JP2018099025A - Apparatus and method for starting and operating ac motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce wasteful power consumption when operating an AC motor such as a three-phase squirrel-cage induction motor or a three-phase synchronous motor and to suppress an adverse effect on the AC motor when starting.SOLUTION: When a signal 35 from a working machine 9 detects that a motor 5 is under an unloaded state during operation of the motor 5, a controller 17 checks on a winding temperature 27 of the motor 5. When the winding temperature 27 is lower than a predetermined value, the controller 17 stops the motor 5 to reduce wasteful power consumption. Subsequently, when the motor 5 is under an unloaded state, the controller 17 drives a starting circuit 11 to execute voltage reduction start of the motor 5.SELECTED DRAWING: Figure 1

Description

  The present invention generally relates to an apparatus and method for starting and operating an AC motor, and more particularly to a technique for reducing wasteful power consumption.

  In an AC motor that drives a work machine such as a compressor or a pump, it is desirable to stop the motor when driving the work machine, that is, when the motor is in a no-load state, in order to reduce wasteful power consumption. In a working machine driven by an AC electric motor such as a compressor or a pump, a no-load state frequently occurs. If the electric motor is stopped each time, a large power reduction can be expected.

  However, when the AC motor is restarted after stopping, a large starting current and a large starting torque are generated. As a result, the motor windings (stator and rotor) generate heat to a high temperature or due to mechanical stress, There is a possibility of breakage of the rotor bar due to looseness of the rotor bar and short circuit ring. In addition, a large force is suddenly applied to the work machine, which may adversely affect the work machine. Especially in a high voltage and large capacity AC motor, these adverse effects are remarkable, and frequent stop and restart of the motor may cause damage to the motor or shorten the life. Therefore, the frequency of start-up of a large capacity AC motor is limited to a very low level. For example, even if a no-load condition occurs many times during the day, the current situation is that the vehicle continues to operate all day.

In order to start the AC motor while suppressing the starting current and the starting torque, several reduced voltage starting methods are known. For example, typical reduced voltage starting methods for a three-phase squirrel-cage induction motor include star delta starting, reactor starting, compensator starting, and inverter starting.

  Patent Document 1 and Non-Patent Document 1 disclose devices that perform a reduced voltage starting method different from the above. This starter gradually increases the input voltage of the three-phase induction motor using thyristor phase control.

  This starter can suppress start current and start torque more effectively than traditional star delta start, reactor start and compensator start. In addition, this starting device can reduce power consumption more effectively compared to the inverter starting because there is no useless power loss in the AC / DC conversion and the orthogonal conversion of the inverter. In addition, since this starter has no conversion loss, heat generation is minimal, so that the life of the main body is long, and the necessity for measures against harmonics and noise is low.

JP 2000-201490 "Electronically controlled starter for three-phase induction motors" by Masato Hirata, pages 28-32, Boiler Turbine Avenue 2000 winter issue

  An object of the present invention is to reduce wasteful power consumption during operation of an AC motor.

  Another object of the present invention is to suppress adverse effects on the AC motor when the AC motor is started.

  Another object of the present invention is to make it possible to start the AC motor more appropriately.

  Another object of the present invention is to improve the convenience of a starter for an AC motor.

  An apparatus for starting and operating an AC motor as an example includes a starting circuit that outputs a voltage reduced from the total voltage of the power source to the AC motor when the AC motor is started, and a total voltage of the power source when the AC motor is operating. Is supplied to the AC motor, and a starting circuit and a controller for driving the switch are provided.

The controller may be configured to execute a control process having the following steps.
・ Steps to determine whether the AC motor is loaded or unloaded ・ Steps to determine whether the AC motor is in a restartable state ・ When the AC motor is in operation, If it is determined that the AC motor can be restarted at the same time, open the switch to stop the AC motor.After stopping the AC motor, if it is determined that the AC motor is in a load state, drive the start circuit. Steps for starting the AC motor ・ Steps for starting the AC motor by closing the switch after starting the AC motor

  The above starting and operating device opens the switch and stops the AC motor when it is determined that the motor is in a no-load state and can be restarted at the same time during operation of the motor. As a result, the electric power that was wasted in the conventional operation method of operating the electric motor even in a no-load state is reduced.

  In addition, the above starting and operating device stops the electric motor when it is determined that the electric motor is in a no-load state and can be restarted at the same time. . At this time, since the electric motor is in a restartable state, an adverse effect on the electric motor due to the start is small.

  The determination as to whether or not the motor is in a restartable state can be made based on information related to the temperature state of the motor, for example. Such information may include, for example, motor winding temperature, motor housing temperature, motor noise and vibration, motor start frequency, motor rotation speed and output torque, and the like.

  The determination of whether the electric motor is in a loaded state or an unloaded state can be made based on information related to the operation or stop of the work machine driven by the electric motor. Such information may be, for example, a work machine operation command or stop command, a predetermined parameter value used in the control of the work machine operation and stop, and the like.

  As the starting circuit, one having a plurality of semiconductor switching elements (for example, a pair of thyristors connected in antiparallel for each phase) provided between the power source and the electric motor can be used. Then, the voltage drop start can be performed by controlling the ignition phase angle of these semiconductor switching elements.

  When such a starting circuit is used, the starting voltage can be controlled in an arbitrary pattern by the ignition angle control, so that the adverse effect on the motor due to the starting can be effectively reduced. Therefore, it is possible to loosely set a reference for determining that the electric motor is in a restartable state. As a result, the opportunity to stop the motor at no load increases, and the power consumption can be more effectively reduced.

  The starting and operating device according to the present invention may include a failure countermeasure module for opening or closing the switch manually or automatically when an abnormality or failure occurs in the controller. Thereby, even when the controller is abnormal or faulty, the motor can be started, operated and stopped.

The controller may be configured to perform a fee notification process having the following steps.
・ Steps for grasping the length of time when the AC motor stops in a no-load state ・ Steps for grasping the power consumption when the AC motor is operated in a no-load state ・ Based on the above-mentioned time length and the power consumption, the AC motor A step of calculating the electricity bill or power consumption reduced due to the shutdown in the no-load state and the step of notifying the user of the electricity bill or power consumption reduced

  By the above charge notification process, the user can realize the merit of stopping the motor when there is no load as a specific numerical value.

  The controller is configured to control the ignition phase angle of the semiconductor switching element so that the deviation of the output voltage of the starting circuit is compared with a preset starting voltage pattern at the time of starting the electric motor, and the deviation becomes zero. Good. Thereby, the starting voltage of an electric motor can be made to correspond with a predetermined voltage pattern accurately. By appropriately selecting the voltage pattern according to the specification of the electric motor and the work machine, it is possible to effectively suppress the adverse effect on the starting electric motor.

  The controller may be configured to monitor the rotational speed of the electric motor when starting the electric motor, and to control the timing for closing the switch based on the rotational speed. Accordingly, it is easy to appropriately detect the completion of the start and shift the motor to the operation without being influenced by the magnitude and characteristics of the load applied to the motor at the start.

An example method for starting and operating an AC motor may include the following steps.
・ Steps to determine whether the AC motor is loaded or unloaded ・ Steps to determine whether the AC motor is in a restartable state ・ When the AC motor is in operation, Steps to stop the AC motor if it is determined that the AC motor can be restarted at the same time ・ Steps to start the voltage reduction of the AC motor if it is determined that the AC motor is in a load state after stopping the AC motor Step to start AC motor after starting

  An AC motor start-up and operation device as an example includes a main power supply path for supplying power from a power source to the AC motor, and a maintenance bypass connected in parallel to the main power supply path. The main power supply path includes a start circuit that outputs the reduced AC voltage to the AC motor by switching the AC total voltage from the power source when the AC motor is started, and the AC power source that is connected to the AC power source when the AC motor is in operation. It has a switch that outputs to the motor, a starter circuit, and a controller that drives the switch, and is configured so that power can be supplied from the power source to the AC motor through one or both of the starter circuit and the switch. The maintenance bypass has a maintenance bypass switch that opens and closes the maintenance bypass, and is configured to supply power from the power source to the AC motor through the maintenance bypass during maintenance of the main power supply path.

  As an example, an AC motor start-up and operation device includes a start circuit that outputs a reduced AC voltage to an AC motor by switching all AC voltages from the power source when the AC motor is started, and a power source that is operated when the AC motor is operated. A switch that outputs all of the voltage to the AC motor, a starting circuit, and a controller that drives the switch. The controller has control parameters for controlling the starting circuit and the switch, and drives the starting circuit and the switch using the control parameter. The control parameters can be changed. By appropriately controlling the starting circuit and the switch according to the control parameters, adverse effects on the motor at the start of the motor are suppressed, or the motor is stopped and restarted according to the state of the motor and its load machine. It is possible to control while suppressing the adverse effect of. This is useful for reducing unnecessary power consumption by allowing the motor to be stopped more frequently when the motor is not loaded.

  Examples of the control parameters described above are the start voltage pattern for controlling the output voltage from the start and operation device to the motor when the motor is started, or the output voltage from the start and operation device to the motor when the motor is stopped. The stop voltage pattern may be An example of the starting voltage pattern may be a multi-stage starting voltage pattern configured to increase the output voltage of the starting circuit in multiple stages of three or more stages. This multi-stage starting voltage pattern maintains the current stage voltage for the current stabilization time after raising the output voltage of the starting circuit from the previous stage voltage to the current stage voltage in each stage. This multistage starting voltage pattern is also useful for the purpose of reducing the starting current of the motor and reducing the adverse effects of starting.

  Another example of the control parameter described above is to determine whether to stop the motor during operation of the motor and / or to determine whether to restart the motor once stopped or It may be a condition relating to the state of the electric motor and work machine to do. By controlling the control parameters, the above determination is appropriately performed, and the stop timing and / or restart timing of the motor is appropriately controlled, so that useless power consumption of the motor can be reduced.

