Huawei Digital Power Technologies Co., Ltd.

Tiansan Lin

Jun Wang

Yongbing Gao

Yanzhong Zhang

Fangpo Zhang

Jianfei Lin

Hongmiao Fang

Houjian Xu

Chen Xiao Wang

Minghui Xu

Chen Wang

Yang Hu

Zhiwu Xu

Ting Yu

Kun Wang

Wei Shui

Bo Yu

Jinxiang Zhan

Jieling Tang

Changshuan Sun

Peng Ju

A first input end of a first inverter is connected to a second end of a direct current positive bus, and a second input end of the first inverter is connected to a second end of a neutral bus. A first input end of a second inverter is connected to the second end of the neutral bus, and a second input end of the second inverter is connected to a second end of a direct current negative bus. A controller is configured to control, in startup and shutdown processes, a voltage to ground of the direct current positive bus, a voltage to ground of the direct current negative bus, and a voltage to ground of the neutral bus each to be less than or equal to a preset voltage threshold, to ensure personal safety and device safety.

Photovoltaic system, power supply system, and control method

A power supply system including three output ends of a power converter respectively connected to a first end of a positive/negative direct current bus and a first end of a neutral bus; two input ends of a first inverter respectively connected to a second end of the positive direct current bus and a second end of the neutral bus; two input ends of a second inverter respectively connected to a second end of the neutral bus and a second end of the negative direct current bus; a controller outputs an overvoltage alarm signal when at least one of the following conditions is met: a to-ground voltage of the positive/negative direct current bus or a to-ground voltage of the neutral bus is greater than or equal to the preset threshold.

Bipolar photovoltaic system, power supply system, and redundancy protection method

A photovoltaic system, a power supply system, and an insulation fault detection method. An insulation impedance detection circuit is connected between a bus and the ground. The bus includes the direct current positive bus, the neutral bus, or the direct current negative bus. The insulation impedance detection circuit includes at least a switch. The direct current negative bus is connected to the neutral bus by using an electrical element or a voltage source. A controller obtains insulation impedance based on voltages to ground of the bus that are separately corresponding to the switch before and after the switch is turned on, and determines, based on the insulation impedance, whether there is an insulation fault in the photovoltaic system, to perform protection in a timely manner.

Photovoltaic system, power supply system, and insulation fault detection method

An impedance detection method and a photovoltaic system are provided to help reduce complexity and costs of impedance detection. The method includes: sampling a voltage between a direct current bus and a protective earthing at each of a first time point and a second time point, to obtain a first voltage value and a second voltage value; sampling a leakage current on the direct current bus at each of the first time point and the second time point, to obtain a first current value and a second current value; and calculating an insulation impedance value of a combiner box based on a difference between the first voltage value and the second voltage value and a difference between the first current value and the second current value, to determine whether impedance of the combiner box is abnormal.

Impedance detection method and photovoltaic system

A photovoltaic power generation system includes an inverter, a controller, and at least two direct current branch circuits. The leakage current detection apparatus is configured to: detect a leakage current of the direct current branch circuit on which the leakage current detection apparatus is located and send the leakage current to the controller. The controller is further configured to: when the photovoltaic power generation system runs and a value of a leakage current of the direct current branch circuit exceeds a preset range, determine that an insulation fault occurs on the direct current branch circuit. The system can determine the direct current branch circuit on which the insulation fault occurs in the photovoltaic power generation system, so that measures are taken in time for the direct current branch circuit on which the insulation fault occurs, to eliminate a potential safety hazard.

Photovoltaic power generation system and method

The photovoltaic system includes a first inverter circuit, a second inverter circuit, and a switch circuit. When the switch circuit is in the first state, a first photovoltaic array is connected to the direct current positive bus and the neutral bus through the switch circuit, and a second photovoltaic array is connected to the neutral bus and the direct current negative bus through the switch circuit. When the switch circuit is in the second state, the first photovoltaic array is connected to the neutral bus and the direct current negative bus through the switch circuit, and the second photovoltaic array is connected to the direct current positive bus and the neutral bus through the switch circuit. A potential of the photovoltaic array is changed to prevent a PID effect from occurring when the photovoltaic array is at a negative potential for a long time.

