Interleaved bidirectional DC-DC converter and control method thereof

Abstract

The invention relates to the technical field of power electronics, in particular to a bidirectional DC-DC converter and a control method thereof. For the problems that a constant speed area and a constant power area need to be frequently switched because the running conditions of a permanent magnet motor driving system are generally large in random fluctuation and are relatively complicated, and the torque output capacity and the high-speed power output capacity of a driving motor are poor due to the influence of output fluctuation of a storage battery of an electric automobile, the interleaved bidirectional DC-DC converter and the control method thereof are provided. The dynamic direct current bus voltage regulation is realized, and the direct current bus voltage gain is improved, so thatthe turning speed of the motor is increased, and the overload capacity of the motor is indirectly improved; a constant torque area is expanded to improve the torque output capacity of the motor; andmeanwhile, a weak magnetic area is delayed to be accessed, so that the loss of the driving system is reduced, and the temperature rise of the system is reduced.

Description

technical field [0001] The present invention relates to the technical field of power electronics, and more specifically, to an interleaved parallel bidirectional DC-DC converter and a control method thereof. Background technique [0002] According to the speed of operation, the permanent magnet motor is divided into the constant speed area operation and the constant power area operation area. When switching between the two, it is necessary to switch the control method. However, the operating conditions of the drive system usually fluctuate randomly and are relatively complicated. Frequent switching between the two operating states is required, and at the same time affected by the output fluctuations of the electric vehicle battery, the torque output capability of the drive motor and the power output capability at high speed are greatly challenged. [0003] Studies have shown that increasing the DC bus voltage can increase the turning speed of the motor, indirectly improve th...

AI Technical Summary

Problems solved by technology

[0004] However, as the bridge connecting the drive motor and the inverter, the voltage level of the DC bus not only affects the design of the control algorithm but also affects the design and selection of the hardware part of the control system. If the voltage level of the DC bus is too high, the voltage utilization rate will decrease, and if it is too low, it will easily Causes the overmodulation of the inverter, which will also affect the output characteristics of the system

At the same time, if a fixed DC bus voltage is used, when the inverter controls the inverter output voltage by adjusting the modulation coefficient, it will bring large fundamental frequency band harmonics. Compared with variable DC bus control, the iron consumption of the motor will also increase significantly. Affect the output performance of the drive system

Images