Voice Coil Current Control via Inductive Voltage Compensation
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Solution Overview
Problem
Existing voice coil current controllers face challenges in accurately controlling current across varying loads and power supplies due to manufacturing variances and the need for re-tuning when parameters change, leading to increased system complexity and user inconvenience.
Innovation Solution
A method and apparatus for sensing and compensating for variances in load and voltage in a closed-loop voice coil current controller by exciting the load with a known duty cycle, sensing the end current, and calculating a lumped term representative of supply voltage and electrical characteristics, allowing for automatic adaptation to different loads and power supplies without additional hardware or user intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If power supply voltage feedback and load current feedback are used for compensation, then compensation accuracy is improved, but device complexity increases due to additional sensing circuits and load-identification algorithms
Solution Approach 1:
The patent extracts the voltage feedback function from a separate hardware circuit and implements it through software calculation. By using the existing current sensing circuit to measure load current and calculating voltage indirectly through computational methods, the patent eliminates the need for additional voltage sensing hardware while maintaining compensation accuracy.
Solution Approach 2:
The patent replaces the physical voltage sensing circuit with a computational approach. Instead of using hardware to directly measure voltage, the system uses mathematical calculations based on current measurements and known electrical characteristics to determine and compensate for voltage variations.
2Adaptability or versatility
If the current controller is made tunable by the user to accommodate different loads and power supplies, then adaptability is improved, but ease of operation deteriorates due to requiring user intervention and re-tuning
Solution Approach 1:
The patent implements self-service by enabling the controller to automatically detect and adapt to different load and power supply conditions without user intervention. The system performs self-diagnosis and self-adjustment using computational methods to identify electrical characteristics and optimize control parameters dynamically.
Solution Approach 2:
The patent dynamically changes control parameters based on detected electrical conditions. By continuously monitoring load current and calculating lumped electrical characteristics, the system automatically adjusts controller gains and compensation values to maintain optimal performance across varying operating conditions.
3Reliability
If classical solutions are used to compensate for uncertain plant or load, then compensation performance is improved, but device complexity increases
Solution Approach 1:
The patent implements feedback by continuously measuring load current and using this information to calculate and compensate for voltage and load variations. The system feeds back the measured current to the control algorithm, which adjusts control signals in real-time to maintain accurate current control despite uncertainties in plant or load characteristics.
Data Source
AI summary
A method for sensing and compensating for variances in load and voltage in a closed loop voice coil system is described. A load in a system which included a supply voltage and the load, which includes an inductive element, is excited with a known duty cycle for a time interval. At an end time, at the end of the time interval, the current which flows through the load is sensed. A lumped term based at least in part on the time interval and a change in the load current during the time interval is calculated. The lumped term is representative of the supply voltage and one or more electrical characteristic of the load. A control signal to control a voltage applied to the load may be generated based at least in part on the lumped term. Apparatus and computer-readable media are also described.