Alternator Voltage Regulator Linear Nonlinear Mode Switching
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Solution Overview
Problem
Conventional microprocessor-based voltage regulators in vehicle alternators have limited accuracy due to 10-bit analog-to-digital converter resolution and pulse width modulation (PWM) driver granularity, leading to inaccuracies in voltage regulation, especially when operating above or below the set point voltage.
Innovation Solution
A method that switches between linear and non-linear modes of operation for the PWM duty cycle based on whether the output voltage is above or below the set point, with linear control during undervoltage conditions and a fixed minimum duty cycle during overvoltage conditions to enhance regulation accuracy and prevent overshoot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional linear PWM control is used for both overvoltage and undervoltage conditions, then the control method is simple, but the voltage regulation accuracy is limited by ADC resolution and PWM granularity
Solution Approach 1:
The patent applies dynamics by switching between two different control modes (linear PWM and fixed duty cycle) based on the voltage condition. The controller dynamically selects the appropriate control strategy depending on whether the voltage is above or below the set point, optimizing performance for each condition while maintaining overall system accuracy.
Solution Approach 2:
The patent changes the control parameter (PWM duty cycle behavior) based on the operating condition. In undervoltage mode, linear PWM control is used with full resolution, while in overvoltage mode, a fixed minimum duty cycle is applied. This parameter change allows the system to achieve higher accuracy where needed without the complexity of high-resolution control across all conditions.
2Reliability
If the PWM duty cycle is continuously adjusted in linear mode for both above and below set point voltages, then the control covers the full voltage range, but voltage overshoot may occur during rapid transitions
Solution Approach 1:
The patent applies preliminary anti-action by implementing a fixed minimum duty cycle threshold that prevents the PWM signal from going too low too quickly. This preliminary constraint stops voltage overshoot before it can occur during rapid transitions, ensuring stable voltage regulation while maintaining ease of operation through automatic control.
3Measurement precision
If higher resolution ADC or differential amplifiers are added to improve voltage detection accuracy, then the voltage measurement precision increases, but the system cost increases
Solution Approach 1:
The patent creates a functional copy of high-precision control behavior through software logic rather than hardware upgrades. By implementing intelligent control algorithms that use the existing 10-bit ADC effectively, the system achieves accuracy comparable to 12-bit systems without the cost of additional hardware components.
Solution Approach 2:
The patent changes how the existing ADC output is utilized by applying different control strategies based on voltage conditions. Instead of relying on higher ADC resolution, the system maximizes the effective resolution through conditional control modes, achieving better practical accuracy without hardware changes.
Data Source
AI summary
A method for implementing voltage regulation for an electrical generator device includes comparing an output voltage of the electrical generator device to a desired set point voltage thereof, and generating an output control signal configured to regulate a field current of the generating device. The output control signal is generated in accordance with a linear mode of operation during of one of an overvoltage condition and an undervoltage condition with respect to the desired set point voltage, and wherein the output control signal is automatically set to a predetermined value in a non-linear mode of operation during the other of the overvoltage condition and the undervoltage condition.