  The controller described above may be configured such that the various control parameters it has are controlled by a learned neural network that has learned the function of determining those control parameters. The learned neural network may be provided within the controller, or may be provided outside the controller and configured to be communicatively connected to the controller to provide control parameters to the controller.

  As an example, a parameter control system for an AC motor start-up and operation device includes a server computer communicably connected to one or more AC motor start-up and operation devices located at one or more sites. Each on-site starting and operating device includes a starting circuit that outputs a reduced AC voltage to the AC motor by switching all AC voltages from the power source when starting the AC motor at each site, and a power source when operating the AC motor. A switch that outputs all of the voltage to the AC motor, a starting circuit, and a controller that drives the switch. The controller has control parameters for controlling the starting circuit and the switch, and the control parameters can be changed. In addition, the server computer includes an on-site database that stores on-site data on the AC motors at each site and work machines connected thereto, an inference system that controls control parameters for each site based on the on-site data, and an inference system And an interface for providing control parameters for each site controlled by the controller to each site.

  The above parameter control system provides a control parameter for controlling a voltage applied to each AC motor to an AC motor start and operation device installed in one or a plurality of sites, and controls the control parameter. be able to. By appropriately controlling the control parameters, it is possible to reduce the starting current of the motor and suppress the adverse effect of starting, or to stop unnecessary operation of the motor while suppressing the adverse effect on the motor. This contributes to reducing useless power consumption of the electric motor.

  In the above parameter control system, the starting and operating device of each site may be configured to obtain the site data of each site from a sensor or the like and transmit it to the server computer.

  Furthermore, the inference system of the server computer can have a neural network in which functions or algorithms for controlling the control parameters for each site are machine-learned from the field data of each site. The neural network may be configured to learn the above algorithm using field data supplied to the server computer from each field start and run device. The neural network of the inference system may be configured to acquire a function for automatically determining optimum control parameters by machine learning using a large amount of field data collected from one or more fields. As described above, a learning system for collecting field data from one or a plurality of fields and performing machine learning of a neural network may be provided in the server computer or outside the server computer. By using the reasoning system, it is possible to monitor and optimize the starting and operating states of the motor. It also helps to shorten equipment downtime by predicting, detecting, preventing, and reducing unnecessary inspection work for motors.

1 shows a configuration of an AC motor start-up and operation device according to one embodiment of the present invention. The conditions relating to the winding temperature of the motor for determining whether to continue or stop the operation of the motor when no load is employed in the apparatus will be shown. A part of the flow of one control example of starting and operation of an AC motor performed by the apparatus is shown. The other part of the control flow is shown. The rest of the control flow is shown. Several examples of start voltage patterns and stop voltage patterns that can be used in the same control are shown. The flow of one control example for the display of the reduction electricity bill which the apparatus performs is shown. An example of a configuration of an uninterruptible maintenance circuit that enables maintenance work of the apparatus to be performed during operation of the AC motor is shown. The flow of control of an uninterruptible maintenance circuit at the time of starting of an AC motor is shown. The flow of control of the uninterruptible maintenance circuit when starting and maintaining the operating device during operation of the AC motor is shown. The flow of control of the uninterruptible maintenance circuit at the time of start-up and restoration of the operating device is shown. 1 shows an example of the configuration of a parameter control system for automatically controlling start parameters and stop parameters of the operation and start device of FIG. 1. An example of the configuration of an artificial intelligence system that can be employed in the parameter control system is shown. The example of a multistage starting pattern and a starting parameter is shown.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows the configuration of an AC motor starting and operating apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the starting and operating device 1 is provided between a three-phase AC power source 3 and a three-phase AC motor 5 and can control the input voltage of the motor 5. The electric motor 5 is, for example, a three-phase squirrel-cage induction motor. In order to drive the work machine 9, the output rotary shaft 7 of the electric motor 5 is coupled to the input rotary shaft of the work machine 9. The work machine 9 may be a machine driven by, for example, a compressor, a pump, a blower, or other electric motor. A cooling device (for example, a blower fan) (not shown) for cooling the electric motor 5 is also coupled to the rotating shaft 7 of the electric motor 5.

  The starting and operating device 1 includes a starting circuit 11, a main switch 13, a bypass switch 15, a controller 17, a manual start and stop switch 19, and the like.

  The starting circuit 11 is inserted into a three-phase power line between the power source 3 and the electric motor 5 and controls the three-phase input voltage of the electric motor 5 when the electric motor 5 is started and stopped. In the present embodiment, the starting circuit 11 includes a semiconductor switching element connected in reverse parallel, for example, a pair of thyristors connected in reverse parallel (thyristor stack) as an element of each phase.

  The controller 17 controls the firing phase angle of the three-phase thyristor stack of the starting circuit 11 and gradually increases the input voltage of the motor 5 from a low value, so that the motor 5 can be started at a reduced voltage. . A basic method of starting a reduced voltage of the electric motor 5 using such thyristor phase control is disclosed in Patent Document 1 or Non-Patent Document 1 described above.

  When the electric motor 5 is stopped, the controller 17 controls the ignition phase angle of the three-phase thyristor stack of the starting circuit 11 to gradually reduce the input voltage of the electric motor 5. Can be softly stopped (this is called soft stop). Further, when the motor 5 is stopped, only the one-way thyristor of the three-phase thyristor stack of the start circuit 11 is turned on to apply a DC voltage to the motor 5, thereby causing the motor 5 to function as a generator. 5 and work machine 9 can also be braked (this is called dynamic braking).

  In the three-phase power line between the power source 3 and the electric motor 5, a main switch 13 is further inserted in series with the starting circuit 11 on the temporary side of the starting circuit 11. The main switch 13 is a three-phase electromagnetic switch, and its turn ON and turn OFF are controlled by the controller 17. The starting circuit 11 can function only when the main switch 13 is ON.

  Further, a bypass switch 15 is provided on the three-phase power line in parallel with the starting circuit 11. The bypass switch 15 is a three-phase electromagnetic switch, and its turn ON and turn OFF are controlled by the controller 17. When the bypass switch 15 is ON, the electric motor 5 is directly connected to the power source 3 and the entire voltage is input to the electric motor 5. During the start of the reduced voltage by the starting circuit 11, the bypass switch 15 is turned off. When the reduced voltage start is completed, the bypass switch 15 is turned on, so that the electric motor 5 shifts from the start state to the operation state. When the start is completed, for example, when the output voltage of the start circuit 11 and the power supply voltage coincide with each other, the bypass switch 15 is turned on, and the start circuit 11 and the bypass open / close for a certain period of time (for example, 2 seconds). The devices 15 may be turned on in parallel, and then the starting circuit 11 may be turned off. Thereby, a potential difference and a phase difference can be suppressed, and shock and contact wear when the bypass switch 15 is turned on can be reduced.

  The controller 17 controls the starting and operation of the electric motor 5 by controlling the starting circuit 11, the main switch 13 and the bypass switch 15. The start and operation control performed by the controller 17 includes sub-control for reducing the power consumption of the electric motor 5. This sub-control for power reduction is when the motor 5 is in a no-load state during the operation of the motor 5 (that is, when the operation of the work machine 9 should be stopped or stopped). If the predetermined condition is satisfied, the electric motor 5 is stopped, and then, when the electric motor 5 is loaded again (that is, when the operation of the work machine 9 is to be resumed), the electric motor 5 is started to reduce the voltage. It is a function. Here, the above-mentioned “predetermined conditions” are conditions under which temporary stop of the electric motor 5 is permitted (or restart of the electric motor 5 immediately after the temporary stop). One of the conditions is, for example, that the temperature of the winding (stator winding or / and rotor winding) of the electric motor 5 is lower than a certain threshold temperature. Furthermore, the controller 17 also has a function of notifying (for example, displaying) the user the power charge reduced by the sub-control for reducing power.

  The input signal to the controller 17 includes, for example, an input current signal 21 indicating a three-phase input current to the motor 5, an input voltage signal 23 indicating a three-phase input voltage to the motor 5, and an ON / OFF state of the bypass switch 15. , A winding temperature signal 27 indicating the temperature of the winding of the electric motor 5, a rotation speed signal 31 indicating the rotation speed of the electric motor 5, an operation and stop command 35 of the work machine 9, and the like. Further, other signals indicating some state of the electric motor 5 such as signals (not shown) respectively indicating vibration and sound of the electric motor 5 can also be input signals to the controller 17. The input current signal 21 is provided from, for example, an instrument current transformer CT provided in a three-phase power supply line from the power supply 3. The input voltage signal 23 is provided from, for example, an instrument transformer VT provided on a three-phase power supply line to the electric motor 5. The bypass state signal 25 is provided from an auxiliary contact (not shown) of the bypass switch 15, for example. The winding temperature signal 27 is, for example, in the winding of the electric motor 5 (for example, in the stator winding or the rotor winding) (or a portion close to the stator winding like the casing of the electric motor 5, or A temperature sensor 29 (not only a contact-type temperature sensor but also a non-contact function such as an infrared temperature sensor) provided at a location close to the rotor winding, such as the rotating shaft of an electric motor, or wirelessly A temperature sensor that can transmit a sensing result may be used, or a temperature may be estimated by calculation from other parameters such as a resistance value). The rotation speed signal 31 is provided from a rotation speed meter 33 provided on the output rotation shaft 7 of the electric motor 5, for example. The operation and stop command 35 is an instruction to operate or stop the work machine 9, and is provided from the work machine 9, for example.

