KR101872844B1 - Motor driving method for energy saving via margin power control - Google Patents

Abstract

A method of driving an energy-saving motor through margin-controlled power control according to an embodiment of the present invention includes the steps of: (1) measuring a surface temperature of the motor and comparing the surface temperature with a reference temperature; (2) when the measured surface temperature is lower than or equal to the reference temperature, the supply voltage or the driving frequency of the motor is reduced to a predetermined ratio, and then the motor is driven for a predetermined time to measure the surface temperature of the motor driven for the predetermined time step; And (3) repeating the step (2) until the measured surface temperature exceeds the reference temperature, and when the measured surface temperature exceeds the reference temperature, The supply voltage or the drive frequency is set to the input value of the electric motor so that the supply voltage or the drive frequency necessary for the electric motor to normally operate with respect to the load is minimized below the rated voltage or the rated frequency, .

Description

TECHNICAL FIELD [0001] The present invention relates to an energy saving type motor drive method and apparatus,

More particularly, the present invention relates to a method and apparatus for driving an energy-reduction type motor by minimizing extra power based on surface temperature.

Generally, a permanent magnet constituting a rotor of an induction motor generates a low-temperature potato phenomenon. This is because when the motor is operated under a low temperature condition, the magnet potato is excessively generated by the peak current of the armature coil, The initial magnetic flux density value can not be recovered and magnetic force is lowered. As a result, the operating current of the motor rises and the temperature of the motor and the driving circuit rises. As a result, the motor trips.

In the case of ferrite permanent magnets, the magnetic flux density (Br) is increased by about 0.18 0.20% / and the coercive force (Hc) is about 0.35 0.45% / degree in the magnetic hysteresis curve . In other words, the magnetic hysteresis curve changes according to the temperature. In order to secure the stable magnet characteristics from the low temperature to the high temperature, the armature reaction control technique is required through the current limitation along with consideration of the motor design considering the low- .

Korean Patent Publication No. 10-2007-0074144 discloses a method of detecting a temperature of the motor when a load current flowing through the motor is equal to or higher than a predetermined upper limit value of an overcurrent and determining a temperature operation condition of the permanent magnet from the detected temperature And sets the upper limit value of the overcurrent to be different from each other in accordance with the determined temperature operating condition.

In the past, a method of reducing energy by reducing the voltage or frequency supplied to the motor in a rated manner has been formally applied to inverters and softstarter.

The windings of the motor are transformed into heat loss, such as iron loss and copper loss. The temperature measurement of the winding part is carried out using a direct method using a temperature sensor during operation and an indirect method using a winding resistance value as in equation (1) While the motor is running, it can not be measured by freezing.

Deg (T) = [(R2 - R1) X (234.5 + T1) / R1] - (T2 T1)

Here, R1 is the winding resistance before the temperature rise test, R2 is the winding resistance after the temperature rise test, T1 is the ambient temperature before the temperature rise test, T2 is the ambient temperature after the temperature rise test, and 234.5 is the temperature coefficient of the copper wire.

Conventional inverters and softstarter formally adopt a sensorless method of calculating the temperature by indirect method or a method of saving energy by incorporating an excitation current limiting program. However, the inverter generates more heat than a motor supplied with a sinusoidal wave by outputting a DC square wave, and when the voltage is also decreased in a soft starter using a thyristor, a sinusoidal wave is distorted into a distorted wave and a temperature rise occurs.

In addition, since the temperature is affected by the surrounding environment, it is not possible to reliably calculate by the calculation formula without measuring the temperature during the operation of the motor, and it is not possible to stop from time to time to measure the resistance of the winding during operation. Since the amplitude of the square wave changes with the variation of the carrier frequency and the influence of the temperature on the winding part changes depending on the variation of the carrier frequency, the indirect method of unfamiliarity, which can not apply a constant temperature constant, have.

There is also a device for measuring the surface or internal temperature of an induction motor by a temperature sensor such as a duster, but it is not used for power consumption reduction control, but is used only as a function for protecting the motor from burnout or preventing deterioration.

In such prior arts, as to whether the rated voltage or the rated frequency of the electric motor consumes electric power with a certain amount of spare electric power to the load fluctuation, that is, the electric motor consumes more power than necessary for the output to be supplied to the load, Nor does it provide a solution.

Korean Patent Publication No. 10-2007-0074144

1996 ASHRAE Handbook (American Society for Heating, Refrigeration, and Air Conditioning Engineers), Chapter 39, Motors and Motor Control

It is an object of the present invention to provide a method and apparatus for driving an energy saving type motor by means of margin power control based on a change in surface temperature of the motor due to a decrease in supply voltage or drive frequency.

