Dynamo-Electric Machine Control System with Dynamic Battery Power Limiting
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Solution Overview
Problem
Existing dynamo-electric machine control systems in hybrid vehicles face issues where a fixed limit power leads to excessive battery current when battery voltage decreases, potentially damaging the battery and switching devices, especially in low-temperature environments or due to battery deterioration.
Innovation Solution
A dynamo-electric machine control system that dynamically adjusts the limit power based on battery voltage, incorporating a battery power deriving unit, a limit power determining unit, and a torque limiting unit to prevent excessive current, using both a first and second limit power setting to account for varying battery conditions and control delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed limit power is set in the dynamo-electric machine control system, then the battery power can be limited to or below the predetermined limit power, but when the battery voltage decreases (e.g., in low-temperature environments or due to battery deterioration), an excessive current is drawn from the battery to secure a battery power of a fixed magnitude, which cannot protect the battery or switching devices appropriately
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a fixed limit power value to a dynamically adjustable limit power that varies according to battery voltage conditions. The control unit calculates limit power based on real-time battery voltage measurements, allowing the system to adapt its power limiting behavior to changing battery conditions such as low-temperature environments or battery deterioration, thereby preventing excessive current draw while maintaining reliable operation across diverse operating conditions.
Solution Approach 2:
The patent implements parameter changes by modifying the limit power parameter based on battery voltage variations. Instead of using a constant limit power value, the system adjusts the limit power parameter dynamically according to the measured battery voltage, enabling the control system to respond to changes in battery characteristics and prevent harmful excessive currents while maintaining optimal performance across different battery states.
2Ease of manufacture
If the limit power is set to a fixed value to simplify control, then the control system is easier to implement, but it cannot appropriately protect the battery and switching devices when battery voltage decreases due to environmental factors or deterioration
Solution Approach 1:
The patent applies feedback by implementing a control mechanism that continuously monitors battery voltage and uses this information to adjust the limit power setting. The control unit receives feedback from voltage sensors and dynamically recalculates the appropriate limit power value, creating a closed-loop control system that automatically adapts to changing battery conditions without requiring complex manual configuration or multiple fixed thresholds.
Solution Approach 2:
The system transitions from a static control approach with fixed limit power to a dynamic control approach where limit power is continuously adjusted based on real-time battery voltage measurements. This dynamic adjustment mechanism maintains ease of implementation through automated calculation while significantly improving the reliability and protection capability across varying battery conditions.
Data Source
AI summary
A dynamo-electric machine control system including a dynamo-electric machine and an inverter that is interposed between a battery and the dynamo-electric machine and that controls a current flowing through the dynamo-electric machine, wherein a rotation speed and an output torque of the dynamo-electric machine are controlled by the inverter, the dynamo-electric machine control system includes a battery power deriving unit that derives a battery power to be supplied from the battery when the dynamo-electric machine is operated at the rotation speed and the output torque; a limit power determining unit that variably determines a limit power, which is a maximum allowable value of the battery power, in accordance with a battery voltage; and a torque limiting unit that limits the torque of the dynamo-electric machine such that the battery power derived by the battery power deriving unit does not exceed the limit power.