Integrated Three-Phase PFC Converter Reducing Element Count
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Solution Overview
Problem
Conventional three-phase power factor correction circuits require a high number of elements, leading to low utility rates and increased production costs, while also suffering from inadequate control of total harmonic distortion (THD) due to independent single-phase circuits.
Innovation Solution
An integrated converter with only two power factor correction circuits, each comprising a bridge converter, inductance sets, and DC/DC converters, which effectively manage three-phase AC to DC conversion with reduced element count and improved THD control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If three single-phase power factor correction circuits are combined to control three-phase input current, then the controlling effect of THD is satisfactory and efficiency is higher, but the number of elements in the circuit is higher and system power density is lower
Solution Approach 1:
The patent merges three independent single-phase power factor correction circuits into a single integrated three-phase power factor correction circuit. The three-phase circuit uses shared components (inductors L1-L6, capacitors C1-C6, diodes D1-D18, and switches S1-S6) that are interconnected to simultaneously correct all three phases, reducing the total number of elements while maintaining effective THD control through unified operation.
2Productivity
If three single-phase power factor correction circuits are combined to control three-phase input current, then the controlling effect of THD is satisfactory and efficiency is higher, but the system power density is lower
Solution Approach 1:
The integration of three single-phase circuits into one three-phase circuit reduces the overall component count and occupies less space, thereby increasing power density. The shared magnetic cores and interleaved inductor structures enable efficient energy transfer across all three phases simultaneously, maintaining high conversion efficiency while achieving compact form factor.
3Device complexity
If a three-phase single-switch power factor correction circuit is used, then the number of elements in the circuit is lower and power density is higher, but the three-phase input currents will affect each other and the controlling effect of THD is not good enough
Solution Approach 1:
The patent implements a multi-functional three-phase power factor correction circuit where each switch (S1-S6) and inductor (L1-L6) configuration can independently handle its phase while the entire system works cooperatively. The circuit provides both power factor correction and THD filtering functions across all three phases simultaneously, with each component serving multiple purposes in the overall correction mechanism.
Solution Approach 2:
The patent incorporates control circuits that monitor the three-phase input currents and adjust the switching duties of S1-S6 accordingly. This feedback mechanism detects harmonic distortions in real-time and dynamically adjusts the switching patterns to minimize THD, ensuring that the currents in all three phases are properly regulated without mutual interference.
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 integrated converter achieves high power factor correction with lower element usage, increased power density, and reduced production costs, while maintaining effective THD control and redundancy.
Implementation Method 1
When the switch S1 is switched on, the inductance L1 stores the energy via the way: inductance L1-diode D1-switch S1-middle-line N. When the switch S1 is switched off, the inductance L1 releases the energy
Implementation Method 2
When the voltage is positive, the diode D1 is switched on and the switch S1 is chopped. When the switch S1 is switched on, the inductance L1 stores the energy via the way: inductance L1-diode D1-switch S1-middle-line N
Implementation Method 3
When the switch S1 is switched off, the inductance L1 releases the energy via the way: inductance L1-diode D1-diode D7-capacitor C1-middle-line N, and charges the capacitor C1 and adjusts the duty cycle of the switch S1 according to different requirements to make the output voltage achieve the required value
Data Source
AI summary
An integrated converter having three-phase power factor correction is provided. The integrated converter includes two PFC circuits. Two DC/DC converters are controlled and switched by the integrated converter in accordance with a three-phase AC power source so as to convert the AC power source into a DC power source. The use of the elements in the integrated converter is efficient.