Hybrid Topology Power Converter Zero-Sequence Ripple Reduction
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Solution Overview
Problem
Conventional hybrid topology power converters face challenges in reducing ripple voltage and current of bus capacitors and energy loss, which increases volume and cost due to the need for higher capacitance or more capacitors, and existing soft switch designs are complex and inefficient.
Innovation Solution
Injecting a zero sequence component into the total modulation wave to generate a compensated modulation wave, which reduces ripple voltage and current of the bus capacitor and energy loss, while maintaining performance without increasing capacitance or the number of capacitors, thereby enhancing power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the capacitance of the bus capacitor or the number of capacitors is increased, then the ripple voltage and ripple current are reduced, but the overall volume and fabricating cost are increased
Solution Approach 1:
The patent changes the control parameters of the power converter by injecting a zero-sequence voltage component into the modulation wave. This parameter change optimizes the switching patterns and current distribution, thereby reducing the ripple voltage and current without requiring increased capacitance or additional capacitors, thus avoiding increased volume.
Solution Approach 2:
The patent replaces the conventional approach of physically increasing capacitor size (mechanical solution) with a control strategy involving zero-sequence voltage injection (electrical/control solution). This substitution achieves ripple reduction through intelligent control rather than brute-force hardware expansion, maintaining compact volume.
2Object-affected harmful factors
If the capacitance of the bus capacitor or the number of capacitors is increased, then the ripple voltage and ripple current are reduced, but the fabricating cost is increased
Solution Approach 1:
The patent employs parameter optimization through zero-sequence voltage injection to reduce ripple effects. This control-based approach eliminates the need for additional or larger capacitors, directly reducing component costs and simplifying the manufacturing process while maintaining performance.
Solution Approach 2:
The patent extracts and utilizes the zero-sequence voltage component from the modulation process to achieve ripple reduction. By separating and independently controlling this component, the system can optimize performance without adding hardware, thereby reducing fabricating costs.
3Loss of energy
If soft switch design is implemented, then the energy loss is reduced, but the design complexity is increased and conduction energy loss cannot be effectively reduced
Solution Approach 1:
The patent optimizes energy loss by changing the control parameters through zero-sequence voltage injection. This approach reduces both switching and conduction losses simultaneously by optimizing the switching patterns and current paths, without introducing the complexity of dedicated soft-switching circuits.
Solution Approach 2:
The zero-sequence voltage injection mechanism serves multiple functions simultaneously: it reduces switching losses, reduces conduction losses, and simplifies the overall design. This multi-functional approach eliminates the need for separate soft-switching designs while achieving comprehensive energy loss reduction.
Data Source
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AI summary
A hybrid topology power converter (1) includes a three-level circuit module (2) and a cascaded H-bridge circuit module (3). A control method includes the following steps. Firstly, a zero sequence component (S) is injected into a total modulation wave (P), thereby generating a compensated total modulation wave (P1). Then, a first voltage signal (Vsg) is generated according to the compensated total modulation wave (P1). An H-bridge modulation wave (P2) is generated according to the compensated total modulation wave (P1) and the first voltage signal (Vsg). A three-level driving signal (Vg1) is generated according to the first voltage signal (Vsg), and an H-bridge driving signal (Vg2) is generated according to the H-bridge modulation wave (P2). A duty cycle of at least one switch element of the three-level circuit module (2) is adjusted according to the three-level driving signal (Vg1). A duty cycle of at least one switch elements of the cascaded H-bridge circuit module (3) is adjusted according to the H-bridge driving signal (Vg2).