Electromagnetic Attraction Magnetic Bearing Zero Power Control
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Solution Overview
Problem
Existing electromagnetic attraction type magnetic bearings face challenges in achieving perfect zero power control, leading to increased power loss and complex operation logic due to the need for determining currents based on displacement and speed, which results in unnecessary current consumption and high CPU requirements.
Innovation Solution
The solution involves determining a variable Z proportional to acceleration, allowing the control current of one electromagnet to be set to zero and controlling the other electromagnet based on positive and negative values of Z, reducing the number of parameters and simplifying operation logic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control current is applied to both electromagnets based on displacement and speed parameters, then the float can be maintained at the neutral position, but power loss increases and zero power control cannot be achieved
Solution Approach 1:
The invention changes the control parameter from requiring both displacement and speed to using only displacement. By determining the control current solely based on displacement x and using the formula i = a(X0±x)√(Z/k), the system achieves stable float positioning while enabling zero power control where one electromagnet's current is set to zero, thereby reducing power loss.
2Loss of time
If control current is applied to both electromagnets to generate damping force, then convergence time is shortened, but unnecessary current consumption increases
Solution Approach 1:
The invention implements periodic action by alternating which electromagnet receives control current based on the sign of variable Z. When Z≥0, the first electromagnet is controlled while the second receives zero current; when Z<0, the second electromagnet is controlled while the first receives zero current. This periodic switching maintains damping functionality while ensuring one electromagnet always operates at zero power, reducing unnecessary current consumption.
3Reliability
If control current is applied to both electromagnets to satisfy Lyapunov stability condition, then asymptotic stability is achieved, but perfect zero power control cannot be implemented
Solution Approach 1:
The invention applies segmentation by dividing the control into two separate modes based on the sign of variable Z. The control space is segmented such that when Z≥0, only the first electromagnet is active; when Z<0, only the second electromagnet is active. This segmentation allows the system to maintain Lyapunov stability while achieving perfect zero power control, as one electromagnet is always set to zero current in each mode.
4Measurement precision
If case classification into four cases is used to determine control currents, then control precision is maintained, but operation logic becomes complex and CPU requirements increase
Solution Approach 1:
The invention extracts the essential control requirement from the complex four-case classification and reduces it to a single-variable determination based on displacement x and variable Z. By taking out only the necessary elements (displacement and sign of Z) and eliminating redundant case distinctions, the system maintains control precision while significantly simplifying operation logic and reducing CPU requirements.
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 achieves perfect zero power control, reduces power loss, and simplifies CPU operation, enabling more efficient and stable control of the magnetic bearing without compromising control performance.
Implementation Method 1
electromagnetic attraction type magnetic bearing which always sets the control current of one of electromagnets which face each other to zero
Implementation Method 2
a controller for controlling the electromagnets
Data Source
AI summary
An electromagnetic attraction type magnetic bearing includes at least a pair of electromagnets (1, 2) arranged to face each other, a float (3) arranged between the electromagnets and held at the middle position thereof, a sensor (4) for detecting the displacement of the float (3) from a balance position, and/or the speed thereof, and a controller (5) for controlling the electromagnets (1, 2). The controller (5) determines a variable Z proportional to acceleration in the control direction from the displacement and speed of the float (3), and operates to set the control current of one of the electromagnets to zero and to control only the control current of the other of the electromagnets, depending on the positive and negative values of the variable.