A safety circuit

Abstract

The application discloses a safety circuit, which comprises a first switch circuit, a second switch circuit, a first freewheeling circuit, a second freewheeling circuit, a first power supply of the first switch circuit, a first power supply of the second switch circuit, a second power supply of the first switch circuit, a second power supply of the second switch circuit, a safety loop state signal, a first switch driving power supply circuit, a second switch driving power supply circuit, a first switch driving circuit and a second switch driving circuit; when any one of the first switch circuit and the second switch circuit has a short circuit or open circuit fault, the working power supply of the other switch circuit can be cut off, thereby cutting off the power supply of an electromagnetic brake coil and further reducing the failure rate; the switch circuit can avoid noise, and the circuit structure is simple and the cost is low.

Description

Technical Field

[0001] This invention belongs to the field of brake power supply control technology, and specifically relates to a safety circuit. Background Technology

[0002] For the power supply control of the brake, the current industry-standard technical solution is to use the normally open contacts of two contactors connected in series in the brake's power supply circuit. Both contactor coils are powered by a safety circuit. When the safety circuit is disconnected, the contactor coils are de-energized, their normally open contacts open, the brake power supply is cut off, and the brake is released to stop the elevator. However, the above contactor solution has a series of shortcomings, such as noise from contactor operation causing disturbance to users, the large size of the contactors making it difficult to further reduce the size of the control cabinet, contactor jamming leading to an increase in passenger entrapment failures, and the short electrical life of the contactors affecting the overall lifespan of the elevator. Against this backdrop, with the popularization of the PESSRAL (Programmable Electronic Safety System) elevator, contactless technical solutions based on PESSRAL have gradually emerged in recent years. These solutions employ a multi-channel redundant structure, incorporating two or more programmable systems to achieve low failure rates. While this technical solution can achieve contactless brake power supply control, the cost is a high failure rate and high cost due to the extremely complex multi-channel system, hindering its widespread adoption. Summary of the Invention

[0003] To overcome the above-mentioned technical defects, the present invention provides a safety circuit that can improve the safety of power supply.

[0004] To solve the above problems, the present invention is implemented according to the following technical solution:

[0005] A safety circuit, characterized in that it comprises: a first switching circuit, a second switching circuit, a first freewheeling circuit, a second freewheeling circuit, a first power supply for the first switching circuit, a first power supply for the second switching circuit, a second power supply for the first switching circuit, a second power supply for the second switching circuit, a safety loop status signal, a first switch driving power supply circuit, a second switch driving power supply circuit, a first switch driving circuit, and a second switch driving circuit.

[0006] The first terminal of the brake power supply is connected to the second terminal of the brake power supply through the second switching circuit, the electromagnetic brake coil, and the first switching circuit.

[0007] The first freewheeling circuit is connected in parallel across the two ends of the electromagnetic brake coil, and the first end of the brake power supply is connected to the second end of the brake power supply through the second freewheeling circuit and the first switching circuit.

[0008] The second power supply for the first switching circuit is connected to the first switching drive power supply circuit and the first freewheeling circuit.

[0009] The second power supply of the second switching circuit is connected to the second switching drive power supply circuit and the second freewheeling circuit;

[0010] The safety circuit power supply is connected to the input terminal of the first switch drive power supply circuit through the safety circuit and the first power supply of the first switch circuit.

[0011] The safety circuit power supply is connected to the input terminal of the second switch drive power supply circuit through the safety circuit and the first power supply of the second switch circuit;

[0012] The safety circuit power supply is connected to the safety circuit status signal through the safety circuit. The safety circuit status signal drives the first switch driving power supply circuit and the second switch driving power supply circuit through coupling. The output terminal of the first switch driving power supply circuit is connected to the first switch circuit through the first switch driving circuit. The output terminal of the second switch driving power supply circuit is connected to the first switch circuit through the first switch driving circuit.

[0013] As a further improvement of the present invention, the first switching circuit includes a first switch; the second switching circuit includes a second switch.

[0014] As a further improvement of the present invention, the first switch is a bipolar junction transistor, a field-effect transistor, or an insulated gate bipolar transistor; the second switch is a bipolar junction transistor, a field-effect transistor, or an insulated gate bipolar transistor.

[0015] As a further improvement of the present invention, the first freewheeling circuit includes: a first energy conversion device and a first diode; the second freewheeling circuit includes: a second energy conversion device and a second diode.

[0016] The first terminal of the brake power supply is connected to the second terminal of the brake power supply in sequence through the second switching circuit, the first diode in reverse conduction, the first energy conversion device, and the first switching circuit.

[0017] The first terminal of the brake power supply is connected to the second terminal of the brake power supply in sequence through the second diode (which is conducting in reverse), the second energy conversion device, and the first switching circuit.

