JP5453348B2 - Electric valve drive system - Google Patents

Description

  The present invention relates to an electric valve driving system for driving an electric valve, and more particularly to an electric valve driving system using a single-phase induction motor.

  2. Description of the Related Art Conventionally, there are a wide variety of flow rate control valves that control the flow rate of fluid, such as globe valves, sanders valves, butterfly valves, ball valves, etc., depending on the difference in basic structure. As a drive device for driving an electric valve that electrically opens and closes these valves, for example, those described in Patent Documents 1 and 2 are known.

  The thing of patent document 1 is provided with the electric motor which opens and closes an electric valve, and the electromagnetic brake which performs rotation control of an electric motor. With this configuration, the device disclosed in Patent Document 1 can perform opening / closing control of the electric valve by stopping the electric motor at a predetermined position by the electromagnetic brake.

  Patent Document 2 describes an AC motor that opens and closes an electric valve, an inverter that drives the AC motor, an opening detector that detects the opening of the electric valve, and an electric valve that the opening detector outputs. A controller that feeds back an opening signal and controls the torque of the AC motor for each opening section of the motor-operated valve. With this configuration, the device described in Patent Document 2 can be controlled so that the AC motor does not output more torque than necessary with respect to the torque of the AC motor required for each opening section of the electric valve. ing.

JP-A-10-292877 JP 2009-81935 A

  However, the device described in Patent Document 1 has a configuration in which the electric motor is stopped at a predetermined position by an electromagnetic brake, so that the structure of the apparatus is complicated and wasteful energy is consumed.

  Moreover, since the thing of patent document 2 becomes a structure which drives an alternating current motor by carrying out feedback control of an inverter and controls opening / closing of a motor operated valve, there existed a subject that the structure of an apparatus became complicated.

  The present invention has been made to solve the conventional problems, and an object of the present invention is to provide an electric valve drive system that can suppress useless energy consumption and can drive an electric valve with a simple configuration. .

  The motor-driven valve drive system of the present invention can reduce the number of operation times of the motor-operated valve by placing the feedback loop in a digital controller capable of high-speed response and eliminating the influence of the establishment time of the flow rate control process. In general, the response of flow control in a long pipe may take several tens of seconds for the step response and several minutes for the establishment time with respect to changes in the valve opening. The motor-driven valve drive system can drive the motor-operated valve in anticipation of the established flow rate.

  The motor-driven valve drive system of the present invention is a motor-driven valve drive system that drives an induction motor that opens and closes a motor-operated valve, and includes a target opening for setting the opening of the motor-operated valve and a current opening of the motor-operated valve. An opening difference calculating means for calculating an opening difference indicating a difference from the current opening, an AC power supply means for supplying AC power for driving the induction motor by a drive pulse, and the induction motor is the motor-operated valve. The fully open drive time indicating the time required to change the fully open state from the fully closed state to the fully open state, the ratio of the opening difference with respect to the opening degree in the fully open state of the motor-operated valve, and supply of AC power to the induction motor for a predetermined time And a pulse width calculating means for calculating the pulse width of the drive pulse based on inertia running time indicating a time during which the induction motor is operated by inertia.

  With this configuration, the electric valve drive system of the present invention can drive the induction motor like a pulse motor by supplying a drive pulse having a pulse width calculated by the pulse width calculation means to the induction motor. A driving circuit which does not consume standby power and is required by a pulse motor is also unnecessary. Therefore, the motor-driven valve drive system of the present invention can suppress wasteful energy consumption and drive the motor-operated valve with a simple configuration.

  In the electrically operated valve drive system of the present invention, the electrically operated valve has hysteresis in the valve opening operation and the valve closing operation, and the hysteresis equivalent drive time indicating the time for driving the electrically operated valve to correct the hysteresis. And a hysteresis correction means for correcting the pulse width of the drive pulse by the calculated hysteresis correction value.

  With this configuration, the electric valve driving system of the present invention can correct the hysteresis of the electric valve by the hysteresis correction means.

  In the motor-operated valve driving system according to the present invention, the AC power supply means is a time when the phase of the voltage is 90 degrees behind the time from the time when the voltage applied to the motor-operated valve crosses the zero point. A voltage pulse and a current pulse during a period until the time when the current supplied to the valve crosses the zero point is supplied to the induction motor by the drive pulse.

  With this configuration, the electric valve driving system of the present invention can drive the induction motor like a pulse motor.

  In the motor-driven valve drive system of the present invention, it is preferable that the induction motor is a single-phase saddle type induction motor.

  The present invention can provide a motor-driven valve drive system that has the effect of suppressing wasteful energy consumption and driving a motor-operated valve with a simple configuration.

It is a block block diagram in one Embodiment of the electric ball valve drive system which concerns on this invention. It is a block diagram which shows the hardware constitutions of the electric ball valve drive system which concerns on this invention. In an electric ball valve drive system concerning the present invention, it is an explanatory view about a function of the 1st SSR. In the electric ball valve drive system which concerns on this invention, it is explanatory drawing about the drive pulse which drives a single phase induction motor. In the electric ball valve drive system concerning the present invention, it is a mimetic diagram showing operation of the electric motor by a drive pulse. It is explanatory drawing of the method of calculating | requiring the inertia running time in the electric ball valve drive system which concerns on this invention. It is a flowchart of the main routine in the electric ball valve drive system according to the present invention. It is a flowchart of the valve full open process in the electric ball valve drive system according to the present invention. It is a flowchart of the valve full-close process in the electric ball valve drive system according to the present invention. It is a flowchart of the valve opening process in the electric ball valve drive system according to the present invention. It is a flowchart of the valve closing process in the electric ball valve drive system according to the present invention.

