CN217159264U

CN217159264U - Quick power-off power-on protection circuit

Info

Publication number: CN217159264U
Application number: CN202220662550.XU
Authority: CN
Inventors: 俞超辉
Original assignee: Guangzhou Tianjia Environmental Control Equipment Co ltd
Current assignee: Guangzhou Tianjia Environmental Control Equipment Co ltd
Priority date: 2022-03-25
Filing date: 2022-03-25
Publication date: 2022-08-09
Anticipated expiration: 2032-03-25

Abstract

The utility model relates to a fast power-off power-on protection circuit, which comprises an AC/DC module, a DC/AC module and a charging control circuit, wherein the AC/DC module is simultaneously connected with an AC input power supply and the DC/AC module; the charging control circuit is formed by connecting a relay and a current-limiting resistor in parallel and is connected in series with a bus between the AC/DC module and the DC/AC module; the DC/AC module is also connected with a resistance component I in parallel; the resistance component I comprises resistors R1 and R2 which are connected in series, and the connection position of the resistors is connected with the input end I of the controller MCU; the output end of the MCU is connected with the relay; the device also comprises a resistance component II and a comparator; the resistance component II comprises resistors R3 and R4 which are connected in series, and two ends of the resistor component II are respectively connected with an alternating current input power supply and a GND of a direct current bus; one input end of the comparator is connected with the joint of the resistors R3 and R4, the other input end of the comparator is connected with a reference voltage signal, and the output end of the comparator is connected with the input end II of the MCU. The utility model discloses the impact overcurrent that produces when can effectively avoid fast power off to electrify again.

Description

Quick power-off power-on protection circuit

Technical Field

The utility model relates to a circuit structure, especially a be applied to circuit structure of air conditioner converter, specific electric protection circuit on quick outage that says so.

Background

A direct current bus charging control circuit is usually arranged in a modern direct current frequency converter. The charging control circuit is mainly formed by connecting a relay and a current-limiting resistor in parallel, and can prevent the relay from being attracted during charging, and connect the current-limiting resistor in series into a main loop to limit the impact current. When the bus voltage reaches a preset value, the relay can be attracted to bypass the current-limiting resistor, so that the unit enters a standby or normal operation mode.

However, in daily operation, misoperation of an operator often exists, and the air switch on is immediately switched on after the air switch on the inlet wire of the unit is switched off. During the period from the time when the air switch is turned off to the time when the air switch is turned on again, the voltage of the direct current bus may drop greatly, but the voltage of the direct current bus is not reduced to the minimum critical value of the operation of the switching power supply, so that a weak current system of a main board in the unit is still powered on and is in an operating state. At this time, the relay of the charging loop is still in a pull-in state, and the impedance of the main loop is very small. If the operator closes the switch at this time, it is known from I = C × dU/dt that an overcurrent will occur, which may cause a failure such as burning out of the rectifier, the fuse, or the electrolytic capacitor of the dc bus, and thus a new motherboard component needs to be replaced, resulting in an increase in debugging and after-sales costs.

Therefore, improvements are urgently needed so as to better meet the market demands.

SUMMERY OF THE UTILITY MODEL

The utility model aims at prior art not enough, provide a power protection circuit on quick outage, solved common quick outage in the trade effectively and go up the electricity again and the impact overcurrent problem that produces, devices such as protection rectifier, direct current bus electrolytic capacitor are not damaged, reducible unit debugging and after-sales maintenance cost, fully provided market demand.

The technical scheme of the utility model is that:

a fast power-off and power-on protection circuit comprises an AC/DC module, a DC/AC module and a charging control circuit, wherein the AC/DC module is simultaneously connected with an alternating current input power supply and the DC/AC module, and inputs the alternating current input power supply into the DC/AC module after being rectified; the charging control circuit is formed by connecting a relay and a current-limiting resistor in parallel and is connected in series with a bus between the AC/DC module and the DC/AC module; the DC/AC module is also connected with a resistance component I in parallel; the resistance component I comprises resistors R1 and R2 which are connected in series, and the connection position of the resistors is connected with the input end I of the controller MCU; the output end of the MCU is connected with the relay, so that the MCU can control the action of the relay; the device also comprises a resistance component II and a comparator; the resistance component II comprises resistors R3 and R4 which are connected in series, and two ends of the resistor component II are respectively connected with an alternating current input power supply and a GND of a direct current bus; one input end of the comparator is connected with the joint of the resistors R3 and R4, the other input end of the comparator is connected with a reference voltage signal, and the output end of the comparator is connected with the input end II of the MCU.

Further, the alternating current input power supply is three-phase alternating current or single-phase alternating current.

Further, the AC/DC module comprises a rectifying circuit composed of six diodes.

Further, the DC/AC module is also connected with a capacitor in parallel.

The utility model has the advantages that:

the utility model relates to a rationally, simple structure, the ingenious diode that utilizes in resistance and the AC/DC module constitutes alternating current power supply detection circuitry, under the prerequisite that does not additionally increase the diode, has solved the common fast power failure in the trade and has electrified the impact overcurrent problem that produces again effectively, and devices such as protection rectifier, direct current generating line electrolytic capacitor are not damaged, reducible unit debugging and after-sales maintenance cost, the fully provided market demand.

Drawings

Fig. 1 is a schematic diagram of the present invention applied to a three-phase inverter.