  The operation and stop command 35 described above is used for the controller 17 to know whether the electric motor 5 is in a loaded state or a no-load state. Therefore, one or more parameter values that can be used to determine whether the work machine 9 is to be operated or stopped are determined in place of the operation and stop command 35 or in combination with the operation and stop command 35 to determine load / no load. You may use for. As such parameter values, pressure, temperature, current value, liquid level height, concentration, weight, water quality, photoelectric sensor signal, depth, etc. are selectively or according to the type, role or function of the work machine 9 Can be used in combination. For example, when the work machine 9 is a compressor, the supply pressure of the compressor, the pressure of the air tank, the piping pressure, or the like can be adopted as the parameter value. For example, the storage water level when the work machine 9 is a pump for pumping water, the air volume and / or wind force of the blower when the work machine 9 is a blower, and the dust or carbon dioxide when the work machine 9 is a dust collector Or the temperature to be cooled when the work machine 9 is a refrigerator can be used as the parameter value.

  The winding temperature signal 27 described above is used by the controller 17 to determine whether or not the temporary stop of the electric motor 5 (or restart of the electric motor 5 immediately after the temporary stop) is permitted. Therefore, a signal indicating one or more other characteristic values that can be used as a basis for this determination may be used instead of the winding temperature signal 27 or in combination with the winding temperature signal 27. As such characteristic values, for example, the temperature of a part other than the winding of the electric motor 5, the frequency or time interval of restarting the electric motor 5 in the most recent predetermined period, the power consumption of the electric motor 5 in the most recent predetermined period, the electric motor 5 The rotational speed and output torque of the most recent predetermined period, or the magnitude of noise or vibration of the electric motor 5 can be adopted.

  The output signal from the controller 17 includes, for example, a main opening / closing signal 41 for opening / closing the main switch 13, a bypass opening / closing signal 43 for opening / closing the bypass switch 15, and a point to each thyristor of the starting circuit 11. There is an arc signal 45 and the like.

  Various designs can be adopted for the hardware configuration of the controller 17. In FIG. 1, the controller 17 is illustrated in the form of a somewhat simple model for the sake of easy understanding of the control function of the controller 17, and this model looks like a single computer. However, this is merely an example, and the controller 17 may be configured using, for example, a combination of a plurality of programmable logic controllers, computers, or other electronic circuits.

  According to the configuration example shown in FIG. 1, the controller 17 includes an input / output interface 51, a CPU 53, a storage device 55, a display 57, an operation panel 59, and the like. The input / output interface 51 transmits / receives the above-described input / output signals 21, 23, 25, 27, 31, 35, 41, 43, 45 to / from the above-described devices CT, VT, 9, 11, 13, 15, 29, 33. . The CPU 53 performs information processing for starting and operating the motor 5 and information processing for displaying reduced power. The storage device 55 stores programs and data for the operation of the CPU 53, and provides a work area for the CPU 53. The indicator 57 is, for example, a plurality of display lamps, a liquid crystal display panel, or a combination thereof, and provides the user with predetermined information related to starting and operation of the electric motor 5. The operation panel 59 is, for example, a plurality of manual switches or manual buttons, a touch panel, or a combination thereof, and is operated by the user to perform condition setting and data input related to starting and operation of the electric motor 5.

  The controller 17 may include one or more specific function modules 61 that perform specific functions exclusively. For example, a thyristor phase control circuit that controls the phase angle of the ignition signal 45 to the starting circuit 11 may be provided as the specific function module 61.

  The controller 17 may also include a failure countermeasure module 63. The failure countermeasure module 63 starts and stops the electric motor 5 independently of the normal control of the controller 17 when a failure that prevents normal control in the controller 17 occurs. That is, the failure countermeasure module 63 monitors a failure that occurs in the controller 17 and generates a predetermined failure that prevents normal control of the controller 17 (for example, an error or failure of the CPU 53 or a failure of the display device 57). When recognized, a bypass opening / closing signal 65 different from the bypass opening / closing signal 43 output based on the normal control of the controller 17 is output to the bypass switch 15 to control the opening / closing of the bypass switch 15. Thereby, even when the controller 17 cannot perform normal control, the electric motor 5 can be started, operated, and stopped.

  The manual start / stop switch 19 is a switch for the user to manually perform the same function as the failure countermeasure module 63 described above. That is, when the user knows that the controller 17 cannot perform normal control (for example, the display device 57 is turned off and the state of the controller 17 is unknown to the user), the user starts the manual start / stop button 19. , The bypass opening / closing signal 47 different from the bypass opening / closing signal 43 from the controller 17 can be applied to the bypass switch 15. Thereby, at the time of failure of the controller 17, the user can start, drive and stop the electric motor 5 manually.

  FIG. 2 shows a condition relating to the winding temperature of the motor 5 that is used to determine whether to operate or stop the motor 5 when there is no load and when the motor 17 is started and operated. Indicates.

  As shown in FIG. 2, there are two different set temperatures T1 and T2. If the winding temperature is lower than the lower first set temperature T1, the winding in the motor 5 can be performed even if the motor 5 is stopped when no load is applied (even if the start-up circuit 11 starts a reduced voltage). The temperature is chosen so that problems such as wire overheating do not occur. The higher second set temperature T2 is selected such that if the winding temperature is higher than that, it is safe for the motor 5 to stop the motor 5 regardless of load or no load. . These set temperatures T1 and T2 are set by the operation panel 59 and stored in the storage device 55.

  Therefore, in the first case where the winding temperature is lower than the first set temperature T1, the controller 17 operates the electric motor 5 at the time of load, but stops the electric motor 5 at the time of no load. By stopping the electric motor 5 at the time of no load, useless power consumption of the electric motor 5 is reduced.

  Further, in the second case where the winding temperature is between the first set temperature T1 and the second set temperature T2, the controller 17 operates the electric motor 5 at the time of load and no load. Further, in the third case where the winding temperature is equal to or higher than the second set temperature T2, the electric motor 5 is stopped during both loading and no loading. However, in the third case, the electric motor 5 is not stopped immediately, and the electric motor 5 is kept running until the winding temperature reaches a safe temperature (for example, the first set temperature T1 or less). The motor 5 may be stopped after cooling.

  3, 4 and 5 show the flow of one control example of starting and operation of the electric motor 5 performed by the controller 17.

  As shown in FIG. 3, after the control is started, it is checked whether the automatic mode or the manual mode is selected on the operation panel 59 (step S1). The automatic mode is a mode in which the controller 17 automatically controls the start, operation, and stop of the electric motor 5. The manual mode is a mode in which the user manually controls start, operation, and stop of the electric motor 5.

  If the electric motor 5 manual mode is selected (NO in step S2), “manual” is displayed on the display 57, and it is checked whether the start button of the operation panel 59 is turned on (step S4). When the start button is turned on (YES in step S5), the main switch 13 is turned on (step S6), the bypass switch 15 is turned on (step S7), and “run” is displayed on the display 57. Is displayed (step S8). As a result, the electric motor 5 is started at the full voltage and is put into operation.

  Thereafter, it is checked whether the stop button of the operation panel 59 is turned on (step S9). When the stop button is turned on (YES in step S10), the main switch 13 is turned off (step S6), the bypass switch 15 is turned off (step S12), and “stop” is displayed on the display 57. Is displayed (step S13), and the control ends. Thereby, the electric motor 5 is stopped.

If the automatic mode is selected as a result of checking the selection mode described above (YES in step S2), “automatic” is displayed on the display 57 (step S20), and the “stop” display is turned off (step S20). Step S21). Then, it is checked whether the starting condition is satisfied (step S22). The starting condition is a condition where the electric motor 5 may be started. For example, all the following four sub-conditions are satisfied.
1. The winding temperature of the electric motor 5 is lower than the first set temperature T1.
2. There is no external alarm for the work machine 9.
3. There is no abnormality in the starting and operating device 1.
4). Both the main switch 13 and the bypass switch 15 are in the OFF state.

  When the above start condition is satisfied (YES in step S22), it is checked whether or not the operation command 35 from the work machine 9 is ON (that is, whether or not the work machine 5 should be operated) ( Step S23). If the operation command is ON (YES in step S23), the main switch 13 is turned ON (step S24), and the first timer is started (step S25). The first timer counts a time corresponding to a delay time until the contact of the main switch 13 is reliably closed after the turn-on (excitation) of the main switch 13 is started. If the first timer expires (YES in step S26) (that is, if the main switch 13 is surely turned on), the control proceeds to the process from point A shown in FIG.

  As shown in FIG. 4, firing of the thyristors of the starting circuit 11 is started, and firing of each thyristor is performed such that the output voltage of each phase of the starting circuit 11 rises along a predetermined starting voltage pattern. The phase angle is controlled (step S30). The ignition phase angle is controlled, for example, by feedback of the output voltage of each phase of the starting circuit 11 and adjusting the phase ignition angle so as to eliminate the deviation between the output voltage and the starting voltage pattern. It can be done by the method. Thereby, the reduced voltage start of the electric motor 5 is performed.

  The starting voltage pattern is set in advance on the operation panel 59 and stored in the storage device 55. Alternatively, an appropriate startup pattern is supplied to the controller 17 from the server computer shown in FIG. 12 described later or the artificial intelligence system shown in FIG. May be stored. Alternatively, the starting voltage pattern of the controller 17 may be optimized in real time by a server computer shown in FIG. 12 described later or an artificial intelligence system shown in FIG.

