Delta Electronics (shanghai) Co., Ltd

Qikang Wei

Xuancai Zhu

Feidong Xu

The invention discloses an inverter and a soft-start method for the same. The inverter is electrically connected between a DC power supply and a grid and includes a main power circuit electrically coupled to the grid through a relay, a filter, the relay, and a controller electrically connected with the main power circuit and the relay, respectively. The soft-start method includes: sampling a grid voltage of the grid; calculating an output voltage of the controller, and calculating a virtual current based on the output voltage of the controller, the grid voltage and a virtual impedance; and performing current closed-loop control by taking the virtual current as a feedback signal and sending a relay control signal to turn on the relay when a steady state is reached. The invention enables the soft start of the inverter without increasing any hardware circuit, such as a starting resistor, or the like.

Inverter and soft-start method for the same

A method for identifying type of a grid automatically and an inverter device thereof are provided. The inverter device comprises a power line L, a power line L, a neutral line N and a ground line electrically connectable to a first power line, a second power line, a neutral line and a ground line of the grid, respectively. The method comprises: sampling at least two of voltages between Land L, between Lto N and between Lto N when the two neutral lines are connected, and identifying the type of the grid based on the sampling result; and sampling the voltage between Land Lwhen the two neutral lines are not connected, sampling at least one of a voltage between Land GND and between Land GND with cooperation of a grid-connected switching unit, and identifying the type of the grid based on the sampling results.

Method for identifying the type of a grid automatically and inverter device thereof

A hysteresis control method for inverter and an inverter based on hysteresis control are disclosed. The inverter is electrically connected to a power grid, and the method includes: Step S, sampling a grid voltage V(z) and an output current I(z) of the inverter; Step S, calculating a present period hysteresis bandwidth H(z) based on the grid voltage V(z) sampled in step S; Step S, predicting a next period hysteresis bandwidth H(z+1); Step S, correcting the present period hysteresis bandwidth H(z) based on the next period hysteresis bandwidth H(z+1) obtained in step S, to obtain a final hysteresis bandwidth H(z); and Step S, controlling an output driving signal according to the output current I(z) of the inverter and the final hysteresis bandwidth H(z) to control the operation of the inverter.

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Shanghai, China

Qikang Wei