Heater Controller Circuit for Fail-Safe Heating Element Cutoff
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Solution Overview
Problem
Conventional heater controllers in electric and hybrid vehicles face challenges in securely disconnecting heating elements from the power supply, particularly when the main switch is damaged, leading to continuous current flow and rapid battery discharge due to the high voltage and power electronic components' limitations.
Innovation Solution
A heater controller design with a control unit positioned between the heating element and the output contact, incorporating a serial connection of a switching element and a current sensor, allows for secure switching-off of the heating element by detecting current anomalies and generating control signals to disconnect the power supply, even in case of a short-circuit, using low-voltage components for enhanced reliability and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first switching element is positioned on the high voltage side to control current before it enters the heating element, then the current flow can be disconnected at an early stage in case of defect, but a short-circuit in the switching element can cause complete damage and continuous current flow through the heating element
Solution Approach 1:
A second switching element is introduced as an intermediary safety device positioned between the heating element and the output contact. This second switching element acts as a backup mechanism that can disconnect current flow if the first switching element fails, preventing continuous current flow and battery discharge while maintaining the benefits of high-side switching for early fault detection
Solution Approach 2:
The control unit is configured to detect current flow anomalies beforehand and activate the second switching element as a preventive measure. By monitoring the current through the heating element and detecting when current flows during unintended off-states, the system can preemptively disconnect the circuit before complete damage occurs, cushioning against the harmful effects of switching element failure
2Ease of operation
If power electronic components are used to switch high voltage power from the battery, then adequate switching control is achieved, but the components are vulnerable to failure and cause continuous current drain
Solution Approach 1:
The patent applies different qualities to different parts of the switching system. The first switching element handles high voltage power switching with full control capabilities, while the second switching element is optimized for safety functions with simpler control logic. This local differentiation allows each component to be optimized for its specific function, improving overall system reliability while maintaining ease of operation for the primary switching element
3Reliability
If the control unit is positioned on the low voltage side with a serial connection of switching element and current sensor, then secure switching-off is achieved with enhanced reliability, but the device complexity increases
Solution Approach 1:
The control unit merges multiple functions into a single integrated device: current sensing, anomaly detection, and control of the second switching element. By combining these functions in one unit rather than separating them into distinct components, the patent achieves secure switching-off capability while minimizing the increase in device complexity. The current sensor and control logic are integrated to work together as a unified safety mechanism
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 design ensures a more secure and reliable disconnection of heating elements, preventing unintentional battery discharge and allowing for cost-effective, precise control, with reduced risk of damage to low-voltage switching elements, enabling continued operation after repairing the main switch and minimizing energy waste.
Implementation Method 1
a current sensor, the serial connection comprising the current sensor and the second switching element, the current sensor being configured for detecting a current flow through the heating element and for providing a current signal representing the current through the current sensor
Implementation Method 2
a heating element which is configured for heating at least a portion of air for conditioning the passenger cabin
Data Source
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AI summary
The present invention provides a heater controller (100) for supervising a heating element (155) the heater controller (100) having a power connection port (105, 110) for connecting the heater controller (100) with a power source, the power connection port (105, 110) having an input contact (105) and an output contact (110). Furthermore, the heater controller (100) has a heating element connection port (130, 135) for connecting the heater controller (100) with at least one heating element (155), the heating element connection port (130, 135) having a first (130) and a second (135) connection contact. Additionally the heater controller comprises a first switching element (125) being connected between the input contact (105) and the first contact (130) of the heating element connection port, the first switching element (125) being configured for switching power signals having a voltage of at least 100 V. Furthermore the heater controller (100) has a serial connection (140), comprising a second switching element (145) and a current sensor (150), the serial connection (140) being connected between the second contact (135) of the heating element connection port and the output contact (110), the current sensor (150) being configured for providing a current signal representing a current through the current sensor (150). The heater controller (100) comprises furthermore a control element (160) being connected to the first (125) and second (145) switching element as well as the to the current sensor (150), the control element (160) being configured for providing a first control signal to the first switching element (125) to switch first switching element (125) in an on-state or in an off-state, wherein the control element (160) being furthermore configured for receiving the current signal from the current sensor (150) and for providing a second control signal to the second switching element (145) to disconnect an electrical connection between the second connection contact (135) and the output contact (110) in the case the current signal indicates a current through the current sensor (150) while the first switching element (125) is controlled to be in the off-state.