A Dead Zone Compensation Method for Parabolic Current Control

Abstract

The invention discloses a dead-zone compensation method for parabolic current control. An adopted compensating circuit comprises a dead-zone compensator, a parabolic current controller, a PWM (Pulse-Width Modulation) signal generation unit and a driving circuit which are sequentially connected, and the dead-zone compensator is connected with a direction detection unit and an offset generation unit. The dead-zone compensation method for the parabolic current control comprises the steps that the direction detection unit is used for detecting output current direction of a converter to judge a rising or declining portion of current error signals needing to be adjusted; the offset generation unit generates the needed offset; the dead-zone compensator combines the output current direction and the offset to superpose corresponding offset on the received current error signals and generates improved current error signals; the parabolic current controller generates corresponding parabolic carrier waves according to the improved signals output by the dead-zone compensator, the PWM signal generation unit generates corresponding switch signals, on-off action of a bridge arm of a convertor is driven through a driving circuit, and an advanced time interval is set to be dead time to offset the influence of a dead zone.

Description

Technical field [0001] The invention relates to a dead zone compensation method for parabolic current control. Background technique [0002] When applying voltage-type PWM converters that require high dynamic performance, current tracking control is generally adopted. Current tracking control often uses a hysteresis control method, which has high stability and fast response speed, but the switching frequency changes greatly. [0003] "Parabolic current tracking pulse width modulation controller" (patent number: 200410075770.9) by introducing a pair of parabolic carriers as the boundary of the current error, to achieve the constant switching frequency. In order to prevent the bridge arm from passing through, a certain dead time is usually set before the switch is turned on. The addition of the dead time will affect the current tracking accuracy and the constant switching frequency. [0004] The existing dead zone compensation technology cannot be used in parabolic current control. ...

AI Technical Summary

Problems solved by technology

In order to avoid the straight-through of the bridge arm, a certain dead time is usually set before the switching tube is turned on. The addition of the dead time will affect the tracking accuracy of the current and the constant switching frequency.

[0004] Existing dead zone compensation techniques cannot be used in parabolic current control

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