Eaton Intelligent Power Limited

Santak Electronic (shenzhen) Co., Ltd.

Jiajie Duan

Qiang Chen

Cheng Luo

Jianxiong Yu

Han Li

Dongsheng Li

A ripple control method for a modular cascaded power conversion device is provided. The method obtains, according to a grid voltage vector of three-phase AC power, a second-order fluctuating voltage superposition vector representing the total amount of second-order fluctuating voltages on respective floating DC sides of the three phases; determines a single-phase power control amount of each phase to be transferred from the floating DC sides to a low-voltage DC side; determines a single-module power control amount of each power module to be transferred to a low-voltage DC side thereof; and generates a single-module control signal for controlling the power module, so as to transfer a second-order fluctuating voltage on a floating DC side of the power module to the low-voltage DC side thereof. A modular cascaded power conversion device is also provided.

Ripple control method for modular cascaded power conversion device

The present invention provides an auxiliary pre-charging device for a power converter. The power converter includes at least one power unit with an input end being connected to a medium and high voltage AC power source, and an output end being connected to a low voltage DC bus, wherein the auxiliary pre-charging device includes a switch, a transformer, a pre-charging resistor, and a rectifier sequentially connected in series, one end of the switch is connected to the medium and high voltage AC power source, and an output end of the rectifier is connected to the low voltage DC bus. The present invention also provides a pre-charging method for a power converter, which uses the aforementioned auxiliary pre-charging device to start pre-charging at the low-voltage output end of the power converter.

Auxiliary pre-charging device of power converter, pre-charging method and power converter

The present invention provides a multi-active bridge converter. The converter comprises n multi-active bridges, wherein each of the n multi-active bridges comprises a DC/AC bridge, a single-phase transformer and m AC/DC bridges, where n is greater than or equal to 3, and m is greater than or equal to 1; the single-phase transformer is provided with one primary winding and m secondary windings; the DC/AC bridge is configured to receive a DC input signal, and AC output terminals of the DC/AC bridge are connected to the primary winding of the single-phase transformer; one terminal of the isecondary winding among the m secondary windings of the single-phase transformer is connected to an AC input terminal of the iAC/DC bridge among the m AC/DC bridges, the other terminal of the isecondary winding is connected to the other terminals of the isecondary windings among m secondary windings of single-phase transformers in the remaining (n−1) multi-active bridges, where i is greater than or equal to 1 and less than or equal to m; and positive busbars DC+ and negative busbars DC− of the DC output terminals of all the AC/DC bridges among the n multi-active bridges are respectively connected with each other to serve as DC output terminals of the multi-active bridge converter.

Multi-active bridge (MAB) converter and control method thereof and power conversion device

The present invention provides a Pulse Width Modulation (PWM) method for a Cascaded H-bridge (CHB) converter. Each phase of the converter is provided with n Cascaded H-bridge rectifier circuits, or may also be provided with n Cascaded H-bridge rectifier circuits+1 redundant H-bridge rectifier circuit. The method includes following steps of: S1, generating groups of sinusoidal signals as reference waveforms, and generating n carrier signals having sequentially decreasing levels and equal amplitudes to correspond to the H-bridge rectifier circuit at the first to the nlevels, where the levels of the n carrier signals are cascaded to fill the voltage amplitude of a unipolar half cycle of the reference waveform; and S2, determining PWM signals for controlling power transistors of the corresponding H-bridge rectifier circuits based on each reference waveform and each carrier signal. According to the present invention, the CHB converter allows the MV grid to be directly coupled with a LV side without a conventional transformer, which reduces the heat loss and balances the distribution of heat loss between the power transistors and between the H-bridges at all levels, thus prolonging the service life.

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Shanghai, China

Jiajie Duan