Power Converter Slope Compensation for Waveform Distortion
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Solution Overview
Problem
Conventional power converter control apparatuses face high processing loads due to cyclic calculations for current correction, leading to distortion in alternating current waveforms, which can be reduced by adjusting the inductor current based on slope compensation signals synchronized with alternating-current voltage.
Innovation Solution
A control apparatus for power converters that includes a slope compensation unit generating a slope compensation signal based on alternating-current voltage and adding it to the inductor current, allowing the current controller to adjust the inductor current in peak current mode to follow a sinusoidal command current, thereby reducing distortion and processing load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cyclic calculations for current correction are performed in conventional control apparatuses, then the inductor current can be adjusted, but the processing load increases and distortion in alternating current waveforms occurs
Solution Approach 1:
The patent extracts the slope compensation signal generation from the cyclic calculation process and makes it independent. The slope compensation unit generates the signal based solely on alternating-current voltage without requiring cyclic calculations, thereby removing the source of processing load while maintaining waveform accuracy through proper synchronization.
Solution Approach 2:
The slope compensation signal is generated in advance based on the alternating-current voltage before the current correction cycle begins. This preliminary generation eliminates the need for cyclic calculations during the control loop, reducing processing load while ensuring the compensation is ready when needed for accurate waveform control.
2Manufacturing precision
If the slope compensation signal is synchronized with alternating-current voltage, then distortion in alternating current waveforms is reduced, but the control complexity increases
Solution Approach 1:
The slope compensation unit is designed to generate compensation signals that work across different operating conditions by synchronizing with the alternating-current voltage. This universal approach handles various voltage levels and frequencies through a single mechanism, reducing overall control complexity while maintaining low waveform distortion.
Solution Approach 2:
The synchronization mechanism uses the alternating-current voltage as a reference feedback signal to automatically adjust the slope compensation signal phase and magnitude. This feedback-based synchronization achieves precise waveform control without requiring complex manual tuning or multiple control circuits.
Data Source
AI summary
In a control apparatus for a power converter, a current obtainer obtains a current flowing through an inductor as an inductor current, and a voltage obtainer obtains an alternating-current voltage. A slope compensation unit generates, based on the alternating-current voltage obtained by the voltage obtainer, a slope compensation signal having a slope that depends on the alternating-current voltage, and adds the slope compensation signal to the inductor current obtained by the current obtainer. A current controller controls on-off switching operations of a switch in a peak current mode to thereby cause the inductor current, to which the slope compensation signal has been added, to follow a sinusoidal command current that depends on the alternating-current voltage.