Interleaved PFC Circuit Cost Reduction via Single Resistor
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Solution Overview
Problem
Existing interleaved power factor corrector solutions require multiple current sensors to achieve current balance between switch tubes, leading to high circuit costs.
Innovation Solution
An interleaved power factor corrector design that uses a current sampling resistor and detection components to generate PWM control signals for switch components, allowing current balance control without the need for multiple current sensors, utilizing a single current sampling resistor to detect currents and generate control signals with a half-carrier period difference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple current sensors are used to detect currents in each PFC component, then current balance control between switch tubes can be achieved, but circuit cost increases significantly
Solution Approach 1:
The patent merges the current detection functions by connecting current sampling resistors in series with the switch tubes and utilizing the natural current flow paths. The detection component detects currents I1 and I2 through these resistors, eliminating the need for separate current sensors in each PFC component while achieving current balance control.
Solution Approach 2:
The patent makes the detection component multi-functional by using it to detect multiple currents (I1, I2, and total current) through the current sampling resistors. This single detection component performs the work of multiple current sensors, reducing circuit cost while maintaining current balance control capability.
2Reliability
If current balance control is implemented in interleaved PFC, then switch tube reliability improves, but the control system complexity increases
Solution Approach 1:
The patent implements feedback control by detecting currents I1 and I2 through the current sampling resistors and using these detected values in the control component to regulate the switch tube operations. The control component adjusts the duty cycles of the switch tubes based on the detected current values, ensuring current balance and preventing switch tube failure.
Solution Approach 2:
The patent enables the system to self-regulate current balance by using the detected current values to automatically adjust switch tube operations. The control component uses the detected currents I1 and I2 to generate appropriate control signals, making the system self-correcting without external intervention.
Data Source
AI summary
An interleaved power factor corrector includes a first PFC component, a second PFC component, a current sampling resistor, a current detection component, a voltage detection component, and a control component. The current detection component is configured to detect a current I1, a current I2 and a current Iin. The voltage detection component is configured to detect a voltage U1 inputted into the interleaved power factor corrector and an output voltage U2. The control component is configured to generate, according to the current I1, current I2, current Iin, voltage U1, voltage U2 and a preset target output voltage, a first PWM control signal and a second PWM control signal, in which the first PWM control signal is different from the second PWM control signal by a half of a carrier period. The interleaved power factor corrector has lower circuit cost.