JP2007010627A - Method and apparatus of calculating electricity bill of motor driving system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor driving device and an apparatus for computing power dissipation charge of a motor controlled by it. <P>SOLUTION: An apparatus of calculating the electricity bill of a motor driving system includes a controller 53, connected to an inverter 52 which applies an electric power to the motor according to a motor load, an input section 52 and a display 54 which are connected to the controller 53 inside the motor driving device 5. The controller 53 calculates the instantaneous load electric power Pout of the motor from the output voltage, the output current, and the power factor of the inverter 51; adds the internal power dissipation Pi of the motor driving device 5 to the Pout; computes the total P of the momentary power dissipation, converts the P into the power dissipation Ph per hour; computes the charge to the electrical energy consumption of the motor driving device 5 and the motor, by multiplying the Ph by the power rate unit price Ec and acting time T which are input from the input section 52; and displays on a display 54. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and apparatus for calculating an electric charge for a motor drive system, and more particularly, to a method and apparatus for calculating a charge related to the electric energy consumption of a motor drive system in which a motor is controlled by a motor drive apparatus.

  The motor drive device controls the rotation speed of the motor to be within a predetermined range. For this purpose, the motor drive is provided with an inverter.

  And the motor drive device provided with such an inverter can adjust the output power of a motor according to an actual load. This prevents the problem of wasted power that has occurred with conventional fixed speed motors.

  Such motor driving devices are widely used in homes (for example, air conditioners, refrigerators, microwave ovens, etc.).

  Moreover, since the electric power consumption by use of a motor is large also industrially, use of such a motor drive device is spreading also in an industrial field.

  The motor drive device having such an inverter has a function of saving energy. However, the user is unable to know the electrical energy consumption of the motor drive itself.

  FIG. 1 is a block diagram showing the configuration of a conventional motor drive system.

  The motor driving device 3 is disposed between the motor 2 and the electric meter 1. One end of the electric meter 1 is electrically connected to the power source 11.

  Therefore, the user needs to calculate the usage fee of the consumed electric energy by multiplying the value (meter value) read from the electricity meter 1 by the unit price of electricity bill. This is inconvenient for the user.

  Furthermore, the electric meter 1 is rarely provided exclusively for one motor driving device 3, but rather is often shared by a plurality of various electric facilities. Therefore, in many cases, it is impossible to know the energy consumption amount of each motor driving device 3 and the motor 2 connected thereto only by reading the electric meter.

  Furthermore, the electricity meter 1 can only show cumulatively the energy consumed so far, not the exact energy consumed within a specific time range.

  Furthermore, the electric meter 1 is generally provided by a power company for counting the electric energy consumption of a house.

  Therefore, such an electric meter 1 is practically not provided independently to each electric facility or equipment, and it is not economical to provide each electric facility (here, a motor drive device). .

  On the other hand, some conventional motor drive devices include only a display for display and an input unit for input, but do not have a function of calculating electric energy consumption.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for individually and easily calculating a power consumption fee in a motor drive system including a motor drive device and a motor controlled by the motor drive device, and an apparatus therefor. It is.

  The present invention for solving the above object is a method for calculating a charge of electric energy consumption in a motor drive system having a motor and a motor drive device that controls the motor, and (a) an output of the motor drive device Calculating instantaneous load power Pout from the voltage, output current, and power factor; and (b) adding instantaneous power consumption Pi by adding internal power consumption Pi of the motor driving device to the instantaneous load power Pout. And (c) multiplying the total P of instantaneous power consumption by the operation time T of the motor drive unit and the unit price of electricity Ec to charge the electric energy consumption of the motor drive system A method of calculating an electricity charge for a motor drive system.

  In addition, the present invention for solving the above-described object is an electric charge calculation device for calculating a charge of electric energy consumption of a motor drive system having a motor and a motor drive device including an inverter for controlling the motor. An input unit for inputting an operating time and a power unit price, an output voltage, an output current, and a power factor of the inverter connected to the inverter, and the operating time and the power input from the input unit. A motor drive system electricity comprising: a control unit that calculates a charge of electric energy consumption from a unit price of charge; and a display that is connected to the control unit and displays the charge calculated by the control unit. It is a charge calculation device.

  According to the present invention, the output voltage, the output current, and the power factor from the motor drive device are obtained, the instantaneous load power of the motor is calculated from these, and the total instantaneous power consumption is calculated by the motor drive device. Calculated by adding internal power consumption. Then, in order to obtain the total charge of electric energy consumption, the input operation time and the power charge unit price are multiplied by the instantaneous total power consumption. This allows the user to charge for electricity that corresponds to the power consumed by each motor and the motor connected to it, including the power consumed by the motor drive during a specific time (input operating time). Can be known individually and easily.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 2 is a block diagram showing the overall configuration of the motor drive system in the present embodiment, FIG. 3 is a flowchart showing the flow of the electric charge calculation method of this motor drive system, and FIG. 4 is this motor drive. It is a block diagram which shows the internal structure of the motor drive unit used for the system.

