Parallel Inverter Modules for High-Current Motor Drives
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Solution Overview
Problem
Conventional motor drive apparatuses face challenges in reducing costs while increasing current capacity, as reducing chip area to lower costs leads to decreased current capacity, making it difficult to achieve both cost reduction and current increase.
Innovation Solution
The motor drive apparatus employs inverter modules with multiple switching element pairs connected in parallel, each pair consisting of two switching elements in series, and a control unit generating PWM signals to drive these modules, allowing for high current capacity and cost-effective operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the chip area of switching elements is reduced to lower cost, then manufacturing cost decreases, but current capacity decreases
Solution Approach 1:
The patent divides the switching element into multiple smaller chips (first switching element chip and second switching element chip) that are connected in parallel. Each chip has a smaller area, reducing individual manufacturing cost, while the parallel connection maintains high current capacity. This segmentation allows cost reduction without sacrificing performance.
Solution Approach 2:
The patent combines multiple switching element chips in parallel within the inverter module. By merging multiple smaller chips functionally through parallel connection, the system achieves the current capacity of a single large chip while benefiting from the lower cost and higher yield of multiple smaller chips.
2Productivity
If the chip area of switching elements is reduced to improve yield, then manufacturing yield increases, but current capacity decreases
Solution Approach 1:
The switching element is segmented into multiple smaller chips, which improves manufacturing yield during dicing from the wafer. The parallel arrangement of these smaller chips compensates for the reduced individual current capacity, achieving both high yield and sufficient total current capacity.
Solution Approach 2:
The patent changes the configuration parameter from a single large chip to multiple smaller chips connected in parallel. This parameter change transforms the system so that the total current capacity is the sum of individual chip capacities, allowing yield improvement without current capacity loss.
3Quantity of substance
If multiple switching element pairs are connected in parallel to increase current capacity, then current capacity increases, but device complexity increases
Solution Approach 1:
The patent merges multiple switching element pairs into a unified inverter module structure with common connection terminals. This merging approach increases current capacity while minimizing complexity by using shared connection paths and a standardized module interface, avoiding the need for complex individual control circuits for each parallel element.
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 enables both cost reduction and increased current capacity, effectively addressing the limitations of conventional systems by utilizing parallel switching elements and intelligent PWM signal management.
Implementation Method 1
a control unit generating a PWM signal used to drive the inverter modules with PWM
Data Source
AI summary
A motor drive apparatus driving a motor as a three-phase motor converting direct current into three-phase alternating current, includes: inverter modules and equivalent in number to phases of the motor; and a control unit generating PWM signals used to drive the inverter modules with PWM. The inverter modules each include a plurality of switching element pairs connected in parallel, each of the switching element pairs including two switching elements connected in series.