It is another object of the present invention to provide a method and apparatus for driving an energy-reduction type motor with margin power control that can determine whether an electric motor is capable of reducing energy by reducing a supply voltage or a driving frequency.

A method of driving an energy-saving type motor with idle power control according to embodiments of the present invention includes the steps of: (1) measuring a surface temperature of the motor and comparing the surface temperature with a reference temperature; (2) when the measured surface temperature is lower than or equal to the reference temperature, the supply voltage or the driving frequency of the motor is reduced to a predetermined ratio, and then the motor is driven for a predetermined time to measure the surface temperature of the motor driven for the predetermined time step; And (3) repeating the step (2) until the measured surface temperature exceeds the reference temperature, and when the measured surface temperature exceeds the reference temperature, And setting the supply voltage or the driving frequency to the input value of the electric motor.

The reference temperature may be set to a surface temperature of the motor that is kept constant when the motor is driven at a rated voltage or a rated frequency for a predetermined time.

If the load current of the motor after the decrease of the supply voltage or the drive frequency is greater than the load current of the motor before the decrease in step (2), the supply voltage or the drive frequency of the immediately preceding step exceeding the reference temperature It is possible to set the input value of the motor.

Increasing the supply voltage or the drive frequency inputted to the motor to a supply voltage or a drive frequency two steps before the reference temperature, when the reference temperature is exceeded; And lowering the supply voltage or the drive frequency inputted to the electric motor to a supply voltage or a drive frequency immediately before the reference temperature is exceeded.

Judging whether or not the electric motor is an electric motor that can be driven by reducing the available electric power based on at least one of (0) the rated voltage or frequency of the electric motor, the supply voltage and the driving frequency, the variation amount of the load current, It is possible to further include the step of

Wherein the step (0) includes: measuring a first load current of the motor after driving the motor at a rated voltage or a rated frequency for a predetermined time; Measuring the second load current of the motor after driving the motor for a predetermined time by reducing the rated voltage or the rated frequency to the predetermined ratio; And determining that the motor is a motor that can be driven by reducing the available power if the second secondary load current is smaller than the first primary load current.

If the second load current is larger than the first load current, it is possible to determine that the motor is a motor that can not be driven by reducing the available power.

An apparatus for driving an energy-saving type motor with idle power control according to an embodiment of the present invention includes a temperature detector for detecting a surface temperature of the motor at predetermined time intervals; The method comprising the steps of: decreasing a supply voltage or a driving frequency of the motor by a predetermined ratio until the measured surface temperature exceeds a reference temperature, and driving the motor for a predetermined time; And a drive control unit for setting the supply voltage or the drive frequency of the immediately preceding step exceeding the reference temperature to the input value of the electric motor.

The energy-saving type motor driving apparatus through the margin power control may further include a current detecting unit for detecting a load current of the motor.

Wherein the drive control unit controls the supply voltage or the drive frequency of the immediately preceding step to exceed the reference temperature when the load current of the motor after the decrease of the supply voltage or the drive frequency is larger than the load current of the motor before the decrease, It is possible to set it as an input value.

The energy-reduction type motor driving apparatus through the margin power control may further include a power line communication unit for transmitting and receiving control signals and data to and from other peripheral devices through the power line by the drive control unit.

The drive control section can determine whether the electric motor is capable of driving by reducing the available electric power based on at least one of the rated voltage or frequency, the supply voltage and the drive frequency, the amount of change of the load current, and the surface temperature.

Wherein the drive control unit reduces the first load current of the motor measured after driving the motor at a rated voltage or a rated frequency for a predetermined period of time and the rated voltage or the rated frequency at the predetermined ratio to drive the motor for a predetermined time, It is possible to compare the second load current of one of the motors and determine the motor as a motor that can be driven by reducing the available power when the second load current is smaller than the first load current.

According to the energy saving type motor drive method and apparatus using the margin power control according to the embodiments of the present invention, the supply voltage or the drive frequency of the motor is minimized based on the surface temperature of the motor, so that the energy consumption of the motor can be reduced .

In addition, according to the method and apparatus for driving an energy-reduction type motor through the margin power control according to the embodiments of the present invention, it can be confirmed that the electric motor can reduce the supply voltage or the driving frequency to realize energy saving.

