Boosting Shunt Regulator for Vehicle AC Generator Power Optimization
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Solution Overview
Problem
Conventional power generation systems in vehicles operate at fixed load voltage, leading to reduced power output at low and high engine speeds, and are prone to overheating, especially in applications like snowmobiles, which compromises engine starting and maintenance of battery charge levels during high current draws from accessories like winches.
Innovation Solution
A shunt regulator that utilizes a low voltage AC generator with fewer windings and low loss field effect transistors (FETs) to boost AC voltage to DC bus voltage, enabling efficient power generation at varying engine speeds and reducing heat generation, allowing for placement flexibility and potential batteryless operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional fixed load voltage operation is used, then system simplicity is maintained, but power output is reduced at low and high engine speeds
Solution Approach 1:
The patent implements variable voltage operation where the AC generator voltage is dynamically adjusted based on engine speed. At low and high RPM ranges, the system operates at reduced voltage to maximize power output, while maintaining proper voltage at mid-range speeds. This dynamic operation resolves the contradiction by allowing power optimization across the entire RPM spectrum without requiring complex multi-speed gearing.
Solution Approach 2:
The system changes the operating voltage parameter of the AC generator based on engine speed conditions. By reducing the nominal voltage at certain RPM ranges and using a step-up transformer to achieve the required DC bus voltage, the system extracts maximum power at all engine speeds. This parameter change approach enables improved power output without proportionally increasing system complexity.
2Power
If large currents are produced by the magneto to provide required vehicle power, then power demand is met, but overheating occurs
Solution Approach 1:
The patent reduces the operating voltage and current parameters of the AC generator by using fewer windings and operating at lower nominal voltages. The required power is delivered by increasing the number of pulses per revolution and using a step-up transformer rather than increasing current. This parameter change reduces I²R losses and heat generation in the magneto while maintaining the ability to meet vehicle power demands.
Solution Approach 2:
The system replaces the conventional approach of delivering power through high current with a transformed approach using a step-up transformer to deliver the same power at lower current. This substitution reduces thermal losses in the generator windings and allows the magneto to operate at lower temperatures while still meeting vehicle power requirements.
3Power
If manual start system is used, then engine starting is possible, but sufficient power is not generated at low engine speeds
Solution Approach 1:
The system dynamically adjusts the AC generator voltage to be lower at low RPM ranges, which increases the current capability at these speeds. This dynamic voltage adjustment enables the generator to produce sufficient power during manual cranking operations to reliably energize the engine control unit and support starting, resolving the contradiction between power generation and starting reliability.
4Power
If AC generator has fewer windings to produce lower voltage, then power generation improves, but voltage boosting is required
Solution Approach 1:
The patent introduces a step-up transformer as an intermediary device between the low-voltage AC generator and the DC bus. The transformer efficiently steps up the lower AC voltage to the required level for rectification to DC bus voltage. This intermediary approach resolves the contradiction by enabling the generator to operate at optimal lower voltages for maximum power extraction while still delivering the required voltage for vehicle operation through the transforming intermediary.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances power generation at low and high engine speeds, reduces heat and weight, and improves idle stability, enabling smaller AC generator flywheels and cost savings, while maintaining proper battery charge levels during accessory use.
Implementation Method 1
The shunt regulator utilizes low loss field effect transistors (FETs) to implement switching transformations more efficiently than conventional regulators
Implementation Method 2
an AC generator mechanically coupled to the combustion engine, wherein the AC generator is operable to generate AC voltages
Data Source
AI summary
A direct-current (DC) power generation system for a vehicle, a boosting shunt regulator, and a method of regulating the output of an AC generator with the boosting shunt regulator are provided. The boosting shunt regulator includes gated power switches electrically coupled between AC generator contacts and output contacts. A shunt operates the power switches at duty cycles selected to boost the AC voltages output by the AC generator.