JPH04137299U - Magnetic bearing control device - Google Patents

Abstract

(57) [Summary] [Purpose] This invention makes it possible to reduce power consumption by reducing the excitation current to the main electromagnet required to maintain the rotor's levitation during a power outage to a smaller value than in normal times. The purpose of the present invention is to provide a control device for magnetic bearings. [Structure] In this invention, when a power outage detection circuit 14 detects a power outage, a load determination circuit 15 determines the main electromagnet that holds the rotor 1 floating, and a levitation position command circuit 16 determines a control circuit. 12, the target position of the levitation of the rotor 1 is changed in a direction in which the excitation current value to the main electromagnet that keeps the rotor 1 levitation is decreased compared to that during normal operation.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This idea is based on a magnetic shaft that can reduce power consumption, especially during power outages. This invention relates to a receiver control device.

0002

[Conventional technology]

Traditionally, magnetic bearings used in turbomolecular pumps etc. have been Detects the floating position of the rotor and adjusts the magnetic force of the electromagnet based on this detected value. The rotor is then controlled to remain floating at the target position.

0003 For example, in the magnetic bearing shown in Fig. 4, the weight of the rotor 1 increases from the upper side to the lower side in the figure. The case where the electromagnets 2a, 2b and the electromagnet 3a are arranged in this way is shown. , 3b are the radials by the radial sensors 2a', 2b', 3a', 3b', respectively. The radial direction of rotor 1 is controlled by the magnetic force adjusted based on the detected value of the rotor 1 direction. Furthermore, the electromagnets 4a, 4b and the electromagnets 5a, 5b are connected to the axis by the position sensor 6. The axial direction of the rotor 1 is controlled by the magnetic force adjusted based on the detected value of the axial direction. Control.

0004 If the rotor 1 is not controlled to maintain its levitation, the rotor 1 In particular, the magnetic force of the electromagnets 4a and 4b has a predetermined weight. The rotor 1 is pulled upward in the figure based on the detected value from the position sensor 6. It is necessary to maintain the levitation so that it reaches the target position (position X in the diagram). In particular, the excitation current to the main electromagnets 4a and 4b for keeping the rotor 1 floating is low. Due to the need to keep the weight of the magnet 1 floating, the excitation current for other electromagnets is This results in a large current value.

[0005] However, if a power outage occurs, electromagnets 4a and 4b and electromagnets 5a and 5b will naturally Since the excitation current is no longer supplied, it is necessary to keep the rotor 1 floating at high speed. The rotor 1 falls onto the bearing (not shown) while still rotating at high speed. This is a problem that can cause a downward touchdown phenomenon and damage bearings, etc. There is a case.

[0006] Therefore, this type of magnetic bearing is used in the event of a power outage, although it is not shown in the diagram. Alternatively, use a backup battery or use regenerated power from the motor. In order to keep the rotor 1 floating, use a backup power source in case of a power outage. There is.

[0007]

[Problem that the idea aims to solve]

By the way, in order to keep the rotor 1 floating at the target position, as described above, In the case of the main electromagnet that performs the function, that is, the magnetic bearing shown in Fig. 4, In particular, it is necessary to supply a large excitation current to the electromagnets 4a and 4b. , if a battery is used as a backup power source during a power outage, the of electricity and the battery capacity decreases.

[0008] Therefore, power outages may occur repeatedly or the battery may be damaged until charging is complete. If the deterioration of the rotor 1 is severe, it becomes impossible to maintain the levitation of the rotor 1. , rotor 1 descends onto the bearing while rotating at high speed, damaging the bearing, etc. This will result in

[0009] In addition, we have developed a battery-less system that uses regenerated power from the motor as a backup power source. In this case, the excitation current to the main electromagnets 4a and 4b that keep the rotor 1 floating is Excitation electricity to electromagnets 5a, 5b and other electromagnets 2a, 2b, 3a, 3b, etc. If the power consumption of the magnetic bearing consisting of the sum of the currents exceeds the regenerated power, the floating of rotor 1 It is no longer possible to hold the top, and rotor 1 is in a high-speed rotation state as in the case above. This will cause it to fall onto the bearing and damage the bearing.

0010 This idea was made in view of the above circumstances, and its purpose is to However, during a power outage, the excitation power to the main electromagnets required to keep the rotor floating is Magnetism that can reduce power consumption by reducing the current value to a smaller value than normal. An object of the present invention is to provide a bearing control device.