FIG. 1 is a flowchart of a method of driving an energy-reduction type motor using spare power control according to an embodiment of the present invention,
FIG. 2 is a functional block diagram of an energy-reducing type motor drive apparatus using spare power control according to an embodiment of the present invention,
FIG. 3 is a detailed view of a method of driving an energy-saving type motor using spare power control according to an embodiment of the present invention,
4A and 4B are detailed views of a long-range and short-range motor drive system to which an energy-reduction type motor drive method based on margin power control according to an embodiment of the present invention is applied,
5A and 5B are detailed views of a long-range and near-field motor drive system employing an inverter to which an energy-reduction type motor drive method based on margin power control according to an embodiment of the present invention is applied,
6A and 6B are detailed views of a long-range and short-range motor drive system employing a voltage regulator to which an energy-reduction type motor drive method based on margin power control according to an embodiment of the present invention is applied.

The following embodiments are a combination of elements and features of the present invention in a predetermined form. Each component or characteristic may be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. In addition, some of the elements and / or features may be combined to form an embodiment of the present invention. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments.

Embodiments of the present invention may be implemented by various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

For a hardware implementation, the method according to embodiments of the present invention may be implemented in one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) , Field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to embodiments of the present invention may be implemented in the form of a module, a procedure or a function for performing the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only a case directly connected but also a case where the part is electrically connected with another part in between. In addition, when a part includes an element, it means that the element may include other elements, not excluding other elements, unless specifically stated otherwise.

Also, the term module as used herein refers to a unit for processing a specific function or operation, which can be implemented by hardware, software, or a combination of hardware and software.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention, and are not intended to limit the scope of the invention.

FIG. 1 is a flow chart of a method of driving an energy-saving type motor using spare power control according to an embodiment of the present invention, and FIG. 2 is a flowchart illustrating a method of driving the energy-saving type motor driving apparatus according to an embodiment of the present invention Block diagram.

Referring to FIGS. 1 and 2, a method and an apparatus for driving an energy-saving type motor through an idle power control according to an embodiment of the present invention will be described in detail.

The electric motor driving apparatus 100? According to the instant embodiment of the present invention includes a temperature detecting unit 120 for measuring the surface temperature of the electric motor 110, and a controller 120 for sufficiently supplying the output required by the load, And a drive control unit 140 for driving the motor 110. The current detection unit 130 detects a load current of the motor 110. The display unit 130 displays a surface temperature of the motor, (150).

The drive control unit 140 first determines whether the electric motor 110 can be driven at a power lower than the allowable power according to the proposed method at S110 and then when the temperature detection unit 120 measures the surface temperature of the electric motor 110 The drive control unit 140 compares the reference temperature with the measured surface temperature (S120). When the measured surface temperature is equal to or lower than the reference temperature, the drive control unit 140 reduces the supply voltage or the drive frequency of the motor 110 by a predetermined ratio, and drives the motor for a predetermined time. The drive control unit 140 repeats the above process until the surface temperature measured by the temperature detection unit 120 exceeds the reference temperature, in the temperature detection unit 120 and the drive control unit 140.

If the measured surface temperature exceeds the reference temperature, the drive control unit 140 sets the supply voltage or the drive frequency of the immediately preceding step exceeding the reference temperature as the input value of the motor (S150). That is, even under such a supply voltage or drive frequency, the motor 110 can sufficiently supply the output required by the load under the rated static pressure or frequency, but also can reduce the available power under the rated input at design to the maximum, This is possible.

Here, in this embodiment, the surface temperature of the motor, which is kept constant when the motor is driven at rated voltage or rated frequency for a predetermined time, is set as the reference temperature.

The drive control unit 140 determines whether the load current of the motor 110 detected by the current detector 130 is reduced even in the supply voltage or drive frequency state of the maximum reduction power state, It is possible to more precisely control the supply voltage or the driving frequency in the maximum reduction power state by determining whether the load current also decreases together.

When the measured surface temperature exceeds the reference temperature, the drive control unit 140 raises the supply voltage or the drive frequency input to the motor 110 to a supply voltage or drive frequency two steps before the reference temperature, , The supply voltage or the driving frequency of the motor 110 is reduced to the supply voltage or the driving frequency of the immediately preceding stage when the supply voltage or the driving frequency inputted to the motor 110 exceeds the reference temperature, Can supply.

The drive control unit 140 controls the motor 110 based on at least one of the rated voltage or frequency of the motor 110, the supply voltage and the drive frequency, the amount of change in the load current, and the surface temperature before driving the motor 110 with the minimum allowable power. It is preferable to determine whether the motor 110 is a motor that can be driven by reducing the available power.

