CN215498271U

CN215498271U - Control device of direct-current power supply and air conditioner

Info

Publication number: CN215498271U
Application number: CN202121585832.6U
Authority: CN
Inventors: 金国华; 叶唤涛; 方林
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2021-07-13
Filing date: 2021-07-13
Publication date: 2022-01-11
Anticipated expiration: 2031-07-13

Abstract

The utility model discloses a control device of a direct current power supply and an air conditioner, wherein the control device comprises: the control unit is configured to determine the self-energizing time of the control unit under the condition that the control unit is powered by the switching power supply after the alternating-current power supply is powered on, and initiate a second switching instruction under the condition that the self-energizing time of the control unit reaches the set time; and initiating a first switching command under the condition that no error occurs in the wiring of the input end of the three-phase alternating current power supply; the first switch unit is configured to be switched from a normally open state to a closed state under the condition of receiving a second switch instruction; and the second switch unit is configured to be switched from a normally open state to a closed state under the condition of receiving the first switch instruction. According to the scheme, the direct-current load is controlled to be not electrified under the condition that the phase sequence of the three-phase power is connected in a wrong mode, so that the direct-current load is protected.

Description

Control device of direct-current power supply and air conditioner

Technical Field

The utility model belongs to the technical field of power supplies, particularly relates to a control device of a direct-current power supply and an air conditioner, and particularly relates to a direct-current power supply scheme, a direct-current load protection circuit and a method, and an air conditioner with the direct-current power supply scheme and the direct-current load protection circuit.

Background

With the development trend of frequency conversion and direct current of electrical appliances (such as air conditioners), the application of direct current loads is more and more extensive. The application of the direct current load brings the problem of direct current bus design.

In the related scheme, the direct-current buses are obtained through alternating-current rectification and filtering, and the bus filtering capacitor is a high-voltage bus capacitor. When a direct current load (such as an air conditioning unit) adopts three-phase power supply, the problem of wrong phase sequence connection often occurs, and the direct current load is abnormal.

Fig. 1 is a schematic structural diagram of a dc power supply circuit. The dc supply circuit shown in fig. 1 includes: the device comprises an alternating current power supply terminal H1, a phase sequence control circuit, an MCU (microprogrammed control Unit), other weak current direct current loads M2, a capacitor C1, a capacitor C2, a diode D1, a relay K1, a switching power supply, a zero line N terminal, an L1 phase line terminal, a filter, a resistor R1 (cement resistor), a rectifier bridge DB1 and a direct current bus load M1.

The zero line N connection port and the live line L connection port (specifically, the phase line L1, the phase line L2 and the phase line L3) of the alternating current power supply connection terminal H1 are connected to the MCU after passing through the phase sequence control circuit. After the direct current power supply circuit is electrified for a set time length, the control end of the MCU can send a control signal START1 to electrify the coil of the relay K1 to close the normally open contact of the relay K1, so that the resistor R1 is cut out by short circuit. And the power supply end of the MCU is connected to the first connecting end of the switching power supply, and the switching power supply can supply power to the MCU. And the second connection end of the switching power supply is connected to other weak current direct current loads M2. And the capacitor C2 is connected in parallel with the first connection end of the rectifier bridge DB1 and the second connection end of the rectifier bridge DB 1. And the third connection end of the switching power supply is connected to the first connection end of the capacitor C2. And the fourth connection terminal of the switching power supply is connected to the second connection terminal of the capacitor C2. The first connection end of the direct current bus load M1 is connected to the first connection end of the capacitor C2. And a second connection end of the direct current bus load M1 is connected to a second connection end of the capacitor C2.

