Switching power supply delay protection circuit and magnetic suspension air conditioning system

Abstract

The utility model discloses a switching power supply delay protection circuit and a magnetic suspension air conditioning system, which are arranged in a compressor control system DCDC power supply with a magnetic suspension bearing, and are characterized by comprising at least two front-end diodes, the negative electrode of each diode is respectively connected with the output end of a corresponding comparison circuit; a TRIG pin of the timing chip U1 is connected with the joint of the positive electrode of each diode and the pull-up resistor R1, an OUT pin of the timing chip U1 is connected with a third resistor R3 and a first transistor T1, and the first transistor T1 is connected with a capacitor E1 in parallel; a CONT pin is connected with a third capacitor C3; a VCC pin is connected in series with a first capacitor C1 through a second resistor R2; the joint of the Zener diode ZD1 and the fourth resistor R4 is connected with an interlock circuit and a DCDC control chip through another diode D4 and a fifth resistor R5. The speed of the magnetic suspension bearing of the compressor in the magnetic suspension air-conditioning system is safely reduced; and after the magnetic suspension bearing is safely decelerated, the shaft is dropped, so that the service life and reliability of the magnetic suspension compressor are improved.

Description

Technical Field

[0001] The present application relates to the field of magnetic levitation air - conditioning systems, and more particularly, to a delay protection circuit for a switching power supply in a magnetic levitation air - conditioning system. Background Art

[0002] Magnetic levitation centrifugal compressors are widely used in air - conditioning systems due to their high operating efficiency, low noise, low maintenance cost, light body, and small starting current. As Figure 1 shown, in the electrical system of a magnetic levitation air - conditioner, the external three - phase power is connected to the input end of the frequency conversion cabinet. The output end of the frequency conversion cabinet is connected to the permanent magnet synchronous motor in the magnetic levitation compressor. The DC bus in the frequency conversion cabinet is connected to the input end of the DCDC power supply. The output end of the DCDC power supply is connected to the input end of the MBC controller. The output end of the MBC controller is connected to the magnetic levitation bearing to control its suspension. The PLC control cabinet is connected to the above - mentioned various execution components, detects the operation and fault status of each component, and sends control instructions to the frequency conversion cabinet to control the permanent magnet synchronous motor.

[0003] To ensure the life and reliability of the magnetic levitation compressor, under various operating conditions, it is necessary to ensure that the bearing safely decelerates before stopping the suspension and dropping the shaft.

[0004] During the operation of the unit, the magnetic levitation bearing rotates at a high speed. When the existing DCDC power supply has faults such as over - temperature, over - current, and over - voltage inside, the power supply will immediately output a fault signal and at the same time turn off the output. The MBC controller stops controlling the suspension of the magnetic levitation bearing due to power failure. At this time, the PLC control cabinet detects the power - supply fault signal and has no time to send a shutdown instruction to the frequency conversion cabinet to decelerate the bearing, resulting in the magnetic levitation bearing dropping the shaft at a high - speed state, reducing the life and reliability of the magnetic levitation compressor, and even directly damaging the bearing. Summary of the Utility Model

[0005] The technical problem to be solved by the present application is to provide a delay protection circuit for a switching power supply and a magnetic levitation air - conditioning system, so that the magnetic levitation bearing of the compressor in the magnetic levitation air - conditioning system can safely decelerate; and the shaft drops after the magnetic levitation bearing safely decelerates, improving the life and reliability of the magnetic levitation compressor.

[0006] The present application adopts the following technical solutions to solve the above - mentioned technical problems:

[0007] A delay protection circuit for a switching power supply is provided in the DCDC power supply of a compressor control system with a magnetic levitation bearing, and is characterized by including:

[0008] At least two front - end diodes, the positive poles of each front - end diode are connected to the same pull - up resistor or the first resistor R1, and the negative poles of each diode are respectively connected to the output ends of the corresponding comparison circuits;

[0009] The timing chip U1, the TRIG pin is connected to the connection point of the positive poles of each diode and the pull-up resistor R1, the OUT pin is connected to the third resistor R3 and the first transistor T1, and the first transistor T1 is in parallel with the capacitor E1; the CONT pin is connected to the third capacitor C3; the VCC pin is connected in series with the first capacitor C1 through the second resistor R2;

[0010] The voltage stabilizing diode ZD1, after being connected in series with the fourth resistor R4, is in parallel with the capacitor E1, and at the connection point of the voltage stabilizing diode ZD1 and the fourth resistor R4, it is connected to the interlock circuit through another diode D4 and the fifth resistor R5.

