Power Converter Circuit with Bipolar Charging for High Density
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Solution Overview
Problem
Existing power conversion systems face challenges in achieving high power density and efficiency due to the use of capacitors with non-zero DC bias, which reduces energy storage capability, and require separate stages for DC-AC and AC-DC conversion, leading to increased component count and costs.
Innovation Solution
A power converter circuit that utilizes multi-level ceramic chip capacitors with bipolar charging and discharging to maintain average DC voltage near zero, allowing for compact, efficient, and reliable single-stage conversion between DC and AC, reducing energy losses and component count by using Class 2 MLCCs and controlling current flow through six phases of the AC cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional capacitors with non-zero DC bias are used in power conversion systems, then the circuit can operate with simple topology, but the energy storage capability of capacitors is reduced and power density is limited
Solution Approach 1:
The patent changes the operating parameters of the capacitor by implementing bipolar charging and discharging cycles that maintain the average DC voltage near zero. This parameter change allows Class 2 MLCCs to operate in their optimal range, maximizing their energy storage capability and enabling high power density conversion.
Solution Approach 2:
The patent employs periodic bipolar charging and discharging action across six phases of the AC cycle. This periodic action ensures the capacitor voltage alternates between positive and negative values, maintaining near-zero average DC bias and maximizing energy storage efficiency throughout each cycle.
2Reliability
If separate stages are used for DC-AC and AC-DC conversion, then each conversion stage can be optimized independently, but the component count increases and system complexity increases
Solution Approach 1:
The patent implements a universal single-stage converter that can perform both DC-AC and AC-DC conversion functions. The same circuit topology and components are used regardless of conversion direction, eliminating the need for separate stages and reducing overall system complexity while maintaining conversion efficiency.
Solution Approach 2:
The patent enables bidirectional operation where the converter can switch between DC-AC and AC-DC modes. By allowing the conversion process to work in reverse, a single circuit performs multiple functions that traditionally required separate dedicated stages.
3Quantity of substance
If Class 2 MLCCs are used with bipolar charging, then energy storage density is maximized, but the circuit requires complex switching control
Solution Approach 1:
The patent segments the AC cycle into six distinct phases, with specific switching patterns for each phase. This segmentation simplifies the control logic by breaking down the complex bipolar charging process into manageable discrete steps, making the switching control more systematic and implementable.
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 solution enables high-density, efficient power conversion with reduced energy losses and component count, improving reliability and cost-effectiveness for applications like solar inverters, electric vehicles, and home appliances by utilizing Class 2 MLCCs and controlling current flow through six phases of the AC cycle.
Implementation Method 1
a first reactive network is connected between the first common node and the second common node, and the first reactive network comprises a storage capacitor
Data Source
AI summary
A circuit for converting DC to AC power or AC to DC power comprises a storage capacitor, boost and buck inductors and switching elements. The switches are controlled to steer current to and from the storage capacitor to cancel DC input ripple or to provide near unity power factor AC input. The capacitor is alternately charged to high positive or negative voltages with an average DC bias near zero. The circuit is configured to deliver high-efficiency power in applications including industrial equipment, home appliances, mobility devices and electric vehicle applications.