiying Li

Zhaoqing Hu

Ke Wang

Lin Li

Chuanjun Bai

Yifang Sun

Jianmin Xiao

Disclosed in the present invention is a voltage and current control method for a direct-current transmission system. The method comprises: calculating a DC voltage reference value of a voltage source converter of a DC voltage control end, on the basis whether a direct-current voltage end of a direct-current pole of a direct-current transmission system substantially controls a direct-current voltage; using &#xbd; of the calculated direct-current voltage reference value of the voltage source converter as a bridge arm voltage direct-current bias, calculating a difference between the direct-current voltage reference value of the voltage source converter and a measured direct-current voltage value, and inputting the difference into a direct-current voltage control outer loop of the voltage source converter to perform closed-loop control, so as to control the direct-current voltage or the direct current of the direct-current pole. Correspondingly, also provided is a voltage and current control device for the direct-current transmission system. By the means of the present invention, the direct-current voltage and the direct current of the direct-current transmission system provided with the voltage source converter can be effectively controlled.

Voltage and current control method and device for direct-current power transmission system

Provided is an on-line input and quit control method for a voltage-source converter unit. The method achieves the on-line input of a voltage-source converter unit by means of performing steps, such as charging control, deblocking transfer control and operation adjustment control, on a voltage-source converter to be input, and achieves the on-line quitting of the voltage-source converter unit by means of performing steps, such as direct-current voltage reduction control, bypass transfer control and converter blocking control, on a voltage-source converter to be quit. Correspondingly, provided is an on-line input and quit control device for a voltage-source converter unit, which can achieve the on-line steady input and quitting of a voltage-source converter in a series-type hybrid direct-current power transmission system or a series-type flexible direct-current power transmission system, without affecting the normal and stable operation of other already running converters.

On-line input control method, on-line input and quit device for voltage-source converter unit

A method and apparatus for controlling a hybrid direct-current (DC) transmission system. The method comprises: adjusting the total number of inserted sub-modules of a modular multi-level converter and the polarity of an output level of the inserted sub-modules in real time, according to a DC voltage of a rectifier station at other end; or adjusting the total number of inserted sub-modules of a modular multi-level converter and the polarity of an output level of the inserted sub-modules in real time, according to the magnitude of a DC current or DC power; or adjusting the total number of inserted sub-modules of a modular multi-level converter and the polarity of an output level of the inserted sub-modules in real time, according to both the magnitude of the DC current and the DC voltage of the rectifier station at the other end. The method can effectively control the DC voltage and the direct current of a hybrid DC transmission system, avoiding the power transmitting breakdown.

Method and apparatus for controlling hybrid direct-current transmission system

Disclosed in the present invention is a hybrid back-to-back direct current transmission system. The system includes an LCC converter and a VSC converter in a back-to-back connection, and a first changeover switch, a second changeover switch, a third changeover switch and a fourth changeover switch. The first changeover switch is connected to a first alternating current system and the LCC converter; the second changeover switch is connected to the first alternating current system and the VSC converter; the third changeover switch is connected to a second alternating current system and the VSC converter; and the fourth changeover switch is connected to the second alternating current system and the LCC converter. In forward power delivery, the first changeover switch and the third changeover switch are closed; and in reverse power delivery, the second changeover switch and the fourth changeover switch are closed. Thereby, it is ensured that the VSC converter always performs inversion operation in any power direction, so as to avoid the problem of potential commutation failure for the LCC converter when being in inversion operation. Also provided is a fast power flow reversal control method of the hybrid back-to-back direct current transmission system.

Hybrid back-to-back direct current transmission system and power flow reversal control method

A high voltage/ultrahigh voltage direct current transmission inverter side frequency control implementing method includes: transmitting a deviation between the inverter side power grid frequency and rated frequency to the inverter side frequency controller, wherein the frequency controller regulates and outputs a modulation quantity by adopting self-adaptive parameters according to different operation conditions; when the interstation communication is normal, the modulation quantity output of the inverter side frequency controller causes the rectifier side and the inverter side to form a new power/current order through the interstation communication; when the interstation communication is abnormal, converting the inverter side to current control from voltage control and converting the rectifier side to voltage control from current control; superposing the modulation quantity output of the inverter side frequency controller to the power/current order of the inverter side, changing the size of the transmission power to realizing the inverter side frequency control.

Direct current transmission inverter side frequency control method

Disclosed are a play control system and method. The system includes: a display control module for dividing the display screen of electrical equipment, wherein the display control module can divide the display screen into a plurality of display area layouts; a control module for determining the current display area layout and the video signal corresponding to the picture to be displayed in each display area in the current display area layout according to an instruction; and a processing module for according to determination result of the control module, processing each video signal to be displayed according to the display requirement of the display area which needs to display the video signal and providing the processed video signal meeting the display requirement of the corresponding display area to the electrical equipment.

Play control system and method

A signal source which is detachably and electrically connected with a TV is disclosed. The TV has a video output unit and an audio output unit. Driven by the TV, the signal source exchanges a media signal with the TV. The signal source includes an audio input interface which receives an audio signal from an external audio input unit, and a media storage unit which is used for storing the media signal.

Signal processing device and TV with the signal processing device

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Jiangsu, China

Wenqiang Zhao