  In the present embodiment, an example in which the electric valve driving system according to the present invention is applied to an electric ball valve driving system that electrically opens and closes the ball valve will be described. This electric ball valve drive system includes a ball valve as a flow rate adjusting valve for adjusting the flow rate of fluid, and a single-phase induction motor as a driving means for driving the ball valve. Hereinafter, the background of employing a ball valve and a single-phase induction motor will be described before describing the embodiments of the present invention.

  For example, in a cold / hot water mixing facility where hot water and cold water are mixed to obtain hot water of a desired temperature and flow rate, when a system for controlling these flow control valves with an electronic computer is configured, a flow control valve used in the past Pneumatic control valves equipped with positioners with analog or digital signal interfaces, or electric control valves with control devices with similar interfaces are used. Since these conventional control valves are designed on the assumption of feedback control, the interface, that is, the auxiliary control device is always operated in an operating state. This means that each control valve consumes a corresponding standby power, and a system with a large number of control valves consumes a considerable standby power.

  However, as represented by keywords such as low-carbon society, green support, and energy saving that have been screamed in recent years, the configuration of the conventional control valve is not preferable because it tends to reduce unnecessary standby power.

  In view of this, the present inventor has examined the flow rate control valve driving means and the flow rate control valve from the viewpoint of suppressing wasteful energy consumption.

(Driving means for flow control valve)
The following performance is required for the flow rate control valve driving means for constructing an electronic computer control system that does not consume useless energy.
(1) A control method that consumes as little standby power as possible.
(2) The operation amount can be set in a digital manner (can be directly operated from a computer).
(3) A large driving force for operating the large valve can be generated.
(4) Auxiliary control devices, controllers, converters, etc. (interface) can be simplified.

  First, consider (1) above. For example, consider applying a single-phase induction motor capable of switching the rotation direction by switching the position of the phase advance capacitor with respect to two sets of exciting windings attached at a phase angle of 90 ° to each other. Hereinafter, such a single-phase induction motor will be referred to as a reversible single-phase induction motor. The reversible type single-phase induction motor does not consume standby power while stopped. On the other hand, for reference, let us consider standby power when a valve is controlled using a pulse motor. Since the pulse motor itself has the property of maintaining the current position even if the drive voltage is removed, the pulse motor itself does not consume standby power. However, the complicated drive circuit of the pulse motor consumes a lot of standby power. Therefore, the reversible type single-phase induction motor is superior to the above (1) rather than the pulse motor.

  Next, (2) will be examined. The reversible single-phase induction motor itself is essentially free from digital operation. Compare with a pulse motor for reference. Since the pulse motor is a stepping type, the operation signal is originally digital. Therefore, for the above (2), a pulse motor is inherently excellent, but in the present invention, a driving force is large by driving a reversible single-phase induction motor like a pulse motor, as will be described later. It is possible to construct a control system that takes advantage of the features of a reversible single-phase induction motor such that an auxiliary control device is unnecessary.

  Next, with respect to the above (3), a reversible single-phase induction motor and a pulse motor will be compared. Compared with a reversible single-phase induction motor, a pulse motor cannot be expected to have a large driving force for structural reasons. Further, when the limit of the driving force is exceeded, a phenomenon called step-out occurs and driving cannot be performed. In addition, the pulse motor requires complicated drive circuits, but these drive circuits are not suitable for high power. Therefore, the reversible single-phase induction motor is superior for the above (3).

  Next, with respect to (4), a reversible single-phase induction motor and a pulse motor will be compared. The reversible single-phase induction motor according to the present invention does not require a special auxiliary control device. On the other hand, a pulse motor requires a complicated drive circuit. Therefore, the reversible single-phase induction motor is excellent with regard to the necessity of the auxiliary control device (4).

(Flow control valve)
The following performance is required for a flow control valve for constructing an electronic computer control system that does not consume useless energy.
(1) Low pressure loss when fully open.
(2) No energy is consumed to maintain the set opening.
(3) The flow coefficient for the operation signal can be accurately calculated.
(4) Excellent flow rate reproducibility with respect to operation signals.
(5) When the operation signal is raised once and returned to the original value, the flow rate is accurately restored to the original value.

  Consider the case of a ball valve in response to the above requirements. The fluid passage area of the ball valve when fully open is equal to the cross-sectional area of the pipe with the same diameter, and the pressure loss due to insertion of the valve is infinitely equal to zero. Therefore, the ball valve satisfies the requirement (1).

  Next, the ball valve itself has a structure capable of maintaining a constant opening degree against the reaction force of the fluid. Sanders valves and many other flow control valves require a force that always keeps the valve depressed in some way, such as air pressure, to push back the fluid pressure. In this regard, the ball valve does not require energy to maintain a constant opening. From the above, the ball valve satisfies the requirement (2).