Fig. 2 is a schematic diagram of the present invention applied to a single-phase inverter.

Fig. 3 is a logic block diagram of the present invention.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and examples.

Embodiment one, as shown in fig. 1.

A fast power-off and power-on protection circuit applied to a three-phase frequency converter comprises an AC/DC module, a DC/AC module and a charging control circuit,

the AC/DC module includes six diodes: d1, D2, D3, D4, D5 and D6 form a rectifying circuit. The AC/DC module is simultaneously connected with a three-phase alternating current input power supply and the DC/AC module to form a rectifying bus circuit of the three-phase frequency converter, and the alternating current input power supply can be rectified and then input into the DC/AC module.

The charging control circuit is formed by connecting a relay K1 and a PTC resistor in parallel, is connected in series with a bus between the AC/DC module and the DC/AC module, and can ensure that the relay K1 is not attracted during charging and the PTC resistor is connected in series with a main loop to limit impulse current. When the bus voltage reaches a preset value, the relay K1 is attracted, the PTC resistor is bypassed, and the unit enters a standby or normal operation mode.

The DC/AC module is also connected with a resistance component I in parallel. The resistance component I comprises resistors R1 and R2 which are connected in series, and the connection position of the resistors is connected with the input end I of the controller MCU. The output end of the MCU is connected with the relay, so that the MCU can control the action of the relay.

The DC/AC module is also connected with an electrolytic capacitor in parallel or a capacitor assembly formed by connecting a plurality of capacitors in parallel, and can filter and store energy for the direct current bus voltage rectified by the AC/DC module.

The utility model discloses still include resistance component II and comparator U1A. The resistance component II comprises resistors R3 and R4 which are connected in series, two ends of the resistor component II are respectively connected with an alternating current input power supply L3 and GND of a direct current bus, and a closed voltage division loop can be formed by the resistor component II and diodes D4 and D5 in the AC/DC module. One input end of the comparator U1A is connected with the joint of the resistors R3 and R4, the other input end is connected with a reference voltage signal, and the output end is connected with the input end II of the MCU.

The working process of the embodiment is as follows:

1. the voltage signal obtained at the junction of R3 and R4 is Vin.

2. The Vin signal is a half-wave DC voltage signal with large ripple, and is input to a U1A comparator, and is compared with a reference voltage Vref, and the comparator outputs a square wave signal S2 with the same frequency as the AC power supply.

3. The S2 signal is input into the MCU system and participates in the pull-in logic of the control relay K1 together with the direct current bus signal S1, when an operator pulls down the air switch, the S2 signal is lost, and the MCU detects that S2 is abnormal, and immediately cuts off the relay K1; when the switch is closed again and the power is on, the S2 signal is recovered, the MCU makes logic judgment according to the logic block diagram, and as shown in FIG. 3, whether the K1 relay is attracted or not is determined.

Example two, as shown in fig. 2.

A quick power-off and power-on protection circuit is applied to a single-phase frequency converter. The second embodiment is substantially the same as the first embodiment, and the main difference is that the AC/DC module in the second embodiment includes four diodes D1, D2, D3, and D4. In the second embodiment, the ac input power is a single-phase ac power, and therefore, the resistance component II is connected to the live line L.

The working process of the second embodiment is the same as that of the first embodiment.

The utility model discloses alternating current power supply detection circuitry is constituteed to the diode in ingenious utilization resistance and the AC/DC module, under the prerequisite that does not additionally increase the diode, has solved common fast power failure in the trade and has supplied the electricity again and produce the impact overcurrent problem effectively, and devices such as protection rectifier, direct current generating line electrolytic capacitor are not damaged, reducible unit debugging and after-sales maintenance cost, fully provided market demand.

The utility model discloses the part that does not relate to all is the same with prior art or can adopt prior art to realize.

Claims

1. A fast power-off and power-on protection circuit comprises an AC/DC module, a DC/AC module and a charging control circuit, wherein the AC/DC module is simultaneously connected with an alternating current input power supply and the DC/AC module, and inputs the alternating current input power supply into the DC/AC module after being rectified; the charging control circuit is formed by connecting a relay and a current-limiting resistor in parallel and is connected in series with a bus between the AC/DC module and the DC/AC module; the DC/AC module is also connected with a resistance component I in parallel; the resistance component I comprises resistors R1 and R2 which are connected in series, and the connection position of the resistors is connected with the input end I of the controller MCU; the output end of the MCU is connected with the relay, so that the MCU can control the action of the relay; the device is characterized by also comprising a resistance component II and a comparator; the resistance component II comprises resistors R3 and R4 which are connected in series, and two ends of the resistor component II are respectively connected with an alternating current input power supply and a GND of a direct current bus; one input end of the comparator is connected with the joint of the resistors R3 and R4, the other input end of the comparator is connected with a reference voltage signal, and the output end of the comparator is connected with the input end II of the MCU.

2. The power-on protection circuit for rapid power failure according to claim 1, wherein the ac input power source is a three-phase ac power source or a single-phase ac power source.

3. A fast power-off power-on protection circuit as claimed in claim 1, wherein said AC/DC module comprises a rectifying circuit consisting of four or six diodes.

4. A fast power-off power-on protection circuit as claimed in claim 1, wherein said DC/AC module is further connected in parallel with a capacitor.