Motor Control Device Zero-Phase Current Detection Error Reduction
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Solution Overview
Problem
The detection of zero-phase current is prone to errors when zero-phase voltage is output during current detection periods, leading to incomplete removal of zero-phase current in motor control systems.
Innovation Solution
A control device for motors is designed with a configuration that separates the zero-phase voltage output period from the current detection period, ensuring they do not overlap, allowing for accurate detection of phase currents without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If zero-phase voltage is output during current detection period, then zero-phase current can be reduced, but detection error of zero-phase current increases
Solution Approach 1:
The control period is segmented into distinct first period (zero-phase voltage output) and second period (current detection), preventing overlap between voltage output and current detection operations. This temporal segmentation eliminates detection errors caused by simultaneous voltage application while maintaining the benefits of zero-phase current reduction.
Solution Approach 2:
The control device implements periodic alternating between first period (outputting zero-phase voltage pulse to reduce zero-phase current) and second period (detecting phase currents). This periodic action allows the system to achieve zero-phase current reduction while ensuring accurate current detection during dedicated detection windows.
2Loss of energy
If zero-phase voltage pulse is output continuously, then zero-phase current reduction is maintained, but current detection accuracy deteriorates
Solution Approach 1:
Instead of continuous zero-phase voltage output, the system uses periodic pulsing during first periods interspersed with second periods for current detection. This periodic action maintains average zero-phase current reduction while ensuring periodic verification of current accuracy for reliable motor control.
Solution Approach 2:
The system detects phase currents during second periods and uses this feedback information to adjust control strategies. The detected current values are used to verify zero-phase current reduction effectiveness and maintain motor control reliability through closed-loop adjustment.
Data Source
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AI summary
It is an object of the present invention to reduce detection error of zero-phase current. A control device of a motor in which a winding is independently connected for each phase, the control device including: a control unit controlling a voltage applied to the motor on the basis of a torque command value, wherein the control unit provides a first period in which a zero-phase voltage pulse for outputting a zero-phase voltage for reducing a zero-phase current which is determined based on an alternating current of each phase is output, and a second period in which a current of each phase flowing in the motor is detected, and the first period and the second period are not overlapped.