  Further, since the ball valve has a simple structure, the relationship between the rotation angle of the operation shaft and the fluid passage cross-sectional area can be expressed by a clear mathematical expression. This indicates the possibility of calculating an operation amount (valve operation rotation angle) corresponding to the target flow rate. By calculating and setting the manipulated variable for the target flow rate, it is possible to converge faster than the feedback method. Therefore, the ball valve satisfies the requirement (3).

  Next, (4) will be examined. The effective operation area of the ball valve is reduced to approximately 60% except for the closing area of 20% on the closing side and the saturation area of 20% on the opening side. Therefore, it is said that the ball valve is generally not suitable for control applications because it has a steep rise characteristic. In this respect, the ball valve does not satisfy the requirement (4).

  Further, the ball valve generates hysteresis due to backlash of the drive unit speed reducer and play between the drive shaft and the valve body. If hysteresis exists, it will not return to the original flow rate when it is returned downward by the amount manipulated in the upward direction. That is, the ball valve does not satisfy the requirement (5).

  Accordingly, the present inventor has realized a control system with a relatively low standby power by satisfying the above requirements (4) and (5) by correcting the ball valve by software.

(Embodiment)
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  First, the configuration of the embodiment of the electric ball valve drive system according to the present invention will be described.

  As shown in FIG. 1, the electric ball valve drive system 10 in this embodiment drives an electric ball valve 30. The electric ball valve drive system 10 constitutes an electric valve drive system according to the present invention.

  The electric ball valve drive system 10 includes a target opening setting unit 11, a target opening determination unit 12, an addition unit 13, a pulse width calculation unit 14, a rotation direction determination unit 15, a hysteresis correction unit 16, a current opening acquisition unit 17, A fully open / close processing unit 18, a drive pulse output unit 19, and a semiconductor relay (SSR) 20 are provided.

  The electric ball valve 30 includes a reversible single-phase induction motor 31 and a ball valve 32. The electric ball valve 30 constitutes an electric valve according to the present invention. The single-phase induction motor 31 is composed of, for example, a single-phase saddle type induction motor driven by a commercial power supply (100 volts) of 60 Hz. The ball valve 32 has, for example, a resin valve body and a resin valve shaft. Instead of the single-phase induction motor 31, for example, a three-phase induction motor may be used. In this case, a three-phase AC semiconductor relay is used. Further, the ball valve 32 is not limited to resin, and may be made of metal, for example.

  The target opening degree setting unit 11 sets a target opening degree Nd for setting the ball valve 32 to a predetermined opening degree. This target opening degree Nd is represented by a value from 0 indicating the fully closed state of the ball valve 32 to 100 indicating the fully open state.

  Specifically, the target opening setting unit 11 inputs, for example, a current flow rate value acquired by a flow meter connected to the ball valve 32 and a flow rate setting value set by an operator, and the electric ball valve 30 The flow rate manipulated variable is calculated. The target opening setting unit 11 stores in advance flow rate opening conversion data indicating the relationship between the flow manipulated variable and the target opening Nd, and sets the obtained flow manipulated variable to the target based on the flow opening conversion data. The opening degree Nd is converted. When the relationship between the flow manipulated variable and the target opening degree Nd can be expressed by a mathematical expression, the flow manipulated variable is converted into the target opening degree Nd by calculation.

  The target opening degree determination unit 12 determines the range of the target opening degree Nd set by the target opening degree setting unit 11 and outputs data of the target opening degree Nd to the addition unit 13 when 0 <Nd <100. When Nd = 0 or Nd = 100, the data on the target opening degree Nd is output to the fully open / closed processing unit 18.

  The adding unit 13 inputs the target opening degree Nd and the current opening degree Na indicating the current opening degree of the ball valve 32, and obtains an opening degree difference ΔN (= Nd−Na) between them. . Here, the current opening degree Na is represented by a value from 0 indicating the fully closed state of the ball valve 32 to 100 indicating the fully opened state. Therefore, the opening degree difference ΔN is represented by 0 to 100.

  The pulse width calculation unit 14 calculates a drive pulse width for driving the single-phase induction motor 31 via the SSR 20 using [Equation 1] and [Equation 2]. The pulse width calculation unit 14 constitutes a pulse width calculation unit according to the present invention.

[Equation 1]
Drive pulse width (seconds) = drive time (seconds)-inertia travel time (seconds)

[Equation 2]
Drive time (seconds) = Fully open drive time (seconds) × Opening difference ΔN / 100

  Here, the fully open drive time refers to the drive time required for the single-phase induction motor 31 to change from the fully closed state (opening degree 0%) of the ball valve 32 to the fully open state (opening degree 100%). The fully open state and the fully closed state are detected by an open limit switch 37 and a close limit switch 38, which will be described later. The inertia running time will also be described later.

