PWM Rectifier Charging System for Electric Vehicles
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Solution Overview
Problem
Traditional electric automobile charging systems face issues with high power consumption, low power factor, harmonic pollution, and long charging durations, which hinder the popularization of electric vehicles due to their impact on the power grid and battery service life.
Innovation Solution
A PWM rectification and converting voltage/current pulse charging system that includes a rectifier module with a three-phase full-controlled bridge converter, bi-directional DC-DC converter, and a double closed-loop control system, employing DSP for sinusoidal current control and unity power factor, eliminating the need for harmonic suppression and reactive power compensation devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional phase-controlled rectification technology is used for high power charging equipment, then charging power is increased, but power factor decreases and harmonic pollution increases
Solution Approach 1:
The patent changes the rectification method from traditional phase-controlled rectification to PWM (Pulse Width Modulation) rectification. This parameter change enables the system to achieve high power factor (close to unity) and low harmonic distortion by precisely controlling the switching timing and duty cycle of power devices, thereby resolving the contradiction between high power and low power factor/harmonic pollution
Solution Approach 2:
The patent replaces the traditional mechanical/thyristor-based phase-controlled rectification system with an electronic PWM control system using IGBTs or IPMs. This substitution enables more precise control of current waveform and power factor, eliminating the need for complex harmonic suppression devices while maintaining high charging power
2Loss of time
If charging power is increased to reduce charging duration, then charging speed is improved, but impact on power grid increases
Solution Approach 1:
The patent implements a double closed-loop control system with current inner loop and voltage outer loop. The system continuously monitors input current, output voltage, and battery state, adjusting PWM duty cycle in real-time to maintain optimal charging current while keeping power factor high. This feedback mechanism enables fast charging without causing excessive impact on the power grid
Solution Approach 2:
The patent employs dynamic control of charging parameters through PWM technology, allowing the system to adaptively adjust charging current based on battery state and grid conditions. The bi-directional DC-DC converter dynamically regulates voltage and current transformation, enabling fast charging while maintaining grid stability through real-time parameter optimization
3Device complexity
If traditional charging mode is used, then system complexity is reduced, but charging duration increases and battery service life decreases
Solution Approach 1:
The patent segments the charging process into multiple modes (constant current charging, constant voltage charging, and pulse charging) that can be automatically switched based on battery state. The charging system is divided into modular components: PWM rectifier module, bi-directional DC-DC converter module, and control module. This segmentation enables sophisticated charging strategies without excessive system complexity
Solution Approach 2:
The patent implements a multi-functional charging system that can operate in multiple charging modes (CC, CV, pulse charging) and supports both charging and discharging operations through the bi-directional DC-DC converter. The control system universally manages different battery types and charging scenarios, achieving fast charging and battery protection without significantly increasing system complexity
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 system achieves high power factor, low harmonic content, and fast charging with reduced battery damage, extending battery life and reducing power grid pollution, while supporting multiple charging modes for efficient energy conversion.
Implementation Method 1
the rectifier module rectifies an alternating current from power input and forms steady DC output voltage after smoothing
Implementation Method 2
the AC-side of the PWM rectifier adopts a filter inductance which realizes a control of AC-side unity power factor and four-quadrant operation of the PWM rectifier and filters harmonic current
Implementation Method 3
in the DC converter module, a bi-directional DC-DC converter is employed to realize a multiple modes of charging for a storage battery
Data Source
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AI summary
The invention discloses a kind of electric automobile PWM rectification and converting voltage/current pulse charging system which is the charging system for large storage battery. The system includes rectifier module and charging module. The former links with AC network and charge module respectively. The said charging system also includes DC charging management module and the charging module is composed of DC input module and DC output module. The said rectifier module, DC input module and DC output module, DC charging management module are independent and connected together by CAN bus. The electric automobile PWM rectification and converting voltage/current pulse charging system of this invention is simply structured with a small size and features wide range of application e.g. charging for all lead and zinc storage batteries. It greatly reduces the duration for charging storage batteries and is worthy of scale popularizing.