Starting-up current surge suppression failure detection circuit for elevator power supply

Abstract

The utility model belongs to the technical field of elevator power supplies, and particularly discloses a starting current surge suppression failure detection circuit for an elevator power supply, which comprises a negative temperature resistor N1, a direct current constant current source A1, a direct current constant voltage source V1 and a hysteresis comparator U1, the negative temperature resistor N1 is arranged close to a current limiting circuit, the output end of the direct current constant current source A1 is electrically connected with one end of the negative temperature resistor N1, and the output end of the direct current constant current source V1 is electrically connected with the other end of the negative temperature resistor N1. The in-phase input end of the hysteresis comparator U1 is electrically connected to a line between the direct current constant current source A1 and the negative temperature resistor N1, and the inverted input end of the hysteresis comparator U1 is electrically connected with the direct current constant voltage source V1. According to the utility model, the failure detection circuit is designed, under the condition that a basic startup current surge suppression function is satisfied, a startup current surge suppression failure self-detection function is added, and when an electronic switch of the startup current surge suppression circuit fails, timely protective shutdown can be realized, and further expansion of faults is avoided.

Description

Technical Field

[0001] This utility model relates to the field of elevator power supply technology, and in particular to a start-up current surge suppression failure detection circuit for elevator power supplies. Background Technology

[0002] Because AC power supply primary rectifier circuits require large-value capacitors, a short-term large current is generated on the power supply side at the moment of power-on, commonly known as a startup current surge. In actual use of elevator control platforms, since one elevator control platform can often only control 4-5 floors, multiple elevator control platforms are installed simultaneously in high-rise buildings. Typically, 12-15 elevator control platforms need to be powered on simultaneously. At this time, the startup current surge will be very large, enough to trip the distribution box. To ensure the normal operation of the equipment, it is necessary to suppress the startup current surge.

[0003] like Figure 1 As shown, a typical elevator power supply with start-up current surge suppression includes a rectifier circuit, a current limiting circuit, an electronic switch, a working status judgment circuit, a filter circuit, and a voltage conversion circuit. One end of the rectifier circuit is electrically connected to the power input terminal. The other end of the rectifier circuit is electrically connected to the current limiting circuit and one end of the electronic switch. The other end of the current limiting circuit is electrically connected to the other end of the electronic switch and one end of the filter circuit. The other end of the filter circuit is electrically connected to one end of the voltage conversion circuit. The other end of the voltage conversion circuit is electrically connected to the output. The third terminal of the electronic switch is electrically connected to the working status judgment circuit. The other end of the working status judgment circuit is electrically connected to the third terminal of the voltage conversion circuit.

[0004] Figure 1 The surge suppression function of the elevator power supply shown lacks a self-diagnostic capability. If the electronic switch fails, the current-limiting circuit will operate continuously, significantly reducing power efficiency and wasting energy, which contradicts the principles of green energy conservation. Furthermore, prolonged operation of the current-limiting circuit will generate high temperatures, potentially causing a fire and posing a safety hazard.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this utility model, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0006] The purpose of this invention is to solve the technical problems existing in the background art. To this end, a power-on current surge suppression failure detection circuit for elevator power supplies is provided.

[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0008] A surge current suppression failure detection circuit for elevator power supply includes a negative temperature resistor N1, a DC constant current source A1, a DC constant voltage source V1, and a hysteresis comparator U1. The negative temperature resistor N1 is arranged close to the current limiting circuit. The output terminal of the DC constant current source A1 is electrically connected to one end of the negative temperature resistor N1, and the other end of the negative temperature resistor N1 is grounded. The non-inverting input terminal of the hysteresis comparator U1 is electrically connected to the line between the DC constant current source A1 and the negative temperature resistor N1, and the inverting input terminal of the hysteresis comparator U1 is electrically connected to the DC constant voltage source V1.

[0009] The following is a further defined technical solution of this utility model: the positive terminal of the DC constant voltage source V1 is electrically connected to the inverting input terminal of the hysteresis comparator U1, and the negative terminal of the DC constant voltage source V1 is grounded.

[0010] Compared with the prior art, the present invention has the following technical effects:

[0011] This invention incorporates a failure detection circuit, which, while fulfilling the basic function of suppressing power-on current surges, adds a self-test function for power-on current surge suppression failure. When the electronic switch of the power-on current surge suppression circuit fails, it can promptly and protectively shut down the device, preventing the fault from escalating further.

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a structural connection block diagram of an existing elevator power supply with start-up current surge suppression technology;

[0015] Figure 2 This is a structural connection block diagram of an elevator power supply with start-up current surge suppression failure detection function according to this utility model;

[0016] Figure 3 This is a circuit connection diagram of the failure detection circuit of this utility model;

[0017] Figure 4 This is a schematic diagram of the structure of the negative temperature resistor N1 arranged close to the current limiting circuit in this utility model. Detailed Implementation

[0018] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0019] like Figure 2-4 As shown, this embodiment provides a power supply start-up current surge suppression failure detection circuit (hereinafter referred to as failure detection circuit) for elevator power supply.

