Modular Brake Actuator Frequency Control for Partial Load Stability
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Solution Overview
Problem
Existing modular braking units lack efficient control mechanisms to regulate power conversion into heat, leading to unstable operation and inefficient energy dissipation, especially under varying load conditions.
Innovation Solution
A method for operating a modular braking unit that includes submodules and a braking resistor in series, where a voltage with both direct and alternating components is generated to control the power converted into heat, with the modulation frequency adjusted based on the partial load factor to optimize energy dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed voltage is applied to the braking unit, then the power conversion into heat is simple to control, but the operation becomes unstable under varying load conditions and energy dissipation efficiency decreases
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed voltage control system to a dynamic voltage control system. The voltage applied to the braking unit is continuously adjusted based on the operating point (partial load factor), allowing the system to adapt to varying load conditions and maintain stable operation. This dynamic adjustment resolves the contradiction by enabling operational stability without requiring overly complex control mechanisms, as the adjustment is based on a straightforward parameter (partial load factor).
Solution Approach 2:
The patent employs parameter changes by modifying the voltage parameter dynamically according to the operating point. Instead of using a fixed voltage, the system changes the voltage parameter in response to varying load conditions, thereby maintaining stable and efficient energy dissipation. This approach improves reliability by adapting to different operating conditions while avoiding excessive control complexity through the use of a single key parameter (voltage) for adjustment.
2Productivity
If the modulation frequency is kept constant, then the control system is simple, but energy dissipation efficiency decreases under partial load conditions
Solution Approach 1:
The patent applies dynamics by making the modulation frequency variable rather than constant. The modulation frequency is adjusted according to the partial load factor, allowing the system to optimize energy dissipation efficiency under different operating conditions. This dynamic adjustment improves productivity by ensuring efficient energy dissipation even at partial load, while the control system complexity remains manageable because the adjustment is based on a clear relationship with the operating point.
3Speed
If a high modulation frequency is used, then the energy dissipation response is faster, but losses increase and efficiency decreases at low power levels
Solution Approach 1:
The patent applies dynamics by making the modulation frequency variable rather than fixed at a high value. The modulation frequency is adaptively adjusted according to the operating point and partial load factor, allowing the system to achieve fast energy dissipation response when needed (at high power levels) while reducing the frequency at low power levels to minimize losses. This resolves the contradiction by optimizing the response speed-to-loss ratio across different operating conditions.
4Reliability
If the voltage is adjusted dynamically based on operating point, then operational stability and efficiency improve, but the control mechanism becomes more complex
Solution Approach 1:
The patent employs parameter changes by dynamically adjusting the voltage parameter based on the operating point (partial load factor). This single-parameter adjustment approach improves operational stability and efficiency while avoiding excessive control mechanism complexity. The control mechanism remains relatively simple because it focuses on adjusting one key parameter (voltage) in response to a clearly defined operating condition (partial load factor), rather than implementing a complex multi-parameter control system.
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 enables precise control of power conversion into heat, stabilizes the modular braking unit's operation over extended periods, and adapts to varying load conditions, improving efficiency and reliability.
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
Figure 2~3
Figure 4
AI summary
The invention relates to a method for operating a modular braking actuator (1), wherein the modular braking actuator (1) comprises at least one submodule (2) and a braking resistor (3) arranged in a series circuit (4). To improve the modular braking actuator, it is proposed that a voltage (uBR) is generated by means of the at least one submodule (2), wherein the generated 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 over time by the modular braking actuator (1) is converted into heat in the braking resistor (3), wherein a modulation frequency (fM) of the alternating component (uBR,aDC) is varied as a function of a partial load factor (α) of the modular braking actuator (1). The invention further relates to a control device (10) configured to carry out such a method.The invention further relates to such a modular brake actuator (1) with such a control device, as well as to a modular drive unit (20) comprising a modular multilevel power converter (21) and a modular brake actuator (1).