JP2008086091A - Motor control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost motor control system which can be used as a service facility in a semiconductor manufacturing line, etc. <P>SOLUTION: For example, AC power source supplied from a terminal IN is inputted into an inverter circuit INV, and the output of this INV is inputted into a motor Mn for usual operation via a switch SWn2, etc., and also is inputted into the motor Mr for auxiliary operation via a switch SWr2, and the like. Furthermore, AC power supplied from the terminal IN is inputted into Mn via a switch SWn3, etc. and also is inputted into Mr via the switch SWr3, and the like. At normal operation, INV drives Mn by switching on or switching off the SWn2/SWr2, and at fault, etc. of Mn, INV drives Mr by switching on/off the SWn2/SWr2. According to the circumstance, Mn is driven directly by the AC power by the route via the SWn3, without using INV, and Mr is driven directly by the AC power by the route via the SWr3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric motor control system, and more particularly to an electric motor control system used as utility equipment in a semiconductor production line or the like.

  For example, various factories such as semiconductor production lines are usually equipped with so-called utility facilities that manage electric power, water, air, and the like used in the factories. Typical examples of utility equipment include an electric motor such as a motor. By controlling the number of rotations of the motor, the supply amount of water, adjustment of air, and the like are performed.

  For example, in a semiconductor production line, a semiconductor wafer is processed in a clean room with very few particles (dust) in the air. In order to keep the number of particles in the clean room small, it is necessary to precisely control the ventilation and exhaust air to the clean room. Further, when processing a semiconductor wafer, pure water and various liquid substances are required, and water supply and waste water to the clean room must be appropriately controlled. Such control can be realized, for example, by controlling the number of rotations of an electric motor (motor) provided in a blower, an exhaust fan, a water supply pump, a wastewater pump, or the like by an inverter circuit or the like.

  FIG. 3 is a schematic diagram illustrating a configuration example of an electric motor control system. In the motor control system shown in FIG. 3, for example, a three-phase AC power supply AC supplied from the outside is connected to the switchboard BD via a three-phase cable CBL1, and the switchboard BD is connected via two three-phase cables CBL2 and CBL3. The motor is connected to two motors Mn and Mr. Here, the motors Mn and Mr are, for example, the same motor for a blower, and one motor Mn is for normal operation and the other motor Mr is for preliminary operation. That is, in a semiconductor production line or the like, if such a motor fails, the motor Mn is usually damaged, and normally, the motor Mn is operated, and safety is ensured by providing the motor Mr as a backup in case of failure. Yes.

  FIG. 4 is a circuit diagram showing a configuration example in the switchboard of FIG. 3 in the motor control system studied as a premise of the present invention. The switchboard BD shown in FIG. 4 has a configuration including two inverter circuits INVn and INVr corresponding to the two motors Mn and Mr. One inverter circuit INVn receives AC power from a terminal IN via a breaker BRn, a switch SWn and a coil Ln1, and the output of INVn is connected to a motor Mn via a coil Ln2, a thermal relay SRn and a terminal OUn. Is done. AC power from the terminal IN is also input to the other inverter circuit INVr via the breaker BRr, the switch SWr and the coil Lr1, and the output of the INVr is connected to the motor Mr via the coil Lr2, the thermal relay SRr and the terminal OUr. Is done. In normal times, the motor Mn is driven by turning on SWn, and when it fails, the motor Mr is driven by turning on SWr.

  However, it is very rare that the inverter circuit normally fails, and it is wasteful in terms of cost to provide a relatively expensive inverter circuit for normal use and spare use. In addition, since such an inverter circuit handles a large power of 40 kW, for example, a size of 50 cm square or the like is necessary, and it may be difficult to insert two into the switchboard BD.

  Therefore, an object of the present invention is to provide a low-cost motor control system. The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  An electric motor control system according to the present invention includes a first motor, a second motor used in the event of a failure, an inverter circuit that receives an AC power supply and outputs a first signal for controlling the rotational speed of the motor, A first switch that transmits the first signal to the first motor and a second switch that transmits the first signal to the second motor are provided. Then, for example, the first switch / second switch is driven to be turned on / off during normal operation, whereby the first motor is driven by the inverter circuit. When the first motor fails, the first switch / second switch is driven. By driving the two switches off / on, the second motor is driven by the inverter circuit. In this way, a low-cost electric motor control system can be realized by adopting a configuration in which the first motor or the second motor can be driven by a common inverter circuit.

