Mechanical Switch Braking Resistor for Drive System
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Solution Overview
Problem
Existing converter arrangements for electric drives lack simplicity and reliability in braking operations, particularly for regenerative consumers, as they require complex semiconductor switches and are prone to high failure rates due to temperature sensitivity and radiation exposure, leading to increased costs and safety concerns, especially in high-altitude applications.
Innovation Solution
The use of a mechanical switch, such as a circuit breaker or vacuum contactor, to connect the braking resistor to the intermediate circuit, eliminating the need for semiconductor switches and their complex control units, thereby simplifying the converter arrangement and enhancing reliability by reducing sensitivity to temperature and radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If semiconductor switches are used to connect the braking resistor to the intermediate circuit, then the converter arrangement can control braking energy conversion, but the system becomes complex and prone to failure due to temperature sensitivity and radiation exposure
Solution Approach 1:
The patent replaces semiconductor switches with a mechanical circuit breaker to connect the braking resistor to the intermediate circuit. This substitution eliminates the temperature sensitivity and radiation exposure issues inherent in semiconductor devices, significantly improving reliability in harsh environments while reducing control system complexity
Solution Approach 2:
The mechanical circuit breaker is designed as a simple, robust component that can be replaced if needed, eliminating the need for complex monitoring and control systems required for semiconductor switches. This approach trades the longevity of semiconductor devices for simplicity and reliability in critical braking functions
2Ease of manufacture
If semiconductor switches with complex control units are used, then precise control of braking energy is achieved, but costs increase due to monitoring and control requirements
Solution Approach 1:
The mechanical circuit breaker replaces the automated semiconductor switch control system, eliminating the need for complex control units, temperature monitors, and radiation shielding. This substitution significantly reduces manufacturing costs while maintaining adequate braking control through simple mechanical operation
Solution Approach 2:
The mechanical circuit breaker operates autonomously through thermal-magnetic tripping mechanisms that automatically open the circuit when excessive current or temperature conditions occur, eliminating the need for external control systems and monitoring devices
3Reliability
If semiconductor switches are used in high-altitude applications, then the converter arrangement can function, but failure rates increase due to radiation exposure and temperature extremes
Solution Approach 1:
The mechanical circuit breaker is inherently resistant to radiation and temperature extremes that plague semiconductor devices at high altitudes. This substitution eliminates the need for expensive radiation-hardened components and thermal management systems, improving reliability in aerial and high-altitude applications
Solution Approach 2:
The mechanical circuit breaker creates a physically robust switching mechanism that operates independently of atmospheric conditions, radiation levels, and temperature variations, effectively creating an 'inert' operating environment immune to the harmful factors present in high-altitude applications
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 simplifies the converter arrangement, reduces costs associated with semiconductor switches and their monitoring, and increases the availability of the brake system, ensuring safe and reliable braking operations, especially in high-altitude and high-load applications where semiconductor switches are prone to failure.
Implementation Method 1
the braking resistor being electrically connectable to the intermediate circuit by means of a mechanical switch for converting kinetic energy present on the electrical machine into heat
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a power converter arrangement (1) comprising a grid-side power converter (2), a load-side power converter (3), an intermediate circuit (4), and a braking resistor (5), wherein the grid-side power converter (2) and the load-side power converter (3) are connected to each other on the DC side via the intermediate circuit (4), the grid-side power converter (2) being designed as a diode rectifier. To simplify the power converter arrangement for braking a drive and to ensure the reliable and safe execution of a braking process, it is proposed that the braking resistor (5) be electrically connected to the intermediate circuit (4) by means of a mechanical switch (6).Furthermore, the invention relates to a drive system (10) with such a converter arrangement (1), wherein the grid-side converter (2) is connected to a power supply network (12) and the load-side converter (3) is connected to an electric machine (13) and wherein the electric machine (13) is designed as an asynchronous machine.