Boost Converter Control Unit Current Sensor Abnormality Detection
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Solution Overview
Problem
In boost converter devices, abnormality in the current sensor detecting reactor current leads to unstable feedback control, preventing the boost voltage from converging to its command value, necessitating effective abnormality detection methods.
Innovation Solution
The boost converter device employs a control unit that reduces the carrier frequency or duty command value to detect the amplitude of current ripple, allowing for the identification of current sensor abnormalities by distinguishing between normal and abnormal ripple amplitudes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback control of reactor current is implemented using current sensor detection, then boost voltage control precision is improved, but reliability deteriorates due to current sensor abnormality causing loss of control capability
Solution Approach 1:
The control unit performs preliminary abnormality detection of the current sensor by analyzing current ripple amplitude before normal feedback control operations. By detecting sensor abnormalities in advance through ripple analysis during specific periods (when carrier frequency is reduced or duty command value is reduced), the system prevents faulty sensor data from compromising feedback control reliability.
2Measurement precision
If carrier frequency is reduced to enhance current ripple detection, then measurement precision of current sensor is improved, but productivity deteriorates due to extended detection period
Solution Approach 1:
The control unit performs current sensor abnormality detection periodically at specific intervals rather than continuously. By reducing carrier frequency or duty command value only during designated detection periods and then restoring normal operating parameters, the system achieves accurate ripple amplitude measurement while minimizing impact on overall system productivity.
3Measurement precision
If duty command value is reduced to amplify current ripple for detection, then measurement precision is improved, but power output deteriorates during detection period
Solution Approach 1:
The control unit temporarily reduces the duty command value only to the extent necessary for adequate current ripple detection, rather than maintaining full reduction. This partial action approach amplifies current ripple sufficiently for reliable sensor abnormality detection while minimizing the impact on power output during the detection period.
Data Source
AI summary
A boost converter device includes a converter, a current sensor which detects a reactor current flowing through a reactor, and a control unit which controls the converter by using feedback control of the reactor current. The control unit executes at least one of reducing a carrier frequency which is used in the control of the converter and reducing a duty command value which is used in the control of the converter, detects an amplitude of current ripple by the current sensor during execution of the reduction of the carrier frequency or the reduction of the duty command value, and detects the current sensor as being abnormal in a case where the amplitude of the current ripple is less than a predetermined current fluctuation range at the time of abnormality of the current sensor.