Electric vehicle, and control system and electric heating device thereof
Solution Overview
Problem
Conventional thin film resistance heaters in electric vehicles face challenges in maintaining stable operation, particularly during cold starts or slow charging, due to current inrush and surge, which can shock the electrical system and affect the power battery pack, leading to unstable operation.
Innovation Solution
The electric heating device incorporates multiple resistance heating units connected in parallel with independent switches and a controller that selectively turns on or off these switches based on vehicle conditions, allowing for various working modes to manage current and power, including single-resistance, full-resistance, and combined-resistance heating modes, without relying on PWM control for all conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a thin film resistance heater is used for heating, then heating efficiency is improved, but current inrush and surge occur causing electrical system instability
Solution Approach 1:
The heating system is divided into multiple independent heating elements (first heating element and second heating element) that can be controlled separately. This segmentation allows the system to distribute the total heating power across multiple elements, reducing the current inrush and surge when heating is activated, while maintaining the required heating efficiency.
Solution Approach 2:
The system dynamically adjusts the working state of individual heating elements based on real-time detection of heating tube temperature and ambient temperature. The controller selectively activates or deactivates specific heating elements according to temperature conditions, enabling adaptive current management that prevents electrical system instability while maintaining optimal heating performance.
2Reliability
If multiple heating elements are used to prevent current surge, then electrical system stability is improved, but device complexity increases
Solution Approach 1:
The heating elements are designed with multi-functionality, serving both as heating sources and as temperature sensors through their self-heating effect. The same heating tubes (first and second heating elements) are used to generate heat and simultaneously detect temperature conditions, eliminating the need for separate sensing components and reducing overall system complexity.
Solution Approach 2:
The heating elements perform self-detection of their own temperature state through their inherent thermal properties. The system utilizes the temperature characteristics of the heating tubes themselves to determine when to activate or deactivate specific elements, rather than requiring external sensors, thereby simplifying the system architecture.
3Power
If PTC heater is used for heating, then heating function is achieved, but power control accuracy deteriorates due to temperature-dependent impedance
Solution Approach 1:
The system changes the operating parameters of the heating elements by selectively activating different elements (first or second heating element) based on temperature conditions. This parameter change approach allows the system to maintain accurate power control by choosing appropriate heating elements whose characteristics match the current temperature regime, avoiding the impedance variability issues of PTC heaters.
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 ensures stable and reliable operation of the electric heating device across various conditions by adjusting resistance values and power distribution, preventing system instability and enabling efficient temperature control without causing electrical shocks or overcurrent issues.
Implementation Method 1
electric energy is converted into heat energy by a heating element in the electric heating device
Data Source
AI summary
The present application discloses an electric vehicle, and an electric heating device and a control system thereof. The electric heating device includes: n resistance heating units, independently electrically connected in parallel with each other; n switches, electrically connected in series with respective resistance heating units for independently controlling power-on or power-off of the respective resistance heating units; and a controller, configured to selectively turn on or turn off any at least one of the n switches according to a working condition of the electric vehicle, wherein n is a natural number equal to or greater than 2.