More specifically, the drive control unit 140 measures the first load current of the motor after driving the motor 110 at a rated voltage or a rated frequency for a predetermined period of time, and outputs the rated voltage or the rated frequency at the predetermined ratio The second load current of the motor is measured. If the second load current is less than or equal to the first load current, the motor is judged to be a motor that can be driven by reducing the available power .

Here, if the second load current is larger than the first load current, the drive controller 140 may determine that the motor is a motor that can not be driven by reducing the available power.

The present inventor has provided the above energy-saving type motor devices to measure the surface temperature of the induction motor directly, unlike the prior art, thereby realizing the conventional formal energy saving.

According to the reference, the power supply voltage supplied to the induction motor is supplied slightly higher than the rated value in consideration of the voltage drop. Even if the voltage supplied at rated voltage is supplied 10% lower than the rated voltage of the induction motor, Is made so that it does not get crowded. (References: <1996 ASHRAE Handbook (American Society for Heating, Refrigeration, and Air Conditioning Engineers), Chapter 39 Motors and Motor Control)

The present inventor found that even if the induction motor supplied with the power supply voltage is reduced by only 10% of the voltage, the induction motor is not damaged and the current is reduced by 10% as the voltage is reduced by 10% In other words, we have come to realize that energy is basically saved by 20%.

If the voltage is reduced by 10%, the power consumption is reduced by about 10% even if the current is similar without increasing or decreasing.

In addition, there are other factors that can save energy for the induction motor. The efficiency of the induction motor is shown in Eq. (2).

Efficiency η = (Output / Input) X 100 = (Output / Output + Loss) X 100 (%) ------- (2)

However, when calculating the capacity of the electric motor, the inventor puts a little margin on the capacity in consideration of load fluctuation or voltage fluctuation. However, if the safety factor is excessively increased, the capacity of the electric motor becomes larger than necessary, And the power loss increases as the input value increases.

Nevertheless, the induction motor, which has a capacity shortage due to a design mistake at the time of commissioning, is replaced with a high capacity motor. However, since the spare capacity is often applied to the industrial equipment, We want to reduce the energy that is wasted to be consumed until.

In particular, in a load using a speed reducer, the speed reducer itself acts as a load as the speed reduction ratio is higher.

Table 1 shows the minimum value of the supply voltage to the motor and the corresponding load current, the number of revolutions and the power consumption in the single-phase induction motor according to the embodiment of the present invention when the energy- .

The single-phase induction motor with the result as shown in Table 1 has a rated voltage of 220 V, a rated capacity of 60 W, a rated current of 0.6 A and a reduction ratio of 30: 1. When the applied voltage is lowered sequentially, V has no effect at all, and even if the voltage is lowered a little, it drives without much trouble.

Test results for single-phase induction motor Supply voltage (V) Load current (A) Number of revolutions (rpm) Power consumption (VA) Decrease (%) Remarks 220 0.61 59 134 100 210 0.57 59 120 90 200 0.54 59 108 80 190 0.50 59 95 71 180 0.46 59 83 62 170 0.42 59 71 53 160 0.38 58 61 46 Difficulty driving 150 0.34 48 51 38 Difficulty driving

The load of the induction motor can be divided into the constant torque load and the double torque load. The torque of the induction motor depends on the size of the load connected to the shaft. When the supply voltage is reduced to the induction motor operated by the constant torque load, the motor generated torque decreases in proportion to the square of the voltage and the motor generated torque is smaller than the load required torque. do. However, when the full load torque is less than the rated torque, such as the 2-stroke torque load, the slip does not increase even if the rotational speed decreases, and the required power decreases in proportion to the third power of the rotational speed.

Here, the constant torque refers to a case where the rotational force, which is referred to as torque, does not change even if the rotational speed is reduced as in the case of a transfer device, and the torque increase refers to a torque used for a gas or fluid, such as a blower pump.

In addition, even if the constant torque load is used, the reducer itself operates most of the load. Therefore, in the case of an induction motor having a constant torque load with a safety factor set higher than necessary, even if the supply voltage is reduced by a margin, It is possible to reduce the actual load loss as well as the no-load loss according to the margin in designing. In addition, when idling, such as a hydraulic pump or a cutter, the standby power can be reduced to a minimum by lowering the existing fixed supply voltage during standby.

Reducing the supply voltage and the number of revolutions within the range of the load torque and the rotation speed that do not cause trouble in the normal operation can reduce the unnecessary reactive power of the copper loss and iron loss as well as increase the efficiency properly.

According to the algorithm proposed by the present inventor, it is possible to prevent the induction motor from being overheated due to a voltage or rotation speed which is lower than the rated value, and to find out hidden small losses, thereby saving energy as much as possible.