  Some examples 101, 103, 105 of possible starting voltage patterns are shown in FIG. A starting voltage pattern 101 indicated by a solid line is a starting method called “soft start” in which the output voltage of each phase is monotonously increased from the initial voltage V0 to the power supply voltage Vs during the starting time Tst. Another starting voltage pattern 103 indicated by a one-dot chain line shows a sudden increase in voltage in a voltage region (primary dangerous speed region) where the rotational speed of the rotating machine (electric motor 5 and work machine 9) passes a predetermined primary dangerous speed. This is a starting method for avoiding harmful effects such as vibration expansion in the primary dangerous speed range by passing through here quickly. The starting voltage pattern 105 indicated by a broken line is a pattern in which, when the required torque at the time of initial operation (beginning of movement) of the rotating machine is large, a high voltage is first temporarily applied to start the rotating machine, and then the voltage is dropped. This is a start method called “kick start” in which soft start is performed as in 101. As in these examples, the starting voltage pattern can be arbitrarily set or controlled. Parameters that define the starting voltage pattern (for example, initial voltage V0, starting time Tst, primary dangerous speed range Vfc1 and Vfc2, primary dangerous speed avoidance time Tfc, kick voltage Vk, kick time Tk, etc.) This is referred to as “starting control parameter”. The motor 5 can be started with an optimal starting voltage pattern by appropriately setting or controlling the starting control parameter according to the characteristics of the electric motor 5 and the work machine 9, so that the motor 5 is overheated and mechanical load is started. Can be more effectively suppressed than the conventional starting method. In FIG. 6, the parallel operation time Tpd1 is a time for turning on the start circuit 11 and the bypass switch 15 in parallel immediately after the start pattern is completed, and this can also be included in the start control parameter.

Referring to FIG. 4 again, while the reduced voltage start is being performed by the thyristor phase control in step S30, “starting” is displayed on display 57. Thereafter, it is checked whether or not the reduced voltage start is completed (step S32). Completion of the start-up can be determined, for example, based on whether one or a combination of two or more of the following three sub-conditions or all of them are satisfied.
1. The rotation speed of the electric motor 5 was stabilized at the rated rotation speed.
2. The output voltage of the starting circuit 11 (input voltage of the electric motor 5) was stabilized at the rated voltage.
3. The current flowing through the starting circuit 11 (input current of the motor 5) was stabilized at the rated current.
4). A predetermined starting time has elapsed.
In particular, the first sub-condition that the rotation speed of the motor 5 is stabilized at the rated speed is effective regardless of the load applied to the motor 5. Therefore, the start completion may be determined only by the first sub-condition.

  When the start is completed (YES in step S32), the bypass switch 15 is closed and the entire voltage is applied to the motor 5 (step S33), and then the ignition of the thyristor of the start circuit 11 is stopped (step S34). ). Thereby, the electric motor 5 starts operation. Then, the display 57 erases the display of “being started” (step S35) and displays “running” (step S36). Then, the controller 17 recognizes that the electric motor 5 is in operation (step S37). In addition, a certain time (for example, 2 seconds) is set between steps S33 and S34, and during that time, the starter circuit 11 and the bypass switch 15 are turned on in parallel, and then the starter circuit 11 is turned off. Good. Thereby, a potential difference and a phase difference can be suppressed, and shock and contact wear when the bypass switch 15 is turned on can be reduced.

  Thereafter, it is checked whether or not the stop command 35 from the work machine 5 has been turned ON (that is, whether the work machine 5 should be stopped or the electric motor 5 has become unloaded) (step S38). When the stop command is turned on (YES in step S38), it is checked whether or not the winding temperature of the electric motor 5 is lower than the first set temperature T1 (step S39). As a result, if the winding temperature is higher than the first set value (NO in step S39), it means that stopping the motor 5 now and restarting it after a short time may adversely affect the motor 5. Therefore, the control returns to step S33, and the operation of the electric motor 5 is continued.

  On the other hand, if the winding temperature is lower than the first set value in step S39 (YES in step S39), it does not adversely affect the motor 5 even if the motor 5 is stopped now and restarted after a short time. Means that. In this case, control proceeds to the process from point B shown in FIG.

If the stop command for the work machine 9 is not ON in step S38 described above (NO in step S38), it is checked whether the stop condition is satisfied (step S40). The stop condition is a condition for stopping the work machine 5 due to an abnormal situation. For example, one of the following three sub-conditions is satisfied.
1. The winding temperature of the electric motor 5 is higher than the second set temperature T2.
2. An external alarm for work machine 9 occurred.
3. An abnormality occurred in the starting and operating device 1.

  If the stop condition is not satisfied in step S40 (NO in step S40), the control returns to step S33, and the operation of the electric motor 5 is continued.

  On the other hand, if the stop condition is satisfied in step S40 (YES in step S40), it means that the motor 5 should be stopped because an abnormal situation has occurred. In this case, control proceeds to the process from point C shown in FIG.

  Referring to FIG. 5, the process from point B is control when the stop command for motor 5 is turned ON during operation of motor 5 (that is, when motor 5 is in a no-load state). In this control, the thyristor of the starting circuit 11 is fired with a phase angle of zero (step S50), and then the bypass switch 15 is opened (step S51). Thereby, the entire voltage of the power source 3 is applied to the electric motor 5 only through the starting circuit 11.

  Thereafter, thyristor phase control of the starting circuit 11 is performed, and the voltage applied to the electric motor 5 is reduced to 0 V along a predetermined stop voltage pattern (step S52). This phase control can also be performed by a feedback control method that eliminates the deviation between the output voltage of the start circuit 11 and the stop voltage pattern, as in the start. Here, the stop voltage pattern is set in advance on the operation panel 59 and stored in the storage device 55. Alternatively, an appropriate stop voltage pattern is supplied from the server computer shown in FIG. 12 described later or the artificial intelligence system shown in FIG. 13 to the controller 17 at the time of initial setting or at the time of initial setting and thereafter and stored. It may be stored in the device 55. Alternatively, the stop voltage pattern of the controller 17 may be optimized in real time by a server computer shown in FIG. 12 or an artificial intelligence system shown in FIG.

  Some examples 106, 107, 108 of possible stop voltage patterns are shown in FIG. A stop voltage pattern 106 indicated by a solid line in FIG. 6 is a stop method called “soft stop” in which the output voltage of each phase is monotonously lowered from the power supply voltage Vs to zero during the stop time Tsp1. When the work machine 9 is a water pump, when the work machine 9 is a water pump, the stop voltage pattern 107 indicated by the alternate long and short dash line is used to prevent the water hammer effect that occurs when the work machine 9 is suddenly stopped. In this method, the voltage is lowered to the one-stage voltage drop Vfd, and then maintained at the one-stage voltage drop Vfd for the water hammer prevention time Twh, and then lowered to zero over the two-stage voltage drop time Tsd. The stop voltage pattern 108 indicated by a broken line first sets the output voltage to zero during the reverse phase switching time Tch in order to use the reverse phase braking of the AC motor 5 and switches the AC motor 5 to the reverse phase during that time. After that, the soft stop voltage Vss is maintained for the reverse phase braking time Tbk, and then is lowered to zero over the stop time Tsp2. Although not shown in the figure, it is also possible to perform dynamic braking by applying a DC voltage between the two wires of the AC motor 5. As in these examples, the stop voltage pattern can be set arbitrarily. In this specification, various parameters for defining the stop voltage pattern, that is, for controlling the stop operation (for example, the stop time Tsp1, the one-stage voltage drop time Tfd, the two-stage voltage drop time shown in FIG. 6). Tsd, one-step voltage drop Vfd, reverse phase switching time Tch, reverse phase braking time Tbk, stop time Tsp2, soft stop voltage Vss, etc.) are referred to as “stop control parameters”. By appropriately setting or controlling the stop control parameter according to the characteristics of the electric motor 5 and the work machine 9, the electric motor 5 can be stopped with an optimal stop voltage pattern. Note that the parallel operation time Tsp2 immediately before the start of the stop shown in FIG. 6 is a time for turning on the start circuit 11 and the bypass switch 15 simultaneously in parallel, and this can also be included in the stop control parameter.

  Furthermore, dynamic braking can be applied as needed during this stopping process. That is, only the one-way thyristor of the starting circuit 11 is ignited and a direct current is applied to the electric motor 5, thereby operating the electric motor 5 as a generator and applying braking. The braking force can be adjusted by the ignition phase angle of the thyristor, that is, the height of the voltage applied to the motor 5. For example, when the inertial force of the work machine 9 is large and a desired stop cannot be achieved simply by reducing the voltage of the motor 5, the motor 5 can be stopped more desirably by applying a dynamic brake.

  When the above-described stop process is completed, the starting of the thyristor of the starting circuit 11 is stopped (step S53), and the display of “in operation” is turned off (step S54). Subsequently, the second timer is started (step S56). The second timer counts a predetermined time that should be set for safety after the thyristor of the starting circuit 11 is stopped until the main switch 13 is opened.

  When the second timer counts up (YES in step S56), the main switch 13 is opened (step S57), and “stop” is displayed on the display 57 (step S58). Thus, the control is completed for the time being, and the work command of the work machine 9 is turned ON (that is, the operation of the work machine 9 is to be resumed, that is, the electric motor 5 is loaded again). . Thereafter, when the work command is turned ON, control resumes from the process shown in FIG. Therefore, as long as the automatic mode is still selected (YES in step S22) and the start condition is satisfied (YES in step S23), the electric motor 5 is started again (process after step S24).

  Referring to FIG. 5 again, the process from point C shows the control when the stop condition is satisfied (YES in step S40 in FIG. 4). In this control, it is checked whether or not the winding temperature of the electric motor 5 is lower than the first set temperature T1 (step S60). If the winding temperature is not lower than the first set temperature T1 (NO in step S60), the control returns to step S33 shown in FIG. 4 to cool the electric motor 5, and the winding temperature is set to the first set temperature T1. The operation of the electric motor 5 is continued until it becomes lower.

  If the winding temperature is lower than the first set value T1 in step S60 shown in FIG. 5 (YES in step S60), the control proceeds to the process from step S50 already described, and the electric motor 5 is stopped.

