Power converter device having a capacitor and a reactor adjacent to each other on the same circuit board
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Solution Overview
Problem
Existing power converters require additional components like ferrite cores and snubber circuits to counter noise when connecting reactors to printed circuit boards, increasing cost and size, and making it difficult to mount reactors directly on the boards.
Innovation Solution
A power converter configuration with a film capacitor and reactor mounted on the same circuit board, forming a resonant circuit to eliminate the need for noise countermeasures, and using a refrigerant cooling system to simplify the layout and reduce component size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reactor is connected to the printed circuit board via wiring, then the reactor can be electrically connected to the circuit board, but additional noise countermeasures (ferrite core and snubber circuit) are required, increasing cost and size
Solution Approach 1:
The reactor is directly mounted on the printed circuit board and electrically connected through pad patterns formed on the board, merging the reactor mounting structure with the circuit board structure. This eliminates the need for separate wiring connections and associated noise countermeasures, thereby reducing device complexity while maintaining electrical connection reliability.
2Area of stationary object
If the reactor is mounted on the printed circuit board, then the layout area can be reduced, but the reactor cannot be easily mounted due to its relatively large size
Solution Approach 1:
The reactor is divided into a separate mounting portion and an electrical connection portion. The mounting portion can be independently handled and attached to the circuit board, while the electrical connection portion integrates with the pad patterns on the board. This segmentation makes the mounting process easier despite the reactor's size, while still achieving compact layout.
3Volume of stationary object
If a capacitor with relatively small capacity is used, then the device size can be reduced, but noise countermeasures (snubber circuit or ferrite core) become necessary
Solution Approach 1:
The patent converts the potential harmful effect of using a small-capacity capacitor (which would normally require noise countermeasures) into a benefit by directly mounting the reactor on the circuit board. The close proximity of the reactor to the capacitor and other circuit elements creates a compact configuration where the reactor's inductance naturally compensates for capacitor ripple currents, eliminating the need for additional noise countermeasures while maintaining small device volume.
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 configuration allows for a more compact power converter layout, reduces the need for noise countermeasures, and simplifies wiring, while effectively cooling the converter and inverter circuits using a refrigerant system.
Implementation Method 1
the capacitor (12) and the reactor (L) form a resonant circuit, whose resonant frequency is set such that a ripple current component included in the direct current outputted from the converter circuit (11) passes through the resonant circuit, and a current component having a same frequency as a carrier frequency of the inverter circuit (13) is attenuated
Implementation Method 2
a radiator (50) which cools the converter circuit (11) and the inverter circuit (13) using a refrigerant flowing through a refrigerant circuit (120) performing a refrigeration cycle
Data Source
AI summary
A power converter includes: a converter circuit converting an alternating current to a direct current; a reactor electrically connected to one of output terminals of the converter circuit; a capacitor electrically connected to the other output terminal of the converter circuit and the reactor; and an inverter circuit electrically connected to the capacitor converting the direct current to an alternating current. The capacitor is a film capacitor. The capacitor and the reactor are mounted on an identical circuit board.