Three-Level PFC Bus Voltage Control for Full-Bus Load Switching
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Solution Overview
Problem
The application of three-phase power in household electrical appliances can lead to overvoltage issues when converted to DC power, potentially causing damage to circuits, loads, and posing safety risks.
Innovation Solution
A method involving a three-level active Power Factor Correction (PFC) unit with upper and lower half bus capacitors, which converts three-phase power to DC power while controlling the full bus load to stabilize the bus voltage within a predetermined interval, thereby preventing overvoltage or undervoltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If three-phase power is converted to DC power without voltage control, then power conversion is achieved, but overvoltage occurs causing circuit damage and safety hazards
Solution Approach 1:
The patent implements a voltage detection and feedback control mechanism where the controller continuously monitors the DC bus voltage and adjusts the switching states of the PFC unit and load devices to maintain voltage within safe operating ranges, preventing overvoltage damage while enabling power conversion
Solution Approach 2:
The patent introduces a controller as an intermediary device that mediates between the power conversion process and the load, actively regulating voltage levels to prevent harmful overvoltage conditions while maintaining efficient power transfer
2Loss of energy
If full bus load is turned off and only half bus load is operated, then power consumption is reduced, but bus voltage becomes unstable
Solution Approach 1:
The patent employs dynamic load management where the controller dynamically adjusts the operating state of the full bus load based on real-time voltage conditions, transitioning between active and inactive states to maintain voltage stability while optimizing power consumption
Solution Approach 2:
The patent changes the operational parameters of the load devices by controlling their switching states and duty cycles, adjusting these parameters dynamically to maintain bus voltage within acceptable ranges while minimizing energy loss
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
The method effectively stabilizes the bus voltage, enhancing the service life and operational safety of household electrical appliances by preventing voltage extremes.
Implementation Method 1
a three-level active Power Factor Correction (PFC) unit... configured to convert an inputted three-phase power to output a first DC power and a second DC power
Implementation Method 2
an upper half bus capacitor and a lower half bus capacitor connected in series between a positive terminal of a Direct Current (DC) bus and a negative terminal of the DC bus
Data Source
AI summary
Provided are a method for controlling a full bus load to discharge in a household electrical appliance and related apparatuses. In the method, in response to determining that a half bus load is turned on and a full bus load is turned off, a voltage difference between a first DC power and a second DC power is determined to obtain a voltage difference. The first DC power and the second DC power are obtained by converting three-phase power through a three-level active PFC unit. Subsequent to the voltage difference between the first DC power and the second DC power being determined, a full bus load is controlled to be turned on or off based on the voltage difference to stabilize a half bus voltage in a predetermined voltage interval.