  As described above, in the automatic mode, when the motor 5 is operating in a load state, the controller 17 changes the winding temperature of the motor 5 to the first set temperature T1 if the motor 5 shifts to a no-load state. As long as it is lower (that is, there is no problem if the motor 5 is restarted within a short time thereafter), the motor 5 is stopped to prevent wasteful power consumption. Thereafter, when the electric motor 5 shifts to the load state again, the controller 17 starts to reduce the voltage of the electric motor 5 and resumes operation. On the other hand, when the winding temperature of the electric motor 5 is higher than the first set temperature T1 (that is, if the electric motor 5 is restarted within a short time thereafter, the electric motor 5 may be adversely affected), the controller 17 Even when the electric motor 5 is in a no-load state, the operation of the electric motor 5 is continued, thereby preventing a restart that causes an adverse effect.

  FIG. 7 shows the flow of an example of control performed by the controller 17 for displaying the reduced electricity bill.

As shown in FIG. 7, operation data of the electric motor 5 is collected. As the operation data, for example, the following data in a predetermined period (for example, the current month) is collected.
w1: Power consumption when the motor 5 has been operated without load until now (for example, average value)
w2: Power consumption when the electric motor 5 has been operated in the load state so far (for example, average value)
t1: The length of time when the motor 5 has been stopped under no load until now
t2: Length of time when the motor 5 has been operated without load until now
t3: The length of time when the electric motor 5 has been operated in the load state until now. This data collection is repeated periodically. Thereby, the operation data is updated to the latest value substantially in real time.

  Here, “when the motor 5 is operated in a no-load state” means that the motor 5 cannot be stopped even in the no-load state because the winding temperature is equal to or higher than the first set temperature T1. Further, “when the motor 5 is stopped in a no-load state” means a case where the motor 5 is stopped in a no-load state because the winding temperature is lower than the first set temperature T1. The power consumption w1, w2 is calculated from the three-phase current signal 21 and voltage signal 23 shown in FIG. The time lengths t1, t2, and t3 are measured by counting clock signals in the controller 17.

Based on the collected operation data, the following electric energy in the predetermined period (for example, the current month) is calculated (step S14).
X: The amount of power reduced by stopping the motor 5 in the no-load state so far (the amount of power that would have been wasted if the motor 5 was not stopped)
Y: The amount of power consumed by operating the electric motor 5 without load until now
Z: Electricity consumed by operating the electric motor 5 under load until now

When average values are used as w1 and w2, the power reduction amount X and the power consumption amounts Y and Z can be calculated as follows, for example.
X = w1 × t1
Y = w1 × t2
X = w2 × t3

Based on the reduction and power consumption X, Y, Z and the electricity rate unit price c for the predetermined period, the reduced electricity rate P and the consumed electricity rate Q are calculated as follows (step S76).
P = X × c
Q = (Y + Z) × c
Here, the electricity bill unit price c is set in advance on the operation panel 59 (step S74) and stored in the storage device 55 (step S75).

  The calculated reduced electricity charge P and consumed electricity charge Q are displayed on the display 57 (step S77). In particular, by knowing the reduced electricity bill P, the user can realize the merit of power consumption reduction provided by the starting and operating device 1.

  FIG. 8 shows a configuration example of an uninterruptible maintenance circuit that makes it possible to perform the above-described starting and maintenance work of the operating device 1 while the AC motor 5 is operating.

  In FIG. 8, reference numeral 1 refers to the starting and operating device described above (see FIG. 1). However, the bypass switch 15 is shown outside the block of the starting and operating device 1 for easy understanding of the explanation of the subsequent control flow.

  As shown in FIG. 8, the uninterruptible maintenance circuit 110 has a main power supply path 111 as a path for supplying power from the three-phase AC power source 3 to the AC motor 5 in addition to the main power supply path 111 passing through the starting and operating device 1. 111 has a maintenance bypass 113 connected in parallel.

  A pair of connectors (for example, plug connectors) 115 and 117 are provided on the upstream side and the downstream side of the start of the main power supply path 111 and the operating device 1. These connectors 115, 117 make it possible to mechanically and electrically incorporate and remove the starting and operating device 1 from the main power supply path 111. Paired maintenance switches (for example, electromagnetic switches) 119 and 121 are provided on the upstream side of the upstream connector 115 and the downstream side of the downstream connector 117 of the main power supply path 111. These maintenance switches (for example, electromagnetic switches MC-1, MC-2) 119, 121 can electrically connect and disconnect the set of the starting and operating device 1 and the connectors 115, 177 to the main power supply path 111. And

  The maintenance bypass 113 is a path for supplying power to the AC motor 5 during start-up and maintenance of the operating device 1. The maintenance bypass 113 is provided with a maintenance bypass switch (for example, an electromagnetic switch MC-MS) 123 for opening and closing the bypass. The maintenance bypass 113 is also provided with an overload prevention switch (for example, a thermal relay) 125 for detecting and preventing an overload of the AC motor 5 during start-up and maintenance of the operating device 1.

  A circuit breaker 127 is provided on the upstream side of the upstream connection point between the main power supply path 111 and the maintenance bypass 113. The circuit breaker 127 is for forcibly stopping power supply at the time of starting and puncturing (short-circuiting) the thyristor of the operating device 1.

  Further, a changeover switch (COS) 129 that can be manually operated is provided. The changeover switch 129 is a switch for switching between the maintenance mode (M) and the normal operation mode (N). The change-over switch 129 controls the maintenance switches 119 and 121, the maintenance bypass switch 123, and the starting and operating device 1 as described later.

9, 10 and 11 show an example of the control flow of the uninterruptible maintenance circuit 110 described above. FIG. 9 shows the flow of control when the AC motor 5 is started, FIG. 10 shows the control flow when the start and maintenance of the operation device 1 are performed, and FIG. The control flow is shown.
In FIG. 9, FIG. 10, FIG. 11 and the following description referring to those drawings, for the sake of clarity, the maintenance switches 119 and 121 of the main power supply path 111 shown in FIG. ”,“ MC-2 ”, the switch 123 of the maintenance bypass 113 is abbreviated as“ MC-MS ”, the bypass switch 15 of the starting and operating device 1 is abbreviated as“ MC-BP ”, and The changeover switch 129 is abbreviated as “COS”.

  As shown in FIG. 9, when AC motor 5 is started, first, maintenance is performed with MC-1 and MC-2 being in an ON state, main power supply path 111 being able to function effectively, and MC-MS being in an OFF state. The bypass 113 for use is in an invalid (open) state (step S80).

  Under this state, the starting and starting circuit 11 of the starting and operating device 1 is driven to perform a reduced voltage starting of the AC motor 5 (S81). After the decompression start is completed and all the voltages are applied to the AC motor 5, the MC-BP is turned on (S82). Subsequently, the start circuit 11 is stopped and the normal operation of the AC motor 5 is started ( S83).

  Thereafter, when starting and maintaining the operating device 1, as shown in FIG. 10, during normal operation of the AC motor 5 (step S90), for example, the COS is manually switched from the normal mode to the maintenance mode. (S91). Then, in response to the signal indicating the maintenance mode from the COS, the following steps S92 to S95 are performed in order.

  That is, the MC-MS is turned on to enable the maintenance bypass 113 (S92). Thereafter, the starting circuit 11 of the starting and operating device 1 enters a stopping operation (MC-BP is kept in an ON state during the stopping operation) (S93). Thereafter, when the starting circuit 11 stops, MC-1 and MC-2 are turned OFF, and the starting and operating circuit 1 and the connector set are electrically disconnected from the main power supply path 111. Thereafter, MC-BP is turned off (S95). As a result, the starting and operating device 1 is electrically separated from the power supply path of the AC motor 5 and power is supplied to the AC motor 5 through the maintenance bypass 113.

  Under this state, the connector that connects the controller 17 and the other circuits in the starting and operating device 1 is removed, for example, manually, and the controller 17 is disconnected from the other circuits (S96). Thereafter, the connectors 115 and 117 of the starting and operating device 1 are removed manually, for example, and the starting and operating device 1 is separated from the main power supply path 111 (S97).

  As described above, it is possible to perform start-up and maintenance work of the operation device 1 while the operation of the AC motor 5 is continued.

  After that, when the start-up and maintenance of the operation device 1 are finished and restored, the connectors 115 and 117 of the start-up and operation device 1 are manually connected to the main power supply path 111 as shown in FIG. Thus, the starting and operating device 1 is incorporated into the main power supply path 111 (S100). Further, the controller 17 in the starting and operating device 1 is coupled to other circuits by connectors (S101). Thereafter, the control parameters set before the maintenance are reset in the controller 17 (S102). Here, as already described with reference to FIG. 6, the control parameter refers to various parameters for defining the start voltage pattern and / or the stop voltage pattern, that is, for controlling the start operation and / or the stop operation. It is a parameter.

  Thereafter, the COS is switched from the conventional maintenance mode to the normal operation mode (S103). In response to the signal indicating the normal operation mode from the COS, the following steps S104 to S106 are performed in order.

  That is, MC-BP of the starting and operating device 1 is turned on (S104), and then MC-1 and MC-2 are turned on (S105). As a result, full voltage is supplied to the AC motor 5 through the MC-BP of the starting and operating device 1, that is, the bypass switch 15. Thereafter, the MC-MS is turned off (S106), and the maintenance bypass 113 is opened.

  This completes the start-up and restoration of the operating device 1. Through the processes shown in FIGS. 9 to 11, the normal operation of the AC motor 5 is maintained without interruption.

  As a modification of the configuration shown in FIG. 8, an additional starting and operating device 1 or another type of starting device may be incorporated in the maintenance bypass 113. This makes it possible to stop and restart the AC motor 5 as necessary during the start-up and maintenance work of the operating device 1.

  FIG. 12 shows a configuration example of a parameter control system for automatically controlling the control parameters of the driving and starting device 1.

