Motor Torque Control with Transition Period

Solution Overview

Problem

Motorized vehicles experience noise and vibration due to rapid torque changes between driven and non-driven states, caused by gear backlash, which affects efficiency and comfort during motor control in electrical vehicles.

Innovation Solution

An apparatus that intermittently operates the motor by alternating between driving and coasting periods, with a transition period using a third torque within a predetermined range, to manage torque changes and reduce noise and vibration, while optimizing system efficiency and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the motor is driven with the torque of highest efficiency by switching between positive and negative torque, then power consumption is reduced, but gear teeth collide causing noise and vibration

Engineering Contradiction:

Improvepower consumptionVSAvoidnoise and vibration

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The control device applies a preliminary action by setting a transition period before the motor torque switches from positive to negative (or zero). During this transition period, the motor torque is set to a value within a predetermined range that prevents gear tooth collision. This preliminary action eliminates the harmful collision effect before it can occur, while still allowing the motor to operate at high efficiency points for the majority of the cycle.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention introduces dynamics by making the motor torque adjustable during the transition period rather than immediately switching between extreme values. The torque is dynamically set to a intermediate value within a predetermined range, allowing smooth transition that prevents gear tooth collision while maintaining overall system efficiency.

Inventive Principle:

Principle #15Dynamics

2Use of energy by moving object

If the motor is intermittently driven with high efficiency torque, then power consumption is reduced, but rapid torque changes cause gear backlash collision

Engineering Contradiction:

Improvepower consumptionVSAvoidgear collision damage

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The control device applies a preliminary action by setting a transition period before the motor torque switches from positive to negative (or zero). During this transition period, the motor torque is set to a value within a predetermined range that prevents gear tooth collision. This preliminary action eliminates the harmful collision effect before it can occur, while still allowing the motor to operate at high efficiency points for the majority of the cycle.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention applies beforehand cushioning by introducing a transition period with intermediate torque values that cushion the abrupt change between positive and negative torque. This cushioning effect prevents the direct collision of gear teeth that would occur with immediate torque reversal, thereby protecting the gear system from damage while maintaining the intermittent high-efficiency operation pattern.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Productivity

If torque switches rapidly between driven and non-driven states, then motor efficiency is improved, but teeth collision causes noise and vibration

Engineering Contradiction:

Improvemotor efficiencyVSAvoidnoise and vibration

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The control device applies a preliminary action by setting a transition period before the motor torque switches from positive to negative (or zero). During this transition period, the motor torque is set to a value within a predetermined range that prevents gear tooth collision. This preliminary action eliminates the harmful collision effect before it can occur, while still allowing the motor to operate at high efficiency points for the majority of the cycle.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention applies periodic action by introducing a transition period as a regular part of the motor operation cycle. The motor torque follows a periodic pattern: positive torque during driving period, then intermediate torque during transition period, then negative or zero torque during coasting period. This periodic structure with built-in transition phases maintains motor efficiency while eliminating the harmful effects of abrupt torque switching.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS10680540B2Apparatus for controlling motorized vehicle

Publication Date: 2020.06.09 DENSO CORP

AI summary

In an apparatus for controlling a motorized vehicle, a rotary electric machine controller is configured to perform intermittent operation by periodically alternating between a driving period and a coasting period. A torque determiner is configured to determine a first torque during the driving period and a second torque during the coasting period. A transition period determiner is configured to determine whether to set a transition period between the driving period and the coasting period. If the transition period is determined to be set, the torque determiner determines a third torque between the first torque and the second torque and within a predetermined rang. The rotary electric machine controller sets the transition period between the driving period and the coasting period and drive the rotary electric machine with the third torque during the transition period.