Magnetic suspension bearing drive circuit

Abstract

The invention belongs to the technical field of magnetic suspension bearings, and particularly relates to a magnetic suspension bearing driving circuit which is characterized by comprising a first asymmetric half-bridge power amplification circuit and a second asymmetric half-bridge power amplification circuit which are connected in parallel, a plurality of nodes exist in the first asymmetric half-bridge power amplification circuit and the second asymmetric half-bridge power amplification circuit, and the control circuit can be switched to drive the electromagnetic bias magnetic suspension bearing or the permanent magnet bias magnetic suspension bearing by switching the connection mode between the nodes. The invention provides a magnetic suspension bearing driving circuit which is formed by connecting two asymmetric half-bridge power amplification circuits in parallel, the circuit structure is changed by changing the connection mode of an access load winding, the connection mode between circuit nodes is switched, and switching of the two magnetic suspension bearing driving circuits is achieved. Therefore, the controller of the same model can compatibly control the permanent magnet biased magnetic bearing and the electromagnetic biased magnetic bearing, and the development cost and the management cost are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetic suspension bearings, and in particular relates to a magnetic suspension bearing driving circuit. Background Art

[0002] The magnetic levitation high-speed motor relies on the magnetic bearing controller to achieve stable and reliable suspension of the rotor in the center of the mechanical space. Among them, the actuator controlled by the magnetic bearing controller is called an active magnetic bearing. Active magnetic bearings are mainly divided into two types, namely permanent magnet biased magnetic bearings and electromagnetic biased magnetic bearings. In permanent magnet biased magnetic bearings, the permanent magnet generates a bias magnetic field and the winding coil generates a control magnetic field; while the electromagnetic biased magnetic bearing generates the above two magnetic fields at the same time through the winding coil.

[0003] Since the bias magnetic field of the permanent magnet biased magnetic bearing has been established, the relative magnetic poles of the magnetic bearing are usually connected in series to form a winding, which needs to be driven by a full-bridge power amplifier circuit, which can generate current in two directions. The windings on the relative magnetic poles of the electromagnetic biased magnetic bearing are usually driven separately and need to be driven by two asymmetric half-bridge circuits to generate unidirectional winding currents respectively. The above two driving circuits have different topological structures. Usually, in the case of two different magnetic bearing solutions, it is necessary to design and match two magnetic bearing controllers, which increases development costs and management costs. Summary of the invention

[0004] The present invention is to solve the problems existing in the above-mentioned prior art and provides a magnetic levitation bearing drive circuit, comprising: a first asymmetric half-bridge power amplifier circuit and a second asymmetric half-bridge power amplifier circuit connected in parallel, there are several nodes in the first asymmetric half-bridge power amplifier circuit and the second asymmetric half-bridge power amplifier circuit, by switching the connection method between the nodes, the control circuit can be switched to drive an electromagnetic biased magnetic levitation bearing or a permanent magnet biased magnetic levitation bearing.

[0005] Further, the first asymmetric half-bridge power amplifier circuit includes a capacitor CXa, field effect transistors QXa1, QXa2, diodes DXa1, DXa2, and a resistor RXa, one end of the capacitor CXa is connected to the drain of the field effect transistor QXa1, and the other end is connected to the anode of the diode DXa1, the source of the field effect transistor QXa1 is connected to the cathode of the diode DXa1, and the connection node is recorded as node a3; the cathode of the diode DXa2 is connected to the drain of the field effect transistor QXa1, the anode of the diode DXa2 is connected to the drain of the field effect transistor QXa2, and the connection node is recorded as node a2, and the source of the field effect transistor QXa2 is connected to the anode of the diode DXa1; the node a3 is connected to the resistor RXa, and the other end of the resistor RXa is recorded as node a1; the nodes a1 and a2 serve as the output ends of the first asymmetric half-bridge power amplifier circuit; The second asymmetric half-bridge power amplifier circuit includes a capacitor CXb, field effect transistors QXb1, QXb2, diodes DXb1, DXb2, and a resistor RXb. One end of the capacitor CXb is connected to the drain of the field effect transistor QXb1, and the other end is connected to the anode of the diode DXb1. The source of the field effect transistor QXb1 is connected to the cathode of the diode DXb1; the cathode of the diode DXb2 is connected to the drain of the field effect transistor QXb1, and the anode of the diode DXb2 is connected to the drain of the field effect transistor QXb2. The connection node is recorded as node b2, and the source of the field effect transistor QXb2 is connected to the anode of the diode DXb1; the node b1 is connected to the resistor RXb, and the other end of the resistor RXb is recorded as node b1; the nodes b1 and b2 serve as output ends of the second asymmetric half-bridge power amplifier circuit.

[0006] Furthermore, the nodes are connected via switches or wires, and the switches include switch SW1 and switch SW2. Both ends of switch SW1 are connected to node a3 and node b2, respectively, and both ends of switch SW2 are connected to node a2 and node b1, respectively.