The dc power supply VDD is coupled to the input terminal of the START1 via the capacitor C1. The dc power supply VDD is connected to the cathode of the diode D1, and is also connected to the anode of the diode D1 through the coil of the relay K1. The input terminal of the control signal START1 is connected to the anode of the diode D1. The first connecting end of the normally open contact of the relay K1 is connected with the first connecting end of the resistor R1; and a second connecting end of a normally open contact of the relay K1 is connected with a second connecting end of the resistor R1 and a third connecting end of the rectifier bridge DB 1. The third connection end of the rectifier bridge DB1 is connected with the first connection end of the filter through a resistor R1. And a fourth connection end of the rectifier bridge DB1 is connected with the second connection end of the filter. And a third connecting end of the filter is connected with a zero line N wiring terminal. And the fourth connecting end of the filter is connected with an L1 phase line connecting terminal. When the direct current power supply circuit is powered on, the resistor R1 carries out current limiting, the capacitor C2 is prevented from being charged too fast, and the capacitor C2 is protected. The resistor R1 is cement resistor. And the neutral line N connecting terminal and the L1 phase line connecting terminal are single-phase power supplies from a three-phase alternating current power supply.

The dc power supply circuit shown in fig. 1 is a circuit for direct dc power supply, in which ac power is input and then rectified and filtered. The dc power supply circuit shown in fig. 1 has a problem that a dc high-voltage load is abnormal due to a wrong connection. For example: if the phase voltage Ua is mistakenly connected to the line voltage Uab, the high-voltage capacitor of the bus is damaged due to overvoltage; the dc load is damaged by the dc voltage being too high. Specifically, when the power supply of the electrical equipment (such as an air conditioner) unit adopts three-phase power supply, if the power supply voltage of the main board is wrongly connected to the line voltage Uab from the phase voltage Ua

This can result in damage to the high voltage bus capacitance due to overvoltage.

The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a control device of a direct current power supply and an air conditioner, which aim to solve the problem that when a direct current load of electrical equipment is powered by three-phase electricity, if the phase sequence of the three-phase electricity is connected in a wrong way, the direct current load is abnormal, and achieve the effect of protecting the direct current load by controlling the direct current load to be not powered under the condition that the phase sequence of the three-phase electricity is connected in a wrong way.

The utility model provides a control device of a direct current power supply, comprising: the direct current power supply includes: the switching power supply, the first switching unit, the first rectifying unit and the first bus capacitor unit; the direct current power supply further comprises: the second switch unit, the second rectifying unit and the second bus capacitor unit; the control device of the direct current power supply comprises: a control unit; the single-phase alternating-current power supply led out from the input end of the three-phase alternating-current power supply can provide a first bus voltage after passing through the first switch unit, the second switch unit, the first rectifying unit and the first bus capacitor unit so as to supply power to a first direct-current bus load; the first switch unit and the second switch unit are both in a normally open state; the single-phase alternating-current power supply led out from the input end of the three-phase alternating-current power supply can provide a second bus voltage after passing through the second rectifying unit and the second bus capacitor unit so as to supply power to the switching power supply; the switching power supply can supply power to the control unit and the second direct current bus load; wherein the control unit is configured to initiate a first switching instruction in the event that no error has occurred in the wiring of the input of the three-phase alternating current power supply in the event that the control unit itself has been powered by the switching power supply after the three-phase alternating current power supply is powered on; determining the self-energizing time of the control unit, and initiating a second switch instruction when the self-energizing time of the control unit reaches the set time; the first switch unit is configured to be switched from a normally open state to a closed state under the condition that the second switch instruction is received; the second switch unit is configured to be switched from a normally open state to a closed state under the condition that the first switch instruction is received.

In some embodiments, the first bus capacitor unit comprises: a first capacitor; the second bus capacitor unit includes: the second capacitor and the third capacitor are connected in series; the capacitance of the first capacitor is larger than that of the second capacitor; the capacitance of the first capacitor is larger than that of the third capacitor.