[0011] In the above technical solution, three front-end diodes are provided.

[0012] In the above technical solution, the interlock circuit is arranged between the delay protection circuit and the DCDC control chip U2.

[0013] In the above technical solution, the Comp pin of the DCDC control chip U2 is connected to the output end of the interlock circuit.

[0014] In the above technical solution, in the interlock circuit, a transistor and a resistor are connected in series, and are in parallel with another circuit in which a resistor and a transistor are connected in series; and the B pins of the two transistors are both connected to the resistor of the other parallel circuit.

[0015] In the above technical solution, when over-temperature, over-current, and over-voltage occur inside the power supply, the output signals of the corresponding comparison circuits are set to low level; after passing through the first resistor R1 and the front-end diodes, the TRIG pin of U1 is pulled low, the OUT pin becomes high level, the DISCH pin is open-drain, and the VCC charges the first capacitor C1 through the second resistor R2.

[0016] In the above technical solution, when the charging voltage exceeds two-thirds of the VCC, the OUT pin becomes low level, the DISCH pin is open-drain low level, and the first capacitor C1 quickly discharges through the DISCH pin of the timing chip U1.

[0017] In the above technical solution, the timing chip U1 is a 555 timing chip.

[0018] In the above technical solution, the maintaining time of the high level of the OUT pin of the timing chip U1 is set to (t3 - t1) = 1.1 * R2 * C1. And it is set that during this period, the OUT pin charges the capacitor E1 through the current limiting of the third resistor R3, and when the voltage rises to a certain value ( Vzd+ Vth )), the voltage stabilizing diode ZD1 conducts, and when the voltage across the fourth resistor R4 reaches Vth ), it triggers the operation of the backend interlock circuit, pulls down the Comp pin of the DCDC control chip to turn off the output of the DCDC power supply.

[0019] Among them, the threshold voltage triggered by the interlock circuit is Vth, and the voltage across the voltage-regulator diode ZD1 after conduction is Vzd. Only when the charging voltage of the capacitor E1 reaches (Vzd + Vth) can the voltage across the resistor R4 reach Vth, thereby triggering the operation of the interlock circuit.

[0020] In the above technical solution, the voltage of the OUT pin Vout charges the capacitor E1 through the third resistor R3 until the voltage reaches ( Vzd+ Vth ), or the time for the delay protection circuit to delay the trigger signal from time t1 to time t2 and then trigger the power-off is:

[0021] t = t2 - t1 = -R3 × E1 × .

[0022] Among them, is a negative number. Two negatives make a positive, and the obtained time t is a positive number.

[0023] Furthermore, the present utility model protects a magnetic levitation air-conditioning system adopting the above delay protection circuit.

[0024] Compared with the prior art, the beneficial effects of the present utility model are:

[0025] A delay protection circuit is designed inside the DCDC power supply of the magnetic levitation air-conditioning system, so that when the DCDC power supply has faults such as overheating, overcurrent, and overvoltage, the power supply immediately outputs a fault signal, and after a delay period, it triggers the protection to turn off the power supply output. After the PLC control cabinet detects the DCDC power supply fault, it has time to send a shutdown instruction to the frequency conversion cabinet, so that the magnetic levitation bearing can safely decelerate and then power off and drop the shaft, improving the service life and reliability of the magnetic levitation compressor. Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, so they should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0027] Figure 1 It is the electrical structure diagram of the compressor control of the existing magnetic levitation air-conditioning system.

[0028] Figure 2 It is the compressor control structure diagram of the improved magnetic levitation air-conditioning system in the embodiment of the present application.

[0029] Figure 3 It is the structure diagram of the delay protection circuit in the embodiment of the present application.

[0030] Figure 4 This is the timing diagram of the delay protection circuit of the present application. Specific embodiments

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Components of the embodiments of the present application generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations.

