Boost Converter Current Sensor Offset Correction
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Solution Overview
Problem
Existing control systems for boost converters struggle to accurately learn and correct offset values of current sensors due to temperature characteristics, leading to inadequate control when no current flows, especially in varying temperature conditions.
Innovation Solution
Implementing an electronic control unit that performs intermittent step-up control and offset learning of the current sensor within a prescribed temperature range, using a correction value calculated from the learned offset value and sensor temperature to adjust detected current values, and storing this data in nonvolatile memory for future reference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offset value learning is executed when no current flows in the current sensor, then the offset value can be learned, but the learned offset value becomes inaccurate due to temperature characteristics of the current sensor
Solution Approach 1:
The patent applies parameter changes by introducing temperature as a correction parameter. The electronic control unit learns the offset value at different temperatures and stores multiple offset values corresponding to different temperature ranges. When operating, the system selects and applies the appropriate offset value based on the current temperature, thereby compensating for temperature characteristics and maintaining accurate current detection across varying temperatures.
2Productivity
If the boost converter is operated continuously for normal power conversion, then power conversion efficiency is maintained, but the offset value cannot be learned because current always flows in the current sensor
Solution Approach 1:
The patent applies periodic action by executing offset value learning at specific intervals rather than continuously. The electronic control unit performs offset learning when the boost converter is stopped or when current through the sensor is zero, while maintaining normal continuous operation for power conversion. This periodic learning approach ensures both continuous productivity and periodic calibration of the current sensor offset.
Solution Approach 2:
The patent applies preliminary action by performing offset value learning in advance during stop periods before normal operation resumes. The electronic control unit utilizes the stop period to learn and update the offset value, preparing the accurate calibration data before the next power conversion cycle begins. This ensures the system is properly calibrated before resuming productive operation.
3Device complexity
If the current sensor offset is not corrected for temperature, then the control system is simple, but the boost converter cannot be appropriately controlled under temperature variation
Solution Approach 1:
The patent introduces temperature as an additional parameter for offset correction, moving from a single offset value to temperature-dependent offset values. The electronic control unit includes temperature detection functionality and selects appropriate offset values based on measured temperature, achieving accurate control under temperature variation while maintaining relatively simple system architecture through software-based compensation.
Data Source
AI summary
In a control system of a boost converter and a control method of the control system, when a temperature of a current sensor of a boost converter is within a prescribed temperature range, an electronic control unit performs i) executing intermittent step-up control of the boost converter and learning of an offset value of the current sensor, and ii) controlling the boost converter using a corrected current value. The corrected current value is a value obtained by correcting a detected value of the current sensor using a correction value. The correction value is calculated using the learned offset value and the temperature of the current sensor.