Direct-current bus voltage ripple compensation method

Abstract

The invention provides a direct-current bus voltage ripple compensation method. Under the condition that the amplitude of direct-current bus voltage ripple is large, a compressor can still normally work, and a large-capacity capacitor is not needed. According to the method, compensation calculation is carried out on alpha-axis voltage component Ualpha and beta-axis voltage component Ubeta after reverse-PARK conversion output respectively to obtain corresponding voltage component Ualpha' after alpha-axis compensation and voltage component Ubeta' after beta-axis compensation, and then the voltage component Ualpha' after alpha-axis compensation and the voltage component Ubeta' after beta-axis compensation are input to an SVPWM loop; in the compensation calculation process, a fixed constant index used for correcting a closed-loop system where a direct-current bus is located, target output voltage Uref of the closed-loop system where the direct-current bus is located and actual output voltage Udc of the closed-loop system where the direct-current bus is located are utilized. By means of the method, material cost and power consumption of a control circuit are greatly lowered, and design workers no longer need to consider the stress problem of a control circuit board.

Description

technical field [0001] The invention relates to a method for compensating ripples of a DC bus voltage in an inverter air conditioner. Background technique [0002] like figure 1 As shown, it is the principle of the FOC algorithm of the existing inverter air conditioner controller. figure 1 In the reverse PARK transformation, it directly enters the SVPWM module. In practice, since the amplitude of the DC bus voltage fluctuates, and when the load becomes heavier, the ripple of the bus voltage will become larger. The on-time is less than expected, causing the compressor current setpoint to be less than expected. Since the controller is controlled by closed-loop feedback, in this case, the dynamic tracking accuracy of the controller will become poor, and may cause the compressor to stop. [0003] In order to avoid the above situation, the current practice is to add aluminum electrolytic capacitors with large withstand voltage, capacitance and ripple current at the front end....

AI Technical Summary

Problems solved by technology

However, this approach brings about a sharp increase in cost, so the cost of traditional inverter air conditioner controllers has remained high

In addition, due to the huge size and weight of the capacitor itself, the designer cannot ignore the force of the large capacitor on the circuit board. Therefore, the actual product must take corresponding protective measures to protect the control board or directly place the large capacitor on the circuit board instead. Hanging in the air conditioner, but this will inevitably lead to an increase in material costs and assembly costs

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