  The rotation direction determination unit 15 determines a rotation direction in which the ball valve 32 is rotated in a direction in which the opening degree difference ΔN is zero. For example, when the sign of the opening degree difference ΔN is positive, the rotation direction determination unit 15 determines that it is necessary to operate the single-phase induction motor 31 in the direction in which the ball valve 32 is opened (hereinafter referred to as “forward rotation direction”). To do. On the other hand, when the sign of the opening degree difference ΔN is negative, the rotation direction determination unit 15 determines that it is necessary to operate the single-phase induction motor 31 in the direction in which the ball valve 32 is closed (hereinafter referred to as “reverse rotation direction”). . Then, the rotation direction determination unit 15 outputs information indicating normal rotation or reverse rotation to the hysteresis correction unit 16.

  The hysteresis correcting unit 16 changes the rotation direction of the single-phase induction motor 31 to the rotation direction opposite to the previous rotation and starts to move the ball valve 32, and the valve body of the ball valve 32 is temporarily moved along with the rotation of the single-phase induction motor 31. The hysteresis equivalent drive time (DRIVE_HIS) for correcting hysteresis that does not move automatically is calculated. The calculation of the hysteresis equivalent drive time (DRIVE_HIS) will be described later.

  Further, when correcting the hysteresis, the hysteresis correction unit 16 corrects the drive pulse width calculated by the pulse width calculation unit 14 based on the calculated hysteresis equivalent drive time (DRIVE_HIS). The drive pulse width data from the hysteresis correction unit 16 is output to the drive pulse output unit 19.

  Further, the hysteresis correction unit 16 acquires the position information of the valve body of the ball valve 32 from the drive pulse width data output to the drive pulse output unit 19, and outputs this position information to the current opening degree acquisition unit 17. It has become. The hysteresis correction unit 16 constitutes a hysteresis correction unit according to the present invention.

  The current opening degree acquisition unit 17 is based on the position information of the valve body from the hysteresis correction unit 16 and the open limit signal and the close limit signal from the open limit switch 37 and the close limit switch 38 which will be described later. Na is acquired.

  The fully open / close processing unit 18 drives the SSR 20 to perform a process of fully opening the ball valve 32 or a process of fully closing the ball valve 32.

  The drive pulse output unit 19 receives drive pulse width data for driving the single-phase induction motor 31 from the hysteresis correction unit 16 and the fully open / closed processing unit 18 and outputs the drive pulse having the input drive pulse width to the SSR 20. It is supposed to be. The drive pulse output unit 19 constitutes AC power supply means according to the present invention.

  The SSR 20 outputs a drive pulse from the drive pulse output unit 19 to the single phase induction motor 31 to drive the single phase induction motor 31.

  FIG. 2 is a block diagram showing a hardware configuration of the electric ball valve driving system 10 in the present embodiment. The electric ball valve drive system 10 is connected to a personal computer (hereinafter referred to as “PC”) 41 operated by an operator via a LAN, and includes a digital controller 42 that controls the SSR 20, and drives the electric ball valve 30. It is like that. The SSR 20 includes a first SSR 21, a second SSR 22, a third SSR 23, and a fourth SSR 24.

  The digital controller 42 has a storage unit (not shown) for storing a program, and by executing the program installed in the storage unit, the target opening setting unit 11 and the target opening determination unit shown in FIG. 12, an addition unit 13, a pulse width calculation unit 14, a rotation direction determination unit 15, a hysteresis correction unit 16, a current opening degree acquisition unit 17, a fully open / close processing unit 18, and a drive pulse output unit 19.

  The electric ball valve 30 includes a forward direction driving coil 34 that drives the single-phase induction motor 31 in the forward direction of the ball valve 32, a reverse direction driving coil 35 that drives the single-phase induction motor 31 in the reverse direction of the ball valve 32, A center tap 36 is provided between the forward direction drive coil 34 and the reverse direction drive coil 35.

  The electric ball valve 30 is provided with an open limit switch 37 at a mechanical position corresponding to the fully open state of the ball valve 32, and a closed limit switch 38 at a mechanical position corresponding to the fully closed state of the ball valve 32. It has been. The open limit switch 37 and the close limit switch 38 are operated at the positions of the open upper limit and the close lower limit, respectively, by cams attached to the rotating shaft of the single-phase induction motor 31.

  The open limit switch 37 has a first output terminal 37a connected to the third SSR 23, a second output terminal 37b connected to the forward rotation direction drive coil 34, and an input terminal 37c connected to the first SSR 21. In the open limit switch 37, when the ball valve 32 is in a state other than the fully open state, the input terminal 37c and the second output terminal 37b are connected, and when the ball valve 32 is in the fully open state, the input terminal 37c and the first output are connected. Terminal 37a is connected. Hereinafter, a state in which the input terminal 37c and the second output terminal 37b are connected is referred to as an open state of the open limit switch 37, and a state in which the input terminal 37c and the first output terminal 37a are connected is ON. It is called a state.

  The closed limit switch 38 has a first output terminal 38 a connected to the fourth SSR 24, a second output terminal 38 b connected to the reverse direction driving coil 35, and an input terminal 38 c connected to the second SSR 22. In the closed limit switch 38, the input terminal 38c and the second output terminal 38b are connected when the ball valve 32 is in a state other than the fully closed state, and when the ball valve 32 is in the fully closed state, the input terminal 38c and the second output terminal 38b are connected. 1 output terminal 38a is connected. Hereinafter, a state in which the input terminal 38c and the second output terminal 38b are connected is referred to as an OFF state of the closed limit switch 38, and a state in which the input terminal 38c and the first output terminal 38a are connected is ON. It is called a state.