Further, in the method of transferring the data measured by the temperature detector 120 proposed by the present inventor to the drive control unit 140, in the case where the operation device such as the induction motor and the inverter is at a remote location, , The wiring cost is added and the noise due to the eddy currents and harmonics generated by the induction motor power line, especially the power line of the induction motor using the inverter, is low even when the carrier frequency is lowered, Lt; / RTI &gt; In such a long distance, a stable power line communication (PLC) method can be applied for data transmission, and a shielded cable can be used in a short distance.

Here, the temperature detector 120 may be implemented as a sensor capable of measuring temperature such as thermocouple, Pt, and a duster.

FIG. 3 is a detailed view of a method of driving an energy-saving type motor through margin power control according to an embodiment of the present invention. FIGS. 4 (A) and 4 (B) FIGS. 5A and 5B are diagrams illustrating a method of driving an energy-reduction type motor using spare power control according to an embodiment of the present invention. 6A and 6B are detailed views of a remote and short-range motor drive system employing the applied inverter. Each of Figs. 6A and 6B is a schematic view of a voltage regulator to which an energy- And Fig. 5 is a detailed view of a long-distance and short-range electric motor drive system employing the present invention.

Hereinafter, an energy-reduction type motor driving algorithm based on the margin power control according to the present invention and energy saving type motor devices using the same will be described in detail with reference to FIGS. 3 to 6B.

Internal configuration

The difference between the surface temperature and the ambient temperature that occurs when the induction motor is in normal operation is called temperature rise and is expressed in degrees.

The temperature rise of the induction motor is the highest in the winding part and mainly occurs due to the copper loss and iron loss. According to the insulation class (Y, A, E, B, F, H, C) To 180 ° C, which includes an ambient temperature of 40 ° C. When the specified temperature is exceeded, it is the start temperature at which the insulator is expanded and the deterioration starts.

 The induction motor is most commonly produced with E or B insulation. The maximum permissible temperature of the winding is 120 ° C and the upper limit of the ambient temperature of the induction motor is 50 ° C. The temperature of the windings is about 10 ~ 30 ℃ higher than the surface temperature, so the allowable temperature rise is 40 ~ 60 deg. The maximum permissible temperature of induction motor surface of E class insulation is 80 ~ 90 ℃ .

In reference to UL (Underwriters Laboratories) standard of USA, which is a worldwide certification body related to electrical and electronic products, T.P (Thermal Protector), which is a thermal overheat protection device, must be installed in the winding part of the induction motor.

When the supply voltage is lowered by the phase control using the thyristor in the induction motor used for the constant torque load, the sinusoidal wave of the perturbation is distorted into the distorted wave and the temperature rise in the winding portion is caused. (Shown in Figs. 1, 4 to 6) to which the proposed algorithm is applied is an apparatus which is applied only within a range where the load current for energy saving is reduced, so that the maximum energy saving within the temperature range allowed by the induction motor The algorithm of Fig. 3 is applied to obtain the effect.

Before the motor is driven by the algorithm proposed in FIG. 3, as shown in the operation condition analysis table shown at the upper left of FIG. 3, it is not suitable for energy saving before the start of energy saving operation, A preliminary analysis is performed in order to avoid such problems.

1) The rating according to the rated capacity of the induction motor before the energy saving operation, such as whether the receiving voltage supplied to the motor is higher than or less than the rated voltage of 380 V, Comparison of current and actual load current and prediction of maximum reduction of actual load current due to decrease of supply voltage.

2) Full-load current variation and production speed influence by variable rotation frequency.

3) Current surface temperature of the induction motor and the surrounding conditions of the induction motor.

3, an energy saving type motor driving method according to an embodiment of the present invention will be described in detail.

After the operation is started under the rated condition of the motor and after 10 minutes elapse (S411), the surface temperature of the induction motor is measured S412) and the normal voltage is supplied to the induction motor having the rated load. Here, when the temperature rise is 10 minutes, the condition change is considered to be 5% less than the static pressure. When the measured temperature is 60 ° C or less, the voltage or frequency is firstly reduced by 5% (S412, S413).

