Brushed DC Compressor Motor Current Control
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Solution Overview
Problem
Compressor units for vehicle compressed air supply systems face challenges with high power drain during startup and shutdown, as well as load-dependent rotational speed changes, leading to inefficient operation and acoustic anomalies.
Innovation Solution
An electronic control module is used to manage the operating current of a brushed DC electric motor, implementing soft start and shutdown modes through chronologically variable threshold current limitation, PWM actuation, and rotational speed regulation, minimizing peak currents and gradients, and compensating for pressure-dependent rotational speed variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a compressor unit is actuated by a compressor unit relay and driven by a DC brushed motor, then the motor can be controlled for reversing current, but the power drain is high during switching on and shutting down
Solution Approach 1:
The patent replaces the mechanical relay-based switching system with an electronic control module that uses semiconductor switches (MOSFETs or IGBTs) to control the brushed DC motor. This electronic substitution eliminates the high inrush currents and power drains associated with mechanical relay switching, while maintaining reliable motor control through electronic protection circuits that monitor and limit current during switching operations.
2Reliability
If a brushed DC electric motor is used for high load requirements and reliability, then the motor can handle high loads, but the operating current needs to be limited for efficient operation
Solution Approach 1:
The control module continuously monitors the operating current of the brushed DC motor and implements feedback control to limit the current to optimal levels. The system adjusts the duty cycle of PWM signals and controls the firing angle of semiconductor switches based on real-time current measurements, ensuring the motor operates at peak efficiency while maintaining the reliability benefits of brushed motor construction for high-load automotive applications.
3Ease of operation
If soft start is implemented using thyristors and timer elements, then the motor can start smoothly, but the control circuit becomes costly and complex
Solution Approach 1:
The control module is designed as a multi-functional integrated circuit that combines soft start capability, current limiting, shutdown control, and rotational speed regulation in a single device. By using a microcontroller-based system with integrated PWM generators and protection circuits, the patent eliminates the need for separate thyristor-based soft start circuits and timer elements, reducing both cost and complexity while maintaining all necessary motor control functions.
4Adaptability or versatility
If the compressor operates under different load conditions, then the compressor can adapt to varying demands, but the rotational speed changes lead to acoustic anomalies
Solution Approach 1:
The control module dynamically adjusts the operating parameters of the brushed DC motor based on real-time load conditions, using PWM technology to vary the effective voltage and control rotational speed. The system incorporates acoustic noise compensation algorithms that detect and counteract noise-generating speed variations, maintaining optimal rotational speed ranges even under varying load conditions, thereby reducing acoustic anomalies while preserving load adaptability.
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 approach reduces power consumption, minimizes acoustic noise, and ensures stable compressor operation by precisely controlling the operating current and rotational speed, enhancing the reliability and efficiency of the compressor unit.
Implementation Method 1
The semiconductor switch, and therefore the electric motor, are actuated by a control device with a pulse width-modulated voltage. The rotational speed of the electric motor can be controlled by means of the pulse/pause ratio of this voltage.
Implementation Method 2
An electronic control module is used to manage the operating current of a brushed DC electric motor, implementing soft start and shutdown modes through chronologically variable threshold current limitation
Implementation Method 3
rotational speed regulation, minimizing peak currents and gradients, and compensating for pressure-dependent rotational speed variability
Data Source
AI summary
A compressor for producing compressed air, in particular for a compressed air supply system of a vehicle, includes an electric motor in the form of a brushed direct current electric motor. The compressor has at least one first and one second compressor step, which can be driven by the electric motor. The motor can be controlled by means of an electronic control module of a control device by limiting an operational flow of the motor.