Pulse Pattern Generation for Motor Inverter Loss Reduction

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Solution Overview

Problem

Existing pulse pattern generation devices for motor inverters effectively reduce iron loss but fail to minimize copper loss.

Innovation Solution

A pulse pattern generation device that calculates effective current and estimates iron loss to generate a pulse pattern using an evaluation function, incorporating weight adjustment coefficients to emphasize either effective current or iron loss reduction, thereby minimizing copper loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the evaluation function includes both effective current and iron loss with weight adjustment coefficients, then both copper loss and iron loss can be reduced, but the device complexity increases

Engineering Contradiction:
Improvecopper loss and iron lossVSAvoidevaluation function complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The evaluation function incorporates dynamic weight adjustment coefficients (a and b) that can be modified based on operating conditions. This dynamic approach allows the system to adaptively balance between effective current and iron loss minimization, managing the complexity through flexibility rather than rigid fixed-weight structures

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The weight adjustment coefficients are pre-configured or pre-optimized for different operating ranges. By establishing the weighting scheme in advance rather than calculating it in real-time during pulse generation, the system manages computational complexity while still achieving dual loss reduction

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3787174B1Pulse pattern generating device
Publication Date: 2023.05.03 TOYOTA INDUSTRIES CORP
  • EP3787174B1 patent drawingFigure 1
  • EP3787174B1 patent drawingFigure 2
  • EP3787174B1 patent drawingFigure 3~4

AI summary

The pulse pattern generation device 70 includes a line voltage application unit 71 that applies line voltage to coils of the motor, and an induced voltage application unit 72 that applies induced voltage to the coils of the motor. The pulse pattern generation device 70 includes a current calculation unit 73 that calculates a current i that flows when induced voltage is applied to the coils U, V, and an effective current calculation unit 74 that calculates an effective current from the current i. The pulse pattern generation device 70 includes a pattern generation unit 76. The pattern generation unit 76 generates a pulse pattern using an evaluation function including the effective current Irms and the iron loss Wi as evaluation items.