Huawei Digital Power Technologies Co., Ltd.

Huawei Technologies Co., Limited

Huawei Digital Technologies Co., Ltd.

Xinyu Yu

Kai Xin

Yanzhong Zhang

Peng Dong

Jianqiang Wang

Junjie Li

Yongbing Gao

Fei Xu

Song Wan

Fuqiang Xu

Fangcheng Liu

Lei Shi

Yunfeng Liu

Wei Li

Zhiwu Xu

Xudong Wang

Haibin Guo

Lin Li

Shuchao Wang

Yuan Yao

Zisen Qu

Jiaguang Fu

A power supply system, an inverter, and a method for controlling positive and negative bus voltages of an inverter. The power supply system includes at least one group of inverters, each group of the at least one group of inverters includes a primary inverter and at least one secondary inverter corresponding to the primary inverter, an input end of the primary inverter is coupled to a direct current power supply corresponding to the primary inverter, an input end of the secondary inverter is coupled to a direct current power supply corresponding to the secondary inverter, and a three-phase output end of the primary inverter is coupled to a three-phase output end of the secondary inverter and then is connected to an alternating current power grid.

Power supply system, inverter, and method for controlling positive and negative bus voltages of inverter

The embodiments provide an RSCC and a control method thereof. The RSCC includes an input capacitor, an output capacitor, N parallel RSC branches, and a controller. The controller is configured to: determine an average value of characteristic currents of N resonance units; and reduce a duty cycle of a control signal of a charging switch in a first switch unit when determining that a characteristic current of a first resonance unit is greater than the average value, where a corresponding branch is in a charging stage when the charging switch is turned on; or reduce a duty cycle of a control signal of a discharging switch in a first switch unit when determining that a characteristic current of a first resonance unit is less than the average value, where a corresponding branch is in a discharging stage when the discharging switch is turned on.

Resonant switched capacitor converter and control method thereof

The photovoltaic power generation system includes a controller and M groups of DC-DC circuits. Each group of DC-DC circuits include N DC-DC circuits, where M is a positive integer, and N is an integer greater than 1. An input end of each DC-DC circuit is connected to at least one photovoltaic unit, and each photovoltaic unit includes at least one photovoltaic module. The controller controls the N DC-DC circuits in each group of DC-DC circuits to sequentially start online IV curve scanning and controls a time interval at which two adjacent DC-DC circuits start online IV curve scanning to be less than duration of online IV curve scanning performed by one DC-DC circuit. The photovoltaic power generation system can reduce a fluctuation of a power output during online IV curve scanning, reduce duration of online IV curve scanning performed by the photovoltaic power generation system.

Photovoltaic power generation system, photovoltaic inverter, and IV curve scanning method

A voltage conversion unit includes a positive voltage conversion apparatus and a negative voltage conversion apparatus. The inverter unit includes a positive inverter and a negative inverter. A negative output end of the positive voltage conversion apparatus and a positive output end of the negative voltage conversion apparatus are connected to a first end of a neutral wire, and a negative input end of the positive inverter and a positive input end of the negative inverter are connected to a second end of the neutral wire. When the neutral wire current does not meet the preset current range, the controller control the positive voltage conversion apparatus and the negative voltage conversion apparatus to change output voltages when output power remains unchanged, so that the neutral wire current meets the preset current range.

Bipolar power supply system and control method

A power supply system and a grid connection control method. The power supply system includes a power supply, an inverter, a transformer, a power station collection module, and an inverter collection control circuit. The inverter collection control circuit is configured to obtain an amplitude value and a frequency of an output voltage of the inverter, obtain an inverter power adjustment signal based on the amplitude value and the frequency of the output voltage, and control, based on the power station power adjustment signal and the inverter power adjustment signal, the inverter to output a target output power. Additionally, an output power of the inverter may be adjusted by using the power station collection module and the inverter collection control circuit. A structure is simple, and a control method is simple. This improves control precision and adjustment efficiency, reduces control time, and reduces control costs.

Power supply system and grid connection control method

A three-level neutral point clamped inverter includes four switch units. When an average value of an output current of the three-level neutral point clamped inverter is greater than a first current threshold or less than a second current threshold, only one of the four switch units is controlled to perform a high-frequency operation, to reduce power consumption caused by a high-frequency operation. The average value of the output current is an average value of the output current of the three-level neutral point clamped inverter in a switching cycle. The first current threshold is a positive number, and the second current threshold is a negative number. Power consumption caused by the high-frequency operation of the switch unit in the inverter may be reduced, and electric energy conversion efficiency of the inverter may be improved. A time period in which two switch units perform complementary operations at high frequency is very small.

Photovoltaic system, inverter, and control method

A photovoltaic cell detection method includes determining a first output power working at a first voltage and a second output power working at a second voltage, where a difference between the first output power and the second output power is less than a power difference threshold, and where both the first output power and the second output power are greater than 0; controlling the photovoltaic cell to work at the first voltage, and obtaining first infrared image information of the photovoltaic cell; and controlling the photovoltaic cell to work at the second voltage, and obtaining second infrared image information of the photovoltaic cell, where both the first infrared image information and the second infrared image information are used to jointly detect whether the photovoltaic cell is faulty.

