Power Factor Correction Circuit Wave Skipping
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Solution Overview
Problem
Power factor correction (PFC) circuits face challenges in maintaining accurate voltage and current measurements, especially at low loads, leading to inefficiencies and increased power losses due to random on/off operations and decreased signal quality.
Innovation Solution
Implementing a PFC circuit that employs wave skipping by shutting down 60 Hz rectified half sine wave input intervals, allowing for improved efficiency and accuracy in power measurement, even at light loads, by ensuring the current sensing resistor is sized for the lowest expected current and using a processing component to enable/disabled AC line wave skipping based on threshold voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the current sensing element is sized to minimize power loss at highest rated output power and lowest rated input voltage, then power loss is reduced, but voltage signal becomes very small with poor signal to noise ratio at lowest rated output power and highest rated input voltage
Solution Approach 1:
The patent applies dynamics by making the PFC circuit operable in two distinct modes (continuous conduction mode and wave skipping mode) that can be dynamically switched based on operating conditions. The controller dynamically adjusts the conduction angle and switching frequency to maintain optimal measurement accuracy across varying load conditions, transforming a static sensing element into a dynamically adaptable measurement system.
Solution Approach 2:
The patent changes operating parameters by adjusting the conduction angle and switching frequency based on the operating mode. In wave skipping mode, the controller modifies the duty cycle and timing parameters to ensure sufficient voltage signal generation during light load conditions, while maintaining power efficiency through parameter optimization rather than hardware changes.
2Use of energy by moving object
If PFC circuit is randomly turned on and off to support variable loads and save energy, then energy efficiency is improved, but current measurement accuracy deteriorates
Solution Approach 1:
The patent implements periodic action through wave skipping mode, where the PFC circuit operates in discrete periodic intervals rather than continuously or randomly. The controller enables the PFC circuit for specific conduction angles during each AC line cycle and skips other cycles, creating a structured periodic operation pattern that maintains measurement accuracy while improving energy efficiency.
Solution Approach 2:
The patent uses feedback by continuously monitoring the voltage signal from the sensing element and adjusting the PFC circuit operation accordingly. The controller receives feedback about the operating conditions and dynamically modifies the conduction angle and switching timing to maintain optimal measurement accuracy even when the circuit is operated in wave skipping mode for energy efficiency.
3Measurement precision
If sense resistance is increased to improve current measurement, then measurement accuracy is improved, but power loss increases and operating efficiency reduces
Solution Approach 1:
The patent applies dynamics by dynamically adjusting the effective sensing resistance through the wave skipping operation. Rather than using a fixed high sense resistance that would cause continuous power loss, the system dynamically activates the sensing element only during specific conduction intervals, maintaining measurement accuracy when needed while minimizing power loss during idle periods.
Solution Approach 2:
The patent changes the operational parameters of the sensing element by controlling the conduction angle and duty cycle. This allows the system to achieve sufficient measurement accuracy through optimized timing and duration of sensing element activation, eliminating the need to increase sense resistance and thereby avoiding the associated power loss penalty.
4Measurement precision
If PFC circuit operates at light loads with continuous conduction, then measurement accuracy is maintained, but energy efficiency deteriorates
Solution Approach 1:
The patent applies dynamics by implementing a dynamic operating mode selection mechanism that switches between continuous conduction mode and wave skipping mode based on load conditions. The controller dynamically determines the optimal mode and adjusts the conduction angle accordingly, enabling the system to maintain measurement accuracy at light loads while improving energy efficiency through mode transition.
Solution Approach 2:
The patent changes the operational parameters by adjusting the conduction angle and switching frequency based on the selected mode. In wave skipping mode for light loads, the controller reduces the duty cycle and extends the skip intervals, thereby maintaining sufficient measurement accuracy while significantly reducing energy consumption compared to continuous conduction.
Data Source
AI summary
Systems and methods for increasing power measurement accuracy for power factor correction (PFC) are disclosed. An exemplary method may include providing a PFC circuit for a power supply, the PFC circuit having a bulk capacitor connected to a rectified AC line. The method may also include measuring output load. The method may also include enabling AC wave skipping if the measured output load drops below a threshold value.