Circuit for improving arc discharge of band-type brake contactor

Abstract

The invention discloses a circuit for improving arc discharge of a band-type brake contactor, which comprises a band-type brake coil YBK, a band-type brake contactor KMB, a band-type brake controller, an MOS tube module and an elevator controller, and is characterized in that the band-type brake coil YBK is used for power-on brake loosening and power-off brake mounting, the band-type brake contactor KMB is used for connecting a power supply to the band-type brake coil YBK, and the MOS tube module is used for circuit switching and current control. An elevator needs to be started and stopped through band-type brake cooperation of a main machine, a band-type brake contactor controls a band-type brake coil to be repeatedly powered on to be loosened and powered off to be switched on, and the device is designed for reducing arc discharge and burning of the band-type brake contactor. According to the circuit, when an elevator is started, a band-type brake strong excitation voltage is firstly output and loaded on a band-type brake coil, a band-type brake maintaining voltage is output after the band-type brake strong excitation voltage is stabilized, the maintaining voltage is about half of the strong excitation voltage, and when the elevator is ready to stop, the current in the band-type brake coil is reduced in advance to the current range in which a band-type brake contactor can be reliably disconnected within the service life. And zero-speed small-band-type-brake current band-type brake is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of electrical control, and in particular relates to a circuit for improving arcing of a brake contactor. Background Art

[0002] As the load and speed of elevators continue to increase, the current of the main engine brake coil is also getting larger and larger. The brake contactor used is very likely to have the signal end burn out or fail during use. In order to reduce the damage to the brake contactor, the voltage and current of the brake coil need to be reduced through the circuit.

[0003] At present, power electronics technology is mature, and the application of contactor-free solutions in elevators is also gradually maturing. For circuits with direct current impact such as brakes, power electronic devices can be used to reduce voltage and current, and then the control component contactor can be used to disconnect. This can reduce the failure rate of elevators and increase the service life of elevators. Therefore, a circuit to improve the arcing of brake contactors is urgently needed. Summary of the invention

[0004] In order to solve the defects in the prior art, the present invention provides a circuit for improving arcing of a brake contactor.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] The present invention provides a circuit for improving arcing of a brake contactor, comprising:

[0007] Brake coil YBK, used to release the brake when power is on and to close the brake when power is off;

[0008] The brake contactor KMB is electrically connected to the left and right ends of the brake coil YBK and is used to connect the brake coil YBK to a power source;

[0009] A brake controller, which is communicatively connected with the elevator controller and is used to control PWM output;

[0010] The MOS tube module for circuit switching and current control includes a first MOS tube Q1, a second MOS tube Q2, a third MOS tube Q3, a fourth MOS tube Q4, a voltage dividing resistor R1, a freewheeling resistor R2 and a diode D1. The drains of the first MOS tube Q1, the second MOS tube Q2, the third MOS tube Q3 and the fourth MOS tube Q4 are electrically connected to the left end of the brake contactor KMB, the base of the first MOS tube Q1 is electrically connected to the PWM control 1 signal end of the brake controller, the base of the second MOS tube Q2 is connected to the PWM standby 1 signal end of the brake controller, and the first M The source electrodes of the OS transistor Q1 and the second MOS transistor Q2 are electrically connected to the left end of the brake coil YBK; the base electrode of the third MOS transistor Q3 is electrically connected to the PWM control 2 signal terminal of the brake controller, the base electrode of the fourth MOS transistor Q4 is connected to the PWM standby 2 signal terminal of the brake controller, and the source electrodes of the third MOS transistor Q3 and the fourth MOS transistor Q4 are electrically connected to the left end of the brake coil YBK through the voltage-dividing resistor R1; the voltage-dividing resistor R1 is used to share the voltage loaded on the brake coil YBK; the diode D1 is used to form a freewheeling circuit; the freewheeling resistor R2 constitutes a freewheeling circuit;

[0011] The elevator controller is used to control the start and stop of the elevator, the output of the brake contactor KMB and the setting of the current value of the brake coil YBK.

[0012] Preferably, the cathode of the diode D1 is electrically connected to the left end of the brake coil YBK, the anode of the diode D1 is electrically connected to the second end of the freewheeling resistor R2, and the first end of the freewheeling resistor R2 is electrically connected to the right end of the brake coil YBK.