  The first SSR 21 is configured to apply an AC voltage of, for example, 60 Hz and 100 volts to the forward direction driving coil 34 when an opening signal for performing the opening control of the ball valve 32 is input from the digital controller 42. As a result, the single-phase induction motor 31 is driven to rotate the ball valve 32 in the normal rotation direction.

  The second SSR 22 is configured to apply an AC voltage of 100 volts to the reverse direction driving coil 35 when a closing signal for performing the closing control of the ball valve 32 is input from the digital controller 42. As a result, the single phase induction motor 31 is driven to rotate the ball valve 32 in the reverse direction.

  The third SSR 23 is configured to output an open limit signal indicating the fully open state of the ball valve 32 to the digital controller 42 when the open limit switch 37 changes from the OFF state to the ON state.

  The fourth SSR 24 is configured to output a closed limit signal indicating the fully closed state of the ball valve 32 to the digital controller 42 when the closed limit switch 38 changes from the off state to the on state.

  Next, the function of the first SSR 21 will be described with reference to FIG.

  3 is a power supply voltage applied to the single-phase induction motor 31, the middle stage of FIG. 3 is an inductive load current flowing through the single-phase induction motor 31, and the lower stage of FIG. 3 is a ball valve output from the digital controller 42 to the first SSR 21. An example of a drive pulse for opening 32 (denoted as an open signal in FIG. 2) is shown. As shown in the figure, the phase of the inductive load current is 90 degrees behind the power supply voltage.

  As shown in the lower part of FIG. 3, when the first SSR 21 inputs an open signal that is in the ON state in the period from time T1 to T3, the single-phase induction motor 31 is from time T2 to T4 due to the zero cross characteristic of the first SSR21. It is driven by the voltage and current during the period.

  Specifically, the first SSR 21 does not apply a voltage to the single-phase induction motor 31 at time T1, but applies the voltage to the single-phase induction motor 31 after waiting for time T2 when the power supply voltage crosses zero. Further, the first SSR 21 does not stop the voltage application to the single-phase induction motor 31 at the time T3, but stops the voltage application to the single-phase induction motor 31 after the time T4 when the inductive load current crosses zero. As a result, the single-phase induction motor 31 is driven by being supplied with power by the voltage and current in the shaded area shown in FIG.

  The shaded area voltage and current signals have a time width of 4.16 milliseconds, which is a 1/4 cycle time of 60 Hertz when using a 60 Hertz commercial power supply. Therefore, the minimum time width in which the first SSR 21 can be driven is 4.16 milliseconds. The first SSR 21 is an integral multiple of a half cycle time of 60 Hz (hereinafter referred to as a “1/2 cycle waveform”) to this 60 Hz signal of a 1/4 cycle time (hereinafter referred to as a “¼ cycle waveform”). The single-phase induction motor 31 is driven. This is shown in FIG.

  The voltage and current supplied to the single-phase induction motor 31 are not limited to the shaded area shown in FIG. For example, the configuration may be such that the single-phase induction motor 31 is driven with electric power for a period from the time when zero crossing occurs at the fall of the power supply voltage until ¼ cycle has elapsed. Specifically, a contact relay can be used in a system that allows contact wear, response delay, or switching noise. In this case, the waveform differs from that shown in FIG. If there is, the single-phase induction motor 31 can be driven.

  Next, the drive pulses for driving the single-phase induction motor 31 and the waveforms of the voltage and current actually supplied to the single-phase induction motor 31 will be described with reference to FIG. Here, the power supply frequency is 60 hertz.

  In FIG. 4, n is an integer representing the timing of each half cycle unit starting from the end of the first quarter cycle waveform generated after power-on. For example, when the fully open drive time is 12.5 seconds, n = 1500. This n is similar to the number of driving pulses of a pulse motor that drives from 1500 to 1050 with a full pulse.

  As shown in FIG. 4, the n-th driving time is (2n + 1) / 240 seconds. For example, the timing at which the single-phase induction motor 31 activated via the first SSR 21 at time T0 can be stopped corresponds to n = 1, 2, 3, 4 since the first SSR 21 has a zero-cross characteristic. The driving time is 83, 29.16, 37.50 milliseconds. Therefore, if the first SSR 21 is driven with a drive pulse having a pulse width from T0 to T3, the first SSR 21 drives the single-phase induction motor 31 for 37.5 milliseconds corresponding to n = 4 from T0 to T3. become. Even when a calculation error such as a rounding error is included in the pulse width calculated by the pulse width calculation unit 14 shown in FIG. 1, for example, if the calculation error of the pulse widths T0 to T2 is between T1 and T3, The driving result is T3. Here, n has an effect of normalizing the drive pulse including the calculation error.

  Further, as described above, in a system in which contact wear, response delay, or switching noise generation is allowed, a single-phase induction motor 31 using a contact relay with a drive time of (2n + 1) / 240 seconds corresponding to n. Can also be driven.

