PFC Converter Controller High Frequency Component Management
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Solution Overview
Problem
Conventional power factor correction (PFC) converters in vehicle charging systems face challenges in controlling high frequency components of alternating current (AC) power, leading to overcurrent input due to distorted external power sources, which decreases controller responsiveness and results in inefficiencies.
Innovation Solution
A system that includes a power supply unit, a PFC converter unit, and a controller to extract high frequency components from AC power, determine their frequency, and limit output power when frequencies exceed a predetermined value, using filtering units and sensors to manage input and output currents effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the PWM switching frequency of the switching element in the PFC converter is increased to reduce the size of magnetic substance and single product, then the size reduction is achieved, but the control period of PFC must be shortened and controller responsiveness decreases when distorted power is applied
Solution Approach 1:
The controller proactively detects high frequency components in the input AC power before they cause overcurrent conditions, and preemptively limits the output power of the PFC converter. This preliminary action prevents the distorted power from affecting controller responsiveness and causes input overcurrent phenomena, while allowing the system to operate with higher PWM frequencies for compact size.
Solution Approach 2:
The controller continuously monitors the input AC power for high frequency components and uses this feedback to dynamically adjust the output power of the PFC converter. When distorted power is detected, the controller responds by limiting output power, which maintains stable operation and prevents overcurrent conditions, thereby preserving controller responsiveness despite high PWM switching frequencies.
2Speed
If the control period of PFC is shortened to match high PWM frequency, then faster control response is achieved, but it becomes impossible to control PFC by 1 period per period of PWM
Solution Approach 1:
The controller dynamically adapts its control period based on the detected high frequency components in the input power. Instead of using a fixed control period that must synchronize with PWM frequency, the controller adjusts the control period in real-time to match the actual power conditions, enabling effective control regardless of PWM frequency while maintaining stable operation.
3Adaptability or versatility
If the PFC converter uses external power source with distorted power, then system adaptability is improved, but responding performance of controller decreases causing input overcurrent phenomenon
Solution Approach 1:
The controller applies preliminary anti-action by detecting high frequency components in distorted power from external sources and preemptively limiting output power before overcurrent conditions can develop. This prevents the distorted power from degrading controller responding performance, allowing the system to maintain reliable operation across various external power sources with different quality levels.
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
Prevents overcurrent input to the PFC converter unit by limiting output power based on high frequency components, thereby enhancing controller responsiveness and system efficiency.
Implementation Method 1
a first filter unit filtering a high frequency ripple component included in the AC power input to the PFC converter unit to extract a high frequency
Implementation Method 2
a rectifier positioned between the power supply unit and the PFC converter unit and rectifying the AC power input from the power supply unit
Implementation Method 3
a power factor correction (PFC) converter unit connected to the power supply unit and converting the AC power supplied from the power supply unit into a DC power
Data Source
AI summary
A system of controlling a charging apparatus for a vehicle may include a power supply unit supplying an AC power, a power factor correction (PFC) converter unit connected to the power supply unit and converting the AC power supplied from the power supply unit into a DC power and supplying the converted DC power to a load, and a controller extracting a high frequency component from the AC power input to the PFC converter unit, determining a frequency of the extracted high frequency component, and limiting, when the determined frequency is equal to or greater than a predetermined value, output power from the PFC converter unit to a value lower than the predetermined value.