AC Motor Control Apparatus for Electric Vehicle Voltage Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control apparatuses for electric vehicles face challenges in stabilizing voltage on the power supply line due to variations in the balance of power between AC motors, leading to potential damage to electronic equipment and increased costs with high-performance voltage converters and large capacitance smoothing capacitors, while also struggling to maintain a small size and low cost.
Innovation Solution
A control apparatus comprising a power conversion unit, a system voltage control unit, and a motor driving unit that adjusts input power to the AC motor by changing the direction of current or voltage based on rotation speed and torque, using reactive power to stabilize system voltage without affecting torque generation, thereby reducing voltage variations without the need for advanced converters or capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voltage boosting converter with better performance and a smoothing capacitor with a larger capacitance are used to stabilize voltage, then voltage stabilization is improved, but cost increases
Solution Approach 1:
The AC motor serves dual functions: both as a motor for driving wheels and as a generator for power restoration to the secondary battery. This self-service approach allows the system to stabilize voltage without requiring additional high-performance voltage boosting converters or large capacitance smoothing capacitors, thereby reducing cost while maintaining voltage stabilization
Solution Approach 2:
The AC motor is designed to perform multiple functions: it can serve as a motor for driving the vehicle wheels and simultaneously as a generator for restoring power to the secondary battery. This multi-functionality eliminates the need for separate dedicated components for voltage stabilization, reducing overall system cost
2Reliability
If a voltage boosting converter with better performance and a smoothing capacitor with a larger capacitance are used to stabilize voltage, then voltage stabilization is improved, but device size increases
Solution Approach 1:
The AC motor serves dual functions: both as a motor for driving wheels and as a generator for power restoration to the secondary battery. This self-service approach allows the system to stabilize voltage without requiring additional high-performance voltage boosting converters or large capacitance smoothing capacitors, thereby reducing device size while maintaining voltage stabilization
Solution Approach 2:
The AC motor is designed to perform multiple functions: it can serve as a motor for driving the vehicle wheels and simultaneously as a generator for restoring power to the secondary battery. This multi-functionality eliminates the need for separate dedicated components for voltage stabilization, reducing overall system size
3Reliability
If the inverter is controlled to make the sum of energies of the two AC motors equal to 0, then voltage stabilization is improved, but control complexity increases
Solution Approach 1:
The control apparatus continuously monitors the operating state of the AC motors and adjusts the inverter control accordingly. By using feedback from the actual power balance between motors, the system dynamically adjusts control parameters to maintain voltage stability without requiring overly complex predetermined control strategies
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 solution effectively stabilizes system voltage while meeting the requirements of a small size and low cost, suppressing voltage variations and maintaining torque stability, even under changing operating conditions, without the need for high-performance converters or large capacitors.
Implementation Method 1
a voltage boosting converter for raising a voltage generated by a DC power supply
Implementation Method 2
inverters are capable of serving as a component for converting the raised DC voltage appearing on the power supply line into an AC voltage for driving one of the AC motors
Implementation Method 3
a smoothing capacitor connected to the power supply line smoothes the voltage appearing on the power supply line
Data Source
AI summary
A control apparatus for a vehicle controls the input power of an AC motor to reduce the difference between a target value and detected value of the system voltage. When a rotation speed of the AC motor increases to be higher than a predetermined value or when a command value of a torque generated by the AC motor increases to be greater than a predetermined value, a current vector is adjusted to a value on a lagging side in order to control the input power of the AC motor. Thus, an input power operation quantity required for stabilizing the system voltage can be realized with a high degree of reliability. When the rotation speed and the command value decrease, the current vector is adjusted to a value on a leading side in order to control the input power of the AC motor.