[0018] As a further improvement of the present invention, the first energy conversion device includes a transformer, and the second energy conversion device includes a transformer.

[0019] As a further improvement of the present invention, the second power supply of the first switching circuit includes: a first voltage shaping circuit, and the second power supply of the second switching circuit includes: a second voltage shaping circuit.

[0020] The first energy conversion device is connected to the first switch drive power supply circuit through the first voltage shaping circuit;

[0021] The second energy conversion device is connected to the second switching drive power supply circuit through the second voltage shaping circuit.

[0022] As a further improvement of the present invention, the first switch driving power supply circuit includes: a first normally open contact of the relay, a first normally closed contact of the relay, a first signal coupler, and a first energy storage element; the second switch driving power supply circuit includes: a second normally open contact of the relay, a second normally closed contact of the relay, a second signal coupler, and a second energy storage element.

[0023] The two ends of the relay coil are respectively connected to the safety circuit status signal and the relay drive signal;

[0024] The safety circuit status signal is connected to the first terminal of the first signal coupler, the second terminal of the first signal coupler is connected to the first switch drive signal, the first power supply of the first switch circuit is connected to the fourth terminal of the first signal coupler through the first normally closed contact of the relay, the first energy storage element, and the first normally open contact of the relay, the second power supply of the first switch circuit is connected to the fourth terminal of the first signal coupler through the first normally open contact of the relay, and the third terminal of the first signal coupler is connected to the first switch circuit through the first switch drive circuit.

[0025] The safety circuit status signal is connected to the first terminal of the second signal coupler, the second terminal of the second signal coupler is connected to the second switch drive signal, the first power supply of the second switch circuit is connected to the fourth terminal of the second signal coupler through the second normally closed contact of the relay, the second energy storage element, and the second normally open contact of the relay, the second power supply of the second switch circuit is connected to the fourth terminal of the second signal coupler through the second normally open contact of the relay, and the third terminal of the second signal coupler is connected to the second switch circuit through the second switch drive circuit.

[0026] As a further improvement of the present invention, the first switch driving power supply circuit includes: a first normally open contact of the relay, a first normally closed contact of the relay, a first signal coupler, and a first energy storage element; the second switch driving power supply circuit includes: a second normally open contact of the relay, a second normally closed contact of the relay, a second signal coupler, and a second energy storage element.

[0027] The two ends of the relay coil are respectively connected to the safety circuit status signal and the relay drive signal;

[0028] The safety circuit status signal is connected to the first terminal of the first signal coupler, the second terminal of the first signal coupler is connected to the first switch drive signal, the first power supply of the first switch circuit is connected to the fourth terminal of the first signal coupler through the first normally closed contact of the relay and the first energy storage element, the second power supply of the first switch circuit is connected to the fourth terminal of the first signal coupler through the first normally open contact of the relay, and the third terminal of the first signal coupler is connected to the first switch circuit through the first switch drive circuit.

[0029] The safety circuit status signal is connected to the first end of the second signal coupler, the second end of the second signal coupler is connected to the second switch drive signal, the first power supply of the second switch circuit is connected to the fourth end of the second signal coupler through the second normally closed contact of the relay and the second energy storage element, the second power supply of the second switch circuit is connected to the fourth end of the second signal coupler through the second normally open contact of the relay, and the third end of the second signal coupler is connected to the second switch circuit through the second switch drive circuit.

[0030] As a further improvement of the present invention, the present invention also includes: a voltage converter, the input terminal of which is connected to the safety circuit; the output terminal of the voltage converter outputs the first power supply of the first switching circuit, and the output terminal of the voltage converter outputs the first power supply of the second switching circuit.

[0031] Furthermore, the present invention also provides a control method for a safety circuit, applied to the aforementioned safety circuit, comprising the following steps:

[0032] When the elevator is not running, the first switch drive power circuit and the second switch drive power circuit are disconnected to de-energize the first switch circuit and the second switch circuit, thereby de-energizing the electromagnetic brake coil and closing the brake.

[0033] When the elevator starts, after the safety circuit is connected, at least after a set delay time, the first switch drive power circuit and the second switch drive power circuit are connected to energize the first switch circuit and the second switch circuit, and the electromagnetic brake coil is energized so that the brake is opened.

[0034] When any component fails, causing the first switching circuit to remain on or off, the second power supply to the second switching circuit loses power, causing the second switching circuit to remain off, the electromagnetic braking coil loses power, and the brake closes.

[0035] When any component fails, causing the second switching circuit to remain on or off, the second power supply to the first switching circuit loses power, keeping the first switching circuit off, and the electromagnetic braking coil loses power, causing the brake to close.

