An integrated electric vehicle power conversion device and its control method

Abstract

The invention discloses an integrated electric vehicle power conversion device and a control method thereof, belonging to the field of electric vehicles. The device has a motor drive mode and a grid-connected mode, and the device includes: an inverter circuit, a magnetically integrated coupling inductor, and an AC filter capacitor module, motor interface module, grid interface module and control module; only in the motor drive mode, the motor interface module connects the three-phase motor to the device; only in the grid-connected mode, the grid interface module connects the three-phase grid to the device; The inverter circuit is used to generate the required drive voltage in motor drive mode and the required control voltage in grid-connected mode; the magnetically integrated coupled inductor is used to suppress high frequency between inverters in motor drive mode Circulating current, and in the grid-connected mode together with the AC filter capacitor module for current filtering. The invention can ensure that the device does not have any impact on the motor when the device is connected to the grid under the premise of ensuring high integration, and at the same time improves the power quality.

Description

technical field [0001] The invention belongs to the field of electric vehicles, and more specifically relates to an integrated electric vehicle electric energy conversion device and a control method thereof. Background technique [0002] The power conversion device in a pure electric vehicle generally includes a motor-driven inverter, a DC / DC converter and an on-board charger. Limited by the limited space and cost in the car, the power level of the current on-board charger is generally between 3kW and 12kW, which is difficult to meet the needs of users for fast charging. On the other hand, the power level of the motor-driven inverter is generally 40kW to 120kW, but usually the inverter unit does not participate in the operation during charging, and the related equipment is idle. From the point of view of electric energy conversion, both motor-driven inverters and grid-connected inverters belong to the link of AC-DC conversion, and there is no essential difference. Therefor...

AI Technical Summary

Problems solved by technology

The second type is to reuse the motor inverter only, and add an additional set of filters for grid connection. The first type of device is highly integrated, but the grid connection process has a significant impact on the motor. Loss and temperature rise, vibration and noise, etc.

On the other hand, in the first type of device, since the filter is only an L-type filter, the filtering capability is very limited, and the switching frequency of the motor inverter is usually only 5kHz to 10kHz, so the grid-connected operation in this case , the power quality may not meet the standard requirements of the power grid

For the second type of integrated device, the additional filter is idle when the motor is driven, so the overall integration of the device is relatively low

At the same time, the second type of device also has the problem of common-mode leakage current, that is, in the process of motor control, the common-mode voltage of the three-phase half-bridge inverter will excite high-frequency shaft current in the motor, which seriously affects the life of the motor

[0004] In general, the comprehensive performance of the existing integrated electric vehicle power conversion devices still needs to be further improved

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