[0013] Preferably, the first MOS transistor Q1 , the second MOS transistor Q2 , the third MOS transistor Q3 , and the fourth MOS transistor Q4 are NMOS transistors.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention controls the voltage and current of the brake coil YBK, thereby avoiding the situation where the brake contactor KMB is always arcing and disconnecting, and prolongs the service life of KMB. The present invention controls the change of the brake coil opening voltage and the maintenance voltage by switching the MOS tube circuit; when the elevator is about to brake, the PWM wave given to the MOS tube is reduced, thereby reducing the current flowing through the brake coil YBK, thereby realizing low-current braking; the brake controller obtains the host brake current information in the elevator controller, and changes the output of PWM control 2 through calculation, which can adapt to most host brake coils. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a circuit principle diagram of a circuit for improving arcing of a brake contactor according to the present invention;

[0017] Figure 2 The present invention discloses a controller output timing diagram of a circuit for improving arcing of a brake contactor. DETAILED DESCRIPTION

[0018] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0019] Example 1

[0020] like Figure 1 to Figure 2 As shown, this embodiment provides a circuit for improving arcing of a brake contactor, including a brake coil YBK, a brake contactor KMB, a brake controller, a MOS tube module for circuit switching and current control, and an elevator controller.

[0021] In this embodiment, the brake coil YBK is used to release the brake when power is supplied and to apply the brake when power is removed.

[0022] In this embodiment, the brake contactor KMB is electrically connected to the left and right ends of the brake coil YBK, and is used to connect the brake coil YBK to a DC110V power supply.

[0023] In this embodiment, the brake controller is communicatively connected with the elevator controller to control the PWM output;

[0024] In this embodiment, the MOS tube module for circuit switching and current control includes a first MOS tube Q1, a second MOS tube Q2, a third MOS tube Q3, a fourth MOS tube Q4, a voltage dividing resistor R1, a freewheeling resistor R2 and a diode D1. The drains of the first MOS tube Q1, the second MOS tube Q2, the third MOS tube Q3 and the fourth MOS tube Q4 are electrically connected to the left end of the brake contactor KMB, the base of the first MOS tube Q1 is electrically connected to the PWM control 1 signal end of the brake controller, the base of the second MOS tube Q2 is connected to the PWM standby 1 signal end of the brake controller, and the sources of the first MOS tube Q1 and the second MOS tube Q2 are electrically connected to the left end of the brake coil YBK; The base of the third MOS tube Q3 is electrically connected to the PWM control 2 signal terminal of the brake controller, the base of the fourth MOS tube Q4 is connected to the PWM standby 2 signal terminal of the brake controller, and the source of the third MOS tube Q3 and the fourth MOS tube Q4 are electrically connected to the left end of the brake coil YBK through the voltage-dividing resistor R1; the voltage-dividing resistor R1 is used to share the voltage loaded on the brake coil YBK; the diode D1 is used to form a freewheeling loop; the freewheeling resistor R2 constitutes a freewheeling loop; the cathode of the diode D1 is electrically connected to the left end of the brake coil YBK, the anode of the diode D1 is electrically connected to the second end of the freewheeling resistor R2, and the first end of the freewheeling resistor R2 is electrically connected to the right end of the brake coil YBK. The first MOS tube Q1, the second MOS tube Q2, the third MOS tube Q3, and the fourth MOS tube Q4 are NMOS tubes.

[0025] In this embodiment, the elevator controller is used to control the start and stop of the elevator, the output of the brake contactor KMB and the setting of the current value of the brake coil YBK.

[0026] The working principle of this embodiment is further described below:

[0027] At time t1 on the elevator start-up timing diagram, the KMB of the elevator controller and the PWM control 1 signal terminal of the brake controller are output simultaneously, the KMB coil is energized, and the signal terminals 1 and 2 of the brake contactor KMB are closed, and the positive pole of DC110V is introduced into the drain of the first MOS tube Q1. Since the PWM control 1 signal terminal of the brake controller and the KMB coil are output simultaneously, the base g1 of the first MOS tube Q1 is energized. When the capacitor between the base g1 and the source of the first MOS tube Q1 is fully charged, the drain and source of the first MOS tube Q1 are connected, so that the positive pole of DC110V is connected to the left end of the brake coil YBK. Since the 3rd and 4th signal terminals of the brake contactor KMB are also closed at this time, the right end of the brake coil YBK is connected to the negative pole of DC110V, so the brake coil YBK is loaded with DC110V at this time. When the host brake is closed and opened, it is necessary to overcome the static mechanical force of the host brake. Therefore, when the host brake is just opened, the brake coil YBK requires a larger voltage, generally requiring full voltage. For a quick response, the brake voltage is DC110V.

[0028] The brake coil YBK is energized to release the brake. When the brake coil YBK is energized to release the brake, the elevator can run. The current range of the brake coil YBK is from 1A to 5A, so the current that the first MOS tube Q1, the second MOS tube Q2, the third MOS tube Q3, and the fourth MOS tube Q4 in the circuit can withstand must be above 6A.

