Apparatus for controlling motor and method for controlling motor

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Solution Overview

Problem

Existing motor control methods for home appliances face challenges in accurately estimating the rotor position without position detection sensors, leading to potential issues with starting torque, rotation direction, and user dissatisfaction due to inaccurate rotor position estimation and increased motor rotation.

Innovation Solution

A motor control apparatus and method that applies a first pattern voltage to estimate stator resistance followed by a second pattern voltage to estimate the rotor position, separating these signals to improve accuracy and reduce motor rotation, using a controller to manage the inverter and apply specific voltage patterns to minimize torque ripple and rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If sensorless control is used to avoid expensive position detection devices, then device complexity and cost are reduced, but measurement precision of rotor position deteriorates

Engineering Contradiction:

Improvestructure complexityVSAvoid rotor position detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary estimation process using multiple voltage patterns (first pattern voltage and second pattern voltage) applied at different timing to indirectly determine rotor position and stator resistance without direct sensing. This mediator approach allows sensorless control while improving measurement precision through calculated estimation rather than direct measurement.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary actions by first applying a first pattern voltage to estimate stator resistance before applying a second pattern voltage to estimate rotor position. This preliminary estimation of resistance provides a foundation for more accurate position detection, resolving the contradiction by preparing the system in advance for precise measurement without sensors.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If different waveforms are applied to estimate rotor position during initial start-up, then adaptability is improved, but motor rotation increases causing estimation inaccuracy

Engineering Contradiction:

Improveinitial position detection capabilityVSAvoidmotor rotation stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent segments the initial start-up process into distinct phases: first applying a first pattern voltage to estimate stator resistance, then applying a second pattern voltage to estimate rotor position. This segmentation separates the estimation tasks into independent steps, reducing motor rotation during each phase while maintaining adaptability for accurate initial position detection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses periodic action by applying voltage patterns in a specific sequence and timing manner. The first pattern voltage is applied initially, followed by the second pattern voltage after a predetermined time elapses. This periodic application of different voltage patterns allows the motor to settle between measurements, reducing rotation instability while maintaining detection capability.

Inventive Principle:

Principle #19Periodic action

3Productivity

If stator resistance and rotor position are estimated simultaneously, then productivity is improved, but measurement precision deteriorates due to motor rotation from torque generation

Engineering Contradiction:

Improveinitial start-up speedVSAvoid rotor position estimation accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the simultaneous estimation process into sequential steps: first estimating stator resistance using a first pattern voltage, then estimating rotor position using a second pattern voltage applied after a predetermined time. This segmentation prevents torque generation during resistance estimation, eliminating motor rotation that would interfere with position measurement, while maintaining overall productivity through efficient sequential processing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by first completing the stator resistance estimation before initiating rotor position estimation. This preliminary completion of the resistance measurement phase ensures the motor remains stationary during the critical position measurement phase, improving precision while maintaining productivity through streamlined sequential operations.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11926951B2Apparatus for controlling motor and method for controlling motor

Publication Date: 2024.03.12 LG ELECTRONICS INC

AI summary

Disclosed are a motor control apparatus and a motor control method. Specifically, the motor control apparatus includes an inverter part configured to convert a direct current (DC) input into an alternating current (AC) output and provide the AC output to the motor, and a controller configured to control the inverter part in relation to driving of the motor, and the controller controls the inverter part to apply a first pattern voltage having the same phase to the motor and then apply a second pattern voltage having different phases to the motor.