Booster Voltage Control for EPS Overshoot Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electric power steering (EPS) boosters experience overshooting of output voltage during initial states, such as engine startup or reset, leading to increased manufacturing costs and unstable output voltage, as they require larger capacitors or reduced responsiveness to prevent overshooting.
Innovation Solution
A booster system with a control section that determines the initial state based on start or restart signals, gradually increasing the target voltage and duty ratio limits to prevent overshooting, and adjusts feedback gain for responsive control, ensuring stable output voltage without increasing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the smoothing capacitor is replaced by a larger one to resist excessively boosted voltage during overshooting, then the output voltage stability is improved, but the manufacturing costs increase
Solution Approach 1:
The control section performs preliminary detection of the initial state using a start signal or restart signal, and proactively limits the duty ratio before voltage overshooting can occur. This preventive approach eliminates the need for larger capacitors to handle excessive voltage during overshoot events.
Solution Approach 2:
The control section uses feedback control based on the deviation of output voltage from target voltage, combined with initial state detection, to dynamically adjust the duty ratio. This closed-loop control prevents overshooting by continuously monitoring and correcting the boosting process.
2Reliability
If the responsivity of the booster control is lowered to prevent overshooting, then the output voltage stability is improved, but the manufacturing costs increase and the output voltage becomes unstable
Solution Approach 1:
The control system dynamically adjusts the duty ratio based on the detected initial state. During the initial state, the duty ratio is limited to prevent overshooting, while after the initial state ends, the duty ratio can increase to improve responsivity. This dynamic adaptation resolves the contradiction between stability and responsiveness.
Solution Approach 2:
The control section changes the duty ratio parameter based on the operational state. By detecting the initial state through start/restart signals, the system adjusts the duty ratio to appropriate values, preventing overshooting during initialization while maintaining high responsivity during normal operation.
3Speed
If the duty ratio is increased to improve the boosting performance, then the output voltage reaches target faster, but the output voltage overshoots during initial state
Solution Approach 1:
The control section detects the initial state in advance using start or restart signals and proactively limits the duty ratio before significant voltage overshooting can occur. This preliminary detection and control adjustment prevents the contradiction between fast voltage rise and overshooting.
Solution Approach 2:
The control section applies preliminary anti-action by limiting the duty ratio during the detected initial state, counteracting the tendency toward overshooting before it occurs. After the initial state ends, the duty ratio limitation is removed, allowing fast voltage rise without overshooting.
Data Source
AI summary
A booster includes a booster circuit and a microcomputer. The booster circuit outputs an output voltage. The output voltage is obtained by boosting a power supply voltage. The microcomputer controls the output voltage through a feedback control based on the deviation of the output voltage from a target voltage. The microcomputer determines whether the booster is in an initial state based on a start signal or a restart signal. When determining that the booster is in the initial state, the microcomputer corrects the target voltage such that the target voltage gradually increases from the power supply voltage as time elapses until a predetermined period elapses from the start of the initial state.