KR101251476B1 - Motor starter circuit including sparkless switches and average current detection circuits for three phase induction motors and the method using it - Google Patents

Abstract

PURPOSE: A motor starter circuit including sparkless switches and average current detection circuits for three phase induction motors and a method using the same are provided to simplify the configuration of a switch box and to improve space utilization. CONSTITUTION: A first relay(RLY1) is connected to a first phase(L1) for controlling a three phase electric motor. A second relay(RLY2) is connected to a second phase(L2) for controlling the three phase electric motor. A third relay(RLY3) is connected to a first wire(W1) for a change to a normal direction. A fourth relay(RLY4) is connected to a second wire(W2) for a change to a reverse direction. A second triac semiconductor(TR2) is connected to a first input terminal(IN1) for checking the contact point movement state of the relays and to the second phase. A third triac semiconductor(TR3) is connected to a third phase(L3). A MOC(Metal Oxide Semiconductor) produces control signals for the third triac semiconductor and the second triac semiconductor.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a three-phase rectifier circuit including an arc-free switching and current sensing function, and a method of using the same,

The present invention relates to a rectifier circuit for a three-phase motor having an arc-free opening and closing and current sensing function, and more particularly, to a rectifier circuit for a triac motor, To a starter which limits the electric arc of the relay open / close contact and at the same time includes current detection for the motor overload protection function.

Korean Patent No. 1053759, which is a conventional invention, relates to an electronic relay for a single-phase induction motor having a high compatibility with a motor which can minimize start-up failures by modeling the start-up torque curve with an induced voltage, An induced voltage detection circuit for detecting the induced voltage of the starting winding proportional to the rotation speed of the motor, and a voltage detection circuit for detecting the voltage across the two terminals of the triac semiconductors, A window comparing circuit for detecting a point voltage, detecting a zero point current of a starting winding current during starting, and starting the triac semiconductors by turning on the zero point voltage of the motor line voltage according to the signal of the window comparing circuit, During start-up, according to the signal of the window comparator circuit, The starting voltage of the starting winding is inputted from the induced voltage detecting circuit during the starting, and the variable ratio of the induced voltage proportional to the acceleration torque of the electric motor And the microcomputer turns off the triac when the acceleration torque begins to decrease after confirming that the starting torque is the maximum with the acceleration torque being the maximum value.

Korean Patent No. 1036387 discloses a normal / reverse rotation control device for a three-phase motor in which an arc is not generated when a rotational direction is switched in a three-phase motor. The apparatus of the present invention comprises a three-phase motor, first and second triacs, first and second triac photodrivers, and between the output of the first triac and the second triac and the two-phase input (V, W) Phase motor to be forwardly or reversely rotated in accordance with the on / off operation of the forward / reverse operation switch, a relay for switching the direction of connection to the lead-in line in accordance with the forward / reverse control signal, And a normal / reverse control circuit part for controlling the erroneous photodiode, wherein the normal / reverse control circuit part comprises a normal / reverse operation switch and a first triad photo driver and a second triad photo driver which are turned off A triac control unit for interrupting a current flowing to the relay contact; and a control unit for controlling the three-phase motor in the reverse direction And a relay control section for connecting the contacts of the relay so that the three-phase motor is rotated forward by exciting the coil of the relay after the T2 delay time when the forward / reverse operation switch is turned on.

However, in the above-mentioned prior arts, there is a risk of short circuit and other accidents due to an operation deviation between the control signal and the contact movement due to the electric arc of the open / close contact.

Also, in the above-mentioned conventional inventions, it is difficult to consider the thermal accumulation state of the motor when there is no continuity of the applied current due to frequent start of the electronic overcurrent relay at the time of overload protection, and the thermal relay (bimetal) Unstable, and slow operation time.

According to an aspect of the present invention, there is provided a semiconductor device comprising: a semiconductor TRIAC contact and a relay contact for starting an electric motor in series, the semiconductor contact being kept in an OPEN state when the motor starts, The internal MCU confirms that the movement of the relay contact is completed through the input signal, and by switching the semiconductor contact to the CLOSE state, it is possible to limit the cumulative wear and tear of the contact, which is the main cause of the breakage caused by the electric arc, It is an object of the present invention to provide a normal and reverse circuit device for a three-phase motor including an arc-free switching and current sensing function that can prevent a short circuit and other accidents due to an operation deviation and simplify a configuration of a distribution box.

In the present invention, two temperature sensors are used to detect the temperature of the heat sink attached to the triac, which is increased in proportion to the average value of the electric current of the motor during the operation of the motor, This circuit is a three-phase rectifier circuit for three-phase motors including an arc-free switching and current sensing function, which can protect the motor by calculating the average value of the motor current by checking the overload and heat accumulation state of the motor by comparing the two temperature differences through digital circuits In order to solve the problem.