[0036] Compared with the prior art, the present invention has the following advantages: when either the first switch circuit or the second switch circuit experiences a short circuit or open circuit fault, the power supply of the other switch circuit can be cut off, thereby cutting off the power supply of the electromagnetic braking coil and reducing the failure rate; the use of switch circuits can avoid noise, and at the same time, the circuit structure is simple and the cost is low. Attached Figure Description

[0037] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, wherein:

[0038] Figure 1 This is a schematic diagram of the main circuit structure of the safety circuit described in Example 1;

[0039] Figure 2 This is a schematic diagram of the safety circuit power supply structure in the safety circuit described in Example 1;

[0040] Figure 3 This is a schematic diagram of the structure of the second power supply for the first switching circuit in Embodiment 1;

[0041] Figure 4 This is a schematic diagram of the coil connection of the relay described in Example 1;

[0042] Figure 5 This is a schematic diagram of the structure of the second power supply for the second switching circuit in Embodiment 1;

[0043] Figure 6 This is a schematic diagram illustrating the switching drive waveform of the switching element in Example 1;

[0044] Figure 7 This is a schematic diagram of the structure of the second power supply for the first switching circuit in Embodiment 2;

[0045] Figure 8 This is a schematic diagram of the structure of the second power supply for the second switching circuit in Embodiment 2.

[0046] Labeling Explanation: 1. First switching circuit; 2. Second switching circuit; 3. First freewheeling circuit; 301. First energy conversion device; 302. First diode; 4. Second freewheeling circuit; 401. Second energy conversion device; 402. Second diode; 5. First power supply for the first switching circuit; 6. First power supply for the second switching circuit; 7. Second power supply for the first switching circuit; 701. First voltage shaping circuit; 8. Second power supply for the second switching circuit; 801. Second voltage shaping circuit; 9. Safety circuit status signal; 10. First switch drive power supply circuit; 1001. Relay; 1002. First signal coupler; 1003. First energy storage element; 11. Second switch drive power supply circuit; 1101. Second signal coupler; 1102. Second energy storage element; 12. First switch drive circuit; 13. Second switch drive circuit; 14. Voltage converter;

[0047] 100. Electromagnetic brake coil; 200. Brake power supply; 300. Safety circuit power supply; 400. Safety circuit; 500. First switch drive signal; 600. Second switch drive signal; 700. Relay drive signal. Detailed Implementation

[0048] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only for illustration and explanation of the present invention and are not intended to limit the present invention. In addition, the step numbers S1, S2, etc. in the text are only for distinguishing different steps and do not mean that these steps need to be strictly performed in the order of the numbers.

[0049] Example 1

[0050] This embodiment provides a safety circuit, such as Figure 1 and Figure 2As shown, it includes: a first switching circuit 1, a second switching circuit 2, a first freewheeling circuit 3, a second freewheeling circuit 4, a first power supply for the first switching circuit 5, a first power supply for the second switching circuit 6, a second power supply for the first switching circuit 7, a second power supply for the second switching circuit 8, a safety circuit status signal 9, a first switch drive power supply circuit 10, a second switch drive power supply circuit 11, a first switch drive circuit 12, and a second switch drive circuit 13; the positive terminal of the brake power supply 200 is connected to the negative terminal of the brake power supply 200 through the second switching circuit 2, the electromagnetic brake coil 100, and the first switching circuit 1; the first freewheeling circuit 3 is connected in parallel across the two ends of the electromagnetic brake coil 100, and the positive terminal of the brake power supply 200 is connected to the negative terminal of the brake power supply 200 through the second freewheeling circuit 4 and the first switching circuit 1. The second power supply 7 of the first switching circuit is connected to the first switch drive power supply circuit 10 and the first freewheeling circuit 3; the second power supply 8 of the second switching circuit is connected to the input terminals of the second switch drive power supply circuit 11 and the second freewheeling circuit 4; the safety circuit power supply 300 is connected to the input terminal of the first switch drive power supply circuit 10 through the safety circuit 400 and the first power supply 5 of the first switching circuit; the safety circuit power supply 300 outputs a safety circuit status signal 9 through the safety circuit 400, and the safety circuit status signal 9 drives the first switch drive power supply circuit 10 and the second switch drive power supply circuit 11 through coupling; the output terminal of the first switch drive power supply circuit 10 is connected to the first switch circuit 1 through the first switch drive circuit 12; the output terminal of the second switch drive power supply circuit 11 is connected to the second switch circuit 2 through the second switch drive circuit 13.

[0051] The first signal coupler 1002 and the second signal coupler 1101 can be optocouplers, digital buffers, digital circuit triggers, etc. In this embodiment, optocouplers are preferred.