In some embodiments, the dc power supply further includes: at least one of a filtering unit and a protection unit; under the condition that the direct-current power supply further comprises a filtering unit, the filtering unit is arranged between the single-phase alternating-current power supply and the second rectifying unit; the single-phase alternating current power supply is connected to the second rectifying unit after passing through the filtering unit; the single-phase alternating-current power supply is connected to the first switching unit and the first rectifying unit after passing through the filtering unit; under the condition that the direct-current power supply further comprises a protection unit, the protection unit is arranged between the single-phase alternating-current power supply and the second rectification unit; and the single-phase alternating current power supply is connected to the second rectifying unit after passing through the protection unit.

In some embodiments, in a case that the dc power supply further includes a filtering unit and a protection unit, a zero line of the single-phase ac power supply is connected to an input terminal of the first switching unit after passing through the filtering unit; the output end of the first switching unit is connected to the second input end of the first rectifying unit after passing through the second switching unit; the zero line of the single-phase alternating-current power supply is connected to the first input end of the second rectifying unit after passing through the filtering unit and the protection unit; and the phase line of the single-phase alternating-current power supply is connected to the first input end of the first rectifying unit and the second input end of the second rectifying unit after passing through the filtering unit.

In some embodiments, the protection unit includes: an NTC resistance.

In some embodiments, the first switching unit includes: a first relay and a first resistance module; the second switching unit includes: a second relay; the normally open contact of the first relay is connected with the first resistance module in parallel; and the normally open contact of the first relay and the normally open contact of the second relay are arranged between the zero line of the single-phase alternating-current power supply and the second input end of the first rectifying unit in series.

In some embodiments, the control device of the dc power supply further includes: a phase sequence detection unit; the input end of the three-phase alternating current power supply is connected to the control unit after passing through the phase sequence detection unit; wherein the phase sequence detection unit is configured to detect a current phase sequence of the three-phase alternating current power supply; the control unit initiates a first switching command under the condition that no error occurs in the wiring of the input end of the three-phase alternating current power supply, and the control unit comprises: determining whether the current phase sequence of the three-phase alternating-current power supply meets a preset phase sequence or not, determining that no error occurs in the wiring of the input end of the three-phase alternating-current power supply under the condition that the current phase sequence of the three-phase alternating-current power supply meets the preset phase sequence, and initiating a first switching instruction; and determining the self-energizing time of the control unit under the condition that the second switch unit is switched from a normally open state to a closed state, and initiating a second switch instruction under the condition that the self-energizing time of the control unit reaches a set time.

In accordance with another aspect of the present invention, there is provided an air conditioner including: the control device of the direct current power supply is described above.

Therefore, according to the scheme of the utility model, the switching power supply and the direct current load are respectively rectified and filtered by two different groups of rectifying and filtering units (such as a rectifying bridge and a filter) for supplying power, the MCU is supplied with power by the switching power supply, and the MCU is used for controlling whether the direct current load is electrified or not, so that the direct current load can be electrified under the condition that the phase sequence of three-phase power is normal, and the direct current load cannot be electrified under the condition that the phase sequence of the three-phase power is abnormal; therefore, the direct current load is protected by controlling the direct current load to be not electrified under the condition that the phase sequence of the three-phase power is in a wrong connection.

Additional features and advantages of the utility model will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

FIG. 1 is a schematic diagram of a DC power supply circuit;

FIG. 2 is a schematic structural diagram of a control device of a DC power supply according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of another DC power supply circuit;

FIG. 4 is a control flow diagram of the DC power supply circuit shown in FIG. 3 according to an embodiment;

FIG. 5 is a flowchart illustrating a control method of the DC power supply according to an embodiment of the present invention;

FIG. 6 is a flowchart illustrating an embodiment of initiating a first switch command in the method of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the utility model, and not restrictive of the full scope of the utility model. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

To address the high voltage problem of bus capacitance (i.e., the problem of damage to the high voltage bus capacitance due to overvoltage in the arrangement shown in fig. 1), some arrangements use four high voltage capacitors in series-parallel (i.e., in series and/or parallel). First, however, the cost of this solution is high due to the high cost of the high voltage capacitor; in addition, the area occupied by the four high-voltage capacitors on the PCB (printed circuit board) is large; secondly, when four high-voltage capacitors are used in parallel, the capacitors are often abnormal due to uneven voltage division, so that the reliability is low, and finally, partial direct-current load is damaged or abnormal due to overvoltage.