In this case, if the load current increases without decreasing, it is a constant torque load operated with the full load current as described above. Therefore, if the supply voltage is reduced to the induction motor that is operated, the torque generated by the motor decreases in proportion to the square of the voltage, and the torque generated by the motor becomes smaller than the torque required by the load. Therefore, it is determined that the motor is not an energy saving target because the rotation speed of the motor decreases and the load current increases due to the increase of the slip, and the reduced supply voltage or frequency is returned to the initial state (S414, S415)

However, if the load current decreases, it is judged that it is a reduction target. If the temperature measured by measuring the second temperature after the motor is operated for 10 minutes by reducing the supply voltage or the driving frequency for the first time (S416) It is determined that it is not an energy saving target even though the load current is decreased, and the reduced supply voltage or frequency is returned to the initial state (S417, S418).

However, when the temperature is 60 ° C or lower, the energy is reduced. Therefore, an additional 5% reduction is provided in step 2 (S419) (S421, S422). The condition is set as an energy saving limit value of the induction motor and is continuously used by a value whose supply voltage or frequency is reduced by 5% from the initial value.

However, if the temperature is 60 ° C or lower, the additional 5% reduction is provided (S421, S423), and after 10 minutes of operation (S424) The reduced supply voltage or frequency is returned to the previous stage (S426), and the condition is set as the energy saving limit value of the induction motor concerned, and the supply voltage or frequency is continuously used by the value decreased by 10% from the initial value.

The flowchart shown in FIG. 3 is a simplified representation of a method of driving an energy-saving type motor with an allowance power control according to an embodiment of the present invention. In this way, the supply voltage and the frequency are repeatedly decreased according to the above- (S427) after repeated auto-tuning within the range where the temperature does not exceed 60 ° C, which temperature is virtually set, and within the range of the lowest operation torque and rotational speed required by the equipment, CPUs 450, 560, and 660), and can be continuously used for the same motor. In addition, the induction motor can be influenced by power usage time zone, surrounding environment, and season, so that data is monitored and automatically updated during operation so that it can always respond to external changes.

External configuration

1. An external configuration of an example of a motor drive apparatus to which the proposed invention is applied.

As shown in FIG. 4 (A), in order to measure the temperature generated by the induction motor 410, a thermocouple, Pt, a duster, and the like temperature detecting sensor 420 may be attached in parallel when the ground terminal is attached , And the temperature detection sensor 420 measures the surface temperature of the induction motor. As shown in FIG. 4 (A), in the case of a long distance, parallel connection is made to two of the three power supply lines of the induction motor 410 without any additional wiring, and the MES CPU 450 To the transmitting side.

Here, the PLC module 430 includes an A / D converter 431, a PLC CPU 432, a modulator 433, and a power line interface 434 for power line communication, and the temperature detection sensor 420, And it is preferable to be provided in the connection terminal box of the induction motor.

An AD converter unit 431 for converting the analog measurement data of the temperature detection sensor, which changes in accordance with the temperature, into digital data for transmission through communication; A PLC CPU 432 for setting a communication protocol to digital data and changing it to data for communication, a modulating unit 433 for modulating a PLC using frequency of 60 to 130 KHz, and a power line interface 434 to the induction motor power line, the PLC receiving unit 440 receives the data via the power line without additional additional wiring at a long distance from the rear end of the SCR module 460 and transmits the data to the MES CPU 450.

The MES CPU 450 in which the energy-saving type motor driving algorithm of FIG. 3 is programmed and built in, commands the SCR module 460 to issue an operation command so that the voltage of the energy value reduced by the phase control is supplied to the induction motor.

Referring to FIG. 4B, in the case of a near-field configuration, a temperature measurement value is received and controlled by a separate shield cable without using a PLC. By using various temperature detection sensors 420 capable of measuring temperature, And transmits the detected measurement value to the shield cable capable of shielding the noise caused by the eddy current of the induction motor 410. The MES CPU 450 issues an operation command to the SCR module 460 based on the detected surface temperature data converted into digital data from the A-D converter 431. [

In addition, it is manufactured externally with the same structure so that it can be easily installed after removing the existing magnetic switch and overcurrent relay, and it is equipped with a load side short circuit protection and various communication ports of the conventional inverter and soft starter, The power control panel with built-in voltage regulator can be used to monitor the surface temperature of the induction motor in real time by adopting the MES system which can prepare multiple channels.

2. In case of inverter, external configuration

As shown in FIG. 5 (A), the energy saving method in the inverter can be classified into two types of the low-voltage adjustment and the supply-frequency adjustment. The high efficiency inverter means that the inverter itself has a function In the case of a quadratic torque reduction load such as a pump or a blower, if the number of revolutions is reduced within a limit that does not interfere with the air flow rate or the discharge amount, the power consumption is reduced to a square root as in the case of an inverter fixed at a factory shipment so that the frequency can not be arbitrarily increased. do.