[0032] Therefore, the detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application claimed, but is merely representative of selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0033] It should be noted that like reference numerals and letters denote like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

[0034] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of this application is customarily placed. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present application. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and should not be construed as indicating or implying relative importance.

[0035] In addition, the terms "horizontal", "vertical", "overhanging", etc. do not mean that the components are required to be absolutely horizontal or overhanging, but may be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but may be slightly inclined.

[0036] In the description of the present application, it should also be noted that unless otherwise clearly specified and defined, the terms "arranged", "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0037] In the present application, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over", and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath", and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0038] The features and performance of the present application will be further described in detail below in conjunction with embodiments.

[0039] Embodiment 1

[0040] This embodiment aims at the technical defects of the existing solutions, such as Figures 2 to 4 As shown, inside the DCDC power supply of the compressor control system in a magnetic levitation air-conditioning system, a switching power supply delay protection circuit is designed to form a new magnetic levitation air-conditioning system.

[0041] When faults such as overheating, overcurrent, and overvoltage occur inside the DCDC power supply, the power supply immediately outputs a fault signal and triggers the protection to cut off the power supply output after a delay. During this delay period, the power supply maintains the output to keep the magnetic levitation bearing suspended. After the PLC control cabinet detects the power supply fault signal, it issues a shutdown command to the frequency conversion cabinet within the delay time to safely decelerate the magnetic levitation bearing. After the delay time ends, the DCDC power supply is powered off, and the magnetic levitation bearing safely decelerates and then drops the shaft, improving the life and reliability of the magnetic levitation compressor.

[0042] The delay protection circuit, as Figure 3 shown, includes diodes D1, D2, D3, resistors R1, R2, R3, R4, a 555 timer chip U1, capacitors C1, C2, C3, a capacitor E1, and a zener diode ZD1.

[0043] Among them, the cathodes of diodes D1, D2, D3 are respectively connected to the output terminals of the comparison circuit, as Figure 4As shown, when over-temperature, over-current, or over-voltage occurs inside the power supply, the output signal of the corresponding comparison circuit is at a low level. After passing through the pull-up resistor R1 and diodes D1, D2, and D3, the TRIG pin of U1 is pulled low, the OUT pin becomes high, the DISCH pin is open-drain, and VCC charges C1 through resistor R2. When the charging voltage exceeds (2 / 3)VCC, the OUT pin becomes low, the DISCH pin is at open-drain low level, and capacitor C1 discharges quickly through the DISCH pin.

[0044] Therefore, the duration for which the OUT pin remains high (t3 - t1) = 1.1 × R2 × C1. During this time, the OUT pin charges capacitor E1 with current limited by resistor R3. When the voltage rises to a certain value (Vzd + Vth), zener diode ZD1 conducts. When the voltage across resistor R4 reaches Vth, it triggers the operation of the backend interlock circuit, pulling the Comp pin of the DCDC control chip low to turn off the output of the DCDC power supply. (t2 - t1) is the time for the voltage Vout of the OUT pin to charge capacitor E1 to the voltage (Vzd + Vth) through resistor R3.

[0045] The delay protection circuit delays the trigger signal from time t1 to time t2 before triggering the power-off, that is, the delay time t = t2 - t1 = -R3 × E1 × .

[0046] Embodiment 2

[0047] As Figures 3-4 shown, a delay protection circuit implemented according to this embodiment includes diodes D1, D2, D3, resistors R1, R2, R3, R4, 555 timer chip U1, capacitors C1, C2, C3, capacitor E1, and zener diode ZD1.

[0048] Among them, the cathodes of diodes D1, D2, and D3 are respectively connected to the output terminals of the comparison circuit. As Figure 4 shown, when over-temperature, over-current, or over-voltage occurs inside the power supply, the output signal of the corresponding comparison circuit is at a low level. After passing through the pull-up resistor R1 and diodes D1, D2, and D3, the TRIG pin of U1 is pulled low, the OUT pin becomes high, the DISCH pin is open-drain, and VCC charges C1 through resistor R2. When the charging voltage exceeds (2 / 3)VCC, the OUT pin becomes low, the DISCH pin is at open-drain low level, and capacitor C1 discharges quickly through the DISCH pin.

