TWI625928B - Motor buffer start control system with energy saving - Google Patents

Abstract

The invention relates to a motor buffer start control system with energy saving and power saving, and the integrated control device of the motor buffer starter, the automatic power factor adjuster, the electronic discharger and the static switch is an "integrated module", which is effective Reduce the starting and running current of the motor, increase the service life of the power system equipment, and instantly compensate the power factor without delay. The power quality reaches the set standard, the power system operates more effectively, and the equipment and enterprise are reduced. The cost of electricity increases the substantial benefits; the static switch adopts a fast zero input and zero point cut-off function; and the function of the motor slow starter can greatly reduce the motor starting current and running current.

Description

Motor buffer start control system with energy saving

The invention relates to motor control, in particular to a motor buffer start control system with energy saving.

Since the government's previous energy policy has focused on petrochemical raw materials, it has less emphasis on energy conservation and power conservation. In recent years, the government has vigorously promoted research and manufacturing talents that have cultivated many energy-saving and power-saving technologies. The results will gradually become more fruitful. These materials will provide reference for future researchers. According to the Ministry of Economic Affairs' latest green energy conservation goals, the new president's renewable energy targets will be fully incorporated. The solar photovoltaic installations are twice as large as the old government regulations. More than 50%, the total renewable energy target reached 20,742,000 in 2025. Initially, the total amount of investment in solar energy and offshore wind power reached 1.74 trillion yuan, driving huge business opportunities.

At present, there are many factories in Taiwan that have installed large motor loads of more than 100 horsepower. Among them, the proportion of induction motors is the highest. Due to the starting current of induction motors, it is generally about 5~8 times of the full-load running current, while the starting currents of medium and large induction motors are too large. When it occurs, it will cause a burden on the power system and affect the power supply quality and stability of the power system. Therefore, when the medium and large induction motors start, they should try to A starter is installed to limit its starting current, but it must provide enough torque to drive the load so that the motor can start and run normally.

In order to reduce the starting current of the induction machine, the Y-△ starting method is generally adopted. The purpose is to pull out the six lines of the stator of the three-phase induction motor, and connect it to the Y line when starting. After the starting current drops to a stable value, the wiring is made. Change to △ connection, do full pressure operation, because the phase current when Y is connected is 1 / And the voltage of each winding is only 1/ of the Δ connection , so the starting current of Y is actually only △ connected The advantage of this connection is that the wiring is simple, the cost is low, and the starting current can be effectively reduced. The disadvantage is that the starting torque is small and the acceleration is slow, and it is only suitable for a motor of 5 to 15 horsepower, and can be a loadless starter.

Therefore, the Y-△ starting method has many shortcomings, coupled with the fact that the factory is equipped with more than 100 horsepower motors, causing problems such as excessive current, low power factor and high voltage drop of the factory at the start of the motor load; therefore, the market There is a traditional starter motor controller developed. The power supply has an Automatic Power Factor Regulator (APFR) to reduce the motor running current. However, it uses a magnetic contactor (MC) to control it. The operating time is too long and the starting current of the motor cannot be effectively reduced immediately.

In view of the long distance between the factory large motor and the main power transformer (about 50 ~ 150 meters long); although the automatic power factor adjuster can reduce the motor running current; the electromagnetic contactor control action time is too long, in the motor Short start time (several minutes or seconds) can not effectively reduce the maximum starting current of the motor immediately, resulting in high current, high power factor and high voltage drop of the large motor load. Traditionally, the Y-△ start method (shown in Figure 1) is used, which is directly connected to a motor M' by a Y-Δ starter 1', and the Y-△ starter 1' is further passed through a no-fuse (NFB). The switch S' is electrically connected to a three-phase AC power source P'. The advantages of the connection method are simple wiring, low cost, and can effectively reduce the starting current is small, and the disadvantage is that the starting torque is small and the acceleration is slow, and only applicable. For motors with 5 to 15 horsepower, the unloaded starter, the factory is equipped with more than 100 horsepower motors, causing problems such as high current, low power factor and high voltage drop of the factory at the start of the motor load.