According to an embodiment of the present invention, there is provided a control apparatus of a direct current power supply. Referring to fig. 2, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The direct current power supply includes: the switching power supply, the first switching unit, the first rectifying unit and the first bus capacitor unit. The direct current power supply further comprises: the second switch unit, the second rectification unit and the second bus capacitor unit. The control device of the direct current power supply comprises: a control unit. Fig. 3 is a schematic structural diagram of another dc power supply circuit. A first switching unit, such as relay K1. A second switching unit, such as relay K2. A first rectifying unit, such as a rectifier bridge DB 1. A second rectifying unit, such as a rectifier bridge DB 2. A first bus capacitor unit, such as capacitor C2. And a second bus capacitor unit, such as a capacitor C3 and a capacitor C4. And a control unit, such as an MCU.

The single-phase alternating-current power supply (such as the terminal N and the terminal L1) led out from the input end (such as the terminal N, the terminal L1, the terminal L2 and the terminal L3) of the three-phase alternating-current power supply can provide a first bus voltage after passing through the first switching unit, the second switching unit, the first rectifying unit and the first bus capacitor unit so as to supply power to a first direct-current bus load. The first direct current bus load is a strong electric load. The first switch unit and the second switch unit are both in a normally open state.

And the single-phase alternating-current power supply led out from the input end of the three-phase alternating-current power supply can provide a second bus voltage after passing through the second rectifying unit and the second bus capacitor unit so as to supply power to the switching power supply. The switching power supply can supply power to the control unit and the second direct current bus load. And the second direct current bus load is a weak current load.

Wherein the control unit is configured to initiate a first switching instruction (such as a control signal START2) if no error has occurred in the wiring of the input of the three-phase AC power source after the three-phase AC power source is powered on, if the control unit itself has been powered by the switching power source. The first switching instruction is used for controlling the second switching unit to be changed from an open state to a closed state. And determining the power-on time of the control unit itself, and initiating a second switch command (such as a control signal START1) when the power-on time of the control unit itself reaches a set time. The second switching instruction is used for controlling the first switching unit to be changed from an open state to a closed state. And determining the self-energizing time of the control unit, for example, timing the control unit by using an external timer or a self-clock module of the control unit to obtain the self-energizing time of the control unit.

The first switch unit is configured to be switched from a normally open state to a closed state when the second switch instruction is received.

The second switch unit is configured to be switched from a normally open state to a closed state under the condition that the first switch instruction is received.

Therefore, according to the scheme of the utility model, by arranging two groups of rectifying and filtering units (such as the first rectifying unit and the first bus capacitor unit, the second rectifying unit and the second bus capacitor unit) and two groups of switch units (such as the first switch unit and the second switch unit), the problem of overvoltage damage of the direct-current load caused by the fact that the three-phase power is connected in a wrong way is solved, and the bus of the switching power supply can be protected, and the bus of the direct-current load can also be protected.

In some embodiments, the first bus capacitor unit comprises: a first capacitor. The second bus capacitor unit includes: the second capacitor and the third capacitor are connected in series. A first capacitor, such as capacitor C2. A second capacitor, such as capacitor C3. A third capacitor, such as capacitor C4.

The capacitance of the first capacitor is larger than that of the second capacitor. The capacitance of the first capacitor is larger than that of the third capacitor.