An object of the present invention is to simplify the structure of the power distribution box and to improve the space utilization by designing the forward / reverse control circuit and the overload protection circuit of the motor as an integrated starter.

The present invention relates to a normal circuit device for a three-phase motor comprising a starter circuit, a starter starter circuit, a starter starter circuit, an overload current detector circuit portion, and an MCU, wherein the starter circuit portion includes: A first relay RLY1 that is a relay output contact according to the first relay L1; A second relay RLY2 which is a relay output contact point along the second phase L2 for controlling the three-phase motor; A third relay RLY3 as an output contact connected to the first winding W1 for forward switching; A fourth relay RLY4 that is an output contact connected to the second switching winding W2 for reverse switching; A fifth relay (RLY5) which is a self-maintaining output contact for each rotation direction; A sixth relay RLY6 which is a self-maintaining output contact for the reverse direction in the predetermined direction; A first input terminal (IN1) for checking the contact movement state of the relays; A second triac semiconductor TR2 which is connected to the second phase L2 and is a triac semiconductor element for controlling the three-phase motor; A third triac semiconductor TR3 which is connected to the third phase L3 and is a triac semiconductor element for controlling the three-phase motor; A metal oxide semiconductor (MOC) for generating control signals of the second triac semiconductor TR2 and the third triac semiconductor TR3; A second input terminal IN2 for confirming a contact movement state of the second triac semiconductor TR2; A third input terminal IN3 for confirming a contact moving state of the third triac semiconductor TR3; A fourth input terminal IN4 as an input signal for confirming the open / close state of the STOP control circuit; A fifth input terminal IN5 which is an input signal for confirming the open / close state of the UP control circuit; A sixth input terminal IN6 as an input signal for confirming the open / close state of the DOWN control circuit; A first output terminal OUT1 which is a control signal circuit of the RLY1 and RLY2; A second output terminal OUT2 which is the RLY3, RLY4 control signal circuit; And a third output terminal OUT3 which is a control signal circuit of the second triac semiconductor TR2 and the third triac semiconductor TR3,

When the output contacts of the first relay RLY1 and the second relay RLY2 or the third relay RLY3 and the fourth relay RLY4 for switching the forward / reverse switching for starting the three-phase motor are moved, The semiconductor contact connected in series with the first input terminal IN1, the second input terminal IN2, and the third input terminal IN1, which are the MCU input signals, (TR3), and the tripod semiconductor contacts (TR3, TR3) are connected to the first and second transistors (TR1, IN3) It is checked whether the triac semiconductors TR2 and TR3 are damaged through the input signals of the second input terminal IN2 and the third input terminal IN3 in order to limit the operation of the first relay RLY1 ) And the second relay (RLY2).

In the present invention, the overload current detection circuit unit includes: a first thermistor TH1 as a temperature sensor; A second thermistor TH2 which is a heat sink temperature sensor (Liner Active Thermistor); And an analog-digital converter of an output voltage of the temperature sensing sensor, wherein the MCU uses the thermistors TH1 and TH2 to measure a temperature difference between a heat sink of the triac semiconductor or a case temperature and an ambient temperature Calculates consumed electric power of the triac semiconductor through the following expression (1), detects the triac semiconductor consumed electric power, calculates? Ts according to the inputted rated current set value Is, (O_time x Trip class), and overload protection is implemented when ΔT> kΔTs is compared with the sensed temperature deviation ΔT.

[Equation 1]

P?? T (j-a) / Rth (j-a)? T (h-a) / Rth

? T (h-a) = Th-Ta = ADC2 - ADC1

P? (ADC2 - ADC1) / Rth (h - a)

Rth (ja): Heat resistance index between junction and periphery, ΔT (ha): Difference between heat sink temperature and ambient temperature, where P is the heat dissipated by the triac, ΔT , Rth (ha) is the thermal resistance index between the heat sink and the surrounding area, k is the overload state index, ΔT is the temperature deviation, O_Time is the buffer integration time, Trip class is the overload delay time setting value, An analog-to-digital converter circuit)

