Switched Capacitor Energy Storage for Wide-Range Power Conversion
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Solution Overview
Problem
Existing power conversion circuits face high costs and large sizes due to the need for capacitors with high voltage ratings and capacitance values, which are inefficiently managed in parallel configurations, leading to increased overall size and cost.
Innovation Solution
A power conversion circuit with a series configuration of two capacitors and a switch, where the switch operates in conduction or non-conduction states based on the output voltage of the AC/DC rectifier circuit, optimizing capacitance and voltage ratings to reduce overall size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If capacitors with high voltage ratings and large capacitance values are used in parallel configuration, then the power conversion circuit can handle a wide input voltage range, but the overall size and cost of the capacitors increase
Solution Approach 1:
The patent applies dynamics by making the capacitor configuration changeable through a switch. The circuit can dynamically reconfigure between series and parallel connections of the two capacitors based on the input voltage level. When input voltage is high, capacitors are connected in series to share the voltage stress; when input voltage is low, they are connected in parallel to provide sufficient capacitance. This dynamic reconfiguration allows the use of smaller, lower-rated capacitors while maintaining adaptability across the full input voltage range.
Solution Approach 2:
The patent changes the electrical parameters (connection topology) of the capacitor circuit based on operating conditions. By switching between series and parallel configurations, the effective capacitance and voltage rating parameters of the capacitor bank are adjusted to match the required specifications for different input voltage levels, thereby avoiding the need to always use oversized capacitors rated for maximum voltage and capacitance.
2Adaptability or versatility
If capacitors with high voltage ratings and large capacitance values are used in parallel configuration, then the power conversion circuit can handle a wide input voltage range, but the cost of the capacitors increases
Solution Approach 1:
The dynamic switching mechanism allows the circuit to use cost-effective, lower-rated capacitors in series configuration during high-voltage operation, and only switches to parallel configuration (requiring higher capacitance) during low-voltage operation. This reduces the overall cost compared to using always-high-rated capacitors that would be required for continuous high-voltage handling capability.
Solution Approach 2:
By changing the connection parameters of the capacitors based on voltage conditions, the circuit optimizes the cost-performance ratio. The parameter change allows using cheaper, lower-voltage-rated capacitors most of the time, only requiring higher capacitance values temporarily when voltage is low, thereby reducing overall component cost while maintaining the required input voltage range adaptability.
3Quantity of substance
If the switch is turned on, then both capacitors operate providing largest overall capacitance value, but the rated voltage capability is reduced
Solution Approach 1:
The switch enables dynamic reconfiguration of the capacitor bank. When the switch is closed, capacitors are connected in parallel providing maximum capacitance for low-voltage conditions. When the switch is open, capacitors are connected in series providing maximum voltage capability for high-voltage conditions. This dynamic switching resolves the contradiction by allowing the circuit to have both high capacitance and high voltage capability at different times based on operating requirements.
Solution Approach 2:
The connection topology parameter is changed by the switch state. In parallel connection (switch closed), the effective capacitance is the sum of individual capacitances while voltage rating is that of a single capacitor. In series connection (switch open), the effective voltage rating is the sum of individual voltage ratings while capacitance is reduced. This parameter change allows the circuit to optimize for either capacitance or voltage capability depending on the operating voltage level.
4Strength
If the switch is turned off, then only the high-voltage capacitor operates providing largest overall rated voltage, but the capacitance value is reduced
Solution Approach 1:
The switch provides dynamic control over capacitor configuration. When open, the circuit uses series connection to maximize voltage capability for high-voltage input conditions. When closed, it switches to parallel connection to maximize capacitance for low-voltage input conditions. This dynamic adaptation allows the circuit to have sufficient capacitance value in series mode for high-voltage operation, eliminating the need to always use large-capacitance, high-voltage-rated capacitors.
Solution Approach 2:
The connection configuration parameter is dynamically changed based on input voltage level. In series configuration (switch open), the voltage rating parameter is maximized while capacitance is reduced, suitable for high-voltage operation. In parallel configuration (switch closed), capacitance is maximized while voltage rating is lower, suitable for low-voltage operation. This parameter adaptation resolves the contradiction by matching capacitor characteristics to operating conditions.
Data Source
AI summary
A power conversion circuit, a power conversion system, a power source and a method and a device of controlling the same are provided. The power conversion circuit includes an AC/DC rectifier circuit, a DC/DC conversion circuit and an energy storing circuit coupled between the AC/DC rectifier circuit and the DC/DC conversion circuit. The energy storing circuit includes a first capacitor, a second capacitor and a switch. The first capacitor and the second capacitor are coupled in series. The switch is coupled in parallel with the second capacitor. The switch is configured to turn on when the output voltage of the AC/DC rectifier circuit is smaller than or equal to a threshold value; and turn off when the output voltage of the AC/DC rectifier circuit is larger than the threshold value, wherein the threshold value is smaller than or equal to the rated voltage of the first capacitor.