Synchronous Single-Stage Regulator for Harmonic Current Control
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Solution Overview
Problem
Existing single stage power conversion systems face inefficiencies at high power levels and wide duty cycles due to passive diode commutation, leading to poor power efficiency and high harmonic current, especially when trying to achieve arbitrary harmonic buck and boost voltages with regulated line and DC voltage connections.
Innovation Solution
A bidirectional single stage power converter with synchronous average harmonic current control, using a voltage controlled bridge resonantly coupled through a transformer to a current controlled bridge, employing a synchronous average harmonic current compensator to generate feedback signals for pulse width modulation, allowing independent regulation of isolated line and bus voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If passive diode commutation is used in single stage power converters, then parts efficiency is improved, but power efficiency deteriorates at high power levels and wide duty cycles
Solution Approach 1:
The patent replaces passive diode commutation with active synchronous switching using MOSFETs or IGBTs with anti-parallel diodes. This substitution allows for controlled current commutation through gate-driven switches, eliminating the inherent limitations of passive diode operation at high power levels and wide duty cycles, thereby improving power efficiency while maintaining parts efficiency
Solution Approach 2:
The patent changes the operational parameters of the switching elements from passive diode operation to active synchronous switching. By controlling the duty cycle and switching timing of active devices, the system can operate efficiently across wide duty cycle ranges and high power levels, resolving the contradiction between parts efficiency and power efficiency
2Device complexity
If passive diode commutation is used, then device complexity is reduced, but harmonic current increases
Solution Approach 1:
The patent replaces passive diode commutation with active synchronous switching, which provides controlled current waveforms. The active switches enable precise timing and shaping of current transitions, significantly reducing harmonic content while the control system manages the increased device complexity through coordinated gate drive signals
Solution Approach 2:
The patent implements control systems that monitor and adjust switching timing and duty cycles to minimize harmonic current. By using feedback control, the system can dynamically optimize switching parameters to reduce harmonic distortion while managing the complexity of active switching devices
3Ease of manufacture
If diode and active switch duty cycles are related, then parts efficiency is maintained, but harmonic voltage across resonant network decreases leading to high harmonic current
Solution Approach 1:
The patent introduces independent and dynamic control of duty cycles for active switching devices. By decoupling the duty cycle relationships that exist in diode-based systems, the control system can independently optimize switching parameters to maintain parts efficiency while actively managing harmonic voltage and current through dynamic adjustment of switching timing and duration
4Adaptability or versatility
If bidirectional switches are used to allow arbitrary AC or DC bus voltages, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent implements a unified active switching architecture that can operate in multiple modes (buck, boost, bidirectional power flow) using the same core switching devices. This universal design approach provides adaptability for arbitrary AC or DC bus voltages while avoiding the need for separate circuit topologies, thereby managing device complexity through multi-functional switching elements and control modes
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
This solution enables efficient, independent regulation of isolated line and bus voltages with reduced current conduction losses, improving power efficiency and flexibility in handling arbitrary harmonic buck and boost operations.
Implementation Method 1
a voltage controlled bridge resonantly coupled through a transformer to a current controlled bridge
Implementation Method 2
A load current draws a DC current from an isolated voltage, wherein the average DC current flows from a switching diode, and unsteady current is equilibrated between the switching diode and a capacitor. An unsteady current commutates the switching diodes to result in a pulse width modulated voltage impressed across a DC blocking capacitor and a secondary transformer winding. Coupled transformer windings result in a switching voltage across a resonant network which harmonically filters the coupled current.
Data Source
AI summary
A voltage controlled bridge is coupled to a line voltage and a transformer primary harmonic voltage, and a current controlled bridge is coupled to a line current and a transformer secondary harmonic voltage. A synchronous average harmonic current compensator integrates error between a measure of bridge current and commanded current synchronously over each half of a switching period and samples compensator output to control line current and linearize harmonic coupling between isolated bridges. A synchronous pulse width modulation process tracks commanded line voltage. One or more of a primary harmonic command circuit and secondary harmonic command circuit adjust the harmonic coupling voltage of the voltage controlled and current controlled bridge respectively. Line voltage, line current, and primary and secondary harmonic commands provide generalized line and isolated voltage bus regulation degrees of freedom in a single stage.