The present invention relates to an arc-free opening / closing method using a normal circuit device for a three-phase motor including a starter starting circuit, a starter starting circuit, an overload current detecting circuit portion and an MCU, When a '1' is input through the fourth input terminal IN4, it is determined that the power of the relays is normally supplied, and the fifth input terminal IN5 and the sixth input terminal IN5 are turned on, The open / close state of the external UP and DOWN switches as the forward / reverse start control signals of the motor via the first input terminal IN1, the second input terminal IN2 and the third input terminal IN3, IN1 = 0, IN2 = 0, IN3 = 0, and IN2 = 0 after repeating the abnormality of the contacts of the first relay RLY1, the second relay RLY2, the second triac semiconductor TR2 and the third triac semiconductor TR3, 1 signal from one or more of IN1, IN2, and IN3, The first step does not operate when the detected; When '1' is sensed at the fifth input terminal IN5 or the sixth input terminal IN6, a '1' signal is applied to the first output terminal OUT1 to output the first relay RLY1 for starting the motor and the second relay RLY1 for starting the motor The contacts of the relay RLY2 are closed and after the contact movement has been completed after a predetermined time, signals IN1 = 1, IN2 = 0 and IN3 = 0 are inputted and it is judged as normal, and the second input terminal IN2 and the third input A signal '0' is applied to the first output terminal OUT1 and the first relay RLY1 and the second relay RLY1 are connected to the first output terminal OUT1, (RLY2), and does not operate; When '1' is sensed at the fifth input terminal IN5, a '0' signal is applied to the second output terminal OUT2. On the other hand, if '1' is sensed at the sixth input terminal IN6, IN1 = 1, IN2 = 0, IN3 = 0, and IN2 = 0 when the contact of the third relay RLY3 and the fourth relay RLY4 is moved after a predetermined time by applying a "1" signal to the output terminal OUT2. 1 signal is detected at one or more of the second input terminal IN2 and the third input terminal IN3 when the contact point is moving or there is a problem, The first relay RLY1 and the second relay RLY2 are in an OPEN state and do not operate; and a third step of applying a '0' signal to the first output terminal OUT1 when the first relay RLY1 and the second relay RLY2 are not completed. The second triac semiconductor TR2 and the third triac semiconductor TR3 are controlled by giving a '1' signal to the third output terminal OUT3. When all of them are turned on after a predetermined time, IN1 = 1 and IN2 1 and IN3 = 1 are inputted and the motor is in the normal operation state. If the contact is moving or image forming occurs, at least one of the second input terminal IN2 and the third input terminal IN3 becomes' 0 0 'signal to the third output terminal OUT3 to turn OFF the second triac semiconductor TR2 and the third triac semiconductor TR3 when the contact movement is not completed after a predetermined time When the second triac semiconductor TR2 and the third triac semiconductor TR3 are both turned off and a signal IN1 = 1, IN2 = 0 and IN3 = 0 is inputted after a predetermined time, (RLY1) and the second relay (RLY2) to operate; When a rotation direction signal different from the rotation direction stored in the MCU for instantaneous forward / reverse rotation is input through the fifth input terminal IN5 or the sixth input terminal IN6 during normal operation of the motor, The second triac semiconductor TR2 and the third triac semiconductor TR3 are turned OFF by giving a '0' signal to the second triac semiconductor transistor OUT2 and the second triac semiconductor TR2 is turned off after a predetermined time, The third step and the fourth step are repeated when the signals IN1 = 1, IN2 = 0, and IN3 = 0 are input in the fifth step; When it is confirmed that the STOP switch is in the OPEN state through the fourth input terminal IN4 during the normal operation of the motor, a '0' signal is applied to the third output terminal OUT3 to turn on the second triac semiconductor TR2 and the third The second triac semiconductors TR2 and the third triac semiconductors TR3 are both in the OFF state and the IN1 = 1, IN2 = 0, IN3 = 0 signal And a sixth step of applying a '0' signal to the OUT1 and opening the first relay RLY1 and the second relay RLY2.

