Dynamic Inverter Switching Frequency Control for Eco-Vehicles

Solution Overview

Problem

Conventional inverter control methods for eco-friendly vehicles suffer from fixed switching and sampling frequencies, leading to inefficiencies in switching loss, electromagnetic performance, noise-vibration-harshness (NVH) performance, and control stability, as they do not adapt to varying driving conditions.

Innovation Solution

An inverter control system that dynamically adjusts switching frequency and sampling frequency based on current motor speed, using a controller to generate PWM signals and control the ON/OFF driving of switching elements, transitioning between single-sampling and double-sampling modes depending on the motor speed and operation state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the inverter's switching frequency is set to a low fixed frequency (e.g., 4 kHz), then electromagnetic performance is improved, but noise increases significantly

Engineering Contradiction:

Improveelectromagnetic noiseVSAvoidinverter noise

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent implements dynamic switching frequency adjustment based on motor operating conditions. The controller varies the switching frequency within a range (e.g., 4-8 kHz) depending on motor speed and load, transitioning between low frequency for electromagnetic performance and high frequency for noise reduction, rather than using a fixed frequency throughout all operating conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the switching frequency parameter dynamically according to motor operating conditions. The controller adjusts the switching frequency based on motor speed and load conditions, optimizing the balance between electromagnetic noise suppression and inverter noise reduction across different operating ranges

Inventive Principle:

Principle #35Parameter changes

2Object-generated harmful factors

If the base switching frequency is set to be high over the entire operational area (e.g., 8 kHz), then NVH performance becomes better, but electromagnetic performance is deteriorated and switching loss increases

Engineering Contradiction:

ImprovenoiseVSAvoidswitching loss

Core Design Contradiction:

Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The patent implements dynamic switching frequency adjustment based on motor operating conditions. The controller varies the switching frequency within a range (e.g., 4-8 kHz) depending on motor speed and load, transitioning between low frequency for electromagnetic performance and high frequency for noise reduction, rather than using a fixed frequency throughout all operating conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the switching frequency parameter dynamically according to motor operating conditions. The controller adjusts the switching frequency based on motor speed and load conditions, optimizing the balance between electromagnetic noise suppression and inverter noise reduction across different operating ranges

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If one fixed switching frequency is used over the entire operation area, then device complexity is reduced, but switching loss and electromagnetic performance degradation occur

Engineering Contradiction:

Improvecontrol system complexityVSAvoidswitching loss

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent implements dynamic switching frequency adjustment based on motor operating conditions. The controller varies the switching frequency within a range (e.g., 4-8 kHz) depending on motor speed and load, transitioning between low frequency for electromagnetic performance and high frequency for noise reduction, rather than using a fixed frequency throughout all operating conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the switching frequency parameter dynamically according to motor operating conditions. The controller adjusts the switching frequency based on motor speed and load conditions, optimizing the balance between electromagnetic noise suppression and inverter noise reduction across different operating ranges

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9007013B2Inverter control method and system for eco-friendly vehicle

Publication Date: 2015.04.14 HYUNDAI MOTOR CO LTD

AI summary

Disclosed is an inverter control system and method for an eco-friendly vehicle, by which overall improvements can be obtained in terms of switching loss, electromagnetic performance, noise-vibration-harshness (NVH) performance, control stability, and so forth, when compared to a conventional case in which one fixed switching frequency and one fixed sampling frequency are used over the entire operation area. To this end, the inverter control method for an eco-friendly vehicle which generates a pulse width modulation (PWM) signal according to a switching frequency and a sampling frequency and controls ON/OFF driving of a switching element, in which a controller changes and sets the switching frequency according to a current motor speed, changes and sets a sampling frequency according to the switching frequency, and controls on/off driving of a switching element according to the switching frequency corresponding to the motor speed and the sampling frequency.