In view of the increasing global warming and climate change effects caused by greenhouse gases, in order to arouse the common participation of all people in energy conservation and carbon reduction, and in their lives, the government promotes the “Action Plan for Energy Conservation, Carbon Reduction and No Repentance Measures” and proposes ten No regrets, for the public to refer to practice, in a flexible way, appeal to the public to respond to low-carbon living habits and achieve greenhouse gas reduction effects.

In view of this, the present invention proposes "research and development of a motor buffer start controller applied to a large horsepower of a factory", which can effectively improve the above disadvantages. The main structure of the system is a whole "motor buffer starter" and "automatic power factor adjuster". The advantages of the four control devices, "Electronic Discharger" and "Static Switch" can effectively reduce the motor starting and running current, increase the service life of the power system equipment, and instantly compensate the power factor on the spot without delay. To make the power quality reach the set standard, the power system operates more effectively, reduce the cost of electricity for the equipment and enterprises, and increase the substantial benefits.

The object of the present invention is to provide a motor buffer start control system with energy saving and power saving, and integrate four control devices of motor buffer starter, automatic power factor adjuster, electronic discharger and static switch into a set of "integrated modules". It can effectively reduce the starting and running current of the motor, increase the service life of the power system equipment, and instantly compensate the power factor without delay. The power quality reaches the set standard, the power system operates more effectively, and the power station is reduced. And the company's electricity cost, increase the substantial benefits; the static switch, with a fast zero input, zero point cut off function; contains a motor slow starter function, can significantly reduce the motor starting current and running current.

The present invention has been described in connection with the preferred embodiments of the present invention in accordance with the accompanying drawings.

Referring to FIG. 2 to FIG. 8 , a motor buffer start control system 100 with energy saving and power saving according to the present invention may include a static switch unit 1 , a motor buffer starter 2 , an automatic power factor adjuster 3 , and an electronic device. The discharger 4, as shown in FIG. 3 and FIG. 7, the static switch unit 1, the motor buffer starter 2, the automatic power factor adjuster 3, and the electronic discharger 4 can be combined into one integrated module to achieve modularization. The effect.

The static switch unit 1 can be electrically connected to a capacitor bank 5.

The motor buffer starter 2 is electrically connected to the static switch unit 1; and the motor buffer starter 2 is electrically connected to a three-phase AC power source P through a fuseless switch (NFB, No FuseBreaker) S.

The automatic power factor adjuster 3 is electrically connectable to the static switch unit 1 and the motor buffer starter 2.

The electronic discharger 4 is electrically connectable to the static switch unit 1.

Referring to FIG. 4 and FIG. 5, the static switch unit 1 may include a first control circuit 11 electrically connected in sequence, a first optical coupling switch group 12, and an SCR (Silicon Controlled Rectifier) switch. The component group 13, wherein G1 to G6 represent pins, R, S, and T represent three-phase power connection terminals of the SCR switch switching element group 13, and U, V, and W represent motor connection ends of the SCR switch switching element group 13, To connect a motor M.

The static switch unit 1 of the present embodiment uses a static switch circuit and uses an SCR thyristor module. The component is a SCR, which is a three-terminal Thyristor component. For controlling the current flowing to the load, wherein the A pole is an anode, K is a cathode, and G is a gate; the voltage of the gate must be higher than the cathode to form a PN forward conduction At this time, if the voltage of the A pole is greater than the cathode, it will be like two The pole body is normally turned on; once it enters the conducting state, unless the SCR current is less than the holding current, the SCR will continue to conduct; this circuit has a fast zero input and zero point cutting function, and the technical scope includes the following: 1. Capacitor power factor disk dedicated Static switch, replacing the traditional electromagnetic switch, the instantaneous power factor is not as slow as the traditional electromagnetic switch; 2. Capacitor power factor disk dedicated static switch: improve power quality, increase power system equipment life, with APFR ( Automatic Power Factor Regulator), which compensates for power factor instantly, without delay, allows power quality to reach set standards, and operates the power system more efficiently; 3.SSR (Solid State Relay) solid state Relay, used for heating load, low cost, stable heating; and 4.SSR solid state relay: electric heating system, the temperature difference is small, the finished product is stable, there is no contact of electromagnetic switch, resulting in spark, arc and optical end wear.