Therefore, when the three-phase power supply is adopted for the direct current load, if the phase sequence of the three-phase power is in wrong connection, the problem of abnormal direct current load can be caused. According to the scheme of the utility model, two small-capacity capacitors (such as the capacitor C3 and the capacitor C4 in the figure 3) are connected in series, so that the withstand voltage value of a bus can be improved, and the large-capacity capacitor (such as the capacitor C2 in the figure 3) is controlled by the MCU, so that the problem of overvoltage damage of a direct-current load caused by power failure on three-phase power is solved, the high-voltage direct-current load can be protected, and the reliability of a direct-current power supply scheme is also improved.

In addition, in order to solve the high-voltage problem of the bus capacitor (namely, the problem that the high-voltage bus capacitor is damaged due to overvoltage), when four high-voltage capacitors are used in series-parallel connection (namely, in series connection and/or in parallel connection), the high-voltage capacitors are high in cost, large in occupied area, uneven in voltage division and the like. In a related scheme, four electrolytic capacitors are first used in series-parallel (i.e., in series and/or in parallel). In the scheme of the utility model, two capacitors with small capacity (such as the capacitor C3 and the capacitor C4 in fig. 3) are connected in series to supply power to the MCU, and the direct-current load power supply capacitor (such as the capacitor C2 in fig. 3) is controlled by the MCU, so that the problems of high cost, large space occupied by a PCB (printed circuit board), uneven voltage division and the like existing when the capacitors are connected in series and in parallel to supply power to four direct-current loads are solved, the cost can be reduced, the area of the PCB can be reduced, and even voltage division can be realized. That is to say, compared with the scheme that four electrolytic capacitors are connected in series and in parallel, the scheme of the utility model can reduce the cost, reduce the area of the PCB and realize uniform voltage division.

In some embodiments, the dc power supply further includes: at least one of a filtering unit and a protection unit. A filtering unit, such as a filter. A protection unit, such as a resistor R2. Under the condition that the resistor R2 adopts an NTC resistor, overcurrent protection can be realized, and the power is low, the energy consumption is low, and the occupied space is small.

And under the condition that the direct-current power supply further comprises a filtering unit, the filtering unit is arranged between the single-phase alternating-current power supply and the second rectifying unit. And the single-phase alternating current power supply is connected to the second rectifying unit after passing through the filtering unit. And the single-phase alternating current power supply is connected to the first switching unit and the first rectifying unit after passing through the filtering unit.

And under the condition that the direct-current power supply further comprises a protection unit, the protection unit is arranged between the single-phase alternating-current power supply and the second rectification unit. And the single-phase alternating current power supply is connected to the second rectifying unit after passing through the protection unit.

In some embodiments, in a case that the dc power supply further includes a filtering unit and a protection unit, a zero line, such as a zero line N, of the single-phase ac power supply is connected to the input end of the first switching unit after passing through the filtering unit. And the output end of the first switching unit is connected to the second input end of the first rectifying unit after passing through the second switching unit.

And the zero line of the single-phase alternating-current power supply is connected to the first input end of the second rectifying unit after passing through the filtering unit and the protection unit.

The phase line of the single-phase ac power source, for example, the phase line L1, passes through the filtering unit, and is connected to the first input terminal of the first rectifying unit and to the second input terminal of the second rectifying unit.

The first rectifying unit and the second rectifying unit can adopt diode rectifying bridges.

In some embodiments, the protection unit includes: the NTC resistance, i.e. the resistance R2, is an NTC resistance. By adopting the NTC resistor, the overcurrent protection can be realized, and the power is low, the energy consumption is low, and the occupied space is small.

In some embodiments, the first switching unit includes: the first relay and the first resistance module. First relay such as relay K1, first resistance module such as resistance R1 can play the protect function, if carry out the current-limiting for voltage can not be too high when charging electric capacity C2, is short circuited after first switch element is switched on, satisfies the voltage demand of following direct current load. Of course, the first switch unit further includes peripheral components such as a capacitor C1 and a diode D1.

The second switching unit includes: and a second relay. A second relay such as relay K2. Of course, the second switch unit further includes peripheral components such as a capacitor C5 and a diode D2.