  In this motor drive system, the motor drive device 5 is connected between the motor 4 and the power source 6. Here, the motor 4 is, for example, a three-phase AC motor. The power source 6 is an AC power source for home use or industrial use.

  As will be described later, the motor driving device 5 includes an inverter, and appropriately supplies power from the power source 6 according to the load of the motor 4 (for example, the speed of the motor 4 and the torque of the motor 4). ing.

  Although details of the motor drive device 5 will be described later, a control unit serving as a calculation unit is provided therein, and a charge for electric energy consumption is calculated by the control unit, and the calculated charge is displayed on the display. . This display is provided in the motor drive device 5 in this embodiment.

  A method for calculating the electric charge of the motor drive system will be described with reference to FIG.

  Here, the instantaneous load power P of the three-phase (3Φ) motor is expressed by the following equation (1).

P = 3 × V × I × cos θ (1)
In the formula, V represents a voltage, I represents a current, θ represents an electrical angle, and cos θ represents a power factor.

  The single-phase instantaneous load power is V × I × cos θ.

  In this method of calculating the electric charge of the motor drive system, first, the instantaneous load power Pout is first calculated (step 701).

  Here, the output voltage V, the output current I, and the power factor cos θ are obtained from the motor driving device 5, and the instantaneous load power Pout of the motor 4 is calculated according to the above equation (1). Here, the instantaneous load power Pout is the load power per second.

  Subsequently, a total P of instantaneous power consumption is calculated (step 702). The total instantaneous power consumption P is the sum of the instantaneous load power Pout of the motor 4 and the internal power consumption Pi of the motor driving device 5. That is, P = Pout + Pi.

  Here, the internal power consumption Pi of the motor drive device 5 includes standby power consumption and power consumption of the power module.

  The standby power consumption is the power consumption of the motor drive device 5 when the motor 4 is stopped, which is obtained from the result of long-term measurement of the power consumption of the motor drive device 5. If the electric power of this motor drive system is separately measured with an electric meter as shown in FIG. 1, the total power consumption of the motor 4 and the entire motor drive device 5 can be found. In addition, the power consumption while the motor is stopped is also known, that is, the power consumption during that time becomes the standby power consumption of the motor drive unit alone.

  On the other hand, the power consumption of the power module is a value measured under various operating conditions of the motor drive device 5. The power module itself is a semiconductor module that constitutes an inverter, and the power module itself does not consume much power. However, since there is some variation depending on the electric power output to the motor 4, here, the power module in the motor driving device 5 measured in various operating conditions, that is, in a state where the rotational speed of the motor 4 is controlled in various ways. The power consumption is measured and, for example, the average value is used. In place of the average value, the maximum power consumption of the power module, the power consumption in the operation state that has been used for the longest time (the rotational speed of the motor 4 that has been used for the longest time), etc. May be used.

  And if these internal power consumption Pi is measured beforehand as the internal power consumption of the motor drive device 5, it will not change after that. Therefore, the internal power consumption Pi may be stored and set in the control unit 53 of the motor driving device 5 in advance. In addition, you may make it input later, without memorize | storing beforehand.

  Subsequently, the instantaneous total power consumption P is converted into power consumption per hour (total power consumption per hour Ph) (step 703). This conversion is performed by Ph = 3600 × P.

  Then, the total charge M for the electric energy consumption is calculated from the total power consumption per hour Ph (step 704).

  In calculating the total charge M, first, the total electric power consumption hourly Ph is multiplied by the operation time T in order to obtain the total electric energy consumption.

  Then, the total charge M in the total electric energy consumption is calculated by multiplying the total electric energy consumption by the electric power unit price Ec. That is, M = P × T × Ec. Here, the operation time T is the operation time of the motor drive device 5 input by the user. The power rate unit price Ec is a rate for power consumption per hour, and can also be called a unit price of the power rate. Note that the power unit price Ec may vary depending on the region, contract, etc., so the user inputs it here as appropriate.

  Next, with reference to FIG. 4, the internal configuration of the motor drive device 5 that executes the above-described fee calculation method will be described.

  In the present embodiment, as shown in FIG. 4, the motor drive device 5 includes an inverter 51, an input unit 52, a control unit 53 to which the inverter 51 and the input unit 52 are connected, and a display 54 connected to the control unit 53. And have.

  Here, the inverter 51 is connected to the motor 4 and supplies the electric power for driving the motor 4 according to the load applied to the motor 4 as the motor driving device 5 as shown in FIG.