Therefore, the static switch unit 1 of the present embodiment uses the SCR switch switching element group 13 (ie, the thyristor module), which has a fast turn-on and fast switching speed. Unless the SCR current is less than the sustain current, the SCR will continue to conduct. With fast zero input and zero point cutting function; use SCR thyristor switching element, with electronic fast control function, built-in zero voltage control loop, control at zero point, monitor the output speed of motor M more quickly; In addition to the capacitor group, the size of the discharge resistor is also adjusted at the same time, and the speed of the discharge speed is achieved, which is faster and more stable than the conventional output capacitor group.

The functions and advantages of the static system capacitor bank and the functions or advantages of the compensation system are as follows: a. Immediate response to the compensation requirements. The power factor correction response time can be a single network frequency cycle in such a way as to achieve almost instantaneous compensation; b. Eliminate the transient current generated by the startup capacitor junction. When the capacitor is partially or fully loaded, the connection occurs when its voltage is equal to the network voltage.

The crystal module product of the static switch unit 1 is a module designed for a static capacitor bank to achieve power factor correction compensation; these capacitor banks use a thyristor element instead of a conventional contactor (electromagnetic switch) to connect each group of capacitors. Group 5 and the ideal device where the leakage current is impaired quickly and fluctuatingly (the interval of load changes can be from instant to 2 or 3 seconds).

The static switching unit 1 is designed to connect and disconnect the capacitor bank 5 in tens of milliseconds; they can be used to construct various steps in the capacitor, or to compensate for individual loads, since the connection/disconnection defects must be instant Compensation, for example: in welding equipment, cranes, lifts, etc.

Referring to FIG. 6, the motor buffer starter 2 includes a zero voltage check circuit 21, a second control circuit 22, and a second optical coupler switch group 23; the motor buffer starter 2 can adjust the slow start. Time, start torque and stop time, make the start smooth and smooth, can be built in 3 start modes: slope start, constant current start, constant current plus kick start; use SCR control, no contact, no arc, The matte end wear is equivalent to the semi-permanent service life; the simple wiring, three-in and three-out devices save the cost of manual and complicated wiring; the motor buffer starter 2 can be a microprocessor type with automatic light and heavy load proofing function and Torque control; motor buffer starter 2 can contain CT electronic detection protector: overload protection, source electric phase loss protection, motor M stuck protection, controller over temperature protection, motor M low load (water shortage) protection Ultra-sensitive sensitivity, and no thermal effect, not affected by the ambient temperature; the motor buffer starter 2 of this embodiment can provide three sets of output contacts: with the output contact at startup, after the operation is completed Contacts (by-pass), the system abnormality output contact NO, COM, NC; buffer start motor Example 2 of the present embodiment may provide a dedicated pump motor M gradually stop function, eliminating water hammer to achieve optimal function.

Referring to FIG. 8 again, the electronic discharger 4 can include a bridge rectifier circuit 41 electrically connected in sequence, an RC (resistance capacitor) charge and discharge circuit 42 , a trigger circuit 43 , a power consumption adjustment circuit 44 , and a The power consumption resistor 45, the power consumption adjustment circuit 44 can adjust the power consumption resistor 45 discharge time.

The circuit of FIG. 8 describes that the electronic discharger 4 is electrically connected to the static switch unit 1. The static switch unit 1 is electrically connected between a power terminal and a motor load terminal, and the static switch unit 1 is electrically connected with an automatic power factor adjustment. The automatic power factor adjuster 3 is also electrically connected between the power supply end and the load end, so that the automatic power factor adjuster 3 sends a control signal for selecting to activate the static switch unit 1 or to turn off the static switch unit 1, and the RC The charge and discharge circuit 42 does not operate when the static switch unit 1 is activated, and operates when the static switch unit 1 is turned off to quickly eliminate the transient voltage of the capacitor bank 5 to which the static switch unit 1 is connected, so that the static switch unit 1 When it is started again, it will not cause malfunction or no action. The working principle of this circuit is described below.

When the static switch unit 1 is started, the three-phase AC power source P charges the capacitor bank 5 via the no-fuse switch S, and also supplies power to the bridge rectifier circuit 41, and the output DC power is slowly charged through the RC charge and discharge circuit 42 until After the voltage required by the MOS switch in the flip-flop circuit 43 starts to conduct, the current forms a loop through the resistor. Since the resistance value is small, the gate voltage of the MOS switch in the flip-flop circuit 43 is almost zero, which also causes the trigger circuit 43 to Since the IGBT is turned off, the power consumption resistor 45 has no current passing through, and the power of the capacitor cannot be consumed.

