Current Regulator with Adaptive Duty Cycle for Inductive Load Control
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Solution Overview
Problem
Current current regulators for inductive loads, such as solenoid valves in hydraulic systems, face challenges in quickly adjusting to changes in desired current values, leading to potential mechanical component jamming due to slow stabilization and interference from radio-frequency fluctuations.
Innovation Solution
A current regulator with a dual operating state circuit that adjusts the duty cycle of a pulse-width-modulated signal based on an error signal, using a dither signal only in the steady state to maintain fluctuations around the desired value, and relying solely on the error signal during transitions to rapidly stabilize the current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a radio-frequency periodic signal is superimposed on the desired current value to prevent mechanical component stopping, then the reliability of continuous operation is improved, but the current regulation speed and stability deteriorate due to ongoing fluctuations
Solution Approach 1:
The patent applies dynamics by making the duty cycle adaptive rather than fixed. The control system dynamically adjusts the duty cycle based on the difference between actual and desired current values, allowing rapid response during transitions while maintaining stability during steady-state operation. This dynamic control resolves the contradiction by enabling fast regulation without requiring continuous radio-frequency signal superposition.
Solution Approach 2:
The patent changes the parameter of duty cycle dynamically based on operating conditions. By adjusting the duty cycle proportionally to the current error and inversely to the actual current value, the system achieves fast response when needed (large error) and smooth operation when stable (small error), eliminating the need for radio-frequency signal superposition and thus resolving the speed-reliability contradiction.
2Measurement precision
If a pulse-width-modulated voltage is applied with duty cycle control based on error signal, then the current regulation accuracy is improved, but the response time to changes in desired current value deteriorates
Solution Approach 1:
The patent implements feedback control where the duty cycle is continuously adjusted based on the difference between actual and desired current values. The control system monitors the current state and dynamically modifies the duty cycle to minimize the error, achieving both fast response and high accuracy. This feedback mechanism resolves the contradiction by enabling the system to respond quickly to changes while maintaining precise regulation.
Solution Approach 2:
The patent makes the duty cycle dynamic rather than static, adjusting it in real-time based on the current error and actual current value. This dynamic adjustment allows the system to respond quickly to desired value changes while maintaining accurate regulation, resolving the contradiction between response time and regulation accuracy.
3Reliability
If the duty cycle depends on both error signal and radio-frequency signal, then the prevention of mechanical component stopping is improved, but the complexity of the control system deteriorates
Solution Approach 1:
The patent extracts and eliminates the radio-frequency signal component from the control system, replacing it with a simpler duty cycle adjustment mechanism based on error signal and actual current feedback. This extraction removes the complexity of radio-frequency signal generation and processing while achieving the same reliability goal through more direct control, thus resolving the contradiction between reliability and complexity.
Solution Approach 2:
The patent changes the control approach from radio-frequency signal superposition to duty cycle parameter adjustment. By modifying the duty cycle based on current error and actual current value, the system achieves component protection without the complexity of radio-frequency signal processing, resolving the contradiction between reliability and control system complexity.
Data Source
AI summary
A regulator and a method for regulating a current through a load. The regulator may include, for example, a first circuit portion configured to alternately apply and remove a voltage across the load in accordance with a first signal, the voltage causing a current to flow, and a second circuit portion configured to generate the first signal so as to have a duty cycle that depends upon an amount of the current and a second signal when the amount of current is below a threshold amount, and to generate the first signal so as to have a duty cycle that depends upon the amount of the current but not the second signal when the amount of current exceeds the threshold amount.