Electric Vehicle Drive System Voltage Boosting for High-Speed Efficiency
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Solution Overview
Problem
Existing electric vehicle drive systems face efficiency issues due to reduced power factor and output power when field weakening control is used to maintain high rotation speeds, leading to a limited speed adjustment range and reduced driving efficiency.
Innovation Solution
The electric vehicle drive system incorporates a filtering module, first and second conversion modules, and a controller to boost the voltage of a capacitor, allowing the motor to operate without field weakening control, thereby increasing output power and efficiency by providing sufficient voltage for high-speed operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If field weakening control is used to maintain high rotation speeds, then the motor can operate at high speeds, but the power factor is reduced and output power decreases
Solution Approach 1:
The patent changes the voltage parameter by introducing a boost circuit that increases the DC bus voltage. This allows the motor to operate at high speeds without requiring field weakening control, thereby maintaining both high speed and high output power simultaneously. The voltage parameter adjustment enables the motor to stay in the constant torque region longer into the high-speed range.
2Speed
If field weakening control is used to maintain high rotation speeds, then the motor can operate at high speeds, but driving efficiency is reduced
Solution Approach 1:
The patent applies parameter changes by boosting the DC bus voltage through the boost circuit. This eliminates the need for field weakening control at high speeds, preventing the associated energy losses and maintaining high driving efficiency across a wider speed range.
3Device complexity
If the drive system uses conventional configuration without voltage boosting, then the structure is simpler, but the speed adjustment range is limited
Solution Approach 1:
The patent integrates a boost circuit into the drive system that serves multiple functions: it boosts the DC bus voltage to extend the speed range, and can operate in different modes (boosting mode and non-boosting mode) to adapt to different operating conditions. This multi-functional design extends the speed adjustment range while managing system complexity.
4Adaptability or versatility
If the drive system incorporates voltage boosting capability, then the speed adjustment range is expanded, but the device complexity increases
Solution Approach 1:
The patent merges the boost circuit with the existing inverter structure, sharing common components such as switching devices and control circuits. This integration approach minimizes the additional complexity introduced by the voltage boosting capability while achieving the extended speed adjustment range.
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 expands the speed adjustment range of electric vehicles, enhances driving efficiency, and maintains high power output at high speeds without the need for field weakening control.
Implementation Method 1
the filtering module and the first conversion module form a boost circuit to boost the voltage of a capacitor
Implementation Method 2
the second conversion module converts the direct current into alternating current to transfer the alternating current to the motor
Implementation Method 3
the motor outputs torque to drive the electric vehicle to travel
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
This application discloses an electric vehicle drive system and an electric vehicle driving method, and belongs to the field of electric vehicle technologies. The drive system includes a power battery, a drive, a motor, a detection module, a torque reference module, and a controller, and the drive includes a filtering module, a first conversion module, a first capacitor, and a second conversion module. A positive electrode of the power battery is connected to an input end of the filtering module, and a first output end of the filtering module is connected to an alternating current end of the first conversion module. One end of the first capacitor is separately connected to direct current input ends of the first conversion module and the second conversion module, and the other end of the first capacitor is separately connected to direct current output ends of the first conversion module and the second conversion module and a negative electrode of the power battery. An alternating current end of the second conversion module is connected to the motor. In this application, a bus voltage is boosted, so as to expand a speed adjustment range of an electric vehicle. In this way, output power of the system is increased and driving efficiency is increased without requiring field weakening control.