Two-Wire Battery Discharge Circuit Voltage Balance Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The two-wire discharge circuit of a battery faces issues with bus voltage unbalance due to different action delays of switch transistors, leading to abnormal operation and reduced circuit performance.
Innovation Solution
A method and device that determine and regulate the voltage difference between positive and negative bus voltages using a PI regulator to generate PWM signals, adjusting the duty ratio of switch transistors in each discharge branch to balance the bus voltage and ensure power balance, employing a dual-loop control mechanism involving full-bus voltage and inductor current loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a two-wire discharge circuit is used to save cost by eliminating neutral-wire connection, then device complexity and cost are reduced, but bus voltage unbalance occurs due to different action delays of switch transistors
Solution Approach 1:
The patent implements a voltage difference detection mechanism that continuously monitors the positive and negative bus voltages and feeds back the difference signal to the control unit. This feedback loop enables real-time detection and correction of voltage unbalance caused by switch transistor action delays, thereby maintaining bus voltage balance while using the simplified two-wire discharge circuit structure
Solution Approach 2:
The patent dynamically adjusts the duty ratios of switch transistors in different discharge branches based on the detected voltage difference. By changing the operating parameters (duty ratios) of the switch transistors, the system compensates for action delay differences and maintains balanced bus voltages, resolving the contradiction between simplified circuit structure and voltage balance reliability
2Reliability
If duty ratios of switch transistors are adjusted to balance bus voltage, then bus voltage balance is improved, but control complexity increases
Solution Approach 1:
The patent employs a single control unit that performs multiple functions: detecting voltage differences, calculating compensation amounts, and generating adjusted drive signals for multiple switch transistors. This multi-functional control unit consolidates what could be multiple separate control mechanisms, achieving voltage balance without proportionally increasing control complexity
3Stability of the object's composition
If PI regulator is used to regulate voltage difference signal, then bus voltage stability is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex hardware-based voltage regulation mechanisms with a PI regulator implemented in the control unit's processing system. This software/firmware-based approach achieves stable bus voltage control without requiring additional physical regulatory components, thereby improving stability while minimizing increases in device complexity
Data Source
AI summary
A method and device for controlling a two-wire discharge circuit of a battery, introducing a whole-bus voltage outer loop and an inductive current average value or inductive current actual value closed loop as a main control loop of the two-wire discharge circuit of the battery so as to guarantee a stable voltage of the whole bus. On the basis of the main control loop, duty ratios of switch transistors in respective discharge branches are adjusted to control the respective discharge branches to independently charge and discharge corresponding half-buses so as to balance the bus voltage. The method and the device avoid accessing a central wire of the battery and any additional circuits, and satisfy a technical specification of a three-wire access of the battery, thereby improving a circuit performance of the two-wire discharge circuit of the battery.