Power Conversion System Resonant Capacitor Control
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Solution Overview
Problem
Conventional power conversion systems require expensive, bulky, and unreliable energy storage devices to balance the mismatch between steady DC power from sources like solar panels and pulsating AC power in grids, limiting the adoption of alternative energy sources and back-up power systems due to inefficiencies and high costs.
Innovation Solution
Implementing a power conversion system with constant power control that maintains a controlled impedance, allowing energy storage devices to operate with wider fluctuations, reducing the size and cost of capacitors and eliminating the need for large electrolytic capacitors by storing energy in a higher voltage form on the DC link capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If energy storage devices are used to balance DC power source with AC load, then power transfer effectiveness is improved, but device size, cost, and reliability deteriorate
Solution Approach 1:
The patent changes the operating parameters of the energy storage capacitor by allowing it to operate in a resonant mode at twice the line frequency. This resonant operation enables the capacitor to provide the necessary energy storage with much smaller capacitance values, thereby reducing size and cost while maintaining power transfer effectiveness.
Solution Approach 2:
The patent employs periodic switching of the power converter at twice the line frequency (100 Hz or 120 Hz), synchronized with the AC power waveform. This periodic action allows the system to transfer power in controlled pulses that match the AC cycle, enabling effective power transfer with minimal energy storage requirements.
2Productivity
If energy storage devices are used to balance DC power source with AC load, then power transfer effectiveness is improved, but device cost deteriorates
Solution Approach 1:
The patent changes the operating parameters of the energy storage capacitor by allowing it to operate in a resonant mode at twice the line frequency. This resonant operation enables the capacitor to provide the necessary energy storage with much smaller capacitance values, thereby reducing size and cost while maintaining power transfer effectiveness.
3Productivity
If energy storage devices are used to balance DC power source with AC load, then power transfer effectiveness is improved, but reliability deteriorates
Solution Approach 1:
The patent changes the operating parameters of the energy storage capacitor by allowing it to operate in a resonant mode at twice the line frequency. This resonant operation enables the capacitor to provide the necessary energy storage with much smaller capacitance values, thereby reducing size and cost while maintaining power transfer effectiveness.
4Productivity
If conventional power conversion system is used, then power transfer is achieved, but efficiency deteriorates due to ripple-related losses
Solution Approach 1:
The patent employs periodic switching of the power converter at twice the line frequency (100 Hz or 120 Hz), synchronized with the AC power waveform. This periodic action allows the system to transfer power in controlled pulses that match the AC cycle, enabling effective power transfer with minimal energy storage requirements.
Solution Approach 2:
The patent implements a control system that monitors the AC power waveform and adjusts the switching timing and duration of the power converter to maintain optimal operation. This feedback control ensures that power is transferred efficiently while minimizing ripple and associated losses.
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 improves efficiency, reduces the size and cost of energy storage devices, and enhances reliability by isolating the power source from downstream energy storage, enabling the use of smaller, more reliable components and minimizing ripple-related power losses.
Implementation Method 1
the power conversion system must store the excess energy from the power source during time T1 (shown as the shaded area S), and discharge the stored energy to the load during time T2 (shown as the shaded area D)
Data Source
AI summary
In one embodiment, a power conversion system includes a controller to provide power control to a converter, and a distortion mitigation circuit. In another embodiment, a system includes a converter to transfer power between a power source and a load having fluctuating power demand, and a controller to provide power control, where the controller may selectively disable the power control. In another embodiment, a power conversion system includes a controller to generate a drive signal to provide power control to a power path in response to a sense signal from the power path, where the sense signal is taken from other than the input of the power path, or the drive signal is applied to the power path at other than a first power stage.