[0011]

[Means to solve the problem]

This idea uses the detected value from the position sensor to achieve the above objectives. Based on this, adjust the excitation current to the electromagnet and keep the rotor floating at the target position. a control circuit that causes Detects the current value of the excitation current applied to the electromagnet, and the electromagnet moves the rotor to the target position. a load determination circuit that determines whether it is the main electromagnet that is being held floating at the position; When a power failure is detected in the excitation current power supply, the power failure detection signal is controlled as described above. Inputs the excitation current into the circuit and switches the excitation current supply to the backup power supply for power outages. a power outage detection circuit that instructs the When the power failure detection signal is input from the above power failure detection circuit to the above control circuit, the The levitation target decreases in the direction in which the excitation current value to the main electromagnet that maintains the levitation of the target a floating position command circuit that changes the position; It is characterized by having the following.

0012

[Effect]

This idea allows the load discrimination circuit to detect a power outage when the power outage detection circuit detects the occurrence of a power outage. The main electromagnet that keeps the rotor floating on the road is identified, and the floating position indicator is determined. The control circuit supplies excitation voltage to the main electromagnet that keeps the rotor floating relative to the control circuit. The floating target position can be changed in a direction that reduces the flow value compared to during normal operation. Ru.

[0013]

【Example】

Hereinafter, embodiments of this invention will be described in detail based on the drawings.

[0014] FIG. 1 is a block diagram showing a schematic configuration of a control device according to this invention. The magnetic bearings shown in FIG. 4 are similar to those shown in FIG. Electromagnets 2a, 2b, 3a, 3b and radial sensor 1 that control the radial direction of 2a', 2b', 3a', 3b' and an electric current that controls the axial direction of the rotor 1. It is composed of magnets 4a, 4b, 5a, 5b, their position sensors 6, etc.

[0015] Note that other components such as the drive motor and rotation speed sensor of the rotor 1 are Since this is not directly related to the gist of the invention, illustrations and detailed explanations will be omitted. Also, To make the explanation clear and concise, the control device is connected to the electromagnets 4b and 5b. Only the state is illustrated.

[0016] The position sensor 6 detects the floating position of the rotor 1, and this detected value is transmitted to the position detection circuit. The signal is input to a comparator 11 via a path 10 and then to a control circuit 12.

[0017] Based on the information input from the comparator 11, the control circuit 12 determines whether the The motor 1 is moved to a preset target position, usually by an electromagnet as shown in Figure 2. 4a, 4b and the electromagnets 5a, 5b so as to float to the A line position, which is the intermediate position. It controls the electromagnets 4a, 4b and the electromagnets through an amplifier 13 (AMP). An excitation current is supplied to 5a and 5b.

[0018] As a result, the main electromagnets 4a, 4b and electric power for keeping the rotor 1 floating A predetermined magnetic force is generated in the magnets 5a and 5b, and by adjusting these magnetic forces, the rotor 1 is held floating at the target position A.

[0019] The power failure detection circuit 14 detects whether the excitation current power supply has a power failure during normal operation. When a power outage occurs, a power outage detection signal is input to the control circuit 12. Although not shown, the excitation current is supplied from the commercial power supply used during normal operation. Switch off to backup power in case of a power outage, such as regenerative power from a battery or motor. command to change it.

[0020] The load discrimination circuit 15 controls the weight of the rotor 1 to keep it floating and reach the target position. It detects the current value of the excitation current that is passed through the main electromagnets 4a and 4b. Physically, it detects whether the detected current value exceeds a certain reference value, and The electromagnets 4a and 4b are the main electromagnets that keep the rotor 1 floating at the target position. As a result, the mounting orientation of the magnetic bearing is determined.

[0021] In other words, the mounting orientation of magnetic bearings varies depending on the purpose for which they are used. The axial direction in which the weight of rotor 1 is applied varies depending on the mounting orientation, so An electromagnet to which a large excitation current is applied mainly to maintain the levitation of the motor 1. varies depending on its mounting orientation; for example, if it is installed vertically as in this example, When the rotor 1 is floated, the axial electromagnets 4a and 4b are the main ones for keeping the rotor 1 floating. However, when placed horizontally, the radial electromagnets 2a, 2b and Either the radial electromagnets 3a, 3b, etc. are the main ones for keeping the rotor 1 floating. It becomes a barrel electromagnet.

[0022] Therefore, this load discrimination circuit 15 determines whether the main electric current that keeps the rotor 1 floating is By determining that the magnets are electromagnets 4a and 4b, the control circuit 12 operates as described below. Based on commands from the floating position detection circuit 16, the rotor 1 is Only the excitation current to the electromagnets 4a and 4b that are kept floating should be set to a small current value. I can do it.