Photovoltaic cell detection method, apparatus, and system, medium, and chip

A photovoltaic system includes a controller and two groups of inverters. The two groups of inverters include a positive inverter group and a negative inverter group. The positive inverter group includes at least two inverters: a first inverter and a third inverter. The negative inverter group includes at least two inverters: a second inverter and a fourth inverter. Alternating current output ends of the first inverter and the third inverter are connected in parallel. Direct current input ends of the first inverter and the second inverter are connected in series. Alternating current output ends of the second inverter and the fourth inverter are connected in parallel. Direct current input ends of the third inverter and the fourth inverter are connected in series.

Photovoltaic system, protection method, and inverter system

This application discloses a photovoltaic system and a carrier wave signal synchronization method. The photovoltaic system includes a plurality of inverters and a controller. Each inverter in the photovoltaic system inverts a direct current into an alternating current based on a received carrier wave signal, and transmits the alternating current to a power grid. The controller obtains first output currents of the plurality of inverters in an adjustment period, so that the controller can obtain first output current valid values of the plurality of inverters based on the first output currents of the plurality of inverters.

Photovoltaic system and carrier wave signal synchronization method

A method and apparatus for suppressing cross current including: obtaining a common-mode current and a common-mode injection voltage of each inverter in an inverter parallel system; determining a virtual damping voltage of each inverter based on the common-mode current of each inverter and a preset common-mode damping factor, where if a direction in which a current flows out of the inverter is a positive direction, the preset common-mode damping factor is a negative value, or if a direction in which a current flows into the inverter is a positive direction, the preset common-mode damping factor is a positive value; superimposing the virtual damping voltage on the common-mode injection voltage of each inverter, to obtain a target common-mode voltage of each inverter; and controlling operation of each inverter based on the target common-mode voltage of each inverter and a differential mode voltage of each inverter.

Method and apparatus for suppressing cross current in inverter parallel system

A power line communication (PLC) system includes a PLC signal transmitting end, a PLC signal receiving end, and a power electronic apparatus. The PLC signal transmitting end is connected to the PLC signal receiving end through a power line, and the power electronic apparatus is connected to the power line. The power electronic apparatus is configured to increase output impedance in a first PLC communication frequency band, to reduce interference from an output current of the power electronic apparatus to a PLC signal in the first PLC communication frequency band. The first PLC communication frequency band is a PLC communication frequency band in which the PLC signal transmitting end sends the PLC signal to the PLC signal receiving end. In this way, the interference from the power electronic apparatus to the PLC signal in the first PLC communication frequency band can be reduced without adding an additional passive filter.

Power line communication system, power electronic apparatus, and interference suppression method

Example three-level inverters, control methods, and systems are provided. One example three-level inverter includes a first bus capacitor, a second bus capacitor, a power conversion circuit, and a controller. The first bus capacitor is connected in the middle of the current bus and the power conversion circuit. The power conversion circuit is configured to convert a direct current into a three-phase alternating current for output. The controller is configured to determine a balance reference by using a difference between absolute values of voltages of the positive and negative direct current buses and an even harmonic current in a grid-connected current, where the balance reference is used to enable the three-level inverter to generate a current signal for balancing the voltages of the positive and negative direct current buses.

Three-level inverter, control method, and system

An example system includes an inverter and at least one combiner box. The combiner box includes a plurality of direct current-direct current (DC-DC) circuits and one controller. The controller is configured to: when an output voltage of the combiner box is greater than or equal to a first preset voltage and less than or equal to a second preset voltage, control the combiner box to output a maximum power. When the output voltage of the combiner box is greater than the second preset voltage, the controller controls an output power of the combiner box to decrease as the output voltage increases. The second preset voltage is greater than the first preset voltage, and the maximum power is a sum of maximum powers of all photovoltaic strings connected to the combiner box.

Photovoltaic power generation system, power control method, and combiner box

A common-mode voltage injection control method and apparatus for an inverter. For the method and apparatus, a common-mode voltage for a DPWM mode is calculated based on three-phase port voltages and an output power command; a common-mode voltage for an MPC modulation mode is calculated based on the direct current bus voltage, the three-phase port voltages, and the output power command; a modulation proportion is determined based on a maximum phase voltage peak value of the three-phase port voltages, the direct current bus voltage, and a power factor of the output power command; and a common-mode injection voltage is generated based on the common-mode voltage for the DPWM mode, the modulation proportion, and the common-mode voltage for the MPC modulation mode.

Common-mode voltage injection control method and apparatus for inverter

An input end of each DC-DC conversion circuit in the photovoltaic system is connected to a corresponding photovoltaic string. Output ends of a plurality of DC-DC conversion circuits are connected in parallel to an input end of a DC-AC conversion circuit. A controller performs a partial IV curve scan on each of the DC-DC conversion circuits, and in a scanning process, controls a total input power of the plurality of DC-DC conversion circuits to be consistent with that existing before the scan; and obtains a sum of the maximum input powers of all the DC-DC conversion circuits based on the maximum input power of each of the DC-DC conversion circuits, where a scanned voltage of the partial IV curve scan is less than an open-circuit voltage. The partial IV curve improves scanning efficiency and obtains a maximum input power in a power-limited state, facilitating subsequent power dispatch and control.

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Shanghai, China

Xinyu Yu