  To briefly explain the effects obtained by typical inventions among the inventions disclosed in the present application, a low-cost motor control system can be realized.

  In the following embodiments, when referring to the number of elements, etc. (including the number, numerical value, quantity, range, etc.), unless otherwise specified and in principle limited to a specific number in principle, It is not limited to the specific number, and it may be more or less than the specific number. In the following embodiments, when referring to the shape, positional relationship, etc. of components, etc., the shape, etc., is substantially excluding unless specifically stated or considered otherwise in principle. It shall include those that are approximate or similar to. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

(Embodiment 1)
FIG. 1 is a circuit diagram showing a configuration example of the motor control system according to the first embodiment of the present invention, and shows a circuit in the switchboard (control panel) BD of FIG. 3 described above. As shown in FIG. 1, the electric motor control system according to the first embodiment selects either one of two motors ((three-phase induction) electric motors) Mn and Mr, and converts them into one inverter circuit INV. The main feature is that it can be driven. In FIG. 1, a terminal IN to which a three-phase AC power is input is connected to one end of the breaker BRn, and the other end of the breaker BRn is connected to one end of the switch SWn1. The terminal IN is also connected to one end of the breaker BRr, and the other end of the breaker BRr is connected to one end of the switch SWr1.

  The other ends of SWn1 and SWr1 are commonly connected to the input of the inverter circuit INV via the coil L1. The output of the inverter circuit INV is connected to one end of the switch SWn2 and one end of the switch SWr2 via the coil L2. The other end of SWn2 is connected to one end of thermal relay SRn, and the other end of SWr2 is connected to one end of thermal relay SRr. The other end of SRn is connected to the motor Mn via the terminal OUn, and the other end of SRr is connected to the motor Mr via the terminal OUr.

  Inverter circuit INV receives a three-phase AC power supply as input, and once converted into a DC power supply internally, outputs a three-phase AC signal for controlling the number of revolutions of motors Mn and Mr by on / off control of internal transistors. . In addition, with each of these three phases, each connection wiring actually becomes one set, but in FIG. 1, each connection wiring is omitted as one. The coils L1 and L2 are provided for noise removal, and may be omitted depending on circumstances. The thermal relays SRn and SRr are relays having a protection function of automatically opening contacts when the load current increases abnormally, for example. The motors Mn and Mr are provided in, for example, a blower, an exhaust fan, a water supply pump, a wastewater pump, and the like, where Mn is for normal operation and Mr is for preliminary operation. Each of the switches SWn1, SWn2, SWr1, and SWr2 can be arbitrarily controlled to be turned on / off by using a control unit (not shown), for example.

  In such a configuration, during normal operation, the switches SWn1 and SWn2 are turned on and the remaining switches are turned off, so that power is supplied from the terminal IN to the inverter circuit INV via the breakers BRn and SWn1, and the output thereof Is input to the motor Mn via SWn2 and the thermal relay SRn. On the other hand, when a failure or the like of the motor Mn occurs, the switches SWr1 and SWr2 are turned on and the remaining switches are turned off to supply power from the terminal IN to the inverter circuit INV through the breakers BRr and SWr1. The output is input to the motor Mr via SWr2 and the thermal relay SRr.

  As described above, by using the common inverter circuit INV to drive the normal operation motor Mn or the preparatory operation motor Mr, for example, compared with the case of FIG. The initial cost can be reduced, and since it can be realized with a small area, it can be applied to a small switchboard BD. Therefore, a low-cost electric motor control system can be realized. In FIG. 1, power is supplied to INV by selecting either the route of breakers BRn and SWn1 or the route of BRr and SWr1, but for example, power is supplied to INV through a common route via one breaker and one switch. It is also possible to adopt a configuration in which supply is performed.

  Further, for example, a configuration in which power is supplied to INV from BRn and BRr via a common switch is also conceivable. However, in this case, since the supply current to INV during normal operation and preliminary operation is divided into two equal parts by BRn and BRr, the judgment criteria for shutting down the breaker change due to the occurrence of excess current. There is a fear. Therefore, from the viewpoint of safety, a configuration in which SWn1 and SWr1 are provided as shown in FIG. 1 is desirable.