In addition, the static torque load uses a method of lowering the ground voltage as lower the voltage supplied to the induction motor as in the soft starter voltage regulator. The data shown in Table 2 show that the three phase induction motor has a rated voltage of 380 V, When the base low voltage of the inverter is reduced by about 10% from the rated voltage in the rated capacity of 3 phase 1/2 HP and the rated current of 1.4 A, the load current is reduced by about 10% and the power consumption is also reduced by about 20%.

Therefore, the loss is also reduced to 20%, which is a value on the surface. If the base voltage is unduly reduced, the induction motor will overheat. Therefore, the proposed algorithm of the present inventor drives the motor in the optimal condition . Table 2 shows the inverter operation comparison table.

Inverter operation comparison table Rated voltage (V) Low voltage (V) Load current (A) Power consumption (VA) Decrease (%) Remarks 380 373 0.9 336 100 380 348 0.8 278 83 380 303 0.7 212 63

Of course, since the inverter is a frequency converter, it shifts according to the appropriate number of revolutions per target equipment. Therefore, when the frequency is lower than the rated value, the base low voltage is also lowered and used with appropriate efficiency. The primary current of the inverter is not reduced but the residual power may be generated as inverter loss. However, when operating at low speed at the start of operation and subsequently operating at the rated frequency or higher, the base low voltage is the same as the supply voltage. Therefore, if the base low voltage is lowered, appropriate energy saving effect can be obtained.

Referring to FIG. 5 (A), when the induction motor is driven at a distance and the temperature measurement value is transmitted to the PLC by using the induction motor power supply line as in the remote external configuration of the inverter, When the PLC transmitter 530 transmits data after processing, the PLC receiver 540 receives the measured data from the rear end of the IGBT 570. The MES CPU 550 processes a communication protocol used in various inverters such as a serial communication / RS-485, which is compatible with the inverter CPU 560, and transmits the processed communication protocol to the inverter CPU 560. The inverter CPU 560, And sets the parameters that the IGBT module 570 can perform based on the variable-voltage and frequency-variable data.

Referring to FIG. 5 (B), a temperature measurement value is received and controlled by a separate shield cable without using a PLC communication method in a short distance, and the temperature detected by the various temperature detection sensors 520 The measured value is transferred to a shield cable capable of shielding the noise caused by the eddy current of the induction motor 510, converted into digital data from the AD converter 580, and then converted into digital data in the same manner as the apparatus shown in Fig. (560).

Therefore, such a method can be applied by adding a separate PLC module and the proposed algorithm and device in the currently used inverter control method, and in the inverter control type motor drive system newly manufactured, . In particular, the power control panel with a large number of inverters can be integrated by MES with a large number of channels, so that it is possible to monitor the surface temperature of the induction motor in real time do.

3. For voltage regulators such as soft starters,

Thyristor voltage regulator, such as soft starter, which reduces the starting current generated when the cage induction motor starts, reduces the voltage supplied to the induction motor, or cuts the waveform of the sinusoidal wave. Energy can be saved, but it is difficult to expect a great effect because it is a passive method by calculation formula.

In order to solve the conventional difficulties, the inventor of the present invention has constructed a temperature detecting element such as a thermocouple, a Pt, a dummy, etc., which are processed in order to measure the temperature generated in the induction motor, in parallel when the ground terminal is attached.

As shown in FIG. 6 (A), when the temperature measured by the temperature detecting element is remotely connected to two of the three induction motor power supply lines without additional wiring, And transmits it to the MES CPU 650 through the PLC modules 630 and 640.

When the induction motor is remote and the temperature measurement value is transmitted by the PLC method using the induction motor power supply line as in the remote external configuration of the voltage regulator such as the soft starter, the voltage regulator is similar to the above.

The surface temperature generated by the temperature detection sensor 620 on the surface of the induction motor 610 is processed by the PLC transmission unit 630 and then transmitted to the PLC transmission unit 640. The PLC transmission unit 640 transmits the measurement data The MES CPU 650 in which the proposed algorithm is installed can receive various information from various softstarter such as a serial communication / RS-485 which is compatible with the softstarter CPU 660 And transmits the processed communication protocol to the softstarter CPU 660.

The soft starter CPU 660 sets the parameters that the SCR module 670 can perform such that the voltage of the energy value saved by the phase control is supplied to the induction motor 610.

Referring to FIG. 6 (B), a temperature measurement value is received by a separate shield cable L instead of using a PLC system in a short distance to control the operation of the electric motor.