When the static switch unit 1 is turned off, the no-fuse switch S is turned on, the residual voltage in the capacitor bank 5 can be supplied to the bridge rectifier circuit 41, the output DC current is slowly discharged through the RC charge and discharge circuit 42, and the capacitor bank 5 is fully charged. When the MOS switch in the open circuit trigger circuit 43 is insufficient, the required trigger voltage cannot be turned on, so the current turns into a charging circuit by the resistor and the capacitor until the IGBT in the trigger circuit 43 starts to be turned on after being charged to the required voltage, so the power The consuming resistor 45 has a current passing through, and also consumes the power of the capacitor.

[知知]

1'‧‧‧Y-△ starter

M’‧‧·Motor

S’‧‧‧Fuseless switch

P’‧‧‧Three-phase AC power supply

[this invention]

100‧‧‧Motor buffer start control system with energy saving

1‧‧‧Static switch unit

11‧‧‧First control circuit

12‧‧‧First optical coupling switch set

13‧‧‧SCR switch switching element group

2‧‧‧Motor Buffer Starter

21‧‧‧ Zero voltage check circuit

22‧‧‧Second control circuit

23‧‧‧Second optical coupling switch set

3‧‧‧Automatic factor adjuster

4‧‧‧Electronic discharger

41‧‧‧Bridge rectifier circuit

42‧‧‧RC charging and discharging circuit

43‧‧‧Trigger circuit

44‧‧‧Power consumption adjustment circuit

45‧‧‧Power consumption resistor

5‧‧‧ capacitor bank

S‧‧‧Fuseless switch

P‧‧‧Three-phase AC power supply

G1~G6‧‧‧ pin

R, S, T‧‧‧ three-phase power connection

U, V, W‧‧‧ motor connection

M‧‧ motor

Figure 1 is a block diagram showing the connection of a conventional motor start control with a Y-Δ starter. 2 is a block diagram of a motor buffer start control system connected to the motor and a three-phase power supply with energy saving and power saving according to the present invention. FIG. 3 is a block diagram showing an integrated power module of the motor buffer start control system with energy saving and power saving according to the present invention. 4 is a block diagram of a static switch unit in a motor buffer start control system with energy saving and power saving according to the present invention. FIG. 5 is a schematic circuit diagram of a static switch unit electrically connected to a capacitor bank in a motor buffer start control system with energy saving and power saving according to the present invention. 6 is a circuit block diagram of a motor buffer starter electrically connected to a motor in a motor buffer start control system with energy saving and power saving according to the present invention. FIG. 7 is a block diagram of a motor buffer start control system with energy saving and power saving according to the present invention as an integrated module. FIG. 8 is a block diagram of an electronic discharger in a motor buffer start control system with energy saving and power saving according to the present invention.

Claims (6)

A motor buffer start control system with energy saving and power saving, comprising: a static switch unit; a motor buffer starter electrically connected with the static switch unit; an automatic power factor adjuster, and the static switch unit and the motor buffer The electrical device is electrically connected to the starter; and an electronic discharge device is electrically connected to the static switch unit; wherein the static switch unit comprises a first control circuit electrically connected in sequence, a first optical coupling switch group and an SCR (Silicon Controlled Rectifier) Switching component group. The motor buffer start control system with energy saving according to claim 1, wherein the static switch unit is electrically connected to a capacitor group. The motor buffer start control system with energy saving according to claim 1, wherein the motor buffer starter is electrically connected to a three-phase power source through a no-fuse (NFB) switch. The motor buffer start control system with energy saving according to claim 3, wherein the motor buffer starter is electrically connected to a motor. The motor buffer start control system with energy saving according to claim 1, wherein the motor buffer starter comprises a zero voltage check circuit, a second control circuit and a second optical coupling switch electrically connected in sequence. group. The motor buffer starting control system with energy saving according to claim 1, wherein the electronic arrester comprises a bridge rectifier circuit, an RC (resistance capacitor) charging and discharging circuit, a trigger circuit, and the like, A power consumption adjustment circuit and a power consumption resistor, the power consumption adjustment circuit can adjust the power consumption resistance discharge time.