Modular Brake Actuator Asymmetrical Voltage Control for Stable Braking
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Solution Overview
Problem
Existing modular braking units lack efficient methods for converting electrical energy into heat, particularly in adapting to varying intermediate circuit voltages and ensuring stable operation over extended periods.
Innovation Solution
A modular braking unit comprising submodules and a braking resistor arranged in a series circuit, capable of generating block-shaped or trapezoidal voltages with DC and alternating components. This configuration allows for precise control of power conversion into heat, adapting to any intermediate circuit voltage and ensuring stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional braking unit with symmetrical voltage control is used, then the structure is simple, but the energy conversion efficiency is low and stable operation over extended periods cannot be ensured
Solution Approach 1:
The patent applies asymmetry by using unequal time periods (first time period ≠ second time period) in the block-shaped or trapezoidal voltage generation. This asymmetrical control enables the alternating component to be free of DC components while maintaining precise control over power conversion, thereby ensuring stable operation over extended periods without requiring complex additional control mechanisms.
Solution Approach 2:
The patent implements periodic action through the block-shaped or trapezoidal voltage waveform that alternates between upper and lower voltage values in defined time periods. This periodic voltage pattern enables continuous conversion of electrical energy into heat while maintaining stable operation, resolving the contradiction between reliability and control complexity.
2Power
If more submodules are used to handle higher power, then the power conversion capability increases, but the device complexity and cost increase
Solution Approach 1:
The patent applies dynamics by enabling each submodule to dynamically switch between different voltage states (upper voltage value and lower voltage value) with unequal time periods. This dynamic operation allows the braking unit to achieve high power conversion capability through efficient energy exchange at low voltage and current amplitudes, reducing the number of submodules required compared to conventional static designs.
Solution Approach 2:
The patent changes parameters by using block-shaped or trapezoidal voltage waveforms with unequal time periods instead of conventional symmetrical waveforms. This parameter change enables high power conversion capability with fewer submodules, as the asymmetrical timing optimizes the energy exchange process and reduces the total number of components needed.
3Use of energy by moving object
If symmetrical voltage control is used, then the control is simple, but the energy exchange efficiency is low
Solution Approach 1:
The patent uses asymmetry in the time periods (first time period ≠ second time period) to eliminate DC components from the alternating voltage while maintaining simple block-shaped or trapezoidal waveform generation. This asymmetrical approach improves energy conversion efficiency by enabling more effective power transfer without complicating the control methodology.
Solution Approach 2:
The patent replaces conventional symmetrical voltage control mechanisms with an asymmetrical timing-based control approach. This substitution maintains control simplicity while significantly improving energy exchange efficiency, as the unequal time periods optimize the energy transfer process without requiring complex control algorithms.
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
The modular braking unit achieves efficient conversion of electrical energy into heat with high energy exchange at low voltage and current amplitudes, enabling stable operation and cost-effective design by reducing the number of submodules and capacitor energy requirements.
Implementation Method 1
The resistance of a braking actuator arrangement is often also referred to as a braking resistor, as it is suitable for converting electrical energy from an electrical machine, which is generated as a result of a braking process, into heat.
Data Source
Figure 1
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AI summary
The invention relates to a method for operating a modular braking unit (1), wherein the modular braking unit (1) comprises at least one submodule (2) and a braking resistor (3). To improve the modular braking unit, it is proposed that a block-shaped or trapezoidal voltage (uBR) is generated by means of the submodule (2), wherein the block-shaped or trapezoidal voltage (uBR) has a direct component (uBR,DC) and an alternating component (uBR,aDC), wherein the alternating component (uBR,aDC) is dimensioned such that the electrical energy absorbed on average by the modular braking unit (1) is converted into heat in the braking resistor (3), wherein the alternating component (uBR,aDC) is formed by an upper voltage value (UBR,AC1), which is present for a first time period (τ1), and a lower voltage value (uBR,AC2), which is present for a second time period (τ2).The invention further relates to a control device (10) configured to carry out such a method. The invention further relates to a modular brake actuator (1) having such a control device, as well as to a modular drive unit (20) comprising a modular multilevel power converter (21) and such a modular brake actuator (1).