More specifically, the measured value detected by using various temperature detection sensors 620 capable of measuring temperature is transmitted to a shield cable L capable of shielding noises due to eddy current of the induction motor 610, and AD Converter 680 to digital data and then transmits the digital data to the softstarter CPU 660. [

Therefore, this method can be applied by adding a separate PLC transmission / reception module and the proposed algorithm and device in a voltage regulator method such as a soft starter currently used, and in the case of a voltage regulator method such as a new soft starter, And a power control panel with a built-in voltage regulator such as a number of softstarter can adopt the method that can be transmitted collectively by the proposed algorithm and apparatus that prepare a plurality of channels, The system is configured to monitor the surface temperature of the induction motor in real time.

As described above, in the embodiments of the motor driving apparatus applied to the algorithm proposed in the present invention, the voltage or frequency supplied to the induction motor is reduced to reduce the energy, but the temperature detection sensor And the power line communication (PLC) method is applied. The surface temperature of the induction motor caused by the current flowing in the single-phase, three-phase, small-sized and large induction motors used throughout the industry can be measured by thermocouple, Pt, Etc., and can control the supply voltage and the rotational speed during the operation mode of the induction motor.

That is, as shown in the flowchart of FIG. 1, in which the induction motor is virtually set up as shown in the flowchart of FIG. 1 in which a single-phase, three-phase voltage regulator using a thyristor phase control as in a soft starter, an inverter controlling a motor by modulating a DC voltage into a square wave in a frequency form, The temperature is checked for a certain time and then the voltage is increased when the temperature is checked. If the temperature is not exceeded, the temperature is automatically tuned to be continuously lowered in a stepwise manner. The optimum data is found automatically and stored in the MES CPU.

It will be apparent to those skilled in the art that various modifications, changes, and substitutions are possible, without departing from the essential characteristics and spirit of the invention as disclosed in the accompanying claims. will be. Therefore, the embodiments disclosed in the present invention and the accompanying drawings are intended to illustrate and not to limit the technical spirit of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments and the accompanying drawings . The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention. In addition, claims that do not have an explicit citation in the claims may be combined to form an embodiment or included in a new claim by amendment after the application.

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Claims (14)

A temperature detection sensor for detecting a surface temperature of the electric motor for measuring a temperature generated in the electric motor; a drive control unit for controlling driving of the electric motor and having an inverter; 1. A method for driving an electric motor using an electric motor drive apparatus having a device and a power line communication unit for transmitting and receiving a control signal and data via a power line,
(1) If it is judged that the electric motor is an electric motor that can be driven by reducing the available electric power based on at least one of the rated voltage or frequency of the electric motor, the supply voltage and the driving frequency, the change amount of the load current, Measuring and comparing the measured temperature with a reference temperature;
(2) when the measured surface temperature is lower than or equal to the reference temperature, the supply voltage or the driving frequency of the motor is reduced to a predetermined ratio, and then the motor is driven for a predetermined time to measure the surface temperature of the motor driven for the predetermined time step; And
(3) repeating the step (2) until the measured surface temperature exceeds the reference temperature, and when the measured surface temperature exceeds the reference temperature, Setting a voltage or a driving frequency to an input value of the electric motor,
The determination as to whether the electric motor is an electric motor capable of reducing the available electric power can be performed by determining whether a receiving voltage supplied to the electric motor is higher or lower than a rated voltage, A comparison value between the rated current and the actual load current according to the rated capacity of the electric motor, and a predicted value of the maximum reduction value of the actual load current due to the decrease in the supply voltage of the electric motor,
Wherein the drive control unit lowers the base voltage of the inverter when the motor is operated at a frequency equal to or higher than the rated frequency at the start of operation of the energy saving type motor. The method according to claim 1,
Wherein the reference temperature is a temperature of a surface of the motor that is maintained constant when the motor is driven at a rated voltage or a rated frequency for a predetermined period of time. The method according to claim 1,
If the load current of the motor after the decrease of the supply voltage or the drive frequency is greater than the load current of the motor before the decrease in step (2), the supply voltage or the drive frequency of the immediately preceding step exceeding the reference temperature Wherein the input value of the motor is set to an input value of the motor. delete delete The method according to claim 1,
The step (1)
Measuring a first load current of the motor after driving the motor at a rated voltage or a rated frequency for a predetermined time;
Measuring the second load current of the motor after driving the motor for a predetermined time by reducing the rated voltage or the rated frequency to the predetermined ratio; And
If the second load current is smaller than the first load current, determining that the motor is an electric motor that can be driven by reducing the available electric power. delete delete delete delete delete delete delete delete

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