  The pulse width calculation unit 14 (see FIG. 1) obtains the pulse width of the drive pulse described above, and the first SSR 21 is operated to drive the single-phase induction motor 31.

  In the above description, the first SSR 21 has been described as an example. However, the second SSR 22 operates in the same manner as the first SSR 21 (but operates in the closing direction), and thus the description thereof is omitted.

  Next, the operation of the electric motor by the drive pulse will be described with reference to the schematic diagram shown in FIG. Generally, when starting and stopping an electric motor, as shown in the figure, the electric motor reaches a constant speed in a constant speed region through an acceleration region, and stops through a deceleration region due to inertia. When the electric ball valve 30 is controlled, the variable that can be controlled is the driving time Ton. The operating amount during the deceleration period is the inertia traveling time Tor. As shown in the figure, a time obtained by combining the driving time Ton and the inertia traveling time Tor becomes the actual traveling time TrunAct.

  The method for obtaining the inertia running time will be described with reference to FIG. When driving from the fully closed limit position to the fully open limit position in one operation, N = 1. At this time, the time that the single-phase induction motor 31 actually travels effectively is defined as the actual opening / closing time Tao. The actual opening / closing time Tao is the sum of the drive time Ton (1) that travels at a constant speed by the drive signal and the inertia travel time Tor.

  Similarly, in the case of driving twice, that is, driving 50% twice to reach 100%, N = 2. At this time, the actual opening / closing time Tao is the sum of the drive time Ton (2) that travels at a constant speed by the drive signal and the inertia travel time Tor.

  Furthermore, N = 100 when driving from fully closed to fully open by driving 100 times in 1% increments. Also in this case, the actual opening / closing time Tao is the sum of the drive time Ton (100) that travels at a constant speed by the drive signal and the inertia travel time Tor.

  For example, it is performed as follows. First, the inertia traveling time Tor is set to zero, and the opening difference ΔN is set to 1% of the total opening, and the single-phase induction motor 31 is driven from the closed state to the open state in increments of 1%. At this time, since the inertia running time Tor occurs, it reaches 100% (fully open) before 100 times. When the drive time from the closed state to the open state is 12.5 seconds, the drive time corresponding to 1% is 125 milliseconds. If the inertial running time Tor is zero, it reaches from 1% × 100 times to close to open. Here, the inertia running time Tor is calculated when the open state is reached from the closed state at 1% × 70 times (corresponding to 70%). This means that the driving time Ton = 125 × 70 = 8750 milliseconds is driven for 12500 milliseconds. The inertia running time Tor corresponding to 70 times is 12500-8750 = 3750 milliseconds, and the inertia running time Tor corresponding to one time (1% drive) is 3750 ÷ 70 = 53.57 milliseconds.

  Next, operation | movement of the electric ball valve drive system 10 in this embodiment is demonstrated based on FIGS. First, the main routine will be described with reference to FIG.

  First, the digital controller 42 determines whether or not the target opening degree Nd has been input (step S11). For example, the digital controller 42 calculates a target flow manipulated variable from the current flow rate value acquired by the flow meter connected to the ball valve 32 and the flow rate setting value input by operating the PC 41 by the operator. The target opening degree Nd is obtained using the opening degree conversion data.

  Next, the digital controller 42 determines whether or not Nd = 100 (step S12).

  In step S12, if Nd = 100, the digital controller 42 performs a valve full-opening process (step S20) described later. On the other hand, if Nd = 100 is not true, the digital controller 42 determines whether or not Nd = 0 (step S13).

  In step S13, if Nd = 0, the digital controller 42 performs a valve fully closing process (step S30), which will be described later. On the other hand, if Nd = 0 is not true, the digital controller 42 calculates the opening degree difference ΔN (step S14).

  Next, the digital controller 42 determines whether or not ΔN = 0 (step S15).

  In step S15, if ΔN = 0, the digital controller 42 returns to step S11. On the other hand, if ΔN = 0 is not true, the digital controller 42 calculates the drive pulse width from [Equation 1] and [Equation 2] (step S16).

  Next, the digital controller 42 determines whether ΔN> 0 is satisfied (step S17).

  If ΔN> 0 in step S17, the digital controller 42 performs a valve opening process (step S40) to be described later. On the other hand, when ΔN> 0 is not satisfied, that is, when ΔN <0, the digital controller 42 performs a valve closing process (step S50) described later.

  Then, after executing the processes of step S40 and step S50, the digital controller 42 updates the current opening Na (step S18), stores the updated current opening Na, and returns to step S11.

  Next, the valve fully opening process (step S20) will be described with reference to FIG.

  First, the digital controller 42 turns off the output of the second SSR 22 which is the SSR for closing drive (step S21), waits for a predetermined time (for example, 10 milliseconds) (step S22), and is the SSR for opening drive. The output of the first SSR 21 is turned on (step S23). Here, the predetermined time may be 8.3 milliseconds or more which is a half cycle time of 60 Hz. The processes in steps S21 to S23 are performed in order to prevent the first SSR 21 and the second SSR 22 from being turned on at the same time and causing a malfunction.

  Next, the digital controller 42 outputs a drive pulse to the first SSR 21 which is the SSR for opening driving (step S24).

  Next, the digital controller 42 determines whether or not the open limit switch 37 is turned on (fully opened) (step S25).