(Embodiment 2)
The main feature of the motor control system of the second embodiment is that the motor can be directly driven by a three-phase AC power supply in addition to the configuration of the first embodiment. FIG. 2 is a circuit diagram showing a configuration example of the motor control system according to the second embodiment of the present invention, and shows a circuit in the switchboard BD of FIG. 3 described above. As shown in FIG. 2, in the motor control system of the second embodiment, a switch SWn3 is connected between the other end of the breaker BRn and one end of the thermal relay SRn in FIG. 1, and the other end of the breaker BRr and the thermal relay SRr. The switch SWr3 is connected between one end of each. That is, SWn1 and SWn3 are connected after branching from the other end of BRn, and SWr1 and SWr3 are connected after branching from the other end of BRr. Since the other configuration is the same as that of FIG. 1, detailed description thereof is omitted.

  Using such a configuration, in addition to driving the motors Mn and Mr using the inverter circuit INV, it is possible to directly drive the motors Mn and Mr using a three-phase AC power source supplied to the terminal IN. Become. When driving the motor Mn for normal operation, the SWn3 may be turned on and the others may be turned off. When driving the motor Mr for the preliminary operation, the SWr3 should be turned on and the others may be turned off. do it.

  Such switches SWn3 and SWr3 are used when, for example, it is not necessary to control the rotational speeds of the motors Mr and Mn (when the motor is used for on / off control), or the inverters are less likely. It can also be used as an emergency when the circuit INV fails. Therefore, by using the motor control system of the second embodiment, in addition to the various effects described in the first embodiment, the safety of the motor control system can be further improved.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

  For example, in FIG. 1 and the like, a case where one motor Mn is connected to the terminal OUn is an example. Of course, a plurality of motors Mn are connected in parallel from the terminal OUn without using a switch. The motor Mn may be driven by an inverter circuit at the same time. In this case, a plurality of preliminary operation motors Mr are connected in parallel from the terminal OUr without a switch if necessary. In addition, here, a three-phase motor, which is the most general industrial motor, has been described as an example. However, the present invention can be similarly applied to a configuration such as a two-phase motor and its rotation speed control circuit.

  The motor control system of the present invention is a particularly useful technique when applied to a location where high safety is required, such as a service facility of a semiconductor production line, and is not limited to this, and control when driving the motor by an inverter circuit is not limited thereto. Widely applicable as a system.

1 is a circuit diagram showing a configuration example of an electric motor control system according to Embodiment 1 of the present invention. It is a circuit diagram which shows the structural example in the electric motor control system by Embodiment 2 of this invention. It is the schematic which shows the structural example of an electric motor control system. FIG. 4 is a circuit diagram showing a configuration example in the switchboard of FIG. 3 in the motor control system studied as a premise of the present invention.

Explanation of symbols

IN, OU terminal BR breaker SW switch L coil INV inverter circuit SR thermal relay M, Mn, Mr motor AC AC power supply CBL cable

Claims (5)

A first motor;
A second motor provided in advance as an alternative to the first motor;
An inverter circuit that receives AC power and outputs a first signal for controlling the rotational speed of the motor;
A first switch for transmitting the first signal to the first motor;
A second switch for transmitting the first signal to the second motor;
One of the first switch and the second switch is driven on, and the other is driven off, so that either the first motor or the second motor is driven. system. The motor control system according to claim 1, further comprising:
First and second breakers connected to the AC power source;
A third switch for supplying the AC power to the inverter circuit via the first breaker;
A fourth switch for supplying the AC power to the inverter circuit via the second breaker,
When one of the first motor and the second motor is driven, one of the third switch and the fourth switch is driven on and the other is driven off. Control system. The motor control system according to claim 2, further comprising:
A fifth switch for supplying the AC power to the first motor via the first breaker;
A motor control system comprising: a sixth switch for supplying the AC power to the second motor via the second breaker. The electric motor control system according to claim 1,
The electric motor control system, wherein the inverter circuit and the first and second switches are provided in a switchboard. In the motor control system according to any one of claims 1 to 4,
The motor control system is used as a service facility of a semiconductor production line.

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