Boe Technology Group Co., Ltd.

Beijing Boe Energy Technology Co., Ltd.

Ping Zheng

Peng Zhao

Xiaoyan Han

Peihuan Yang

Hangbin Song

Xuyang Wang

Ming Cui

Jin Li

Jia He

A PV junction unit for joining a plurality of PV strings into a single string, comprising: a plurality of anode branch circuits; an anode busbar adapted to connect with an anode output end of each PV string via one corresponding anode branch circuit; a plurality of cathode branch circuits; a cathode busbar adapted to connect with a cathode output end of each PV string via one corresponding cathode branch circuit; resistors each of which is connected in series in one corresponding anode branch circuit connecting the anode output end of one corresponding PV string with the anode busbar, wherein each resistor has a theoretical resistance; voltage measuring devices each of which is connected in parallel with one corresponding resistor; and a processor connected with each of the voltage measuring devices, the processor configured to determine a current value in one PV string at least based on the theoretical resistance of the resistor in one anode branch circuit connected with the one PV string and based on a voltage value from the voltage measuring device in said one anode branch circuit connected with the one PV string.

PV junction unit, PV junction box and method for monitoring current in PV string

The disclosure provides a three-phase AC phase sequence detecting method, including the steps of:) sampling instant values of three-phase AC electrical signal in real-time;) converting said instant values into electrical signal components in a two-phase still coordinate system in manner of coordinate conversion;) performing an arc tangent calculation on the electrical signal components to obtain a output signal value;) executing step) to step) one or more times, to obtain one or more output signal values;) the output signal values obtained from step) and the one or more output signal values obtained from step) composing a periodic function, if the periodic function is an increasing function within one minimum positive period, the three-phase AC phase sequence is determined to be positive sequence; otherwise, negative sequence. Three-phase AC phase detecting a detecting apparatus using the above detecting method is also provided.

Three-phase AC phase sequence detecting method and apparatus

A method and an apparatus for controlling a Low Voltage Ride Through of a photovoltaic grid-connected inverter. The method for controlling comprises: judging whether a voltage value of a grid is smaller than an upper limit of a low voltage value and is not greater than a lower limit of the low voltage value; when it is judged that a root mean square value of the voltage in the grid is smaller than the upper limit of the low voltage value and greater than the lower limit of the low voltage value, controlling an active current value outputted from the inverter to be equal to a target active current value and controlling a reactive current value outputted to be equal to a target reactive current value, so that a comparison difference between a total current outputted by the inverter in a Low Voltage Ride Through state and a current outputted by the inverter in a normal state is smaller than a preset value. The method and apparatus settle problem that the poor stability is caused since control on the waveform and amplitude of the current is ignored in the Low Voltage Ride Through control on the inverter, such that the total current changes slightly before and after a voltage dip, which can support and stabilize the grid.

Method and apparatus for controlling low voltage ride through of photovoltaic grid-connected inverter

A maximum power point tracking method, device and a photovoltaic power generation system. The maximum power point tracking method involves sampling a present voltage and a present current of a photovoltaic array and obtaining a present power based on the present voltage and the present current. The maximum power point tracking using a difference between the present power and a power for a previous sampling time as a present perturbation power, and based on a ratio of the present perturbation power to a perturbation power for a previous sampling time obtain a gradient perturbation voltage step ratio. Further, the maximum power point tracking obtains a perturbation voltage step based on the gradient perturbation voltage step ratio and the voltage difference between the present voltage and the voltage for the previous sampling time, and control an output voltage based on the perturbation voltage step.

Maximum power point tracking method and device, and photovoltaic power generation system

Embodiments of the present invention provide a photovoltaic (PV) connector, comprising a first connecting unit and a second connecting unit detachably connected with the first connecting unit, wherein the first connecting unit includes a first conductor, a first stop ring, a first housing and a first conductor core provided inside and detachably connected to the first housing; the first conductor is electrically connected with a pressing end of the first conductor core; the first stop ring is detachably connected with the first housing; the second connecting unit includes a second conductor, a second housing, a second stop ring and a second conductor core provided inside and detachably connected to the second housing; the second conductor is electrically connected with a pressing end of the second conductor core; the second stop ring is detachably connected with the second housing.

Photovoltaic connector

The present invention provides an islanding detection method and an islanding detection system. The method includes: acquiring a voltage signal at a grid-connected node of a power generation system, and extracting phase information of the voltage signal; constructing a slip-mode frequency shift islanding detection curve in the form of a quadratic function according to the phase information; and generating a disturbance signal according to the slip-mode frequency shift islanding detection curve, and sending the disturbance signal to an inverter of the power generation system. The method and system can avoid a non-detection zone, and can perform an inverter islanding detection in a fast and accurate manner under simple control.

Growing community of inventors

Beijing, China

Ping Zheng