Active Converter Controller Voltage Error Calibration
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Solution Overview
Problem
Active converters face challenges in suppressing higher harmonics due to variations in stepped-up voltage, leading to either insufficient suppression or exceeding component withstand voltages, resulting in high costs and potential voltage errors from absolute value control.
Innovation Solution
A controller for active converters determines a correction value for voltage detection deviations when not in operation, allowing for proportional step-up control based on this value during operation, thereby reducing component withstand voltage and stabilizing harmonic suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If absolute value control is performed to control output voltage, then voltage control is achieved, but voltage errors accumulate causing unnecessarily high step-up and potential exceeding of component withstand voltage
Solution Approach 1:
The patent performs preliminary calibration when the converter is not in operation to determine correction values for voltage detection deviations. This preliminary action establishes accurate correction values before actual operation begins, preventing error accumulation during voltage control and avoiding unnecessarily high step-up that would exceed component withstand voltage ratings.
Solution Approach 2:
The system uses feedback by continuously monitoring the relationship between input and output voltages during operation, applying the pre-determined correction values to compensate for detection deviations. This feedback mechanism ensures accurate voltage control without accumulating errors that would lead to excessive step-up and potential component failure.
2Reliability
If component withstand voltages are increased to accommodate stepped-up voltage variations, then voltage stability is improved, but manufacturing costs increase
Solution Approach 1:
By performing preliminary calibration to determine accurate correction values before operation, the system minimizes stepped-up voltage variations during actual use. This allows the use of components with lower withstand voltage ratings, reducing manufacturing costs while maintaining voltage stability through precise control based on the calibrated correction values.
Solution Approach 2:
The patent changes the control parameter from absolute voltage values to corrected voltage values that account for detection deviations. This parameter change reduces voltage variations and allows selection of components with optimal (lower) withstand voltage ratings, balancing reliability and manufacturing cost.
3Ease of manufacture
If step-up control is performed independent of component variations to reduce component withstand voltage, then manufacturing cost is reduced, but detection deviation affects voltage accuracy
Solution Approach 1:
The patent performs preliminary calibration to determine correction values that compensate for detection deviations caused by component variations. This preliminary action enables the use of standard components with lower withstand voltage ratings while maintaining voltage detection accuracy through the application of these correction values during operation.
Solution Approach 2:
The system incorporates feedback by applying correction values to compensated voltage detections during operation. This feedback mechanism maintains voltage detection accuracy despite component variations, allowing cost-effective component selection without sacrificing measurement precision.
Data Source
Figure 1
Figure 2(a)~2(c)
AI summary
The present invention is capable of reducing a component withstand voltage and stably suppressing higher harmonics. A controller (4) for an active converter (3) for removing higher harmonics from an input current containing the higher harmonics flowing out from a rectification circuit for converting alternating current into direct current, includes: voltage detection sections (11) and (12) for detecting an input voltage and an output voltage of the active converter (3), respectively; a correction value determination section (13) for determining, when the active converter (3) is not in operation, a correction value used for correcting a detection deviation of the output voltage with respect to the input voltage detected by the voltage detection sections (11) and (12); and a control section (14) for correcting, when the active converter (3) is in operation, the output voltage detected by the voltage detection sections (11) and (12) with the correction value, to perform step-up ratio control.