BSG Voltage Feedback Control for 48V Battery Charge Stability
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Solution Overview
Problem
48V micro hybrid electrical vehicle batteries experience power errors due to torque errors in high-rotational-speed zones, leading to over-charge or over-discharge, which affects their lifespan.
Innovation Solution
A method and apparatus for controlling the voltage of an electricity-generation-starting-up integrated electric machine by acquiring current battery voltage, current battery electric current, and electric-current limit values, determining an initial target voltage, calculating a superposing-voltage value based on the difference between the electric-current limit and battery electric current, and adjusting the target controlling voltage to stabilize the battery voltage, preventing over-charge and over-discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the BSG operates in high-rotational-speed zone to charge the battery, then the charging power is improved, but the torque error causes large power error leading to over-charge or over-discharge
Solution Approach 1:
The patent implements a feedback control mechanism by continuously monitoring the actual battery current and comparing it with the limited current value. Based on the current difference, the system dynamically adjusts the target voltage of the BSG to ensure the actual current remains within the limited range, thereby preventing over-charge or over-discharge while maintaining high charging power.
Solution Approach 2:
The patent changes the voltage parameter dynamically by determining a target voltage based on the difference between limited current value and actual battery current. When the actual current exceeds the limited value, the target voltage is reduced; when it is below the limited value, the target voltage is increased. This parameter adjustment ensures accurate current control while maintaining high power output.
2Temperature
If the battery operates at low temperature, then the available battery electric quantity and power are reduced, but the power error greatly affects the battery causing over-charge or over-discharge
Solution Approach 1:
The patent implements a feedback control mechanism by continuously monitoring the actual battery current and comparing it with the limited current value. Based on the current difference, the system dynamically adjusts the target voltage of the BSG to ensure the actual current remains within the limited range, thereby preventing over-charge or over-discharge while maintaining high charging power.
Solution Approach 2:
The patent changes the voltage parameter dynamically by determining a target voltage based on the difference between limited current value and actual battery current. When the actual current exceeds the limited value, the target voltage is reduced; when it is below the limited value, the target voltage is increased. This parameter adjustment ensures accurate current control while maintaining high power output.
3Device complexity
If conventional voltage control methods are used without current limitation, then the control simplicity is maintained, but the battery experiences over-charge or over-discharge affecting its lifespan
Solution Approach 1:
The patent implements a feedback control mechanism by continuously monitoring the actual battery current and comparing it with the limited current value. Based on the current difference, the system dynamically adjusts the target voltage of the BSG to ensure the actual current remains within the limited range, thereby preventing over-charge or over-discharge while maintaining high charging power.
Solution Approach 2:
The patent changes the voltage parameter dynamically by determining a target voltage based on the difference between limited current value and actual battery current. When the actual current exceeds the limited value, the target voltage is reduced; when it is below the limited value, the target voltage is increased. This parameter adjustment ensures accurate current control while maintaining high power output.
Data Source
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AI summary
The present disclosure provides a method and apparatus for controlling a voltage of an electric machine, applied to a vehicle having an electricity-generation-starting-up integrated electric machine, which relates to the technical field of vehicle controlling. The method includes: when the vehicle is in a voltage-controlling mode, acquiring a current battery voltage, a current battery electric current and an electric-current limit value of the vehicle (101); according to the battery voltage, determining an initial target voltage (102); according to a difference between the electric-current limit value and the battery electric current, determining a superposing-voltage value (103); based on the superposing-voltage value and the initial target voltage, determining a target controlling voltage (104); and based on the target controlling voltage, controlling the battery voltage of the vehicle (105). Accordingly, the vehicle, even if in conditions such as a low temperature, can perform voltage-stabilization controlling by means of voltage superposition, to merely charge the low-voltage loads and the 48V section, and not perform assisting discharging, which can precisely control the voltage, and prevent over-charge and over-discharge of the battery, thereby prolonging the life of the 48V battery.