[0049] Therefore, the duration for which the OUT pin maintains a high level (t3 - t1) = 1.1 × R2 × C1. During this time, the OUT pin charges the capacitor E1 through the current-limiting resistor R3. When the voltage rises to a certain value (Vzd + Vth), the zener diode ZD1 conducts. When the voltage across the resistor R4 reaches Vth, it triggers the operation of the backend interlock circuit, pulling down the Comp pin of the DCDC control chip to turn off the DCDC power output. (t2 - t1) is the time it takes for the voltage Vout of the OUT pin to charge the capacitor E1 to the voltage (Vzd + Vth) through the resistor R3.

[0050] The delay protection circuit delays the trigger signal from time t1 to time t2 before triggering the power-off, that is, the delay time t = t2 - t1 = -R3 × E1 × .

[0051] Based on the change in Embodiment 1, for example, the number of front-end diodes is changed, or the interlock circuit is changed to a simple form. Those skilled in the art can adjust according to requirements, which does not constitute a limitation to this embodiment.

[0052] The embodiments described above are some, but not all, of the embodiments of the present application. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application claimed, but merely represents the selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

Claims

1. A switching power supply delay protection circuit, arranged in a DCDC power supply of a compressor control system with a magnetic bearing, characterized in that include: At least two front-end diodes, each of which has an anode connected to the same pull-up resistor or the first resistor R1, and a cathode connected to an output terminal of a corresponding comparison circuit; Timing chip U1, TRIG pin is connected to the connection point between the anode of each diode and the pull-up resistor R1, OUT pin is connected to the third resistor R3 and the first transistor T1, the first transistor T1 is connected in parallel with the capacitor E1; CONT pin is connected to the third capacitor C3; VCC pin is connected in series with the first capacitor C1 through the second resistor R2; The voltage zener diode ZD1 and the fourth resistor R4 are connected in series and then connected in parallel with the capacitor E1. The connection between the voltage zener diode ZD1 and the fourth resistor R4 is connected to an interlocking circuit through another diode D4 and a fifth resistor R5, and is connected to a DCDC control chip through the interlocking circuit.

2. The switching power supply delay protection circuit according to claim 1 is characterized in that Three front-end diodes are provided.

3. The switching power supply delay protection circuit according to claim 1 is characterized in that The interlock circuit is arranged between the delay protection circuit and the DCDC control chip U2.

4. The switching power supply delay protection circuit according to claim 1, characterized in that The Comp pin of the DCDC control chip U2 is connected to the output end of the interlock circuit.

5. The switching power supply delay protection circuit according to claim 1, characterized in that In the interlocking circuit, a transistor and a resistor are connected in series and in parallel with another resistor and transistor series circuit; and the B pins of the two transistors are connected to the resistor of the other parallel circuit.

6. The switching power supply delay protection circuit according to claim 1, characterized in that When over-temperature, over-current or over-voltage occurs inside the power supply, the output signal of each corresponding comparison circuit is set to a low level; after passing through the first resistor R1 and the front-end diode, the TRIG pin of U1 is pulled low, the OUT pin becomes a high level, the DISCH pin is opened, and VCC charges the first capacitor C1 through the second resistor R2.

7. The switching power supply delay protection circuit according to claim 1, characterized in that When the charging voltage exceeds two-thirds of VCC, the OUT pin becomes a low level, the DISCH pin is an open-drain low level, and the first capacitor C1 is quickly discharged through the DISCH pin of the timing chip U1.

8. The switching power supply delay protection circuit according to claim 1, characterized in that The timing chip U1 is a 555 timing chip.

9. The switching power supply delay protection circuit according to claim 1, characterized in that The high level maintenance time of the OUT pin of the timing chip U1 is set to (t3-t1)=1.1×R2×C1; the OUT pin voltage Vout The capacitor E1 is charged to a set voltage through the third resistor R3 ( Vzd+Vth ) is: t=t2-t1=-R3×E1× 。 10. A magnetic levitation air conditioning system, characterized in that A time delay protection circuit as described in any one of claims 1 to 9 is adopted.

Images