[0023] The floating position command circuit 16 receives a power failure detection signal from the power failure detection circuit 14 to the control circuit 12. If it is input, it is determined by the load determination circuit 15 and the rotor 1 is Only the excitation current of the main electromagnets 4a and 4b, which keep them floating at the target position, is reduced. In order to achieve It is output to the control circuit 12 via the comparator 11 so that

[0024] Next, we will explain the operation of the control device according to this invention based on the flowchart shown in Figure 3. I will clarify.

[0025] When the device is put into the starting state, in step 100 the rotor 1 is connected to the position detection circuit. 10, to the target position (line A position in Fig. 2) set in advance by the control circuit 12, etc. Normal operation is performed while being kept floating.

[0026] Then, in step 101, the power outage detection circuit 14 determines whether or not a power outage has occurred. If the power is disconnected and no power outage has occurred, the process returns to step 100, but if a power outage has occurred, If it is determined that the electromagnet 4 is It is determined whether or not a and 4b are the main electromagnets that keep the rotor 1 floating. If it is determined that it is not the main electromagnet that keeps rotor 1 floating, step It returns to 100 and braking operations are performed, but the electromagnet holding the rotor 1 floating If it is determined that there is a The excitation current value to the electromagnets 4a and 4b that mainly keep the motor 1 floating decreases. A command signal to change the levitation target position in the direction is output.

[0027] Next, in step 104, it is determined whether the floating position of the rotor 1 has been lowered as instructed. is determined, and if it is determined that it has not fallen as instructed, step 103 However, if it is determined that the temperature has decreased as per the command, the process proceeds to step 105. Operation during power outage is performed.

[0028] Then, in step 106, it is determined whether or not the power outage state has ended. If it is determined that the power outage has ended, the process returns to step 100. If it is determined that the rotor 1 is not present, the process proceeds to step 107 to further maintain the levitation of the rotor 1. Whether or not to do so is determined based on information from the rotation speed sensor, etc., and the levitation maintenance of the rotor 1 is performed. If it is determined that the holding is to be continued further, the process returns to step 105, but the levitation of the rotor 1 is If it is determined that the retention should not be continued any longer, it will be terminated and stopped.

[0029] In this way, according to this embodiment, the occurrence of a power outage is detected by the power outage detection circuit 14. In this case, the load determination circuit 15 identifies the main electromagnet that keeps the rotor 1 floating. and the levitation position command circuit 16 provides the control circuit 12 with the levitation position of the rotor 1. The excitation current value to the main electromagnet that performs holding is set to be lower than during normal operation. Since it is configured to change the levitation target position, its power consumption is reduced in the event of a power outage. touch down even when using a backup power supply for power outages. This can prevent damage to bearings, etc., from occurring.

[0030]

[Effect of the idea]

As explained above, according to this invention, the occurrence of a power outage is detected by the power outage detection circuit. If the main electromagnet that keeps the rotor floating is detected by the load discrimination circuit. The levitation position command circuit provides the control circuit with the main function of keeping the rotor levitation. The levitation target position is adjusted so that the excitation current value to the electromagnet is decreased from that during normal operation. It is configured to change its power consumption in the event of a power outage. This prevents the touchdown phenomenon even when using a backup power supply for power outages. Damage to bearings etc. can be prevented.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a control device according to the invention.

FIG. 2 is an explanatory diagram showing a change in a rotor floating target position.

FIG. 3 is a flowchart explaining the operation of the control device according to the invention.

FIG. 4 is a schematic configuration diagram showing a conventional magnetic bearing.

[Explanation of symbols]

1 rotor 10 Position detection circuit 12 Control circuit 14 Power outage detection circuit 15 Load discrimination circuit 16 Floating position command circuit

Claims (1)

[Scope of utility model registration request] [Claim 1] A control circuit that adjusts an excitation current to an electromagnet based on a detected value from a position sensor and keeps the rotor floating at a target position, and detects the current value of the excitation current that is energized to the electromagnet. There is a load discrimination circuit that determines whether the electromagnet is the main electromagnet that keeps the rotor floating at the target position, and when a power outage of the excitation current power source is detected, a power outage detection signal is sent to the control circuit. and a power failure detection circuit that instructs to switch the excitation current supply to the backup power supply in case of a power failure, and when a power failure detection signal is input from the power failure detection circuit to the control circuit, the control circuit maintains the rotor's levitation. 1. A control device for a magnetic bearing, comprising: a levitation position command circuit that changes a levitation target position in a direction in which an excitation current value to a main electromagnet that performs this decreases.