The normally open contact of the first relay is connected with the first resistance module in parallel. And the normally open contact of the first relay and the normally open contact of the second relay are arranged between the zero line of the single-phase alternating-current power supply and the second input end of the first rectifying unit in series.

In some embodiments, the control device of the dc power supply further includes: and a phase sequence detection unit, such as a phase sequence control circuit. The input end of the three-phase alternating-current power supply, such as a zero line N wiring port and a live line L wiring port (specifically, a phase line L1, a phase line L2 and a phase line L3) of an alternating-current power supply wiring terminal H1, is connected to the control unit after passing through the phase sequence detection unit. And a phase sequence detection unit, such as a phase sequence control circuit.

Wherein the phase sequence detection unit is configured to detect a current phase sequence of the three-phase alternating current power supply.

The control unit initiates a first switching command under the condition that no error occurs in the wiring of the input end of the three-phase alternating current power supply, and the control unit comprises:

the control unit is specifically configured to determine whether a current phase sequence of the three-phase ac power supply meets a preset phase sequence, to determine that no error occurs in a connection line of an input end of the three-phase ac power supply when the current phase sequence of the three-phase ac power supply meets the preset phase sequence, and to initiate a first switching instruction. In order to make the phase sequence detection result more accurate, it may be determined that the current phase sequence of the three-phase ac power supply meets the preset phase sequence only when the current phase sequence of the three-phase ac power supply is detected within a certain time (for example, a first set time a seconds). And determining the self-energizing time of the control unit under the condition that the second switch unit is switched from the normally-open state to the closed state, and initiating a second switch instruction under the condition that the self-energizing time of the control unit reaches a set time (such as a second set time B seconds). Of course, when the current phase sequence of the three-phase ac power supply does not satisfy the preset phase sequence, it is determined that an error has occurred in the connection of the input terminal of the three-phase ac power supply, and the first switching instruction is not initiated.

The dc supply circuit shown in fig. 3 includes: the device comprises an alternating current power supply terminal H1, a phase sequence control circuit, an MCU, other weak current direct current loads M2, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a diode D1, a diode D2, a relay K1, a relay K2, a switching power supply, a zero line N terminal, an L1 phase line terminal, a filter, a resistor R1, a resistor R2, a rectifier bridge DB1, a rectifier bridge DB1 and a direct current bus load M1. The resistor R1 is cement resistor, and the resistor R2 is NTC (negative temperature coefficient) resistor. And the neutral line N connecting terminal and the L1 phase line connecting terminal are single-phase power supplies from a three-phase alternating current power supply.

The zero line N connection port and the live line L connection port (specifically, the phase line L1, the phase line L2 and the phase line L3) of the alternating current power supply connection terminal H1 are connected to the MCU after passing through the phase sequence control circuit. After the direct current power supply circuit is electrified for a set time length, the control end of the MCU can send a control signal START1 to electrify the coil of the relay K1 to close the normally open contact of the relay K1, so that the resistor R1 is cut out by short circuit. After the phase sequence control circuit detects the wiring phase sequence of the three-phase alternating current power supply, the MCU sends a control signal START2 according to the detection result of the phase sequence control circuit under the condition that the phase sequence is correct, so that the coil of the relay K2 is electrified to close the normally open contact of the relay K2. After the coils of the relay K1 and the relay K2 are both electrified to close the corresponding normally open contacts, the capacitor C2 can be normally charged, and the direct-current bus load M1 can be electrified.