[0029] After the electromagnetic force of the brake overcomes the mechanical force and opens, it is sufficient to maintain this open state by maintaining the voltage, which is 50% to 60% of the opening voltage. The full-pressure brake enters the maintenance state 2 seconds after opening (time t2). At this time, the PWM control 2 signal end of the brake controller outputs, the PWM control 1 signal end delays shutdown, the third MOS tube Q3 is turned on, the PWM control 1 signal end stops outputting, the first MOS tube Q1 is turned off, and the brake current changes from Q1→YBK to Q3→R1→YBK, completing the uninterrupted switching from Q1 to Q3. At this time, due to the existence of the voltage divider resistor R1, the brake coil YBK is not fully pressurized, but only maintains the voltage.

[0030] The PWM control 1 signal terminal and the PWM control 2 signal terminal outputs in the brake controller have software interlocking. After the brake controller receives the running signal of the elevator controller, the PWM control 1 signal terminal is responsible for fully opening the brake. After a delay of 2S, it switches to PWM control 2 to maintain the voltage and keep the brake open.

[0031] When the elevator is about to stop (at t3), the brake controller controls the output voltage of the PWM control 2 signal terminal according to the obtained host brake current. According to the characteristics of the MOS tube, the resistance between the drain and source of the third MOS tube Q3 increases, and the current passing through decreases, thereby reducing the Q3→R1→YBK brake current. When the elevator is leveled at zero speed, the brake contactor and the third MOS tube Q3 are turned off at the same time. According to different host brake currents, the PWM control 2 signal terminal outputs different voltages. When the host brake current is small, the current drops faster. When the current is large, in order to reduce PWM damage, the current drops slowly. When the elevator stops at the station, the KMB contactor signal terminals 1, 2 and 3, 4 are disconnected, and the current in the brake coil YBK has also dropped at this time. The KMB signal terminal is disconnected at low current, which can greatly reduce arcing, burning and other problems.

[0032] Since the MOS tube also has a service life, PWM standby 1 and standby 2 control outputs are added to the circuit to control the second MOS tube Q2 and the fourth OS tube Q4 respectively, so as to extend the service life of the MOS tube and the brake contactor KMB as much as possible and reduce the elevator failure rate.

[0033] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A circuit for improving arcing of a brake contactor, characterized in that: include: Brake coil YBK, used to release the brake when power is on and to close the brake when power is off; The brake contactor KMB is electrically connected to the left and right ends of the brake coil YBK and is used to connect the brake coil YBK to a power source; A brake controller, which is communicatively connected with the elevator controller and is used to control PWM output; The MOS tube module for circuit switching and current control includes a first MOS tube Q1, a second MOS tube Q2, a third MOS tube Q3, a fourth MOS tube Q4, a voltage dividing resistor R1, a freewheeling resistor R2 and a diode D1. The drains of the first MOS tube Q1, the second MOS tube Q2, the third MOS tube Q3 and the fourth MOS tube Q4 are electrically connected to the left end of the brake contactor KMB, the base of the first MOS tube Q1 is electrically connected to the PWM control 1 signal end of the brake controller, the base of the second MOS tube Q2 is connected to the PWM standby 1 signal end of the brake controller, and the first M The source electrodes of the OS transistor Q1 and the second MOS transistor Q2 are electrically connected to the left end of the brake coil YBK; the base electrode of the third MOS transistor Q3 is electrically connected to the PWM control 2 signal terminal of the brake controller, the base electrode of the fourth MOS transistor Q4 is connected to the PWM standby 2 signal terminal of the brake controller, and the source electrodes of the third MOS transistor Q3 and the fourth MOS transistor Q4 are electrically connected to the left end of the brake coil YBK through the voltage-dividing resistor R1; the voltage-dividing resistor R1 is used to share the voltage loaded on the brake coil YBK; the diode D1 is used to form a freewheeling circuit; the freewheeling resistor R2 constitutes a freewheeling circuit; The elevator controller is used to control the start and stop of the elevator, the output of the brake contactor KMB and the setting of the current value of the brake coil YBK.

2. A circuit for improving arcing of a brake contactor according to claim 1, characterized in that: The cathode of the diode D1 is electrically connected to the left end of the brake coil YBK, the anode of the diode D1 is electrically connected to the second end of the freewheeling resistor R2, and the first end of the freewheeling resistor R2 is electrically connected to the right end of the brake coil YBK.

3. A circuit for improving arcing of a brake contactor according to claim 1, characterized in that: The first MOS transistor Q1 , the second MOS transistor Q2 , the third MOS transistor Q3 , and the fourth MOS transistor Q4 are NMOS transistors.

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