  Here, the control parameters may include arbitrary conditions, variables, constants or functions related to operation and operation control of the starter 1. Thus, the control parameters include, for example, the start voltage pattern and / or the stop voltage pattern itself, as already described with reference to FIG. 6, or for controlling these patterns (ie, start operation and / or Or various set values (for example, controlling the stop operation) (for example, initial voltage Vst, start time Tst, parallel operation time Tpd1, primary dangerous speed range Vfc1 and Vfc2, primary dangerous speed avoidance time Tfc shown in FIG. 6) (Parallel operation time Tpd2, stop time Tsp, one-step voltage drop time Tfd, water hammer prevention time Twh, two-step voltage drop time Tsd, one-step drop voltage Vfd, reverse phase switching time Tch, reverse phase braking time Tbk, stop time Tsp2, etc.) Alternatively, the output voltage or ignition control signal of the starting circuit 11 at each current time while starting or stopping the electric motor 5 may be included. Furthermore, the control parameters include, for example, whether or not to stop the operation of the electric motor 5 and whether or not to restart the operation as described with reference to FIGS. 2 and 3 to 5. Or various conditions relating to the load state and the motor winding temperature for controlling those judgments (for example, the temperature set values T1 and T2 shown in FIG. Etc.) may also be included. The controller 17 of the starting and operating device 1 should be set with optimal control parameters according to the characteristics and operating environment of the AC motor 5 and the work machine 9. In particular, with respect to the control parameters relating to the start of the motor 5 and the determination of the stop and restart of the motor, the start current and voltage drop of the motor 5 are minimized in order to reduce unnecessary power consumption of the motor 5. It is desirable to optimize the control parameters.

  When a person manually sets (controls) a control parameter optimally (for example, using the operation panel 59), the following operations can usually be performed. That is, for example, the control parameter is temporarily set to an initial value that seems to be appropriate to some extent, and then the AC motor 5 is actually started and stopped. Various state data (for example, voltage, current, output torque, rotation speed, winding temperature, etc.) of the AC motor 5 at the time of the trial, and various state data (for example, work machine 9 that is a load of the AC motor 5) When the work machine 9 is a compressor, the discharge pressure of the compressor is measured, and the measurement data is recorded in the data recorder. Based on the record, the set value of the control parameter is manually corrected, and the AC motor 5 is tried to start and stop again. By repeating the control parameter correction and the AC motor start and stop trials several times, the control parameter can be brought close to the optimum value.

  However, such manual parameter optimum setting requires high human skill. In reality, it is difficult for a person in charge at all sites to perform this manual setting appropriately and efficiently. Moreover, a measuring instrument and a data recorder are required for every field. In particular, in order to achieve the object of minimizing the starting current and voltage drop at the start of the AC motor 5 and enabling the AC motor 5 to be stopped and restarted more frequently, thereby reducing wasteful power consumption. In addition, it is very difficult for a person to determine what starting control parameter value is optimal.

  The parameter control system 160 shown in FIG. 12 can improve the above problem situation. The system 160 includes a server computer 161, and the server computer 161 has a function of optimally setting or controlling a control parameter in the controller 17 of the starting and operating device 1. The server computer 161 is communicatively connected with a plurality of starter and controller 1 controllers 17 in different locations via a communication network (for example, a local network in the same office or a wide area network such as the Internet) 163, for example. Can be done. Alternatively, the server computer 161 may be communicably connected to the starting and operating device 1 in a one-to-one relationship.

  The server computer 161 includes, for example, an input / output interface 165 that exchanges data with the controller 17, a CPU 166 that performs calculation processing, a computer program executed by the CPU 166, a storage device 167 that stores and holds data to be processed, and the like. An operation panel 168 for inputting commands and instructions, and a display 169 for presenting various information such as processing results and stored contents to a person. The parameter optimum control function of the server computer 161 can be typically implemented as a computer program stored in the storage device 167, but this is not necessarily the case, and a hardware logic circuit (not shown) Alternatively, it can be implemented as a combination of a hardware logic circuit and a computer program.

  The controller 17 of the starting and operating device 1 can collect predetermined state data from the AC motor 5 and the work machine 9. The state data related to the AC motor 5 includes, for example, voltage data / current data / sound data / vibration data 143 from the current / voltage / sound / vibration sensor set 141 provided in the AC motor 5, and a winding temperature sensor 145. Winding temperature data 147, rotational speed data / torque data 153 from a rotational speed / torque sensor 151 provided on the output shaft of the AC motor 5, and the like. The state data related to the work machine 9 may include, for example, discharge pressure data 157 from the pressure sensor 155 provided at the discharge port of the compressor 9 if the work machine 9 is a compressor. The type of state data related to the work machine may vary depending on the work machine 9. That is, one or more of pressure, temperature, current value, liquid level height, concentration, weight, water quality, photoelectric sensor signal, or depth are selected according to the type, role, or function of the work machine 9 Or they may be combined and employed as state data. For example, when the work machine 9 is a compressor, the supply pressure of the compressor, the pressure of the air tank, the piping pressure, or the like can be adopted as the state data. For example, the storage water level when the work machine 9 is a pump for pumping water, the air volume and / or wind force of the blower when the work machine 9 is a blower, and the dust or carbon dioxide when the work machine 9 is a dust collector Or the temperature to be cooled when the work machine 9 is a refrigerator can be used as the state data.

  The controller 17 has a control database 159 on the storage device 55, and the control database 159 can store a set of state data collected from the AC motor 5 and the work machine 9. The controller 17 can transmit the set of status data stored in the control database 159 to the server computer 161. The state database 159 can also store setting values of control parameters provided from the server computer 161.

  The server computer 161 can receive the status data of each site from the controller 17 of each site. The server computer 161 also receives characteristic data indicating characteristics of the AC motor 5 and the work machine 9 at each site from a predetermined data providing source (for example, an information providing server on a network or an external storage device). can do. Using the received status data and / or characteristic data of each site (hereinafter, the status data and property data relating to the site are collectively referred to as “site data”), for starting and stopping the AC motor 5 at each site A set of optimal values (or optimal approximate values) of the control parameters can be calculated. The server computer 161 can send a set of calculated optimal values (or optimal approximate values) of the control parameters to the controller 17.

  The controller 17 receives a set of optimal values of control parameters from the server computer 161, sets the received optimal value (or optimal approximate value) set in the controller 17, and thereafter sets the optimal value (or optimal approximate value). ) The AC motor 5 can be started and stopped using the set.

  The time when the server computer 161 optimizes the control parameters in the controller 17 may be any time during the operation and stop of the AC motor 5. For example, the control parameter is optimized every time there is a situation where the setting of the control parameter should be changed not only at the time of installation and recovery of the starting and operating device 1 but also due to environmental changes or some other reason. It's okay. Alternatively, the control parameters may be optimized in real time while starting, operating, or stopping the electric motor 5.

  The parameter control system 160 configured in this way can facilitate and optimize the starting of each site and the control parameter control of the operating device 1 without depending on human skill.

  In addition, by using the parameter control system 160, the purpose of minimizing the starting current and voltage drop at the start of the AC motor 5, and the more frequent stop and restart of the AC motor 5 can be thereby enabled, which is wasteful. It is possible to automatically specify and control the optimum parameter value for achieving the purpose of reducing the power consumption. Furthermore, by using an artificial intelligence system as described below for calculating the optimum parameter value, the above object can be achieved more easily.

  FIG. 13 shows a configuration example of an artificial intelligence system that can be employed to optimally control the control parameters by the server computer 161 in the parameter control system 160 described above.

  The server computer 161 includes a computer program or hardware circuit for executing an algorithm for calculating the optimum value of the control parameter. However, since the characteristics and operating environments of the AC motor 5 and the work machine 9 are different for each site, it is difficult for a person to completely program or design a calculation algorithm suitable for the different sites. In order to improve this problem situation, the artificial intelligence system 171 shown in FIG. 13 is configured to automatically construct an optimal calculation algorithm by machine learning using a neural network. The artificial intelligence system 171 is typically implemented as a computer program and stored in the storage device 55 of the server computer 161, but this is not necessarily the case, and a hardware logic circuit (not shown), Alternatively, it can be implemented as a combination of a hardware logic circuit and a computer program.

  As shown in FIG. 13, the artificial intelligence system 171 includes a field database 173, a training data preparation unit 175, a training database 176, a neural network learning unit 177, a neural network deployment unit 179, and a neural network inference unit 181.

  The on-site database 173 stores and holds various types of on-site data necessary for calculating control parameters for each site for one or more sites. The field data of each field includes, for example, characteristic data indicating various characteristics of the AC motor 5 (for example, a starting torque curve indicating the relationship between the torque at the time of starting and the rotational speed, inertia moment data, and the like), the work machine 9 Characteristic data (for example, a starting torque curve indicating the relationship between the starting torque and the rotation speed, and inertia moment data), each set of control parameters that have been actually used before, There may be a set of state data regarding the AC motor 5 and the work machine 9 measured when the AC motor 5 is started with each set of control parameters.

  The source of the field data includes, for example, a controller 17 and other devices at each field (for example, an external storage device connected to the server computer 161, or other information providing server capable of communicating with the server computer 161 through the network 163. Etc.). For example, the various characteristic data of the AC motor 5 and the work machine 9 described above are typically an information providing server on a network that provides characteristic data prepared by the manufacturer of the machine, or stores the data. It can be taken into the on-site database 173 from an external storage device. The set of control parameters actually used at each site can be taken into the site database 173 from the controller 17 at each site or from the neural network inference unit 181 that generated the control data set. In addition, a set of various state data measured at the site can be taken into the site database 173 from the controller 17 at each site. Here, for the purpose of creating training data for machine learning of a neural network and / or a field where the motor 5 is used for practical use, a field where the motor 5 is used for research and development, and / or neural network machine learning. Any site for any purpose, such as a site that uses, can be employed as a source for providing site data.

