Power Factor Correction Control Device for Harmonic Distortion
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Solution Overview
Problem
Power factor correction circuits face challenges in maintaining optimal power factor due to voltage distortion caused by filter parts and capacitors, leading to suboptimal performance, especially in applications with strict harmonic current restrictions like illuminating equipment.
Innovation Solution
A control device for power factor correction circuits that includes an inductor and a switching element, controlled based on pulsating voltage and feedback voltage, with configurations for detecting minimum and amplitude corrections, and zero-crossing timing detection to generate a control pulsating voltage for PWM control, ensuring the inductor current aligns with ideal pulsating voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the inductor current is controlled to follow the full-wave rectified voltage waveform, then the power factor is improved, but the current waveform distortion increases due to voltage distortion from filter parts and capacitors
Solution Approach 1:
The control device generates a reference pulsating voltage waveform in advance that represents the ideal rectified sinusoidal voltage. This reference waveform is used to predict and determine the optimal switching timing for the power factor correction circuit before the actual current flow occurs, ensuring the current follows the ideal waveform pattern rather than the distorted actual voltage waveform
Solution Approach 2:
The control device detects the actual voltage waveform and compares it with the ideal reference pulsating voltage waveform. Based on this comparison and feedback, the control device adjusts the switching timing of the power factor correction circuit to minimize the deviation between the inductor current and the ideal current waveform, thereby reducing harmonic distortion while maintaining high power factor
2Productivity
If the full-wave rectified voltage is used for control, then the power factor correction operates continuously, but the inductor current does not reach zero near the zero-crossing point of the alternating current voltage due to voltage distortion
Solution Approach 1:
The control device generates the reference pulsating voltage waveform in advance that explicitly accounts for the expected zero-crossing behavior. By using this pre-generated ideal reference waveform instead of the actual distorted voltage waveform for control, the device ensures that the inductor current is guided to reach zero at the correct timing corresponding to the zero-crossing point of the original alternating current voltage
Solution Approach 2:
The control device creates a copy of the ideal rectified sinusoidal voltage waveform as a reference signal. This reference copy is then used to control the power factor correction circuit, replacing the use of the actual distorted voltage waveform. This copying approach allows the system to follow the ideal waveform pattern while ignoring the distortions present in the actual voltage
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
This solution enhances power factor correction by minimizing distortion in the inductor current, thereby improving the power factor of the power supply device and reducing harmonic current, especially in applications with stringent harmonic restrictions.
Implementation Method 1
a switching element for controlling an inductor current that flows in the inductor
Implementation Method 2
an inductor that is disposed between a full-wave rectification circuit and an output interconnect line
Implementation Method 3
a full-wave rectification circuit that generates a full-wave rectified voltage by carrying out full-wave rectification of the alternating-current voltage
Data Source
AI summary
A control device of a power factor correction circuit disposed in a power supply device that generates a direct-current output voltage from an alternating-current voltage applied to a power supply terminal pair, the power factor correction circuit including an inductor that is disposed between a full-wave rectification circuit that generates a full-wave rectified voltage by carrying out full-wave rectification of the alternating-current voltage and an output interconnect line to which a smoothing capacitor is connected and to which the output voltage is applied, and is inserted between the full-wave rectification circuit and the output interconnect line, and a switching element for controlling an inductor current that flows in the inductor. The control device controls a state of the switching element based on a pulsating voltage obtained by rectifying a voltage between the power supply terminal pair and the full-wave rectification circuit and a feedback voltage according to the output voltage.