Photovoltaic system and power supply system

A fault isolation apparatus includes a controller and a circuit breaker. When the circuit breaker is located on a bus connected to a DC/DC conversion unit, if a voltage collected by a first voltage collection terminal is a negative value, it indicates that input or output of the DC/DC conversion unit is reversely connected. In this case, if the circuit breaker is controlled to be opened, the DC/DC conversion unit can be prevented from being connected in series to other parallel DC/DC conversion units. If a voltage collected by a first voltage collection terminal is low and a current collected by a current collection terminal is large, it indicates that the DC/DC conversion unit is short-circuited. In this case, if the circuit breaker is controlled to be opened, another component connected in series to the DC/DC conversion unit can also be prevented from backfeeding energy to the DC/DC conversion unit.

Fault isolation apparatus, direct current boost apparatus, and inverter apparatus

Embodiments of this application disclose a design of an inverter and a design of a combiner box, to reduce maintenance costs of a photovoltaic device. According to the inverter or the combiner box provided in the embodiments of this application, when electroluminescence (EL) defect detection is performed on the photovoltaic device, a reverse charging circuit integrated into the inverter or integrated into the combiner box is used to output a direct current to a to-be-tested photovoltaic string of the photovoltaic device. Whether the to-be-tested photovoltaic string has defects is determined based on a light emission status of the to-be-tested photovoltaic string. By using the foregoing designs, maintenance engineers do not need to modify wiring terminals of the photovoltaic device when performing EL defect tests on the photovoltaic device. This helps reduce maintenance costs of the photovoltaic device.

Inverter, combiner box, and photovoltaic system

A direct current-direct current conversion circuit includes: an input inductor, a first capacitor, a second capacitor, a flying capacitor, a first switch, a second switch, a first inductor, a first diode, a first buffer circuit, a third switch, a fourth switch, a second inductor, a second diode, and a second buffer circuit. A power supply, the input inductor, the first diode, the second diode, the first capacitor, and the second capacitor are sequentially connected in series. A first terminal of the flying capacitor is connected between the first diode and the second diode. A second terminal of the flying capacitor is connected between the first switch and the third switch, and the second terminal of the flying capacitor is further connected between the second switch and the second inductor.

Direct current-direct current conversion circuit

A lightning protection apparatus disposed in a photovoltaic power generation system includes first lightning protection units in a one-to-one correspondence with phase lines at a to-be-protected location in the photovoltaic power generation system and a second lightning protection unit connected in series to the first lightning protection units. A first terminal of each first lightning protection unit is connected to a corresponding to-be-protected phase line, and a second terminal of each first lightning protection unit is connected to a first terminal of the second lightning protection unit. A second terminal of the second lightning protection unit is connected to an earth wire. The second lightning protection unit includes at least one gas discharge tube.

Lightning protection apparatus and photovoltaic power generation system

An inverter apparatus is disclosed in this application, which includes a plurality of protection units and a plurality of inverter units. For any protection unit, when a voltage at an input terminal of the protection unit is greater than a voltage at an output terminal of the protection unit, a path between the input terminal and the output terminal of the protection unit is in a forward conducted state; when the voltage at the output terminal of the protection unit is greater than the voltage at the input terminal voltage of the protection unit, the path between the input terminal and the output terminal of the protection unit is in a reverse cut-off state; and when a control terminal of the protection unit receives a first trigger signal, the path between the input terminal and the output terminal of the protection unit is in a reverse conducted state.

Inverter apparatus and power supply system

An inverter in a power generation system converts a direct current that is input from a direct-current-side device into an alternating current for power supply. The inverter includes a control apparatus and a communications apparatus. The control apparatus controls the inverter to convert the direct current that is input from the direct-current-side device into an alternating current for power supply. The communications apparatus is coupled to the control apparatus, and sends a networking information request signal used to request networking information to the direct-current-side device in the power generation system through a direct-current power line, where a frequency of the networking information request signal is within a first frequency band. The communications apparatus also receives the networking information from the direct-current-side device; and sends a control signal to the direct-current-side device, where a frequency of the control signal is within a second frequency band.

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Shanghai, China

Tiansan Lin