Electric Drive Battery Heating Using Motor Windings
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Solution Overview
Problem
Conventional electric vehicle battery heating systems require additional heating apparatuses, increasing cost and space, and suffer from inefficiencies such as uneven heating and low heating efficiency.
Innovation Solution
An electric drive system utilizing an inverter circuit and direct current-direct current conversion circuit to generate heat from the electric excitation synchronous motor windings and excitation winding, without adding extra heating apparatus, adjusting heating power through three-phase currents and excitation currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a PTC resistor heating apparatus is added to heat the power battery pack, then the battery can be heated in low-temperature environments, but the device complexity and cost increase
Solution Approach 1:
The motor windings are designed to serve dual functions: driving the motor during normal operation and generating heat during low-temperature conditions. The excitation winding and three-phase windings can independently or simultaneously provide heating, eliminating the need for separate heating apparatus while maintaining temperature control capability
Solution Approach 2:
The electric drive system uses its own internal components (motor windings and excitation winding) to generate heat for the power battery pack, rather than relying on external heating devices. The system's electrical energy is converted to thermal energy through resistive heating of the windings, enabling self-heating functionality
2Temperature
If a PTC resistor heating apparatus is added to heat the power battery pack, then the battery can be heated in low-temperature environments, but the cost increases
Solution Approach 1:
The motor windings are designed to serve dual functions: driving the motor during normal operation and generating heat during low-temperature conditions. The excitation winding and three-phase windings can independently or simultaneously provide heating, eliminating the need for separate heating apparatus while maintaining temperature control capability
Solution Approach 2:
The heating function is merged with the motor drive system by utilizing the existing motor windings and excitation winding for both propulsion and heating purposes. This consolidation eliminates the need for separate heating components, reducing overall system cost
3Temperature
If conventional heating apparatus is used, then heating function is provided, but space is occupied and heating efficiency is low
Solution Approach 1:
The electric drive system uses its own internal components (motor windings and excitation winding) to generate heat for the power battery pack, rather than relying on external heating devices. The system's electrical energy is converted to thermal energy through resistive heating of the windings, enabling self-heating functionality
Solution Approach 2:
The control module adjusts the heating efficiency by changing electrical parameters: controlling the duty cycle of PWM signals to the excitation winding, and adjusting the amplitude and frequency of three-phase currents to the motor windings. This enables dynamic optimization of heating power based on temperature requirements
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
Reduces costs and saves space by utilizing existing motor components for heating, improving heating efficiency and electrochemical performance of the power battery pack.
Implementation Method 1
An input end of the inverter circuit is connected to the input end of the electric drive system, and an output end of the inverter circuit is connected to three-phase windings of the electric excitation synchronous motor. The inverter circuit converts a direct current provided by the power battery back into an alternating current and provides the alternating current for the three-phase windings
Implementation Method 2
An input end of the direct current-direct current conversion circuit is connected to the input end of the electric drive system, and an output end of the direct current-direct current conversion circuit is connected to an excitation winding of the electric excitation synchronous motor. The direct current-direct current conversion circuit performs direct current conversion on the direct current provided by the power battery pack and provides the direct current for the excitation winding
Implementation Method 3
An output end of the direct current-direct current conversion circuit is connected to an excitation winding of the electric excitation synchronous motor. The direct current-direct current conversion circuit performs direct current conversion on the direct current provided by the power battery pack and provides the direct current for the excitation winding. The controller is configured to control the inverter circuit and the direct current-direct current conversion circuit, to adjust the three-phase currents output by the inverter circuit and adjust the excitation current output by the direct current-direct current conversion circuit, to enable a temperature of the power battery pack to be greater than or equal to a first temperature threshold
Data Source
Figure 1~2
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AI summary
This application relates to the field of electric vehicle technologies, and discloses an electric drive system, a powertrain, a heating method, and an electric vehicle. The electric drive system includes an inverter circuit, a direct current-direct current conversion circuit, and a controller. An input end of the inverter circuit is connected to an input end of the electric drive system, and an output end of the inverter circuit is connected to three-phase motor windings of an electric excitation synchronous motor. An input end of the direct current-direct current conversion circuit is connected to the input end of the electric drive system, and an output end of the direct current-direct current conversion circuit is connected to an excitation winding of the electric excitation synchronous motor. The inverter circuit converts a direct current into three-phase currents and provides the three-phase currents for the three-phase motor windings. The direct current-direct current conversion circuit performs direct current conversion on the direct current and provides the direct current for the excitation winding. The controller is configured to control the inverter circuit and the direct current-direct current conversion circuit, so that a temperature of a power battery pack is greater than or equal to a first temperature threshold. In this solution, a heating apparatus does not need to be disposed when the power battery pack is heated, thereby reducing costs and saving space.