[0052] Furthermore, the first switching circuit 1 includes a first switch; the second switching circuit 2 includes a second switch. The main function of the switching circuit is realized by the switches. The first switch is a bipolar junction transistor (BJT), a field-effect transistor (FET), or an insulated-gate bipolar transistor (IGBT); the second switch is a BJT, FET, or IGBT. Using these devices has the advantages of being noiseless and small in size.

[0053] In the above embodiment, the first freewheeling circuit 3 includes: a first energy conversion device 301 and a first diode 302; the second freewheeling circuit 4 includes: a second energy conversion device 401 and a second diode 402; the positive terminal of the brake power supply 200 is connected to the negative terminal of the brake power supply 200 in sequence through the second switching circuit 2, the reverse-conducting first diode 302, the first energy conversion device 301, and the first switching circuit 1; the positive terminal of the brake power supply 200 is connected to the negative terminal of the brake power supply 200 in sequence through the reverse-conducting second diode 402, the second energy conversion device 401, and the first switching circuit 1.

[0054] The first energy conversion device 301 includes a transformer, and the second energy conversion device 401 includes a transformer.

[0055] like Figure 1 As shown, the second power supply 7 of the first switching circuit includes a first voltage shaping circuit 701, and the second power supply 8 of the second switching circuit includes a second voltage shaping circuit 801; the first energy conversion device 301 is connected to the first switching drive power supply circuit 10 through the first voltage shaping circuit 701; and the second energy conversion device 401 is connected to the second switching drive power supply circuit 11 through the second voltage shaping circuit 801.

[0056] like Figures 3-5As shown, the first switch drive power supply circuit 10 includes: a first normally open contact of relay 1001, a first normally closed contact of relay 1001, a first signal coupler 1002, and a first energy storage element 1003. The second switch drive power supply circuit 11 includes: a second normally open contact of relay 1001, a second normally closed contact of relay 1001, a second signal coupler 1101, and a second energy storage element 1102. The two ends of the coil of relay 1001 are respectively connected to a safety circuit status signal 9 and a relay drive signal 700. The safety circuit status signal 9 is connected to the first end of the first signal coupler 1002, and the second end of the first signal coupler 1002 is connected to the first switch drive signal 500. The first power supply 5 of the first switch circuit is connected to the fourth end of the first signal coupler 1002 through the first normally closed contact of relay 1001, the first energy storage element 1003, and the first normally open contact of relay 1001. The second power supply 7 of the first switch circuit is connected to the fourth end of the first signal coupler 1002 through relay 1001. The first normally open contact of 001 is connected to the fourth terminal of the first signal coupler 1002. The third terminal of the first signal coupler 1002 is connected to the first switch circuit 1 through the first switch drive circuit 12. The safety circuit status signal 9 is connected to the first terminal of the second signal coupler 1101. The second terminal of the second signal coupler 1101 is connected to the second switch drive signal 600. The first power supply 6 of the second switch circuit is connected to the fourth terminal of the second signal coupler 1101 through the second normally closed contact of the relay 1001, the second energy storage element 1102, and the second normally open contact of the relay 1001. The second power supply 8 of the second switch circuit is connected to the fourth terminal of the second signal coupler 1101 through the second normally open contact of the relay 1001. The third terminal of the second signal coupler 1101 is connected to the second switch circuit 2 through the second switch drive circuit 13. The first switch drive signal 500, the second switch drive signal 600, and the relay drive signal 700 are all issued by the elevator control system.

[0057] The first energy storage element 1003 and the second energy storage element 1102 can be capacitors, batteries, etc., and in this embodiment, capacitors are preferred.

[0058] Furthermore, this embodiment also includes a voltage converter 14. When the safety circuit 400 is connected, the voltage converter 14 converts the safety circuit power supply 300 into a first power supply 5 for the first switching circuit and a first power supply 6 for the second switching circuit. When the safety circuit 400 is not connected, there is no voltage output from the first power supply 5 for the first switching circuit and the first power supply 6 for the second switching circuit. If the safety circuit power supply 300 is an AC voltage source, the voltage converter 14 preferably uses an isolation transformer and a shaping circuit to output power with the required electrical characteristics for the subsequent stage. If the safety circuit power supply 300 is a DC voltage source, the voltage converter 14 preferably uses a DC / DC switching power supply composed of an isolation transformer.

[0059] like Figure 6 As shown, the timing of the second switch 2 being turned off can be arbitrarily set within the toff time of the first switch 1.

