Current Regulator Using PWM Duty Cycle Feedback
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Solution Overview
Problem
Conventional current regulators for inductive loads face challenges in accurately regulating current due to non-ideal current profiles and parasitic effects, leading to inefficiencies and potential overcurrents, especially when dealing with loads that exhibit saturation and varying line resistances.
Innovation Solution
A current regulator employing a pulse-width-modulated supply voltage system with a switching circuit and a drive circuit that uses current measurement and reference signals to adjust the duty cycle of the voltage applied to the load, ensuring the mean current value is maintained by integrating these signals and comparing them to initiate new drive cycles, thus compensating for non-ideal current profiles and preventing overcurrents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional hysteresis regulators or two-point regulators are used to regulate current through inductive loads, then the regulation is simple in structure, but the current profile becomes non-ideal due to parasitic effects, leading to inaccurate current control and potential overcurrents
Solution Approach 1:
The patent implements a closed-loop feedback system where the current through the load is continuously measured and fed back to a controller. The controller compares the measured current with a reference current and adjusts the duty cycle of the pulse-width-modulated supply voltage accordingly. This feedback mechanism compensates for non-ideal current profiles caused by parasitic effects, ensuring accurate current control while maintaining a relatively simple regulator structure.
2Measurement precision
If pulse-width modulation is used to regulate current by adjusting duty cycle, then current control accuracy is improved, but the system complexity increases due to additional switching circuits and control mechanisms
Solution Approach 1:
The patent employs a multi-functional controller that integrates several functions into a single device: current measurement, reference current generation, duty cycle calculation, and switching control. This universal controller handles all regulation tasks through pulse-width modulation, achieving high current control accuracy while avoiding the need for multiple separate complex circuits. The controller adapts its operation based on feedback signals, providing both simplicity and precision.
3Measurement precision
If the supply voltage is cyclically applied to compensate for non-ideal current profiles, then current regulation accuracy is improved, but the response time to changes in reference current or load conditions increases
Solution Approach 1:
The patent uses periodic pulse-width-modulated supply voltage applied to the load, with the duty cycle adjusted based on feedback from current measurements. This periodic action allows the system to maintain accurate mean current control while responding quickly to changes in reference current or load conditions. The cyclic nature of the PWM enables the controller to make incremental adjustments at each switching cycle, achieving both accuracy and fast response without requiring excessively long integration periods.
Data Source
AI summary
Current regulators and related method for regulating a current through a load. The current regulator may include, for example, a first circuit configured to determine an amount of current that flows through the load; and a second circuit configured to cause a voltage to be applied across the load, the voltage having a duty cycle that depends on the amount of the current flowing through the load.