Inverter Shunt Resistor Current Detection Pattern
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Solution Overview
Problem
Inverter devices using shunt resistors for current detection face challenges in maintaining precision due to variations in current distribution, which existing methods struggle to address cost-effectively.
Innovation Solution
The design incorporates a specific conductive pattern on a printed board with a shunt resistor, featuring central and protruding regions with controlled area ratios to optimize current flow and distribution, potentially supplemented by current correcting means to ensure uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a shunt resistor is used to detect motor current instead of CT sensors, then cost is reduced, but current detection precision deteriorates due to current distribution variations
Solution Approach 1:
The conductive pattern is designed with non-uniform local characteristics through protruding regions with specific area ratios (0.6-1.6). These local variations in the conductive pattern create controlled current distribution that compensates for the inherent non-uniformity when current flows into the shunt resistor, thereby improving measurement precision without increasing cost
Solution Approach 2:
The invention changes the geometric parameters of the conductive pattern, specifically the area ratio of protruding regions, to optimize current distribution. By adjusting these parameters within the specified range, the current flow angle and distribution into the shunt resistor are controlled, improving detection precision while maintaining the cost-effective shunt resistor approach
2Temperature
If multiple resistive elements are disposed in parallel to reduce heat emission, then heat dissipation is improved, but current detection precision deteriorates due to increased current path variations
Solution Approach 1:
The conductive pattern incorporates protruding regions with controlled area ratios that create local variations in current density. This local quality adjustment ensures uniform current distribution across multiple parallel resistive elements, preventing precision deterioration while maintaining improved heat dissipation
Solution Approach 2:
By changing the geometric parameters of the conductive pattern, specifically the area ratio of protruding regions to terminal regions (0.6-1.6), the invention optimizes current distribution across parallel resistive elements. This parameter adjustment ensures that current flows uniformly through each element, maintaining detection precision while achieving better heat dissipation
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 approach enhances current detection precision while maintaining cost-effectiveness by optimizing the conductive pattern and using parallel resistors to manage current distribution imbalances.
Implementation Method 1
a printed board on which is formed a conductive pattern including a first conductive pattern component that connects the shunt resistor and the first terminal to each other and a second conductive pattern component that connects the shunt resistor and the second terminal to each other
Implementation Method 2
a shunt resistor provided on a direct-current link that interconnects the rectifying component and the inverter
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
It is a problem of the present invention to provide an inverter device whose current detection precision is improved by checking variations in the distribution of current flowing in a shunt resistor without using a separate member. In a printed board (40) of an inverter device (20), a first conductive pattern component (51) connected to a shunt resistor (31) includes a first central region (510), a first right-side protruding region (511) that juts out on the right side from the first central region (510), and a first left-side protruding region (512) that juts out on the left side from the first central region (510). The ratio SA2/SA1 of the area SA2 of the first left-side protruding region (512) to the area SA1 of the first right-side protruding region (511) is set in the range of 0.6 to 1.6, whereby variations in the distribution of current flowing in the shunt resistor (31) can be checked.