[0060] The safety circuit in this embodiment is controlled by the following control method, including the following steps:

[0061] When the elevator is not running, the first switch drive power circuit 10 and the second switch drive power circuit 11 are disconnected, so that the first switch circuit 1 and the second switch circuit 2 are de-energized, the electromagnetic brake coil 100 is de-energized, and the brake is closed. At this time, the elevator control system cuts off the relay drive signal 700, so that the coil of the relay 1001 is not energized, so that the normally open contact of the relay 1001 is in the normally open state, the first switch drive power circuit 10 and the second switch drive power circuit 11 are not conducting, and thus the first switch circuit 1 and the second switch circuit 2 are de-energized.

[0062] When the elevator starts, after the safety circuit 400 is activated, at least after a set delay time, the first switch drive power supply circuit 10 and the second switch drive power supply circuit 11 are activated, so that the first switch circuit 1 and the second switch circuit 2 are energized, the electromagnetic brake coil 100 is energized, and the brake is opened. Specifically, the relay drive signal 700 inputs a low level to the coil of the relay 1001, so that the coil of the relay 1001 is energized, the first switch drive power supply circuit 10 and the second switch drive power supply circuit 11 are turned on, and then the first switch circuit 1 and the second switch circuit 2 are energized. The purpose of the set delay time is to allow the first energy storage element 1003 and the second energy storage element 1102 to obtain sufficient charge from the voltage converter 14.

[0063] When any component fails, causing the first switching circuit 1 to remain open or closed, the second power supply 8 of the second switching circuit loses power, causing the second switching circuit 2 to remain open, the electromagnetic braking coil 100 loses power, and the brake closes.

[0064] When any component malfunctions and causes the second switch circuit 2 to remain open or closed, the second power supply 7 of the first switch circuit loses power, causing the first switch circuit 1 to remain open, and the electromagnetic brake coil 100 loses power and the brake closes.

[0065] The following is a detailed explanation of this embodiment, with reference to the specific implementation process:

[0066] 1. The brake power supply 200 is controlled by the first switch and the second switch to supply power to the electromagnetic brake coil 100. If either the first switch or the second switch is kept open, the connection between the brake power supply 200 and the electromagnetic brake coil 100 can be cut off, thereby cutting off the power supply to the electromagnetic brake coil 100.

[0067] 2. When the brake is released, the first and second switches perform chopping operations. By controlling the duty cycle of the first and second switches, the current of the electromagnetic brake coil can be controlled. During the chopping operation:

[0068] a. When the first switch is off and the second switch is on, the electromagnetic braking coil 100 continues to flow through the second diode 402. At this time, the second energy conversion device 401 is energized. Its primary coil is connected in series with the second diode 402, and the secondary coil outputs electrical power, which together with the second voltage shaping circuit 801 forms the second power supply 8 of the second switching circuit.

[0069] b. When the second switch is turned off, the electromagnetic braking coil 100 continues to flow through the first diode 302 and the resistor. At this time, the first energy conversion device 301 is energized. Its primary coil is connected in series with the first diode 302 and the resistor R, and the secondary coil outputs electrical power, which together with the first voltage shaping circuit 701 forms the first switch second power supply circuit 7.

[0070] 3. When the safety circuit 400 is disconnected, the voltage converter 14 is de-energized, and the first power supply 5 of the first switching circuit and the first power supply 6 of the second switching circuit are disconnected; when the safety circuit 400 is connected, the voltage converter 14 is energized, and the safety circuit power supply 300 is converted into the first power supply 5 of the first switching circuit and the first power supply 6 of the second switching circuit.

[0071] 4. When safety circuit 400 is connected, the voltage value of safety circuit status signal 9 is equal to the voltage value of safety circuit power supply 300; when safety circuit 400 is disconnected, the voltage value of safety circuit status signal 9 is 0.

[0072] 5. The power supply for the coil of relay 1001 is provided by the safety circuit status signal 9. When the relay drive signal 700 is cut off, the coil of relay 1001 is de-energized; when the relay drive signal 700 outputs a low level, the coil of relay 1001 is energized.

[0073] 6. When safety circuit 400 is activated:

[0074] a. When the coil of relay 1001 is de-energized, the first normally open contact and the second normally open contact of relay 1001 open, and the first normally closed contact and the second normally closed contact of relay 1001 close. At this time, the energy of the first power supply 5 of the first switching circuit is stored in the first energy storage element 1003, and the energy of the first power supply 6 of the second switching circuit is stored in the second energy storage element 1102.

