Motor Coil Cooperative Heating Control for Low-Temperature EV Charging
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Solution Overview
Problem
Existing methods for heating lithium-ion batteries in electric vehicles at low temperatures are inefficient, leading to increased costs and the inability of charging, discharging, heating, and torque output processes to cooperate effectively, resulting in prolonged charging times and reduced battery performance.
Innovation Solution
A cooperative control method and apparatus using a reversible PWM rectifier and motor coil to manage heating power, driving power, and charging/discharging power, adjusting currents and duty cycles to optimize heating and charging processes, allowing the battery to be heated through the motor coil's cooling liquid, thereby reducing the need for additional heating apparatus and enhancing process coordination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a PTC heater or heating wire heater is used to heat the battery at low temperature, then the battery can be heated to a predetermined temperature, but the charging time is prolonged and additional heating apparatus increases costs
Solution Approach 1:
The patent combines the heating function with the motor coil, which already exists in the vehicle. The motor coil serves dual purposes: motor operation and battery heating. By controlling the current flow through the motor coil during charging, it generates heat that warms the battery, eliminating the need for separate heating devices and reducing charging time.
Solution Approach 2:
The motor coil is designed to perform multiple functions: it acts as both the motor winding for driving the vehicle and as a heating element for warming the battery at low temperatures. This multi-functionality reduces the number of components needed and eliminates the time loss associated with separate heating processes.
2Temperature
If a PTC heater is used for heating the battery at low temperature, then the battery temperature can be raised, but the heating device cannot implement heating while charging simultaneously
Solution Approach 1:
The heating function is merged with the charging process by using the motor coil as the heating element. During charging, current flows through the motor coil, generating heat that simultaneously warms the battery and occurs during the charging process, enabling heating and charging to happen concurrently rather than sequentially.
Solution Approach 2:
The motor coil continues to perform its heating function throughout the entire charging process. By controlling the current flow through the motor coil during charging, the system maintains continuous heating action alongside the charging operation, ensuring the battery reaches optimal temperature without interrupting the charging process.
3Temperature
If separate heating apparatus is used to heat the battery at low temperature, then the battery can be warmed up, but costs increase due to additional components
Solution Approach 1:
The motor coil is designed to perform multiple functions: it acts as both the motor winding for driving the vehicle and as a heating element for warming the battery at low temperatures. This multi-functionality reduces the number of components needed and eliminates the need for separate heating devices, thereby reducing system complexity and cost.
Solution Approach 2:
The motor coil serves itself by generating heat through its own resistance when current flows through it during charging or motor operation. This self-heating capability eliminates the need for external heating apparatus, reducing system complexity and cost while maintaining the ability to warm the battery when needed.
4Temperature
If heating is performed separately from charging and torque output processes, then the battery can be heated, but the charging, discharging, heating, and torque output processes cannot cooperate effectively
Solution Approach 1:
The patent merges the heating process with the charging and torque output processes by using the motor coil as the heating element. The control system coordinates current flow to simultaneously achieve heating, charging, and torque output when needed, allowing all three processes to cooperate rather than operate separately. This is achieved through coordinated control of the inverter and charging system.
Solution Approach 2:
The system dynamically adjusts the function of the motor coil based on real-time requirements. The control system can switch the motor coil between motor operation mode and heating mode, or operate in both modes simultaneously with coordinated control. This dynamic adaptability allows the charging, heating, and torque output processes to cooperate effectively based on the vehicle's instantaneous needs.
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 reduces costs by eliminating the need for additional heating apparatus, ensures efficient charging and discharging at low temperatures, and achieves cooperative working of charging, heating, and torque output processes, improving overall battery performance and efficiency.
Implementation Method 1
acquiring a first heating power of the motor coil according to the target charging and discharging current
Implementation Method 2
acquiring a second heating power of the motor coil according to the first quadrature axis current and the first direct axis current
Data Source
AI summary
A cooperative control method is disclosed. The cooperative control method includes: acquiring a target heating power, a target driving power, and a target charging and discharging power; acquiring a first heating power of a motor coil according to the target charging and discharging power; acquiring a second heating power of the motor coil according to the target driving power; adjusting a first quadrature axis current and a first direct axis current to a target quadrature axis current and a target direct axis current to cause the difference between the sum of the first heating power and the second heating power and the target heating power to be within the preset range; and acquiring a sampling current value on each phase coil and a motor rotor position, and calculating a duty cycle of each phase bridge arm in a reversible PWM rectifier according to the above information.