Phase Shift Clocking for 180° Interleaved PFC Control
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Solution Overview
Problem
Existing phase shift circuits in interleaved power factor correction circuits face challenges in accurately controlling the phase difference between driving signals for switches in main and sub circuits, leading to increased ripple components and electromagnetic interference.
Innovation Solution
A phase shift circuit that generates a clock signal by changing the negative or positive value of offset components in the input signal within each operating period, using a ramp generation unit, reference signal generation unit, and comparison unit, to maintain a required phase difference of 180° between the driving signals of the main and sub circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a phase shift circuit is used to maintain 180° phase difference between driving signals, then electromagnetic interference is reduced, but the circuit has limited conditions for selecting current sources and difficulty in generating required phase difference
Solution Approach 1:
The patent changes the operating parameters of the phase shift circuit by dynamically adjusting the switching frequency of the secondary circuit based on the phase difference between driving signals. This allows the circuit to adaptively maintain the optimal 180° phase difference without requiring complex fixed-frequency design constraints, thereby reducing electromagnetic interference while simplifying the overall circuit design.
Solution Approach 2:
The patent implements a feedback mechanism that detects the phase difference between driving signals of the main and sub circuits and uses this information to control the switching frequency of the secondary circuit. This feedback loop ensures accurate maintenance of the 180° phase difference, effectively reducing electromagnetic interference while providing clear guidance for current source selection and phase difference generation.
2Reliability
If the phase difference between driving signals is out of 180°, then ripple component of input current is increased, but controlling the phase difference accurately is difficult with existing phase shift circuits
Solution Approach 1:
The patent employs a feedback mechanism that continuously monitors the phase difference between driving signals and adjusts the switching frequency of the secondary circuit accordingly. This ensures accurate maintenance of the 180° phase difference, preventing increases in input current ripple while providing a practical solution for phase difference control that overcomes the limitations of existing phase shift circuits.
Solution Approach 2:
The patent introduces dynamic control of the switching frequency in the secondary circuit based on real-time phase difference conditions. This dynamic adjustment capability allows the circuit to adapt to varying operating conditions and maintain accurate 180° phase difference, thereby minimizing ripple components without being constrained by the fixed limitations of traditional phase shift circuit designs.
Data Source
AI summary
There are provided a phase shift circuit and a power factor correction circuit including the same. The phase shift circuit includes a ramp generation unit charging or discharging a capacitor connected to a switch device to generate a ramp signal, a reference signal generation unit generating a predetermined reference signal from the ramp signal, and a comparison unit comparing the ramp signal with the reference signal to generate a clock signal, wherein at least one of the reference signal generation unit and the comparison unit changes a negative or positive value of offset components included in the reference signal or the ramp signal within every operating period of the switch device.