  If the open limit switch 37 is not on in step S25, the process returns to step S24. On the other hand, if the open limit switch 37 is on in step S25, the digital controller 42 substitutes "100" for the current opening degree Na (step S26).

  Then, the digital controller 42 assigns “1” to the closed hysteresis flag (CL_HIS_FLG) and “0” to the open hysteresis flag (OP_HIS_FLG) (step S27), and returns to the main routine.

  Here, the closed hysteresis flag (CL_HIS_FLG) and the open hysteresis flag (OP_HIS_FLG) are flags for correcting hysteresis generated when the rotation direction of the ball valve 32 is changed, and both have values of “0” or “1”. Take. When the single-phase induction motor 31 operates the ball valve 32 in the forward rotation direction, the digital controller 42 performs the process shown in step S25. On the other hand, when the single-phase induction motor 31 operates the ball valve 32 in the reverse direction, the digital controller 42 substitutes “0” for the closed hysteresis flag (CL_HIS_FLG) and “1” for the open hysteresis flag (OP_HIS_FLG). Perform the process.

  Next, the valve fully closing process (step S30) will be described with reference to FIG.

  First, the digital controller 42 turns off the output of the first SSR 21 that is the SSR for opening driving (step S31), waits for a predetermined time (for example, 10 milliseconds) (step S32), and is the SSR for closing driving. The output of the second SSR 22 is turned on (step S33).

  Next, the digital controller 42 outputs a drive pulse to the first SSR 21 that is the SSR for opening drive (step S34).

  Next, the digital controller 42 determines whether or not the closing limit switch 38 is turned on (fully closed) (step S35).

  If it is determined in step S35 that the closed limit switch 38 is not on, the process returns to step S34. On the other hand, if the closed limit switch 38 is on in step S35, the digital controller 42 substitutes “0” for the current opening degree Na (step S36).

  Then, the digital controller 42 assigns “0” to the closed hysteresis flag (CL_HIS_FLG) and “1” to the open hysteresis flag (OP_HIS_FLG) (step S37), and returns to the main routine.

  Next, the valve opening process (step S40) will be described with reference to FIG.

  First, the digital controller 42 determines whether or not the open hysteresis flag (OP_HIS_FLG) = 0 (step S41). That is, the digital controller 42 determines whether or not the previous rotation direction of the ball valve 32 was the normal rotation direction.

  In step S41, when the open hysteresis flag (OP_HIS_FLG) = 0 (previous rotation direction in the previous time), the digital controller 42 does not correct the hysteresis and proceeds to step S44 described later.

  On the other hand, when the open hysteresis flag (OP_HIS_FLG) = 1 (previous rotation direction in the previous time), the digital controller 42 calculates the hysteresis equivalent drive time (DRIVE_HIS) shown in [Equation 3] (step S42).

[Equation 3]
DRIVE_HIS (seconds) = OP_HIS_FLG x HIS_VALUE (seconds)

  Here, the hysteresis correction set value (HIS_VALUE) is a correction value for correcting the hysteresis, and is a value obtained in advance by experiments. This hysteresis correction set value (HIS_VALUE) is represented by a drive time corresponding to about 5% to 7% of the fully open drive time of the ball valve 32, for example.

  Next, the digital controller 42 corrects the drive pulse width based on the calculated hysteresis equivalent drive time (DRIVE_HIS) based on [Equation 4] (step S43).

[Equation 4]
Drive pulse width (seconds) = Drive pulse width (seconds) + DRIVE_HIS (seconds)

  Next, the digital controller 42 waits for a predetermined time (for example, 10 milliseconds) after turning off the output of the second SSR 22 that is the SSR for the closing drive (step S44) (step S45). Thereafter, the digital controller 42 turns on the output of the first SSR 21 that is the SSR for opening driving (step S46), and outputs a driving pulse from the first SSR 21 (step S47).

  Next, the digital controller 42 acquires the position information of the valve body of the ball valve 32 (step S48), and substitutes "1" for the closed hysteresis flag (CL_HIS_FLG) and "0" for the open hysteresis flag (OP_HIS_FLG). Then (step S49), the process returns to the main routine.

  Next, the valve opening process (step S50) will be described with reference to FIG.

  First, the digital controller 42 determines whether or not the closed hysteresis flag (CL_HIS_FLG) = 0 (step S51). That is, the digital controller 42 determines whether or not the previous rotation direction of the ball valve 32 was the reverse rotation direction.

  In step S51, when the closed hysteresis flag (CL_HIS_FLG) = 0 (the reverse direction is the previous time), the digital controller 42 does not correct the hysteresis and proceeds to step S54 described later.

  On the other hand, when the closed hysteresis flag (CL_HIS_FLG) = 1 (previous rotation direction last time), the digital controller 42 calculates the hysteresis equivalent drive time (DRIVE_HIS) shown in [Equation 5] (step S52).

[Equation 5]
DRIVE_HIS (seconds) = CL_HIS_FLG x HIS_VALUE (seconds)

  Next, the digital controller 42 corrects the drive pulse width based on the calculated hysteresis-corresponding drive time (DRIVE_HIS) based on the above [Equation 4] (step S53).

