Switchable Filter Circuit for DC Bus Voltage Fluctuation Control
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Solution Overview
Problem
Voltage fluctuations on the power feeding path from a DC power supply to motor controllers occur due to resonance caused by motor operation and pulse-width modulation frequencies, leading to instability in the DC bus.
Innovation Solution
A processing apparatus with a filter circuit and controller that adjusts resonance characteristics by switching semiconductor switches in the filter circuit, which includes passive elements like capacitors and inductors, to align with or diverge from motor rotation and PWM frequencies, thereby reducing voltage and current fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single DC power supply feeds multiple motor controllers through a DC bus, then the system structure is simplified and cable quantity is reduced, but voltage fluctuations occur on the DC bus due to resonance between the LC circuit and motor controllers
Solution Approach 1:
A filter circuit is introduced as an intermediary component between the DC power supply and motor controllers. This filter circuit includes resonance frequency adjustment means that can dynamically adjust the resonance frequency to avoid coincidence with motor operation frequencies, thereby eliminating voltage fluctuations while maintaining the simplified single-power-supply structure
Solution Approach 2:
The resonance frequency of the filter circuit is made variable through the resonance frequency adjustment means. By changing the resonance frequency parameter in response to motor operation states (detected via rotation speed or PWM frequency), the system avoids resonant voltage fluctuations without requiring a more complex power supply architecture
2Device complexity
If the resonance frequency of the filter circuit is fixed, then the circuit structure is simple, but voltage fluctuations occur when motor operation frequency coincides with the fixed resonance frequency
Solution Approach 1:
The filter circuit's resonance frequency is transformed from a fixed parameter to a dynamic one. The resonance frequency adjustment means enables the filter circuit to adapt its resonance frequency in real-time based on motor operation conditions, preventing voltage fluctuations caused by frequency coincidence while keeping the filter circuit structure relatively simple
Solution Approach 2:
A feedback mechanism is implemented where the controller detects motor operation frequency (through rotation speed or PWM frequency) and uses this information to adjust the filter circuit's resonance frequency accordingly. This closed-loop feedback ensures the resonance frequency avoids coinciding with motor frequencies, maintaining voltage stability without excessive structural complexity
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
Effectively minimizes voltage and current fluctuations on the power feeding path by controlling resonance frequencies and impedance, ensuring stable power delivery to motor controllers.
Implementation Method 1
the filter circuit adjusts a resonance characteristic across the filter circuit by switching the semiconductor switch included in each of the plurality of predetermined units
Data Source
AI summary
Voltage fluctuations on a power feeding path for feeding power to a motor controller are reduced. A processing apparatus reduces voltage fluctuations on a power feeding path for feeding power from a direct current power supply to at least one motor controller. The apparatus includes a filter circuit and a controller. The filter circuit includes a plurality of predetermined units each including a circuit element and a semiconductor switch. The circuit element includes at least one predetermined passive element. The semiconductor switch controls a current to be fed to the circuit element. The filter circuit is connected to the power feeding path. The controller controls switching of the semiconductor switch included in each of the plurality of predetermined units in the filter circuit to reduce voltage fluctuations or current fluctuations of direct current on the power feeding path.