In the present invention, when the STOP switch is in the closed state, power is supplied to the control circuit and power is supplied to the MCU power supply, and the fourth 1 'through the input terminal IN4, it is judged that the power of the relays is normally supplied. Then, it is determined through the fifth input terminal IN5 and the sixth input terminal IN6 of the external UP The first relay RLY1, the second relay RLY2, the second triangle RLY1, the second relay RLY2 and the second relay RLY2 are connected to each other through the first input terminal IN1, the second input terminal IN2 and the third input terminal IN3, It is judged normally when the signals IN1 = 0, IN2 = 0 and IN3 = 0 are input after repeating the abnormality of the contact point between the bad semiconductor TR2 and the third triac semiconductor TR3 and one of IN1, IN2 and IN3 If the '1' signal is detected, it is not operated. The second triac semiconductor TR2 and the third triac semiconductor TR3 are controlled by giving a '1' signal to the third output terminal OUT3. When all of them are turned on after a predetermined time, IN1 = 1 and IN2 1 and IN3 = 1 are inputted and the motor is in the normal operation state. If the contact is moving or image forming occurs, at least one of the second input terminal IN2 and the third input terminal IN3 becomes' 0 0 'signal to the third output terminal OUT3 to turn OFF the second triac semiconductor TR2 and the third triac semiconductor TR3 when the contact movement is not completed after a predetermined time When the second triac semiconductor TR2 and the third triac semiconductor TR3 are both turned off and a signal IN1 = 1, IN2 = 0 and IN3 = 0 is inputted after a predetermined time, A second step of operating the first relay RLY1 and the second relay RLY2 by operating the first relay RLY1 and the second relay RLY2; When it is confirmed that the STOP switch is in the OPEN state through the fourth input terminal IN4 during the normal operation of the motor, a '0' signal is applied to the third output terminal OUT3 to turn on the second triac semiconductor TR2 and the third The second triac semiconductors TR2 and the third triac semiconductors TR3 are both in the OFF state and the IN1 = 1, IN2 = 0, IN3 = 0 signal And a third step of applying a '0' signal to the OUT1 and opening the first relay RLY1 and the second relay RLY2.

According to the present invention, it is possible to limit the cumulative wear and tear of the contact, which is the main cause of the failure due to the electric arc, to prevent a short circuit and other accidents due to the motion deviation between the control signal and the contact movement, and at the same time to simplify the structure of the power distribution box.

According to the present invention, it is possible to compare the temperature difference through a digital circuit, to check the overload and heat accumulation state of the motor, and to calculate the average value of the motor current to protect the motor.

According to the present invention, the forward / reverse control circuit and the overload protection circuit of the motor can be designed as an integrated starting device, thereby simplifying the configuration of the power distribution box and improving the space utilization.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram of a three-phase motor circuit device having a forward / reverse startup circuit according to an embodiment of the present invention; FIG.
2 shows a circuit device for a three-phase motor including a direct-start circuit according to one embodiment of the present invention.
3 is a circuit diagram of a normal circuit device for a three-phase motor including a current sensing function according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

For the embodiments of the invention disclosed herein, specific structural and functional descriptions are set forth for the purpose of describing an embodiment of the invention only, and it is to be understood that the embodiments of the invention may be practiced in various forms, And should not be construed as limited to the embodiments described in the foregoing description.

The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention.

For example, the triac semiconductors described below may be a semiconductor device capable of controlling an AC voltage, and may be replaced with a silicon controlled rectifier (SCR).

The MCU may also include at least one of at least one microprocessor, microcontroller, and intelligent logic elements capable of performing similar functions.

The rectifying circuit device for a three-phase motor including an arc-free opening and closing and current sensing function according to the present invention includes a starting circuit portion including a forward / backward starting circuit (see FIG. 1) and a direct starting circuit (see FIG. 2) 3) and an MCU (not shown).

The starting circuit includes a first relay RLY1 as a relay output contact according to the first phase L1 for controlling the three-phase motor, a second relay RLY2 as a relay output contact according to the second phase L2 for controlling the three- A third relay RLY3 which is an output contact connected to the first winding W1 for forward switching, a fourth relay RLY4 which is an output contact connected to the second winding W2 for reverse switching, A fifth relay (RLY5) serving as an output contact, a sixth relay (RLY6) serving as a self-maintaining output contact for the reverse direction in the predetermined direction, a first input terminal (IN1) for checking the contact movement state of the relays, A second triac semiconductor TR2 which is a triac semiconductor element for controlling the three-phase motor, a second triac semiconductor TR2 which is connected to a third phase L3 and which is connected to a third triac semiconductor element (TR3), the second triac semiconductor (TR2) and the third triac semiconductor (TR3) A second input terminal IN2 for confirming the moving state of the contact of the second triac semiconductor TR2, a state of contact movement of the third triac semiconductor TR3, A fourth input terminal IN4 as an input signal for confirming the open / close state of the STOP control circuit, a fifth input terminal IN5 as an input signal for checking the open / close state of the UP control circuit, A first output terminal OUT1 which is the control signal circuit of the RLY1 and RLY2, a second output terminal OUT2 which is the control signal circuit of the RLY3 and RLY4, and a sixth input terminal IN6 which is an input signal for checking the open / ).

The signal of each of the input terminals is designed to input a signal of "0" before contact movement and a signal of "1" of contact movement completion. For example, when a signal of "1" is input to the fourth input terminal IN4 Is designed to recognize that the power supply of the relay is normally supplied.