[0075] b. When the coil of relay 1001 is energized, the first normally open contact and the second normally open contact of relay 1001 close, and the first normally closed contact and the second normally closed contact of relay 1001 open. The first switch drive signal 500 triggers the first signal coupler 1002 to conduct, and the first energy storage element 1003 and the second power supply 7 of the first switch circuit supply power to the first switch drive circuit 12, thereby turning on the first switch element. When the first switch drive signal 500 does not trigger the first signal coupler 1002 to conduct, the first switch is turned off. The second switch drive signal 600 triggers the second signal coupler 1101 to conduct, and the second energy storage element 1102 and the second power supply 8 of the second switch circuit supply power to the second switch drive circuit 13, thereby turning on the second switch element. When the second switch drive signal 600 does not trigger the first signal coupler 1002 to conduct, the second switch element is turned off.

[0076] 7. Brake opening sequence and control method when safety circuit 400 is connected:

[0077] a. When the safety circuit 400 is connected, the voltage converter 14 is energized and outputs the first power supply 5 of the first switching circuit and the first power supply 6 of the second switching circuit. The energy of the first power supply 5 of the first switching circuit is stored in the first energy storage element 1003, and the energy of the first power supply 6 of the second switching circuit is stored in the second energy storage element 1102.

[0078] b. The relay 1001 drive signal drives the coil of relay 1001 to be energized, causing the first normally open contact and the second normally open contact of relay 1001 to close, thereby energizing the secondary side of the first signal coupler 1002 and the second signal coupler 1101.

[0079] c. The first switch drive signal 500 and the second switch drive signal 600 output chopper drive signals to control the first switch and the second switch to perform chopper operation.

[0080] d. The chopping operation of the first switch energizes the primary coil of the second energy conversion device 401, and the second energy conversion device 401 outputs the second power supply 8 of the second switching circuit to the secondary side of the second signal coupler 1101 to maintain the power supply of the second switch; the chopping operation of the second switch energizes the primary coil of the first energy conversion device 301, and the first energy conversion device 301 outputs the second power supply 7 of the first switching circuit to the secondary side of the first signal coupler 1002 to maintain the power supply of the first switch;

[0081] 8. The operation of this safety circuit when safety circuit 400 is disconnected during the brake release process:

[0082] When the safety circuit 400 is disconnected, the safety circuit status signal 9 has no voltage output, causing the primary side of the first signal coupler 1002 and the second signal coupler 1101 to lose power. The first switch and the second switch lose their drive and turn off, thereby cutting off the power supply to the electromagnetic brake coil 100.

[0083] Example 2

[0084] This embodiment provides another safety circuit, which differs from Embodiment 1 in that, as Figure 7 and Figure 8 As shown, the first switch drive power supply circuit 10 includes: a first normally open contact of relay 1001, a first normally closed contact of relay 1001, a first signal coupler 1002, and a first energy storage element 1003. The second switch drive power supply circuit 11 includes: a second normally open contact of relay 1001, a second normally closed contact of relay 1001, a second signal coupler 1101, and a second energy storage element 1102. The two ends of the coil of relay 1001 are respectively connected to a safety circuit status signal 9 and a relay drive signal 700. The safety circuit status signal 9 is connected to the first end of the first signal coupler 1002, and the second end of the first signal coupler 1002 is connected to the first switch drive signal 500. The first power supply 5 of the first switch circuit is connected to the first signal coupler 1002 through the first normally closed contact of relay 1001 and the first energy storage element 1003. The fourth terminal is connected to the fourth terminal of the first signal coupler 1002 via the first normally open contact of the relay 1001. The third terminal of the first signal coupler 1002 is connected to the first switch circuit 1 via the first switch drive circuit 12. The safety circuit status signal 9 is connected to the first terminal of the second signal coupler 1101. The second terminal of the second signal coupler 1101 is connected to the second switch drive signal 600. The first power supply 6 of the second switch circuit is connected to the fourth terminal of the second signal coupler 1101 via the second normally closed contact of the relay 1001 and the second energy storage element 1102. The second power supply 8 of the second switch circuit is connected to the fourth terminal of the second signal coupler 1101 via the second normally open contact of the relay 1001. The third terminal of the second signal coupler 1101 is connected to the second switch circuit 2 via the second switch drive circuit 13.

[0085] It should be noted that the positions of the normally closed and normally open contacts of relay 1001 can be adjusted flexibly. The adjustment principle is as follows:

[0086] a. Before the coil of relay 1001 is energized, the secondary side of the first signal coupler 1002 and the second signal coupler 1101 cannot be powered.

[0087] b. After the coil of relay 1001 is energized, the secondary side of the first signal coupler 1002 can only be powered by the second power supply 7 of the first switching circuit, and the secondary side of the second signal coupler 1101 can only be powered by the second power supply 8 of the second switching circuit. The first power supply 5 of the first switching circuit cannot supply power to the secondary side of the first energy storage element 1003 or the first signal coupler 1002, and the first power supply 6 of the second switching circuit cannot supply power to the secondary side of the second energy storage element 1102 or the second signal coupler 1101.