And the power supply end of the MCU is connected to the first connecting end of the switching power supply, and the switching power supply can supply power to the MCU. And the second connection end of the switching power supply is connected to other weak current direct current loads M2. And the capacitor C2 is connected in parallel with the first connection end of the rectifier bridge DB1 and the second connection end of the rectifier bridge DB 1. And the third connection end of the switching power supply is connected to the first connection end of the capacitor C3 and the capacitor C4 which are connected in series. And the fourth connection terminal of the switching power supply is connected to the second connection terminal of the capacitor C3 and the capacitor C4 which are connected in series. The first connection end of the capacitor C3 and the capacitor C4 which are connected in series is connected with the first connection end of the rectifier bridge DB 2. And a second connection end of the capacitor C3 and the capacitor C4 which are connected in series is connected with a second connection end of the rectifier bridge DB 2. The third connection end of the rectifier bridge DB2 is connected with the first connection end of the filter through a resistor R2. And a third connection end of the rectifier bridge DB2 is connected with the second connection end of the filter.

The first connection end of the direct current bus load M1 is connected to the first connection end of the capacitor C2. And a second connection end of the direct current bus load M1 is connected to a second connection end of the capacitor C2. The dc power supply VDD is coupled to the input terminal of the START1 via the capacitor C1. The dc power supply VDD is connected to the cathode of the diode D1, and is also connected to the anode of the diode D1 through the coil of the relay K1. The input terminal of the control signal START1 is connected to the anode of the diode D1. The first connecting end of the normally open contact of the relay K1 is connected with the first connecting end of the resistor R1. The second connecting end of the normally open contact of the relay K1 is connected with the second connecting end of the resistor R1, and is also connected with the third connecting end of the rectifier bridge DB1 after passing through the normally open contact of the relay K2. The third connecting end of the rectifier bridge DB1 is connected with the first connecting end of the filter through the normally open contact of the relay K2 and the resistor R1. And a fourth connection end of the rectifier bridge DB1 is connected with the second connection end of the filter. And a third connecting end of the filter is connected with a zero line N wiring terminal. And the fourth connecting end of the filter is connected with an L1 phase line connecting terminal. When the direct current power supply circuit is powered on, the resistor R1 carries out current limiting, the capacitor C2 is prevented from being charged too fast, and the capacitor C2 is protected. The coil of the relay K2 is connected in parallel with a diode D2 and a capacitor C5. The anode of the diode D2 is connected to the input of the control signal START 2. And the cathode of the diode D2 is connected with a direct current power supply VDD.

The dc power supply circuit shown in fig. 3 is a circuit in which the rectified and filtered high-voltage bus supplies power to the MCU first, and the dc load supplies power through a single rectified and filtered bus with control, and is a circuit with high reliability and protecting the high-voltage dc load.

In the example shown in fig. 3, two capacitors with smaller capacitance values are connected in series, and after the two capacitors with smaller capacitance values are connected in series, the withstand voltage value can reach 900V, so that the requirement that the capacitor is not damaged by a wrong connection line can be met. And if the capacitance value of the capacitor is larger, the time point of electrifying the direct current bus capacitor is controlled through the relay, so that the high-voltage direct current load is protected. For example: and the charge and discharge time point of the large capacitor is controlled through the MCU controller relay, so that the motor is protected.

Fig. 4 is a control flow diagram of the dc power supply circuit shown in fig. 3 according to an embodiment. As shown in fig. 4, the control flow of the dc power supply circuit shown in fig. 3 includes:

step 1, performing rectification filtering power supply on a switching power supply and a direct current load (such as a direct current bus load M1) by respectively using two different rectifier bridges (such as a rectifier bridge DB1 and a rectifier bridge DB 2).

The bus power supply of the switching power supply is obtained by rectifying through a rectifier bridge DB2 and filtering after a capacitor C3 and a capacitor C4 are connected in series. After the capacitor C3 and the capacitor C4 are connected in series, the withstand voltage value of the bus reaches 900V.

The resistor R2 adopts an NTC resistor, and the NTC resistor can meet the power-on requirement because the bus capacitor is only provided with two electrolytic capacitors (the capacitor C3 and the capacitor C4 are connected in series) in the order of dozens of microfarads.

