Alternator Rectifier Gate Voltage Control for Leakage Reduction
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Solution Overview
Problem
In alternators, rectifiers often mistakenly switch on/off transistors due to noise-induced oscillations in the drain-source voltage, leading to energy consumption and performance issues.
Innovation Solution
A rectifier system comprising a gate driving circuit, logic circuit, and comparison circuit that adjusts the gate voltage of the transistor based on a sensing voltage and selection voltages to prevent mistaken switching, thereby improving the rectification process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a transistor is used to rectify AC input voltage, then the rectification efficiency is improved, but leakage current consumes battery energy when the alternator does not generate electricity
Solution Approach 1:
The patent changes the gate voltage parameter of the transistor dynamically. When the alternator is not generating electricity, the control circuit adjusts the gate voltage to reduce the transistor's conductivity, thereby minimizing leakage current and battery energy consumption while maintaining rectification capability when needed.
Solution Approach 2:
The patent implements a feedback mechanism where the control circuit monitors the alternator's generation state and adjusts the transistor's gate voltage accordingly. This feedback loop ensures the transistor operates optimally - fully conductive during rectification and minimally conductive during non-generation periods - resolving the contradiction between rectification efficiency and energy loss.
2Object-affected harmful factors
If noise affects the drain and source of the transistor, then the drain-source voltage oscillates, but the transistor may be switched on or off by mistake
Solution Approach 1:
The patent applies beforehand cushioning by designing the control circuit to anticipate and counteract noise-induced voltage oscillations. The circuit incorporates hysteresis or threshold mechanisms that prevent rapid switching caused by noise, ensuring the transistor only switches when the control signal definitively exceeds the threshold, thus maintaining switching accuracy despite noise presence.
Solution Approach 2:
The control circuit acts as an intermediary between the noisy drain-source voltage and the transistor's switching action. It filters and processes the voltage signals, using comparison circuits or operational amplifiers to determine genuine switching conditions versus noise fluctuations, thereby protecting the transistor from erroneous switching while maintaining responsiveness to valid control signals.
3Stability of the object's composition
If the drain-source voltage oscillates around the conductive voltage, then the transistor switching is affected, but additional circuitry to stabilize voltage increases device complexity
Solution Approach 1:
The patent achieves voltage stabilization using the existing rectifier circuit components serving multiple functions. The same transistors and capacitors used for rectification also provide voltage filtering and stabilization, eliminating the need for separate stabilization circuits. This multi-functionality approach maintains voltage stability around the conductive voltage without significantly increasing device complexity.
Data Source
AI summary
An alternator and a rectifier are provided. The rectifier includes a gate driving circuit, a logic circuit, and a comparison circuit. The gate driving circuit generates a gate voltage, and a control terminal of a transistor receives the gate voltage. The gate driving circuit receives a control signal, and adjusts the gate voltage according to the control signal, so as to control a conductivity degree of the transistor. The logic circuit generates the control signal and a switch signal according to a comparison result and selects a selected voltage according to the switch signal. The comparison result is generated by comparing a sensing voltage of a first terminal of the transistor with the selected voltage.