  Next, the digital controller 42 waits for a predetermined time (for example, 10 milliseconds) after turning off the output of the first SSR 21 that is the SSR for opening driving (step S54) (step S55). Thereafter, the digital controller 42 turns on the output of the second SSR 22 that is the SSR for the closed drive (step S56), and outputs a drive pulse from the second SSR 22 (step S57).

  Next, the digital controller 42 acquires the position information of the valve body of the ball valve 32 (step S58), and substitutes "0" for the closed hysteresis flag (CL_HIS_FLG) and "1" for the open hysteresis flag (OP_HIS_FLG). Then, the process returns to the main routine (step S59).

  As described above, the electric ball valve drive system 10 according to the present embodiment supplies the drive pulse having the pulse width calculated by the pulse width calculation unit 14 to the single phase induction motor 31, thereby pulsing the single phase induction motor 31. It can be driven like a motor.

  As a result, the electric ball valve drive system 10 can realize digital control of a high-power drive system that could not be realized with a pulse motor, and by directly driving the single-phase induction motor 31 with the PC 41 and the digital controller 42, A drive system that eliminates the auxiliary control device and does not generate standby power can be realized.

  Therefore, the electric ball valve drive system 10 can suppress useless energy consumption and can drive the ball valve 32 with a simple configuration.

  The electric ball valve drive system 10 includes a hysteresis correction unit 16 that calculates a hysteresis-equivalent drive time for correcting the hysteresis of the ball valve 32 and corrects the pulse width of the drive pulse by the hysteresis-equivalent drive time. Considering the hysteresis of the valve 32, more accurate control can be realized by software. Therefore, the electric ball valve drive system 10 can accurately reflect the change in the operation amount of the ball valve 32 in the change in the flow rate.

  In addition, the electric ball valve drive system 10 uses the feature of the ball valve 32 that can accurately calculate the flow coefficient for the operation signal indicating the operation amount, and obtains and sets the operation amount for the target flow rate by calculation in advance. It can be converged faster than the method.

  Furthermore, the electric ball valve drive system 10 can reduce the capacity of the water supply pump by using the ball valve 32 having a small pressure loss when fully opened, and can build an energy saving system with a low standby power as a whole.

  In the above-described embodiment, the motor-driven valve drive system according to the present invention has been described as an example applied to the motor-driven ball valve drive system. However, the present invention is not limited to this, and other motor-operated valves can be used. Can also be applied.

  As described above, the motor-operated valve driving system according to the present invention has an effect that the motor-operated valve can be driven with a simple configuration while suppressing wasteful energy consumption, and the motor-operated valve that adjusts the flow rate of fluid is provided. It is useful as an electric valve drive system for driving.

10 Electric ball valve drive system (electric valve drive system)
11 Target Opening Setting Unit 12 Target Opening Determination Unit 13 Adding Unit (Opening Difference Calculation Means)
14 Pulse width calculator (pulse width calculator)
15 Rotation direction determination unit 16 Hysteresis correction unit (hysteresis correction means)
17 Current opening acquisition unit 18 Fully open / closed processing unit 19 Drive pulse output unit (AC power supply means)
20 SSR
21 First SSR
22 Second SSR
23 Third SSR
24th SSR
30 Electric ball valve (motor valve)
31 Single-phase induction motor 32 Ball valve 34 Forward direction drive coil 35 Reverse direction drive coil 36 Center tap 37 Open limit switch 37a First output terminal 37b Second output terminal 37c Input terminal 38 Closed limit switch 38a First output terminal 38b First 2 output terminal 38c input terminal 41 PC
42 Digital controller

Claims (4)

An electric valve driving system for driving an induction motor that opens and closes an electric valve,
An opening degree difference calculating means for calculating an opening degree difference indicating a difference between a target opening degree for setting the opening degree of the electric valve and a current opening degree that is a current opening degree of the electric valve;
AC power supply means for supplying AC power for driving the induction motor by a drive pulse;
A full-open drive time indicating a time required for the induction motor to change the motor-operated valve from a fully-closed state to a fully-open state; a ratio of the opening difference with respect to the opening in the fully-open state of the motor-operated valve; and the induction motor And a pulse width calculating means for calculating a pulse width of the drive pulse based on inertia running time indicating a time during which the induction motor is operated by inertia after supplying AC power to the power source for a predetermined time. The electric valve has hysteresis in the valve opening operation and the valve closing operation,
2. The apparatus according to claim 1, further comprising hysteresis correction means for calculating a hysteresis equivalent drive time indicating a time for correcting the hysteresis by driving the motor-operated valve, and correcting a pulse width of the drive pulse by the calculated hysteresis correction value. The motor-driven valve drive system described.   The AC power supply means is a time at which the phase of the voltage is delayed by 90 degrees from the time from the time when the voltage applied to the motor-operated valve crosses the zero point, and the current supplied to the motor-operated valve is a zero point. 3. The motor-driven valve drive system according to claim 1, wherein voltage pulses and current pulses for a period up to a crossing time are supplied to the induction motor by the drive pulses.   The motor-driven valve drive system according to any one of claims 1 to 3, wherein the induction motor is a single-phase saddle type induction motor.

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