DC/DC Converter Stop Control via Motor Force Redistribution
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Solution Overview
Problem
Existing drive control systems for vehicles face challenges in reducing the loss of direct current/direct current converters while maintaining driving performance, particularly when the required driving force or regenerative braking force changes during the stop of the converter, leading to premature cancellation of the converter's stop state.
Innovation Solution
A drive control system that includes a direct-current power supply, a direct current/direct current converter, and two motors connected via inverters, with a controller executing intermittent step-up or step-down control to manage the converter's stop state by redistributing the driving force or regenerative braking force between the motors, allowing the second motor to output changes in required force when the difference exceeds predetermined values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the stop time of the direct current/direct current converter is extended to reduce loss, then energy loss is reduced, but driving performance decreases when the required driving force changes
Solution Approach 1:
The vehicle's driving force requirement is segmented between two independent motors. The first motor (connected via DC/DC converter) handles baseline driving force, while the second motor (connected directly to battery) handles additional driving force requirements during DC/DC converter stop periods. This segmentation allows the DC/DC converter to stop longer without compromising overall vehicle performance.
Solution Approach 2:
The second motor acts as an intermediary that compensates for the stopped DC/DC converter. When the DC/DC converter stops switching, the second motor provides the necessary additional driving force to maintain vehicle performance, effectively mediating between the converter's need to rest and the vehicle's need for power.
2Loss of energy
If the driving torque of the first motor is limited to extend converter stop time, then converter loss is reduced, but the driving performance decreases
Solution Approach 1:
The system merges the output of two motors to achieve the required vehicle driving force. The first motor provides baseline torque through the DC/DC converter, while the second motor provides additional torque directly from the battery. Their combined output meets the total driving force requirement, allowing the first motor to operate at limited torque during converter stop periods.
Solution Approach 2:
The second motor performs excessive action by providing not just its own driving force but also compensating for the limited output of the first motor. This partial action from the second motor ensures that the total driving force requirement is met even when the first motor's torque is restricted to extend converter stop time.
3Loss of energy
If the stop time of the direct current/direct current converter is extended, then converter loss is reduced, but voltage deviation increases when driving force changes
Solution Approach 1:
The second motor performs preliminary action by being ready to immediately compensate for driving force changes during DC/DC converter stop periods. This pre-positioned capability prevents voltage deviations by ensuring that any increase in required driving force is quickly met by the second motor, maintaining system stability throughout the extended converter stop time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach extends the stop time of the direct current/direct current converter, reducing energy loss and maintaining driving performance by suppressing rapid changes in driving force or regenerative braking force, thus achieving both reduced loss and sustained performance.
Implementation Method 1
The direct current/direct current converter is configured to transform a voltage of the direct-current power supply
Data Source
AI summary
A drive control system includes a battery, a direct current/direct current converter, a first motor, a second motor, and a controller. The battery is a direct-current power supply. The direct current/direct current converter is connected to the battery. The first motor is connected to the direct current/direct current converter, and drives one of a front wheel and a rear wheel. The second motor is connected to the battery, and drives the other one of the front wheel and the rear wheel, which is different from the wheel that the first motor drives. The controller controls step-up operation of the direct current/direct current converter, and executes intermittent step-up control. When a required driving force of a vehicle changes during a stop of the direct current/direct current converter through the intermittent step-up control, the second motor outputs an amount of change in the required driving force.