[0088] The safety circuit in this embodiment is controlled by the following control method, including the following steps:

[0089] When the elevator is not running, the first switch drive power circuit 10 and the second switch drive power circuit 11 are disconnected, so that the first switch circuit 1 and the second switch circuit 2 are de-energized, the electromagnetic brake coil 100 is de-energized, and the brake is closed. At this time, the relay drive signal 700 inputs a high level to the coil of the relay 1001, so that the coil of the relay 1001 is not energized, so that the normally open contact of the relay 1001 is in the normally open state, the first switch drive power circuit 10 and the second switch drive power circuit 11 are not conducting, and thus the first switch circuit 1 and the second switch circuit 2 are de-energized.

[0090] When the elevator starts, the safety circuit 400 is activated. After a set delay time, the first switch drive power circuit 10 and the second switch drive power circuit 11 are activated, so that the first switch circuit 1 and the second switch circuit 2 are energized, the electromagnetic brake coil 100 is energized, and the brake is opened. Specifically, the relay 1001 drive signal inputs a low level to the coil of the relay 1001, so that the coil of the relay 1001 is energized, the first switch drive power circuit 10 and the second switch drive power circuit are turned on, and thus the first switch circuit 1 and the second switch circuit 2 are energized. The purpose of setting the delay time is to allow the first energy storage element 1003 and the second energy storage element 1102 to obtain sufficient charge from the voltage converter 14.

[0091] When any component fails, causing the first switching circuit 1 to remain open or closed, the second power supply 8 of the second switching circuit loses power, causing the second switching circuit 2 to remain open, the electromagnetic braking coil 100 loses power, and the brake closes.

[0092] When any component malfunctions and causes the second switch circuit 2 to remain open or closed, the second power supply 7 of the first switch circuit loses power, causing the first switch circuit 1 to remain open, and the electromagnetic brake coil 100 loses power and the brake closes.

[0093] For the specific real-time process of this embodiment, please refer to Embodiment 1, which will not be repeated here.

[0094] In summary, the present invention has the following beneficial effects:

[0095] The first and second switches of the present invention are bipolar junction transistors, field-effect transistors or insulated gate bipolar transistors. Compared with traditional contactors, they have the advantages of being noiseless and small in size, and do not contain programmable devices, which makes the whole circuit simple in structure, low in failure rate and low in cost.

[0096] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A safety circuit, characterized in that, include: First switching circuit, second switching circuit, first freewheeling circuit, second freewheeling circuit, first power supply for first switching circuit, first power supply for second switching circuit, second power supply for first switching circuit, second power supply for second switching circuit, safety circuit status signal, first switch drive power supply circuit, second switch drive power supply circuit, first switch drive circuit and second switch drive circuit. The first terminal of the brake power supply is connected to the second terminal of the brake power supply through the second switching circuit, the electromagnetic brake coil, and the first switching circuit. The first freewheeling circuit is connected in parallel across the two ends of the electromagnetic brake coil, and the first end of the brake power supply is connected to the second end of the brake power supply through the second freewheeling circuit and the first switching circuit. The second power supply for the first switching circuit is connected to the first switching drive power supply circuit and the first freewheeling circuit. The second power supply of the second switching circuit is connected to the second switching drive power supply circuit and the second freewheeling circuit; The safety circuit power supply is connected to the input terminal of the first switch drive power supply circuit through the safety circuit and the first power supply of the first switch circuit. The safety circuit power supply is connected to the input terminal of the second switch drive power supply circuit through the safety circuit and the first power supply of the second switch circuit; The safety circuit power supply is connected to the safety circuit status signal through the safety circuit, and the safety circuit status signal drives the first switch driving power supply circuit and the second switch driving power supply circuit through coupling; the output terminal of the first switch driving power supply circuit is connected to the first switch circuit through the first switch driving circuit. The output terminal of the second switch drive power supply circuit is connected to the second switch circuit through the second switch drive circuit; When the elevator is not running, the first switch drive power circuit and the second switch drive power circuit are disconnected to de-energize the first switch circuit and the second switch circuit, thereby de-energizing the electromagnetic brake coil and closing the brake. When the elevator starts, after the safety circuit is connected, at least after a set delay time, the first switch drive power circuit and the second switch drive power circuit are connected to energize the first switch circuit and the second switch circuit, and the electromagnetic brake coil is energized so that the brake is opened. When any component fails, causing the first switching circuit to remain on or off, the second power supply to the second switching circuit loses power, causing the second switching circuit to remain off, the electromagnetic braking coil loses power, and the brake closes. When any component fails, causing the second switching circuit to remain on or off, the second power supply to the first switching circuit loses power, keeping the first switching circuit off, and the electromagnetic braking coil loses power, causing the brake to close.