  The training data preparation unit 175 prepares training data using the field data stored in the field database 173. The training data preparation unit 175 may create training data by itself. Alternatively, the training data preparation unit 175 provides field data to an external person or an external computer, causes the person or computer to create training data, and the training data generated from the person or computer is used. You may receive it.

  The training data is used to cause the neural network to learn a control parameter calculation algorithm. The training data includes a combination of problem data to be input to a neural network that performs machine learning and correct answer data that is expected to be output from the neural network. For example, when it is desired that the neural network determine optimum control parameters according to the characteristics of the electric motor 5 and the work machine 9, for example, the problem data includes characteristic data of the AC motor 5 and the work machine 9 at each site. Can be. Those characteristic data can be obtained from the on-site database 173. The correct answer data may include a set of optimal values (or optimal approximate values) of control parameters to be set in the controller 17. In particular, the correct answer data for the starting control parameter is a set of values (or optimal approximate values) optimized so as to minimize the starting current when starting the AC motor 5 and minimize the voltage drop. Is desirable. This optimal value (or optimal approximate value) set can also be obtained from the field database 173. For example, it may have been set in the past in other sites that are conditionally similar (can be set manually or automatically) (even if set for practical purposes, the optimum value is searched for) A set of optimal values (or optimal approximate values) of control parameters (which may be included when set for various research and development purposes) can be used as correct answer data.

  For example, when it is desired to provide a neural network with a function for correcting a control parameter already set at a site to a more optimal one, the problem data of the training data includes the value of the control parameter already set at each site. The set and the state data of the AC motor 5 and the work machine 9 measured when the AC motor 5 and the work machine 9 are started and stopped under the preset settings may be included. In that case, the correct answer data may include data (for example, a set of optimal values after correction) indicating corrections to be performed on the values of the preset control parameters. It is also desirable that this correction data be one that can further reduce the voltage drop by further reducing the starting current when starting the AC motor 5, particularly in the case of the starting control parameter. These problem data and correct answer data are also obtained from the values of control parameters stored in the site database 173, for example, control parameters set in the past in other similar conditions and state data measured in the past. Can do.

  For example, when it is desired that the neural network determine control parameters for optimally determining whether to stop and restart the motor 5, for example, the problem data includes, for example, the AC motor 5 at each site. And characteristic data and status data of the work machine 9 can be included. Those characteristic data can be obtained from the on-site database 173. The correct answer data may include a set of optimal values (or optimal approximate values) of the control parameters for the optimal determination that the controller 17 should have. This optimal value (or optimal approximate value) set can also be obtained from the field database 173. For example, it may have been set in the past in other sites that are conditionally similar (can be set manually or automatically) (even if set for practical purposes, the optimum value is searched for) A set of optimal values (or optimal approximate values) of control parameters (which may be included when set for various research and development purposes) can be used as correct answer data. The neural network not only can determine whether to stop and restart the motor based on learning, based on the current state of the motor 5 (for example, the current winding temperature, etc.). It may be possible to set the controller 17 so that the future state (for example, the future winding temperature, etc.) can be predicted and the above determination can be made based on the prediction. With this predictive control, the starting and operation of the electric motor 5 can be made more appropriate.

  The training database 176 stores the above training data prepared by the training data preparation unit 175.

  The neural network learning unit 177 has a pre-learning neural network 185 prepared in advance. The neural network learning unit 177 inputs the training data problem data to the pre-learning neural network 185, obtains an error between the output data from the pre-learning neural network 185 and the correct data of the training data, and determines the error. Based on this, the learning session of correcting various parameters constituting the calculation algorithm of the pre-learning neural network 185 is repeated many times. Thereby, the pre-learning neural network 185 learns an algorithm for calculating the optimum control parameter.

  When a predetermined learning condition is satisfied, the learning process of the pre-learning neural network 185 ends. As the predetermined learning condition, for example, the output error of the pre-learning neural network 185 is sufficiently small and the decrease in the output error due to repeating the learning session is sufficiently small, or the learning session is performed a predetermined number of times. Can be used.

  The neural network deployment unit 179 deploys the neural network (learned neural network) 187 that has completed the learning process in the neural network learning unit 177 to the neural network inference unit 187, and learns the neural network that has been learned for actual use of control parameter calculation. Make the network 187 available.

  The neural network inference unit 181 reads out the characteristic data of each site and the state data measured at the time of starting and stopping from the site database 173, and inputs the data to the learned neural network 187, so that the learned data is obtained. A set 183 of optimal values (or optimal approximate values) of control parameters for each site is output from the neural network 187. The output optimal value (or optimal approximate value) set 183 of the control parameters for each site is stored in the site database 173 and transmitted to the controller 17 at each site. In the controller 17, the received optimum value (or optimum approximate value) set 183 is stored (set) in the control database 15, and the control parameter setting is used for starting and stopping control thereafter. Alternatively, the neural network inference unit 181 receives field data (in particular, state data at each current time) in real time from each field, and generates a set 183 of optimal values (or optimal approximate values) of control parameters in real time. By providing it to the controller 17 at each site, the controller 17 may be configured to optimally control the start, operation, and stop operation of the AC motor 5 in real time.

  By using the artificial intelligence system 171 configured as described above, an optimal value (or optimal approximate value) set of control parameters is automatically set in the controller 17 of each on-site starting and operating device 1.

  After the automatic setting of the control parameter at the site is once performed in this way, the set value may be corrected so as to be further optimized. In other words, once the control parameters are set, the start and stop of the AC motor 5 is tried on site, the state data at the time of the trial is measured and fed back to the artificial intelligence system 171, and the artificial intelligence system 171 is used using the feedback data. The learned neural network 187 re-outputs a set of values obtained by correcting the previously set control parameters, and then resets the set of corrected values to the controller 17 in the field. Good. By performing this process one or more times, the control parameters at each site can be improved to be more optimal.

  In addition, artificial intelligence can be used to appropriately measure changes in the state data at start and stop due to changes in the operating environment and mechanical properties of the site (for example, changes in machine oil viscosity due to seasonal temperature changes). By feeding back to the system 171, the artificial intelligence system 171 recalculates a new optimal set of control parameters suitable for the changed situation, and updates the parameter settings of the on-site controller 17 with the new set. It may be.

  In particular, with regard to the control parameter for starting, the motor is more frequently used when the motor 5 is unloaded by optimizing the control parameter in a timely manner using a machine learning function so as to minimize the starting current of the motor 5 at each site. 5 can be stopped. Thereby, wasteful power consumption can be more effectively reduced.

  In FIG. 13, one pre-learning neural network 185 and one learned neural network 187 are shown in the artificial intelligence system 171. However, the artificial intelligence system 171 may comprise a plurality of pre-learning neural networks 185 and / or a plurality of learned neural networks 187, which may be assigned, for example, to different sites or to different applications ( For example, based on the usage of calculating the optimal approximate value set of control parameters based on the characteristic data of the AC motor 5 and the work machine 9, and based on the state data as a result of attempting to start and stop with the optimal approximate value set, The use of which the set of optimum approximate values is more optimally corrected, the use of determining whether to stop and restart the electric motor 5 according to the current state of the electric motor 5 and the work machine 9, and the like).

  In FIG. 13, a configuration for performing machine learning, that is, a training data preparation unit 175, training data 176, and a neural network learning unit 177 exist in the artificial intelligence system 171. However, as a modification, the artificial intelligence system 171 does not have a configuration for performing machine learning, and the configuration for performing machine learning may be provided outside the artificial intelligence system 171.

  In FIG. 12 and FIG. 13, the server computer 161 and the artificial intelligence system 171 are provided outside the starting and operating device 1 at each site. However, as a modification, at least a part of the functional elements of the server computer 161 or at least a part of the functional elements of the artificial intelligence system 171 are provided in the starting and operating devices 1 (for example, in the controller 17) at each site. May be. For example, at least the neural network inference unit 181 of the artificial intelligence system 171 shown in FIG. 13 is stored in the controller 17 at each site, for example, a computer program stored in the storage device 55, the specific function module 61, or the like. May be provided as a combination. In that case, the neural network inference unit 181 at each site may be trained (learned) as a function optimized for each site, or may be applied to other sites. It may be one that has been trained as a versatile function that can be applied. In that case, the neural network inference unit 181 at each site inputs various state data sensed in real time at the site and controls the start and / or stop operation of the electric motor 5 at the site in real time. May be configured. Alternatively, the neural network inference unit 181 at each site can be connected to the controller 17 at another site through a communication network, and inputs various state data sensed not only at the own site but also at other sites, It may be configured to control the start and / or stop operation of the on-site electric motor 5. The learned neural network 187 in the neural network inference unit 181 at each site may be updated at any time.

  FIG. 14 shows an example of a multi-stage starting voltage pattern as an example of an employable starting voltage pattern.

  According to the multistage starting voltage pattern 191 shown in FIG. 14, the output voltage of each phase of the starting circuit 11 is increased stepwise from the initial voltage V0 to the power supply voltage Vs in three or more stages. The number of stages is seven in the example of FIG. 14, but this is only an example and may be more or less. At each stage n (n = 1, 2, 3, ....), the output voltage is increased from the previous stage voltage Vn-1 to the current stage voltage Vn over the boost time Trn, and then during the current stabilization time Tsn. The current stage voltage Vn is maintained. The current 193 of the AC motor 5 temporarily increases at each stage when the voltage rises, but decreases and stabilizes to a value equal to or lower than the rated current Ir during the current stabilization time, and then the next stage voltage rises. Is called. Therefore, it is effectively prevented that the AC motor 5 is damaged due to an excessive current at the start. This multistage starting voltage pattern 191 is particularly useful when the inertia (GD square) of the work machine 9 is large. The multi-stage starting voltage pattern 191 is also useful for the purpose of enhancing the power saving effect by minimizing the starting current and voltage drop when starting the motor 5 so that the motor 5 can be stopped more frequently when there is no load. It is.

