Switching Power Supply Damping Resistor Segmentation
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Solution Overview
Problem
Conventional switching power supply devices face efficiency reduction and increased costs due to high losses in damping resistors when using larger-capacitance smoothing capacitors, and heat management issues when no damping resistor is used, leading to increased size and cost.
Innovation Solution
A switching power supply device configuration that includes a chopper circuit, an inverter circuit, a first capacitor between DC bus-bars, a second capacitor in parallel with larger capacitance, and a resistor connected only to the first capacitor, reducing damping resistor losses and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a larger-capacitance smoothing capacitor is used, then heat generation from the smoothing capacitor is reduced, but loss in the damping resistor increases and efficiency decreases
Solution Approach 1:
The patent divides the capacitor system into two separate capacitors: a smoothing capacitor (first capacitor) and a surge absorbing capacitor (second capacitor). The damping resistor is connected only to the smoothing capacitor, not to the surge absorbing capacitor. This segmentation allows the smoothing capacitor to handle high current charging without excessive heat generation, while the surge absorbing capacitor handles resonant current separately, preventing excessive loss in the damping resistor and maintaining efficiency.
2Stability of the object's composition
If a damping resistor is connected to a larger-capacitance smoothing capacitor, then resonant oscillations are suppressed, but heat generation at the damping resistor increases requiring higher allowable-power resistors
Solution Approach 1:
The patent segments the damping function by connecting the damping resistor only to the smoothing capacitor (first capacitor) with smaller capacitance, while the surge absorbing capacitor (second capacitor) with larger capacitance is connected without a series damping resistor. This allows resonant oscillation suppression with a lower-power damping resistor, reducing cost while maintaining stability.
Solution Approach 2:
The patent applies different circuit configurations to different capacitors based on their specific functions. The smoothing capacitor, which handles high current charging, has a damping resistor connected to suppress resonant oscillations locally at that component. The surge absorbing capacitor, which handles voltage surges, is configured without a series damping resistor to avoid excessive power loss. This localized quality approach optimizes both stability and cost.
3Ease of manufacture
If no damping resistor is used, then cost is reduced, but resonant current to the smoothing capacitor increases causing excessive heat generation
Solution Approach 1:
The patent segments the capacitor functions and damping requirements. The smoothing capacitor (first capacitor) is equipped with a damping resistor to suppress resonant oscillations and prevent excessive heat generation. The surge absorbing capacitor (second capacitor) is configured without a series damping resistor. This segmentation allows cost reduction by eliminating the need for a high-power damping resistor while maintaining adequate heat management through the targeted damping resistor on the smoothing capacitor.
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 decreases damping resistor losses and suppresses efficiency reduction, while eliminating the need for additional heat management measures, such as increasing the number of smoothing capacitors, thereby reducing costs and size.
Implementation Method 1
a chopper circuit that adjusts a DC voltage input through a reactor to a desired DC voltage
Implementation Method 2
an inverter circuit that converts an output of the chopper circuit into a desired AC voltage
Implementation Method 3
a first capacitor that is inserted between DC bus-bars that connect the chopper circuit and the inverter circuit; a second capacitor that is connected in parallel to the first capacitor
Implementation Method 4
a resistor that is inserted between the DC bus-bars and only connected to the first capacitor
Data Source
AI summary
A switching power supply device includes: a chopper circuit that adjusts a DC voltage input through a reactor to a desired DC voltage by performing an on/off operation of a switching element; an inverter circuit that converts an output of the chopper circuit into a desired AC voltage; a first capacitor that is provided on a side of the inverter circuit relative to the switching element; a second capacitor that is provided on a side of the inverter circuit relative to the switching element; and a resistor that is in a resonant loop formed by three constituent elements that are the first capacitor, the second capacitor, and a wiring inductance between the chopper circuit and the inverter circuit, where the resistor is connected in series to the second capacitor and inserted between the DC bus-bars.