2. The safety circuit according to claim 1, characterized in that, The first switching circuit includes a first switch; the second switching circuit includes a second switch.

3. The safety circuit according to claim 2, characterized in that, The first switch is a bipolar junction transistor, a field-effect transistor, or an insulated-gate bipolar transistor; the second switch is a bipolar junction transistor, a field-effect transistor, or an insulated-gate bipolar transistor.

4. The safety circuit according to claim 1, characterized in that, The first freewheeling circuit includes: a first energy conversion device and a first diode; the second freewheeling circuit includes: a second energy conversion device and a second diode; The first terminal of the brake power supply is connected to the second terminal of the brake power supply in sequence through the second switching circuit, the first diode in reverse conduction, the first energy conversion device, and the first switching circuit. The first terminal of the brake power supply is connected to the second terminal of the brake power supply in sequence through the second diode (which is conducting in reverse), the second energy conversion device, and the first switching circuit.

5. The safety circuit according to claim 4, characterized in that, The first energy conversion device includes a transformer, and the second energy conversion device includes a transformer.

6. The safety circuit according to claim 4, characterized in that, The second power supply for the first switching circuit includes a first voltage shaping circuit, and the second power supply for the second switching circuit includes a second voltage shaping circuit. The first energy conversion device is connected to the first switch drive power supply circuit through the first voltage shaping circuit; The second energy conversion device is connected to the second switching drive power supply circuit through the second voltage shaping circuit.

7. The safety circuit according to claim 1, characterized in that, The first switch drive power supply circuit includes: a first normally open contact of the relay, a first normally closed contact of the relay, a first signal coupler, and a first energy storage element; the second switch drive power supply circuit includes: a second normally open contact of the relay, a second normally closed contact of the relay, a second signal coupler, and a second energy storage element. The two ends of the relay coil are respectively connected to the safety circuit status signal and the relay drive signal; The safety circuit status signal is connected to the first terminal of the first signal coupler, the second terminal of the first signal coupler is connected to the first switch drive signal, the first power supply of the first switch circuit is connected to the fourth terminal of the first signal coupler through the first normally closed contact of the relay, the first energy storage element, and the first normally open contact of the relay, the second power supply of the first switch circuit is connected to the fourth terminal of the first signal coupler through the first normally open contact of the relay, and the third terminal of the first signal coupler is connected to the first switch circuit through the first switch drive circuit. The safety circuit status signal is connected to the first terminal of the second signal coupler, the second terminal of the second signal coupler is connected to the second switch drive signal, the first power supply of the second switch circuit is connected to the fourth terminal of the second signal coupler through the second normally closed contact of the relay, the second energy storage element, and the second normally open contact of the relay, the second power supply of the second switch circuit is connected to the fourth terminal of the second signal coupler through the second normally open contact of the relay, and the third terminal of the second signal coupler is connected to the second switch circuit through the second switch drive circuit.

8. The safety circuit according to claim 1, characterized in that, The first switch drive power supply circuit includes: a relay, a second normally open contact of the relay, a second normally closed contact of the relay, a first signal coupler, and a first energy storage element; the second switch drive power supply circuit includes: a second normally open contact of the relay, a second normally closed contact of the relay, a second signal coupler, and a second energy storage element. The two ends of the relay coil are respectively connected to the safety circuit status signal and the relay drive signal; The safety circuit status signal is connected to the first terminal of the first signal coupler, the second terminal of the first signal coupler is connected to the first switch drive signal, the first power supply of the first switch circuit is connected to the fourth terminal of the first signal coupler through the first normally closed contact of the relay and the first energy storage element, the second power supply of the first switch circuit is connected to the fourth terminal of the first signal coupler through the first normally open contact of the relay, and the third terminal of the first signal coupler is connected to the first switch circuit through the first switch drive circuit. The safety circuit status signal is connected to the first end of the second signal coupler, the second end of the second signal coupler is connected to the second switch drive signal, the first power supply of the second switch circuit is connected to the fourth end of the second signal coupler through the second normally closed contact of the relay and the second energy storage element, the second power supply of the second switch circuit is connected to the fourth end of the second signal coupler through the second normally open contact of the relay, and the third end of the second signal coupler is connected to the second switch circuit through the second switch drive circuit.

9. The safety circuit according to claim 1, characterized in that, Also includes: A voltage converter, the input of which is connected to the safety circuit; the output of the voltage converter outputs the first power supply of the first switching circuit, and the output of the voltage converter outputs the first power supply of the second switching circuit.

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