  The control unit 53 is a processor module including a processor and a memory, and has a program for executing the above-described fee calculation method.

  The control unit 53 obtains the output voltage V, the output current I, and the electrical angle θ of the inverter 51 from the current flowing through the inverter 51, obtains the power factor cos θ from these, and then outputs the instantaneous output Pout of the motor 4. Is calculated.

  In addition, the input unit 52 inputs the power rate unit price Ec and the operation time T. Here, the operation time T may be input only for the time for which the power consumption fee is desired.

  As a result, the control unit 53 calculates a charge for the electric energy consumption, and then displays the calculated charge on the display 54.

  According to the method and apparatus described above, the motor drive device 5 can essentially calculate a charge for the electric energy consumption and display the result on the display 54. Therefore, by applying the present invention, the electric energy consumed for the motor 4 and the charges associated therewith can be known without any additional measuring instrument. That is, normally, since one motor driving device 5 is provided for one motor 4, if there is a motor driving device 5 to which the present invention is applied, there is no need to add an electric meter or the like. Thus, it is possible to know the usage fee corresponding to the electric energy consumption of the individual motor driving devices 5 and the motors 4 controlled thereby.

  Moreover, since the motor drive device 5 has an arithmetic function, wiring is simple and the cost for it can also be suppressed.

  It should be noted that the calculated fee can be directly viewed on the display 54, or may be obtained by remote operation, for example. For example, the input unit 52 and the display 54 may be provided not in the motor driving device 5 but in a separate place.

  The present invention can take a variety of forms. For example, a storage unit such as a memory unit is further provided in the motor drive device 5 to store instantaneous load power that changes according to the load of the motor 4 and to store the accumulated load power. You may make it calculate the electric energy consumption in the case of a change, and the charge relevant to it. In this case, the instantaneous load power to be stored may be, for example, every second. Of course, it may be every period that is less than 1 second such as 1/10 second or 1/100 second, or conversely, it may be stored every period longer than 1 second such as every 10 seconds or every minute. Good. The subsequent calculation method of the electricity bill is the same as described above.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to such embodiment, Various substitution and a change aspect are possible, and this invention is described in a claim. It goes without saying that it is defined within the specified range.

It is a block diagram which shows the structure of the conventional motor drive system. It is a block diagram which shows the whole structure of the motor drive system in this embodiment. It is a flowchart which shows the flow of the electric bill calculation method of a motor drive system. It is a block diagram which shows the internal structure of a motor drive device.

Explanation of symbols

4 ... Motor,
5 ... Motor drive,
6 ... Power supply,
51 ... Inverter,
52 ... Input section,
53. Control unit,
54. Display.

Claims (6)

A charge calculation method for electric energy consumption in a motor drive system having a motor and a motor drive device for controlling the motor,
(A) calculating an instantaneous load power Pout from the output voltage, output current, and power factor of the motor driving device;
(B) calculating the total instantaneous power consumption P by adding the internal power consumption Pi of the motor driving device to the instantaneous load power Pout;
(C) calculating a charge M of the electric energy consumption of the motor drive system by multiplying the total P of the instantaneous power consumption by an operating time T of the motor drive unit and an electric charge unit price Ec;
An electric charge calculation method for a motor drive system characterized by comprising: Between the step (b) and the step (c),
Converting the total instantaneous power consumption P into the total power consumption Ph per hour;
The electric energy consumption charge M of the motor drive system is calculated by multiplying the total power consumption per hour Ph by the operation time T of the motor drive apparatus and the electric charge unit price Ec. The electric charge calculation method of the motor drive system according to claim 1.   3. The motor drive system according to claim 1, wherein the internal power consumption Pi of the motor drive device is composed of standby power consumption of the motor drive device and power consumption of a power module in the motor drive device. Electricity cost calculation method.   4. The motor according to claim 3, wherein the standby power consumption is power consumption of the motor drive device when the motor is stopped, which is obtained from a result of long-term measurement of power consumption of the motor drive device. Electricity cost calculation method for drive train   4. The electric charge calculation method for a motor drive system according to claim 3, wherein the power consumption of the power module is a value measured in various operating situations of the motor drive device. An electric charge calculation device for calculating a charge of electric energy consumption of a motor drive system having a motor and a motor drive device including an inverter for controlling the motor,
An input unit for inputting the operating time and the unit price of electricity charge;
A control unit connected to the inverter and calculating a charge of electric energy consumption from the output voltage, output current, and power factor of the inverter, and the operation time and the unit price of the electric power input from the input unit;
A display connected to the control unit and displaying a charge calculated by the control unit;
An electric charge calculation device for a motor drive system characterized by comprising:

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