Motor Control Unit for Electric Pump with Adaptive Current Command
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Solution Overview
Problem
Conventional electric pump units for automobile transmissions with idling stop functions face issues of excessive power consumption, heat, and noise due to the electric motor being driven based on a constant current command value, regardless of load conditions, which affects the accuracy of hydraulic pressure control and efficiency.
Innovation Solution
A motor control unit that includes an over-power suppression control unit, which adjusts the current command value based on the comparison between target and present hydraulic pressures, and considers load information to optimize power usage, thereby reducing unnecessary power consumption and noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the electric motor is driven based on a constant current command value regardless of load conditions, then the hydraulic pressure control is simplified, but power consumption increases excessively and heat and noise are generated
Solution Approach 1:
The patent applies dynamics by making the current command value adjustable based on operating conditions. The control unit changes the current command value according to pump rotation speed and hydraulic pressure conditions, transforming the static constant current control into a dynamic adaptive control system that optimizes power consumption while maintaining hydraulic pressure control functionality
Solution Approach 2:
The patent implements parameter changes by modifying the current command value parameter based on detected operating conditions. When hydraulic pressure exceeds the target value or when the pump operates at high rotation speed, the system reduces the current command value parameter, thereby decreasing power consumption and eliminating over-power conditions without compromising hydraulic pressure control capability
2Use of energy by moving object
If the current command value is reduced to suppress over power, then power consumption and heat generation are minimized, but hydraulic pressure supply may become insufficient under high load conditions
Solution Approach 1:
The patent implements feedback control by continuously monitoring hydraulic pressure conditions and pump rotation speed, then using this information to adjust the current command value. The control unit receives feedback about actual hydraulic pressure levels and rotation speed, and automatically modifies the current command to maintain reliable hydraulic pressure supply while optimizing power consumption, preventing both over-power and under-power conditions
Solution Approach 2:
The system dynamically adjusts the current command value based on real-time operating conditions. When load conditions indicate high hydraulic pressure demand, the system increases the current command value to ensure sufficient power supply, while under light load conditions it reduces the current command to minimize power consumption, thereby maintaining reliability across varying operational scenarios
3Reliability
If the auxiliary pump is driven continuously to ensure hydraulic pressure supply during engine stop, then hydraulic pressure availability is maintained, but unnecessary power consumption occurs when hydraulic pressure is already sufficient
Solution Approach 1:
The system implements self-service control where the control unit autonomously monitors hydraulic pressure levels and automatically adjusts pump operation accordingly. When hydraulic pressure from the main pump is sufficient, the control unit stops or reduces auxiliary pump operation without external intervention, eliminating unnecessary power consumption while ensuring hydraulic pressure availability is maintained when needed
Solution Approach 2:
The control system uses feedback from hydraulic pressure sensors to determine when auxiliary pump operation is necessary. By continuously monitoring hydraulic pressure levels in the system, the control unit receives feedback that triggers appropriate pump operation only when hydraulic pressure falls below target levels, preventing unnecessary power consumption during periods when hydraulic pressure is already sufficient
Data Source
AI summary
A control signal output unit obtains a motor control signal by applying a reduction amount for a current command value obtained by an over-power suppression control unit to a current command value from a host control unit. The over-power suppression control unit includes a hydraulic pressure estimation unit that estimates hydraulic pressure, and a current command value correction amount calculation unit that compares a target hydraulic pressure with an estimated hydraulic pressure and outputs the reduction amount for the current command value. Load information indicating whether a load on the pump is a low load or a high load that is higher than the low load is input into a control circuit from the host control unit, and the over-power suppression control unit changes the target hydraulic pressure in accordance with a magnitude of the load indicated by the load information.