Voltage Conversion Device Forward Voltage Correction
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Solution Overview
Problem
Existing voltage conversion devices face challenges in accurately correcting low and high voltage-system voltages due to forward voltage applied to upper arm diodes during charge current flow, affecting sensor detection and output adjustments.
Innovation Solution
A voltage conversion device with a control system that performs zero point and output adjustments using correction maps/equations, estimates forward voltage of the upper arm diode, and adjusts high voltage-system voltage by subtracting it from the power storage voltage, ensuring appropriate voltage correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the discharge resistance is connected in parallel with the high voltage-side capacitor to discharge electric charge, then the capacitor can be discharged when the system main relay is ON and the boost converter is not ON, but forward voltage is applied to the upper arm diode which affects the detection of the VH sensor and causes inappropriate output adjustment
Solution Approach 1:
The patent performs zero point correction and output correction of the VH sensor in advance under specific conditions (when the system main relay is ON, the electric load circuit is not powered ON, and the boost converter is not ON) before normal operation. This preliminary calibration stores correction values that compensate for the forward voltage effect of the upper arm diode, ensuring accurate voltage detection even when forward voltage is present during capacitor discharge operations.
Solution Approach 2:
The patent changes the detection parameters by introducing correction equations that account for the forward voltage characteristics of the upper arm diode. By establishing a relationship between the detected voltage and the actual voltage through correction factors, the system maintains measurement precision despite the presence of forward voltage during discharge operations.
2Measurement precision
If zero point correction and output correction are performed using the VB sensor output value, then the VL sensor and VH sensor can be calibrated, but the forward voltage of the upper arm diode during charge current flow causes inappropriate correction of the VH sensor
Solution Approach 1:
The patent performs sensor corrections in advance under controlled conditions where the boost converter is not operating, thereby eliminating the influence of charge current and forward voltage during the correction process. This timing ensures that corrections are established without the interfering effects of diode forward voltage, improving both measurement precision and correction reliability.
Solution Approach 2:
The system uses feedback from the VB sensor to monitor battery voltage and determines appropriate correction values based on the operational state. By continuously monitoring system conditions and applying corrections based on feedback from voltage sensors, the system maintains accurate voltage detection while compensating for forward voltage effects through dynamically adjusted correction factors.
Data Source
AI summary
There is provided a voltage conversion device that is configured to perform zero point adjustment of a high voltage-system voltage detected by a high voltage-system voltage detector, when a relay is off. The voltage conversion device is also configured to estimate a forward voltage of an upper arm diode and to perform output adjustment of the high voltage-system voltage detected by the high voltage-system voltage detector, based on a voltage calculated by subtracting the forward voltage from a power storage voltage detected by a power storage voltage detector, when the relay is on, a low voltage-system power line has no electric power consumption, and a voltage conversion circuit does not perform voltage conversion. The voltage conversion device is further configured to create a high voltage-system voltage correction map, based on results of the zero point adjustment and the output adjustment of the high voltage-system voltage.