Accordingly, the rectifying circuit device for a three-phase motor including an arc-free opening / closing and current sensing function according to the present invention is characterized in that the first relay RLY1 and the second relay RLY2 for starting the three-phase motor (or motor) The triac semiconductor contacts connected in series with the relays RLY1, RLY2, RLY3, and RLY4 are always kept in the OPEN state when the output contacts of the third relay RLY3 and the fourth relay RLY4 are switched, The contact state is received in real time by the first input terminal IN1, the second input terminal IN2, and the third input terminal IN3, which are the MCU input signals, to confirm that the contact movement is completed first, (IN2) and the third input terminal (IN3) in order to limit abnormal operation of the motor due to short-circuit failure of the triac semiconductors (TR2, TR3). If the triac semiconductors TR2 and TR3 are damaged The first relay RLY1 and the second relay RLY2 are opened to thereby prevent a short circuit and other accidents due to an operation deviation between the control signal and the contact movement. And the overload protection circuit can be designed as an integrated starter to simplify the configuration of the distribution box and to increase the space utilization.

Therefore, the present invention is characterized in that the second input terminal IN2 for confirming the contact movement state of the second triac semiconductor TR2 and the third input terminal IN3 for confirming the contact movement state of the third triac semiconductor TR3 ), It is possible to limit the electric arc of the relay open / close contact by using the contact point of the triac semiconductors and the contact state check circuit.

Hereinafter, each embodiment of the present invention will be described in detail.

Step 1

As shown in FIG. 1, when the STOP switch is in the close state, 24 VDC power is supplied to the control circuit, and power of 5 VDC or less is supplied to the MCU power through the constant voltage IC. When '1' is inputted through IN4 (comparator) It is judged that the power supply is normal and the open / close state of the external UP and DOWN switch of the forward / reverse start control signal of the motor via IN5 and IN6 and the open / close state of contacts of RLY1, RLY2, TR2 and TR3 inside the relay via IN1, IN2 and IN3 Repeat checking for abnormalities. If normal, the IN1 = 0, IN2 = 0, and IN3 = 0 signals are input; otherwise, the relay will no longer operate until the problem is resolved (if a '1' signal is detected in one or more of IN1, IN2, it does not work. At this time, it is possible to display the external abnormality of the relay through additional output contact or LED, if necessary, but the detailed explanation will be omitted in order to simplify the contents.

Step 2

If '1' is detected in IN5 or IN6, '1' signal is applied to OUT1 to CLOSE RLY1 and RLY2 contacts for starting the motor. When the contact movement is completed after a certain time and it is normal, signals IN1 = 1, IN2 = 0, IN3 = 0 are input. Otherwise, it is judged that a triac semiconductor abnormality has occurred (at least one of IN2 and IN3 is detected), and a '0' signal is applied to OUT1 to open RLY1 and RLY2 contacts, and when the problem is solved No more.

Step 3

When '1' is detected in IN5, a '0' signal is applied to OUT2, and when '1' is detected in IN6, a '1' signal is applied to OUT2 and RLY3 and RLY4 contacts for forward / reverse switching are controlled . (At this time, if the internal MCU memorizes the rotation direction (OUT2 state), it can apply the self-holding contact (RLY5, RLY6) as other general output contact function such as other overload state output) After the contact movement is completed, IN1 = 1, IN2 = 0, IN3 = 0 signal is input. If the contact is moving or there is a problem, a '1' signal is detected at one or more of IN2 and IN3. If the contact movement is not completed for more than a certain time (several tens of ms), a '0' signal is applied to OUT1, RLY1 and RLY2 are in the OPEN state and the relay does not operate until the problem is solved.

Step 4

A signal '1' is applied to OUT3 to control TR2 and TR3 (triac semiconductors). After a certain period of time (several milliseconds), when all of them are ON, IN1 = 1, IN2 = 1, IN3 = 1 signal is input and the motor is in the normal operation state. At this time, if a contact is moving or an image is formed, '0' signal is detected at one or more of IN2 and IN3. If the contact movement is not completed for more than a certain time (several tens of ms), a signal "0" is applied to OUT3 to turn off TR2 and TR3 (triac semiconductors). After a certain time (several ms), if both TR2 and TR3 are turned OFF and IN1 = 1, IN2 = 0 and IN3 = 0 are input, '0' signal is applied to OUT1, RLY1 and RLY2 are opened, Does not work until the problem is solved.

Step 5

If TR2 and TR3 (triac semiconductors) are given by giving a '0' signal to OUT3 first, when a rotation direction signal different from the rotation direction memorized in the internal MCU is input through IN5 or IN6 during normal operation of the motor, . If TR2 and TR3 are all OFF after a certain period of time (several ms) and IN1 = 1, IN2 = 0, and IN3 = 0 are input, the above steps 3 and 4 are repeated.