  Various values defining the multistage starting voltage pattern 191, for example, the initial voltage Vo, the number of stages n, each stage voltage Vn, each stage voltage stabilization time Tsn, and the like are set as control parameters in the controller 17 of the starting and operating device 1. Can do. In addition, after setting the parameter values once, starting and stopping can be tried, and the values can be corrected according to the state data measured at that time. These parameter values can be automatically calculated by the parameter setting system 160 described above. In particular, the above-described artificial intelligence system 171 is used to optimize the multi-stage starting voltage pattern 191 at any time or in real time so as to minimize the starting current of the motor 5, thereby reducing the power consumption of the motor 5 using the reduced voltage starting. The effect of conversion can be further increased.

One embodiment of the present invention described above is useful for improving various problem situations in the prior art. As already explained, in the case of rotating equipment such as pumps, fans and compressors, operation at low loads is very inefficient. Therefore, in order to maintain high efficiency by reducing the number of operating units at low loads, many combinations of a unit control system and inverter control have been adopted. However, as an example, in the case of a compressor, the load characteristics change depending on the type of compressor (reciprocating, screw, turbo, etc.), load fluctuation, and the type and manner of capacity control. In order to achieve the highest efficiency, frequent start / stop operations are ideal, but at present, this may shorten the life of the compressor. Therefore, the conditions for starting and stopping the compressor are set with a certain range, and inverter control is also used. In this situation, an embodiment of the present invention may provide the following improvements.
・ The air pressure is detected and predicted by the pressure sensor to optimize the start / stop of the compressor.
・ Efficiently control the number of operating compressors and automatically control the optimum air pressure.
・ Optimize the control of each compressor with an artificial intelligence system.

  The embodiment of the present invention described above is merely an example for explanation, and is not intended to limit the scope of the present invention to that embodiment alone. The present invention can be implemented in various forms different from the above embodiments.

  For example, when the electric motor 5 is in a no-load state, the information for determining whether to stop the electric motor 5 is related to the temperature state of the electric motor 5 instead of or in combination with the winding temperature of the electric motor 5. Other information to be performed (for example, the temperature of other parts of the electric motor 5, the magnitude of noise or vibration of the electric motor 5, the frequency with which the electric motor 5 has been repeatedly started, the elapsed time since the previous starting of the electric motor 5, the electric motor 5 Power consumption, rotational speed and output torque of the electric motor 5, etc.) may be used.

  Further, as information for determining whether the electric motor 5 is in a loaded state or a no-load state, instead of the operation and stop command for the work machine 9 or in combination therewith, other information related to the operation or stop of the work machine 9 (For example, a predetermined state, operation, output, input or function of the work machine 9, an output or input of the electric motor 5, or a command, request, or state related to operation and / or stop of the work machine 9 provided from an external system , Etc.) can also be used.

  The present invention can be applied not only to a three-phase squirrel-cage induction motor but also to other types of AC motors such as a three-phase synchronous motor.

1 AC motor starting and operating device 3 Three-phase AC power supply 5 Three-phase AC motor (three-phase cage induction motor)
9 Work Machine 11 Start Circuit 13 Main Switch 15 Bypass Switch 17 Controller 19 Manual Start and Stop Switch 21 Input Current Signal 23 Input Voltage Signal 25 Bypass State Signal 27 Winding Temperature Signal 29 Temperature Sensor 31 Rotation Speed Signal 33 Rotation Speed Meter 35 Operation and Stop Command 41 Main Open / Close Signal 43 Bypass Open / Close Signal 45 Firing Signal 47 Bypass Open / Close Signal 51 Input / Output Interface 53 CPU
57 Display 59 Operation panel 61 Specific function module 63 Fault countermeasure module 65 Bypass switching signal 101, 103, 105 Start voltage pattern 106, 107, 108 Stop voltage pattern 110 Uninterruptible maintenance circuit 111 Main power supply path 113 Maintenance bypass 115, 117 Connectors 119, 121 Maintenance switch 123 Maintenance bypass switch 159 Control database 160 Parameter control system 161 Server computer 163 Communication network 171 Artificial intelligence system 177 Neural network learning unit 181 Neural network inference unit 185 Pre-learning neural network 187 Trained neural network Network 191 Multi-stage starting voltage pattern

Claims (17)

In an apparatus for starting and operating an AC motor,
A starting circuit that outputs a voltage reduced from the total voltage of a power source to the AC motor when the AC motor is started;
A switch that outputs the total voltage to the AC motor during operation of the AC motor;
A controller for driving the starter circuit and the switch;
The controller is
Determining whether the AC motor is in a loaded state or a no-load state;
Determining whether the AC motor is in a restartable state; and
When determining that the AC motor is in the no-load state and simultaneously in the restartable state during operation of the AC motor, opening the switch to stop the AC motor;
When it is determined that the AC motor has entered the load state after stopping the AC motor, the step of starting the AC motor by driving the starting circuit;
A step of closing the switch and starting operation of the AC motor after starting the AC motor and performing a control process comprising:
Starting and operating device. The starting and operating device according to claim 1,
The starting circuit has a plurality of semiconductor switching elements provided between the power source and the electric motor,
The controller controls an ignition phase angle of the semiconductor switching element when the AC motor is started;
Starting and operating device. The starting and operating device according to any one of claims 1 and 2,
A starting and operating device in which the controller receives temperature-related information related to the temperature state of the AC motor and determines whether the AC motor is in the restartable state using the temperature-related information. In the starting and operating device according to any one of claims 1 to 3,
The controller receives machine operation-related information related to operation or stop of a work machine driven by the AC motor, and the AC motor uses the machine operation-related information to determine whether the AC motor is in the load state or the no-load state. A starting and operating device that determines whether or not In the starting and operating device according to any one of claims 1 to 4,
A failure countermeasure module for manually or automatically opening and closing the switch when an abnormality or failure occurs in the controller;
Starting and operating device. In the starting and operating device according to any one of claims 1 to 5,
The controller further comprises:
Grasping the length of time when the AC motor stops in the no-load state;
Grasping power consumption when the AC motor is operated in the no-load state;
Based on the time length and the power consumption, calculating the electricity bill or power consumption reduced by the AC motor being stopped in the no-load state;
Notifying a user of the reduced electricity bill or power consumption, configured to perform a bill notification process,
Starting and operating device. The starting and operating device according to claim 2.
The controller feeds back an output voltage of the starting circuit when starting the AC motor, and controls an ignition phase angle of the semiconductor switching element based on a deviation between the output voltage and a preset starting voltage pattern. To
Starting and operating device. The starting and operating device according to claim 1,
The controller monitors the rotational speed of the AC motor at the start of the AC motor, and controls the closing timing of the switch based on the rotational speed;
Starting and operating device. The starting and operating device according to any one of claims 1 to 8,
The controller has control parameters for controlling the starting circuit and the switch,
The controller is configured such that the control parameter is controlled by a learned neural network that has learned the function of determining the control parameter;
Starting and operating device. In a method for starting and operating an AC motor,
Determining whether the AC motor is in a loaded state or a no-load state;
Determining whether the AC motor is in a restartable state; and
When the AC motor is in operation, if it is determined that the AC motor is in the no-load state and at the same time the restartable state, the step of stopping the AC motor;
When it is determined that the AC motor is in the load state after the AC motor is stopped, a step of starting to reduce the voltage of the AC motor;
Entering into operation of the AC motor after the reduced voltage start,
How to start and run. In the starting and operating device of an AC motor,
At the time of starting the AC motor, a starting circuit that outputs a reduced AC voltage to the AC motor by switching all AC voltages from a power source;
A switch that outputs the entire voltage of the power source to the AC motor during operation of the AC motor;
A controller for driving the starter circuit and the switch;
The controller has control parameters for controlling the starting circuit and the switch, and the control parameters can be changed.
Starting and operating device. The starting and operating device according to claim 11,
The control parameter controls one or more starting voltage patterns for controlling the output voltage when starting the AC motor, and one of the starting voltage patterns is divided into a plurality of stages of three or more to output the starting circuit. A multi-stage starting voltage pattern configured to increase voltage;
Starting and operating device. The starting and operating device according to claim 11,
The control parameter controls whether to stop the AC motor during the operation of the AC motor, and / or whether to restart the motor once stopped.
Starting and operating device. The starting and operating device according to any one of claims 11 to 13,
The controller is configured such that the control parameter is controlled by a learned neural network that has learned the function of determining the control parameter;
Starting and operating device. In a parameter control system for AC motor starting and operating devices,
A server computer that is communicably connected to a start and operation device of one or more AC motors arranged at one or more sites, or at least a part of the start and operation device at each site is provided With
The start-up and operation device at each site includes a start circuit that outputs a reduced AC voltage to the AC motor by switching all AC voltages from a power source when the AC motor at each site is started, and the AC motor. A switch that outputs the entire voltage of the power source to the AC motor, and a controller that drives the starter circuit and the switch,
The controller has control parameters for controlling the starting circuit and the switch, and the control parameters can be changed,
The server computer has an inference system that controls the control parameters of the controller at each site based on the site data regarding the AC motor at each site and the work machine connected thereto.
Parameter control system. The parameter control system according to claim 15,
The inference system of the server computer has a neural network in which a function for controlling a control parameter of the controller at each site is machine-learned based on the field data at each site, and the neural network is used. And controlling the control parameters of the controller at each site,
Parameter control system. The parameter control system according to claim 16, wherein
A learning system that collects the field data from the one or more fields and causes the neural network to learn the function using the collected field data;
Further equipped with a parameter control system.

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