Hybrid Vehicle Motor Control via Delay Compensation
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Solution Overview
Problem
In hybrid vehicles with separate control units for each electric motor, cooperative control of multiple electric motors faces challenges in maintaining electric power balance due to communication delays, leading to potential loss of synchronization and inadequate power balance control.
Innovation Solution
A control apparatus for hybrid vehicles includes separate control units for each electric motor, a communication path, an estimation unit that corrects for communication delay, and an electric power balance control unit that restricts total electric power within a predetermined range by estimating input/output electric power and adjusting torque to ensure accurate balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If control apparatuses are provided separately and independently for respective electric motors, then the processing load on each control apparatus is reduced and cost is decreased, but synchronization between electric motors is lost due to communication delay
Solution Approach 1:
The invention applies preliminary action by having the first control unit transmit data about the first electric motor in advance before the second control unit needs it for power balance control. The transmission timing is set to be before the usage timing at the second control unit, effectively compensating for communication delay and maintaining synchronization without requiring a centralized control apparatus.
2Productivity
If one control apparatus manages electric power balance for multiple electric motors, then electric power balance control speed is improved, but communication delay causes data recognition to be delayed
Solution Approach 1:
The first control unit transmits data about the first electric motor in advance before the second control unit needs it for power balance control. The transmission timing is set to be before the usage timing, effectively compensating for communication delay and ensuring that the second control unit receives up-to-date information without waiting for delayed communications.
Solution Approach 2:
The invention segments the control functions by having the first control unit responsible for transmitting data about the first electric motor and the second control unit responsible for managing power balance control. This segmentation allows each control unit to operate independently with optimized processing loads while maintaining coordination through timely data transmission.
3Productivity
If a single high-performance ECU is used to control both electric motors, then processing capability is improved, but cost and processing load concentration increase
Solution Approach 1:
The control system is segmented into two independent control units, each controlling one electric motor. The first control unit handles data transmission about the first motor, while the second control unit handles power balance control. This segmentation distributes processing capability across multiple lower-cost units rather than concentrating it in a single high-performance ECU.
Solution Approach 2:
The second control unit performs multiple functions: it controls the second electric motor and simultaneously manages the power balance control for both electric motors. This multi-functionality eliminates the need for a separate centralized control apparatus, reducing overall system complexity and cost while maintaining processing capability.
Data Source
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AI summary
An MG1-ECU (610) and an MG2-ECU (620) are provided independently for respective motor generators (MG1, MG2). The MG2-ECU (620) performs electric power balance control by correcting an MG2 torque command value as required, so that the sum of the MG1 electric power and the MG2 electric power is within a range of allowable input/output electric power (Win to Wout) of a DC power supply (510). The electric power balance control is performed using an estimate of the MG1 electric power based on data obtained by the MG1-ECU (610). The estimate is determined so that a communication delay time between the MG1-ECU (610) and the MG2-ECU (620) is corrected. In this way, the electric power balance control can be performed appropriately for restricting, within a predetermined range, the total input/output electric power of the electric motors as a whole of a hybrid vehicle mounted with a plurality of motor generators (electric motors).