Step 6

If it is confirmed that the STOP switch is in the OPEN state through IN4 during the normal operation of the motor, TR2 and TR3 (triac semiconductors) are controlled by giving '0' signal to OUT3 first. When TR3 is all OFF and IN1 = 1, IN2 = 0, IN3 = 0 signal is input, '0' signal is applied to OUT1 and RLY1 and RLY2 are opened.

As shown in FIG. 2, the rectifying circuit according to the present invention can be operated by performing the first, fourth, and sixth steps regardless of RLY3 and RLY4 for forward / reverse control.

As shown in FIG. 3, the rectifying circuit device for a three-phase motor including the current sensing function according to the present invention has a junction 10, a case 20, a heat sink 30, an ambient air 40, and the like.

Specifically, the present invention detects two or more thermistor temperature sensors and compares the heat sink temperature and the ambient temperature of the triac semiconductors, calculates the consumed power of the triac semiconductors based on the temperature deviation, Detect and use them to implement motor protection.

That is, the normal circuit device for a three-phase motor including an arc-free opening and closing and current sensing function according to the present invention includes a first thermistor (TH1), a heat sink temperature sensor (Liner Active Thermistor) And ADC1 and ADC2 which are analog-digital converter circuits of the sensor output voltage.

Specifically, the consumed power of the triac semiconductors is calculated as shown in Equation 1 below.

[Equation 1]

(Here, P: triac semiconductor power consumption, Rth: thermal resistance (fixed by product design specification), ΔT: temperature variation)

As shown in FIG. 3, the consumed power of the triac semiconductors can be calculated by Equation (2) below.

&Quot; (2) "

P?? T (j-a) / Rth (j-a)? T (h-a) / Rth

(H-a): difference between heat sink temperature and ambient temperature, Rth (h-a): thermal resistance index between heat sink and surroundings)

For convenience, the present invention uses ΔT (ha), but in the case where it is not necessary to attach a heat sink, a thimble and TH2 are attached to a triac case, and Tc is sensed to calculate the consumed power of the triac semiconductor It is possible.

&Quot; (3) "

P?? T (c-a) / Rth (c-a)

(C-a): difference between the triac case temperature and the ambient temperature, Rth (c-a): thermal resistance index between the triac case and the periphery)

Since Rth (h-a) is fixed at the time of designing the product, the consumption power P of the triac semiconductors can be calculated by detecting ΔT (h-a) through the temperature sensor. For this purpose, the THER2 is installed in the heat sink of the triac semiconductor, and its output value Tch is input as a digital signal through the ADC2, and the THERMER TH1 detects the ambient temperature of the product And T 1 (ha) is proportional to the difference between ADC 2 and ADC 1 as shown in Equation (4) below.

&Quot; (4) "

? T (h-a) = Th-Ta = ADC2 - ADC1

P? (ADC2 - ADC1) / Rth (h - a)

At this time, generally, the consumption power of the triac semiconductor is proportional to the product of the threshold voltage (Vt) and the current I as shown in Equation (5) below, and Vt is the design specification of the triac semiconductor, , The current I can be calculated.

&Quot; (5) "

P = Vt I

I = P / Vt

(Rated current, Is) and overload operation delay time set value (Trip class) to the external input signal circuit (I ² T) in order to realize the motor protection (I ² T) function which is generally used generally by using the above- Lt; / RTI >

The MCU of the present invention calculates ΔTs (ha) according to the input rated current set value Is in advance and repeatedly compares ΔT (ha), which is a temperature deviation detected during operation of the electric motor, ) Exceeds the set value DELTA Ts (ha), the accumulation of the O_Time buffer interlocked with the timer built in the MCU is started, and when the DELTA T (ha) exceeds k DELTA Ts (ha), the accumulated O_Time is stored , It is checked whether the temperature state is maintained during the overload operation time (O_Time x Trip class) proportional to the Trip class multiplied by the input Trip class, and if ΔT (ha)> kΔTs (ha) , RLY1, RLY2, TR2, and TR3 are opened to implement overload protection.

The overload state index (k) is set to about 1.15 +/- 10% considering the overload protection operating current vs. the rated current and the internal measurement error of the starter circuit. If the overload state index (k = ΔT (h-a) / ΔTs (h-a)) exceeds 1.7 or more due to an imaging load or constraint load during operation, immediately overload protection is executed irrespective of the overload operation delay time.