[0007] Furthermore, when the magnetic bearing drive circuit is used to control the electromagnetic biased magnetic bearing, the switch SW1 and the switch SW2 are both disconnected, and the two sets of windings of the electromagnetic biased magnetic bearing are respectively connected to the output ends of the first asymmetric half-bridge power amplifier circuit and the second asymmetric half-bridge power amplifier circuit.

[0008] Furthermore, when the magnetic bearing driving circuit is used to control the permanent magnet biased magnetic bearing, the switch SW1 and the switch SW2 are closed, and the two sets of windings of the permanent magnet biased magnetic bearing are connected in series and then connected to the output end of the first asymmetric half-bridge power amplifier circuit.

[0009] Furthermore, the gates of the field effect transistors QXa1, QXa2, QXb1, and QXb2 are all connected to a control circuit for controlling the conduction state of each field effect transistor. The present invention has the following beneficial effects: The present invention provides a magnetic suspension bearing drive circuit, which is composed of two asymmetric half-bridge power amplifier circuits connected in parallel. By changing the connection mode of the load winding, the connection mode between the circuit nodes is switched to change the circuit structure, and the switching of the two magnetic suspension bearing drive circuits is realized, so that the same model controller can be compatible with the control of permanent magnet biased magnetic bearings and electromagnetic biased magnetic bearings, thereby reducing development costs and management costs.

[0010] The magnetic suspension bearing drive circuit provided by the present invention is configured with redundant bus capacitors when controlling a permanent magnet biased magnetic suspension bearing, thereby enhancing the AC ripple capability and improving the capacitor life; and a redundant current sampling circuit is added to achieve fault-tolerant control. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A connection diagram of a magnetic suspension bearing drive circuit provided by the present invention when driving a permanent magnet biased magnetic suspension bearing; Figure 2 for Figure 1 Equivalent circuit topology; Figure 3 This is a connection diagram of the magnetic suspension bearing drive circuit provided by the present invention when driving an electromagnetic biased magnetic suspension bearing. DETAILED DESCRIPTION

[0012] The present invention will be further described below in conjunction with the accompanying drawings. Example

[0013] This embodiment provides a magnetic suspension bearing drive circuit, which can realize dual drive control of permanent magnet biased magnetic suspension bearings or electromagnetic biased magnetic suspension bearings. The circuit schematic diagram is as follows: Figure 1 As shown: The first asymmetric half-bridge power amplifier circuit includes a capacitor CXa, field effect transistors QXa1, QXa2, diodes DXa1, DXa2, and a resistor RXa. One end of the capacitor CXa is connected to the drain of the field effect transistor QXa1, and the other end is connected to the anode of the diode DXa1. The source of the field effect transistor QXa1 is connected to the cathode of the diode DXa1, and the connection node is recorded as node a3; the cathode of the diode DXa2 is connected to the drain of the field effect transistor QXa1, the anode of the diode DXa2 is connected to the drain of the field effect transistor QXa2, and the connection node is recorded as node a2. The source of the field effect transistor QXa2 is connected to the anode of the diode DXa1; the node a3 is connected to the resistor RXa, and the other end of the resistor RXa is recorded as node a1; the nodes a1 and a2 serve as the first asymmetric half-bridge power amplifier. Circuit output end; the second asymmetric half-bridge power amplifier circuit includes capacitor CXb, field effect tubes QXb1, QXb2, diodes DXb1, DXb2, and resistor RXb, one end of the capacitor CXb is connected to the drain of the field effect tube QXb1, the other end is connected to the anode of the diode DXb1, and the source of the field effect tube QXb1 is connected to the cathode of the diode DXb1; the cathode of the diode DXb2 is connected to the drain of the field effect tube QXb1, the anode of the diode DXb2 is connected to the drain of the field effect tube QXb2, the connection node is recorded as node b2, and the source of the field effect tube QXb2 is connected to the anode of the diode DXb1; the node b1 is connected to the resistor RXb, and the other end of the resistor RXb is recorded as node b1; the nodes b1 and b2 serve as the output end of the second asymmetric half-bridge power amplifier circuit. The parallel connection form of the first asymmetric half-bridge power amplifier circuit and the second asymmetric half-bridge power amplifier circuit is that the two ends of the capacitor CXa and the capacitor CXb are connected in parallel.

[0014] When controlling the electromagnetic biased magnetic suspension bearing, the two windings LXa and LXb on the opposite magnetic poles of the electromagnetic biased magnetic suspension bearing are respectively connected to the a1 and a2 nodes of the first asymmetric half-bridge power amplifier circuit and the b1 and b2 nodes of the second asymmetric half-bridge power amplifier circuit. At this time, the first asymmetric half-bridge power amplifier circuit on the left drives the first winding LXa, and the second asymmetric half-bridge power amplifier circuit on the right drives the second winding LXb, respectively generating currents in two directions to realize the control of the electromagnetic biased magnetic suspension bearing.