[0020] like Figure 2 As shown, the third terminal of the current limiting circuit is electrically connected to the failure detection circuit, and the third terminal of the failure detection circuit is electrically connected to the fourth terminal of the voltage conversion circuit.

[0021] The electronic switch is normally open. When the power input is first applied, the voltage is rectified by the rectifier circuit and then charged to the filter circuit through the current limiting circuit. When the output voltage of the filter circuit reaches the starting voltage of the voltage conversion circuit, the voltage conversion circuit starts and begins normal operation, supplying power through the power output. Once the operating status judgment circuit detects that the voltage conversion circuit has entered normal operating condition, it controls the electronic switch to turn on, bypassing the current limiting circuit, thus ensuring stable and efficient operation of the elevator power supply.

[0022] When the electronic switch fails and the bypass function cannot be performed, the current limiting circuit starts to operate. The failure detection circuit will continuously monitor the status of the current limiting circuit, and when a high risk is reached, it will send an alarm signal to the voltage conversion circuit, controlling the voltage conversion circuit to exit normal operation.

[0023] It should be noted that the control program or algorithm involved in the elevator power supply’s start-up current surge suppression process in this embodiment is not within the protection scope of this utility model, and is only used by those skilled in the art to understand the elevator power supply’s start-up current surge suppression.

[0024] like Figure 3 As shown, the failure detection circuit includes a negative temperature resistor N1, a DC constant current source A1, a DC constant voltage source V1, and a hysteresis comparator U1. The negative temperature resistor N1 is positioned close to the current limiting circuit. The output terminal of the DC constant current source A1 is electrically connected to one end of the negative temperature resistor N1, and the other end of the negative temperature resistor N1 is grounded. The non-inverting input terminal of the hysteresis comparator U1 is electrically connected to the line between the DC constant current source A1 and the negative temperature resistor N1. The inverting input terminal of the hysteresis comparator U1 is electrically connected to the DC constant voltage source V1. The positive terminal of the DC constant voltage source V1 is electrically connected to the inverting input terminal of the hysteresis comparator U1, and the negative terminal of the DC constant voltage source V1 is grounded.

[0025] like Figure 4 As shown, on the printed circuit board 3, the negative temperature resistor N1 is arranged close to the current limiting circuit and a low thermal resistance channel is formed by thermally conductive adhesive 2.

[0026] When the electronic switch is working normally, the current limiting circuit 1 only works for a very short time and is then bypassed by the electronic switch. There will be no high temperature rise, so the negative temperature resistor N1 will remain in a high resistance state. The DC constant current source A1 flows through the negative temperature resistor N1, and the two ends of the negative temperature resistor N1 are at a high voltage, which is input to the non-inverting input of the hysteresis comparator U1.

[0027] A DC constant voltage source V1 provides a reference voltage, which is connected to the inverting input of the hysteresis comparator U1. When the electronic switch fails, causing the current limiting circuit 1 to operate for an extended period, the temperature of the current limiting circuit 1 will continuously rise, while the resistance of the negative temperature resistor N1 will continuously decrease. Consequently, the voltage across the negative temperature resistor N1 will also continuously decrease. When the voltage at the non-inverting input of the hysteresis comparator U1 is lower than the voltage at the inverting input, the output of the hysteresis comparator U1 flips to a low level, controlling the subsequent voltage conversion circuit to stop operating.

[0028] At the same time, the risk tolerance can be set by adjusting the voltage of the DC constant voltage source V1.

[0029] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any way. Any person skilled in the art can make many possible variations and modifications to the technical solution of this utility model using the disclosed methods and techniques, or modify it into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of this utility model. Therefore, all equivalent changes made based on the shape, structure, and principle of this utility model without departing from its technical solution should be covered within the protection scope of this utility model.

Claims

1. A surge current suppression failure detection circuit for elevator power supplies, characterized in that, Including negative temperature resistance N1, DC constant current source A1, DC constant voltage source V1 and hysteresis comparator U1, the negative temperature resistance N1 is close to the current limiting circuit arrangement, the output end of the DC constant current source A1 is electrically connected with one end of negative temperature resistance N1, the other end of the negative temperature resistance N1 is grounded, the noninverting input end of the hysteresis comparator U1 is electrically connected on the line between DC constant current source A1 and negative temperature resistance N1, the inverting input end of the hysteresis comparator U1 is electrically connected DC constant voltage source V1.

2. A start-up current inrush suppression deactivation detection circuit for an elevator power supply as defined in claim 1, wherein, The positive electrode of the DC constant voltage source V1 is electrically connected with the inverting input end of the hysteresis comparator U1, and the negative electrode of the DC constant voltage source V1 is grounded.

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