Here, the setting current (Is) and the operation delay time (Trip class) of the external input signal circuit and the method of displaying the overload operation state using the relay or the LED are general, and a detailed description will be omitted.

Therefore, by designing the forward / reverse control circuit and the overload protection circuit of the motor according to the present invention as an integrated starter, it is possible to simplify the structure of the power distribution box and to improve the space utilization.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

RLY1: first relay RLY2: second relay
RLY3: Third relay RLY4: Fourth relay
RLY5: relay 5 RLY6: relay 6
IN1: first input terminal IN2: second input terminal
IN3: Third input terminal IN4: Fourth input terminal
IN5: fifth input terminal IN6: sixth input terminal
TR2: second triac semiconductor TR3: third triac semiconductor
OUT1: first output terminal OUT2: second output terminal
W1, W2, W3: Delta connection of three-phase motor

Claims (4)

In a normal circuit device for a three-phase motor comprising a starter starting circuit and a starter starting circuit, an overload current detecting circuit section, and an MCU, a relay output contact 1 relay (RLY1); A second relay RLY2 which is a relay output contact point along the second phase L2 for controlling the three-phase motor; A third relay RLY3, which is an output contact connected to the forward switching first winding W1 to change the phase of the three-phase current; A fourth relay RLY4 which is an output contact connected to the second switching winding W2 for changing the phase of the three-phase current; A fifth relay (RLY5) which is a self-maintaining output contact for each rotation direction; A sixth relay RLY6 which is a self-maintaining output contact for the reverse direction in the predetermined direction; A first input terminal (IN1) for checking the contact movement state of the relays; A second triac semiconductor TR2 which is connected to the second phase L2 and is a triac semiconductor element for controlling the three-phase motor; A third triac semiconductor TR3 which is connected to the third phase L3 and is a triac semiconductor element for controlling the three-phase motor; A metal oxide semiconductor (MOC) for generating control signals of the second triac semiconductor TR2 and the third triac semiconductor TR3; A second input terminal IN2 for confirming a contact movement state of the second triac semiconductor TR2; A third input terminal IN3 for confirming a contact moving state of the third triac semiconductor TR3; A fourth input terminal IN4 as an input signal for confirming the open / close state of the STOP control circuit; A fifth input terminal IN5 which is an input signal for confirming the open / close state of the UP control circuit; A sixth input terminal IN6 as an input signal for confirming the open / close state of the DOWN control circuit; A first output terminal OUT1 which is a control signal circuit of the RLY1 and RLY2; A second output terminal OUT2 which is the RLY3, RLY4 control signal circuit; And a third output terminal (OUT3) which is a control signal circuit for the second triac semiconductor (TR2) and the third triac semiconductor (TR3)
When the output contacts of the first relay RLY1 and the second relay RLY2 or the third relay RLY3 and the fourth relay RLY4 for switching the forward / reverse switching for starting the three-phase motor are moved, (RLY1, RLY2, RLY3, RLY4) and the triac semiconductor contacts connected in series are always kept in the OPEN state,
The contact state is received in real time by the first input terminal IN1, the second input terminal IN2, and the third input terminal IN3, which are the MCU input signals, to confirm that the contact movement is completed first, (ON)
The triac semiconductors TR2 and TR3 are connected to the input terminals of the triac semiconductors TR2 and TR3 through the input terminals of the second input terminal IN2 and the third input terminal IN3 in order to limit the abnormal operation of the motor due to short- , And TR3), and opens the first relay (RLY1) and the second relay (RLY2) for starting in the event of a damage. The three-phase rectifier circuit . The method according to claim 1,
The overload current detection circuit unit includes:
A first thermistor TH1 as a temperature sensing sensor;
A second thermistor TH2 which is a heat sink temperature sensor (Liner Active Thermistor); And
And an analog-digital converter of the temperature sensor output voltage,
The MCU compares the temperature deviation between the heat sink of the triac semiconductor or the case temperature and the ambient temperature using the thermistors TH1 and TH2 and calculates the consumed power of the triac semiconductor by the following equation A bad semiconductor power consumption is detected,
And calculates ΔTs according to the input rated current set value Is and compares it with the temperature deviation ΔT detected during the operation of the motor. If ΔT> kΔTs is satisfied, the input operation delay time (O_time x Trip class) And the overload protection is realized by the operation of the control circuit of the three-phase motor.
[Equation 1]
P?? T (ja) / Rth (ja)? T (ha) / Rth (ha)
? T (ha) = Th - Ta = ADC2 - ADC1