[0015] When controlling the permanent magnet biased magnetic bearing, the bias magnetic field of the permanent magnet biased magnetic bearing has been established, and the relative magnetic poles of the magnetic bearing need to be connected in series to form a winding (LXa+LXb), such as Figure 2 As shown, the two ends of the series-connected windings are connected to nodes a1 and a2 respectively. At this time, the node connection method is required to change the circuit structure to adapt to the permanent magnet biased magnetic suspension bearing. The node connection method can be achieved by various means. In this embodiment, a switch SW1 is added between nodes a3 and b2, and a switch SW2 is added between nodes a2 and b1. The circuit structure is changed by closing the switches. Its equivalent circuit is as follows Figure 3 As shown, at this time, the magnetic bearing drive circuit is a full-bridge power amplifier circuit composed of the left bridge arm QXa1, QXb2 and the right bridge arm QXb1, QXa2. By modulating the four power tubes, the control of the full-bridge topology circuit can be achieved. At this time, the capacitor CXb serves as a redundant bus capacitor, which can enhance the AC ripple capability and increase the life of the capacitor CXa; the resistors RXa or RXb are redundant with each other and serve as a current sampling circuit to achieve fault-tolerant control of circuit sampling.

[0016] The above generally describes the present invention in detail, but it is obvious to a person skilled in the art that some modifications or improvements can be made to the present invention. Therefore, modifications or improvements that do not depart from the spirit of the present invention are within the scope of protection of the present invention.

Claims

1. A magnetic bearing drive circuit, characterized in that: It includes a first asymmetric half-bridge power amplifier circuit and a second asymmetric half-bridge power amplifier circuit connected in parallel. There are several nodes in the first asymmetric half-bridge power amplifier circuit and the second asymmetric half-bridge power amplifier circuit. By switching the connection method between the nodes, the control circuit can be switched to drive the electromagnetic biased magnetic levitation bearing or the permanent magnet biased magnetic levitation bearing.

2. A magnetic bearing drive circuit according to claim 1, characterized in that: The first asymmetric half-bridge power amplifier circuit includes a capacitor CXa, field effect transistors QXa1, QXa2, diodes DXa1, DXa2, and a resistor RXa, one end of the capacitor CXa is connected to the drain of the field effect transistor QXa1, and the other end is connected to the anode of the diode DXa1, the source of the field effect transistor QXa1 is connected to the cathode of the diode DXa1, and the connection node is recorded as node a3; the cathode of the diode DXa2 is connected to the drain of the field effect transistor QXa1, the anode of the diode DXa2 is connected to the drain of the field effect transistor QXa2, and the connection node is recorded as node a2, and the source of the field effect transistor QXa2 is connected to the anode of the diode DXa1; the node a3 is connected to the resistor RXa, and the other end of the resistor RXa is recorded as node a1; the nodes a1 and a2 serve as the output ends of the first asymmetric half-bridge power amplifier circuit; The second asymmetric half-bridge power amplifier circuit comprises a capacitor CXb, field effect transistors QXb1, QXb2, diodes DXb1, DXb2, and a resistor RXb, one end of the capacitor CXb is connected to the drain of the field effect transistor QXb1, and the other end is connected to the anode of the diode DXb1, and the source of the field effect transistor QXb1 is connected to the cathode of the diode DXb1; The cathode of diode DXb2 is connected to the drain of field effect transistor QXb1, the anode of diode DXb2 is connected to the drain of field effect transistor QXb2, the connection node is recorded as node b2, the source of field effect transistor QXb2 is connected to the anode of diode DXb1; the node b1 is connected to resistor RXb, the other end of resistor RXb is recorded as node b1; the nodes b1 and b2 serve as output ends of the second asymmetric half-bridge power amplifier circuit.

3. A magnetic bearing drive circuit according to claim 2, characterized in that: The nodes are connected via switches or wires. The switches include switch SW1 and switch SW2. Two ends of switch SW1 are connected to node a3 and node b2 respectively. Two ends of switch SW2 are connected to node a2 and node b1 respectively.

4. The magnetic bearing drive circuit according to claim 3, characterized in that: When the magnetic bearing driving circuit is used to control the electromagnetic biased magnetic bearing, the switch SW1 and the switch SW2 are both disconnected, and the two sets of windings of the electromagnetic biased magnetic bearing are respectively connected to the output ends of the first asymmetric half-bridge power amplifier circuit and the second asymmetric half-bridge power amplifier circuit.

5. The magnetic bearing drive circuit according to claim 3, characterized in that: When the magnetic bearing driving circuit is used to control the permanent magnet biased magnetic bearing, the switch SW1 and the switch SW2 are closed, and the two winding groups of the permanent magnet biased magnetic bearing are connected in series and then connected to the output end of the first asymmetric half-bridge power amplifier circuit.

6. A magnetic bearing drive circuit according to any one of claims 2 to 5, characterized in that: The gates of the field effect transistors QXa1, QXa2, QXb1, and QXb2 are all connected to a control circuit for controlling the conduction state of each field effect transistor.

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