P? (ADC2 - ADC1) / Rth (ha)
Rth (ja): Heat resistance index between junction and periphery, ΔT (ha): Difference between heat sink temperature and ambient temperature, where P is the heat dissipated by the triac, ΔT , Rth (ha) is the thermal resistance index between the heat sink and the surrounding area, k is the overload state index, ΔT is the temperature deviation, O_Time is the buffer integration time, Trip class is the overload delay time setting value, An analog-to-digital converter circuit) In an arc-free opening / closing method using a normal circuit device for a three-phase motor comprising a starting circuit portion including a forward / reverse start circuit and a direct starting circuit, an overload current detecting circuit portion and an MCU,
When the STOP switch is in the closed state, power is supplied to the control circuit and power is supplied to the MCU power. When '1' is inputted through the fourth input terminal IN4, it is determined that the power of the relays is normally supplied. The open / close state of the external UP and DOWN switches, which are the forward / reverse start control signals of the motor, via the terminal IN5 and the sixth input terminal IN6 and the open / close state of the first input terminal IN1, the second input terminal IN2, The first relay RLY1, the second relay RLY2, the second triac semiconductor TR2 and the third triac semiconductor TR3 are repeatedly checked through the third input terminal IN3 for IN1 IN1, IN2, IN3, IN1, IN2, IN3, IN3, IN3, and IN3.
When '1' is sensed at the fifth input terminal IN5 or the sixth input terminal IN6, a '1' signal is applied to the first output terminal OUT1 to output the first relay RLY1 for starting the motor and the second relay RLY1 for starting the motor The contact of the relay RLY2 is closed and when the contact movement is completed after a predetermined time and the IN1 = 1, IN2 = 0 and IN3 = 0 signals are inputted, it is determined as normal and the second input terminal IN2 and the third input 1 'at one or more of the terminals IN1 and IN3, it is determined that an abnormality has occurred in the triac semiconductors and a' 0 'signal is applied to the first output terminal OUT1, A second step of opening the contact of the second relay RLY2 and not operating;
When '1' is sensed at the fifth input terminal IN5, a '0' signal is applied to the second output terminal OUT2. On the other hand, if '1' is sensed at the sixth input terminal IN6, IN1 = 1, IN2 = 0, IN3 = 0, and IN2 = 0 when the contact of the third relay RLY3 and the fourth relay RLY4 is moved after a predetermined time by applying a "1" signal to the output terminal OUT2. 1 signal is detected at one or more of the second input terminal IN2 and the third input terminal IN3 when the contact point is moving or there is a problem, The first relay RLY1 and the second relay RLY2 are in an OPEN state and do not operate; and a third step of applying a '0' signal to the first output terminal OUT1 when the first relay RLY1 and the second relay RLY2 are not completed.
The second triac semiconductor TR2 and the third triac semiconductor TR3 are controlled by giving a '1' signal to the third output terminal OUT3. When all of them are turned on after a predetermined time, IN1 = 1 and IN2 = 1, IN3 = 1 signal is inputted and the motor is in the normal operation state,
When a contact is moving or an image is formed, a '0' signal is sensed in at least one of the second input terminal IN2 and the third input terminal IN3. If the contact movement is not completed after a predetermined time, The second triac semiconductor TR2 and the third triac semiconductor TR3 are turned OFF by giving a "0" signal to the output terminal OUT3, and after a predetermined time, the second triac semiconductor TR2 and the third triac 0 'is applied to OUT1 and the first relay RLY1 and the second relay RLY2 are connected to each other when a signal IN1 = 1, IN2 = 0 and IN3 = OPEN and does not operate;
When a rotation direction signal different from the rotation direction stored in the MCU for instantaneous forward / reverse rotation is input through the fifth input terminal IN5 or the sixth input terminal IN6 during normal operation of the motor, The second triac semiconductor TR2 and the third triac semiconductor TR3 are turned OFF by giving a '0' signal to the second triac semiconductor transistor OUT2 and the second triac semiconductor TR2 is turned off after a predetermined time, The third step and the fourth step are repeated when the signals IN1 = 1, IN2 = 0, and IN3 = 0 are input in the fifth step;
When it is confirmed that the STOP switch is in the OPEN state through the fourth input terminal IN4 during the normal operation of the motor, a '0' signal is applied to the third output terminal OUT3 to turn on the second triac semiconductor TR2 and the third The second triac semiconductors TR2 and the third triac semiconductors TR3 are both in the OFF state and the IN1 = 1, IN2 = 0, IN3 = 0 signal A sixth step of applying a '0' signal to OUT1 and opening the first relay RLY1 and the second relay RLY2 when the first relay RLY1 and the second relay RLY2 are inputted;
And a control unit for controlling the three-phase motor. delete

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