The power supply of the direct current load (such as a direct current bus load M1) is rectified and filtered through a rectifier bridge DB1 and a capacitor C2, the charging and discharging time point of the bus capacitor of the direct current bus load M2 (such as a fan) is controlled by a relay K2, and the connection and disconnection of a cement resistor (namely a resistor R1) are controlled by a relay K1.

And 2, when the voltage of the main board power supply is connected with the normal phase voltage 220VAC, firstly, the power supply end of the switching power supply is electrified, and the power supply end of the direct current load (such as the direct current bus load M1) is not electrified. The main chip MCU begins to work, MCU detects through phase sequence control circuit whether three-phase current phase sequence is correct, when MCU detects in first settlement time A second that the phase sequence is normal often, control relay K2 actuation, direct current load (like direct current bus load M1) bus capacitance C2 begins to charge, after second settlement time B second, the electric capacity is charged and is accomplished, relay K1 actuation, mainboard and load normal work.

When the main board power supply voltage is mistakenly connected to the line voltage 380VAC, firstly, the power supply end of the switching power supply is electrified, the bus voltage 537VDC is used, a capacitor C2 is used in the scheme shown in figure 1, the overvoltage burnout of the bus capacitor is caused due to the fact that the withstand voltage value of the bus is not enough, the bus in the scheme shown in figure 3 is serially connected by two small-capacity capacitors (a capacitor C3 and a capacitor C4 are serially connected), the withstand voltage value of the bus is improved, even if the line is connected in a wrong mode, the bus can be normally electrified, the switching power supply normally works, the MCU normally supplies power, the MCU detects the correctness of the phase sequence through a phase controller circuit, if the phase sequence is detected to be abnormal, the relay K2 does not act, the purpose of protecting a direct current load (such as a fan) is achieved, and the main board reports the phase sequence fault.

In this way, the present invention provides a high-reliability dc power supply scheme and a dc load protection circuit, and firstly, two high-voltage bus capacitors with very small capacitance (such as the capacitor C3 and the capacitor C4 in fig. 3) are used in series to supply power to a switching power supply with relatively low power, and an MCU and a dc load with relatively low operating voltage are supplied with power through the switching power supply. After the MCU normally works, the high-voltage bus capacitor (such as the capacitor C2 in fig. 3) with a large power requirement is controlled to work, so as to achieve high reliability and protect the high-voltage dc load.

For example: the high-voltage bus capacitor with extremely small capacity has a withstand voltage value of 450V or more and a capacitance of 150UF or less. The power requirement is large, and the parameter range of the high-voltage bus capacitor is more than 450V, such as more than 150 UF.

Through a large number of tests, the technical scheme of the utility model is adopted, the switching power supply and the direct current load are respectively rectified and filtered by two groups of different rectifying and filtering units (such as a rectifying bridge and a filter) for supplying power, the MCU is supplied with power by the switching power supply, and the MCU is used for controlling whether the direct current load is electrified or not, so that the direct current load can be electrified under the condition that the phase sequence of the three-phase power is normal, and the direct current load can not be electrified under the condition that the phase sequence of the three-phase power is abnormal. Therefore, the direct current load is protected by controlling the direct current load to be not electrified under the condition that the phase sequence of the three-phase power is in a wrong connection.

According to an embodiment of the present invention, there is also provided an air conditioner corresponding to a control device of a direct current power supply. The air conditioner may include: the control device of the direct current power supply is described above.

Since the processing and functions of the air conditioner of this embodiment are basically corresponding to the embodiments, principles and examples of the foregoing devices, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.

Through a large number of tests, the technical scheme of the utility model is adopted, and the switching power supply and the direct current load are respectively supplied with power after being rectified and filtered by two groups of different rectifying and filtering units (such as a rectifying bridge and a filter) aiming at the switching power supply and the direct current load, the switching power supply supplies power to the MCU, and the MCU controls whether the direct current load is electrified or not, so that the direct current load can be electrified under the condition that the phase sequence of three-phase power is normal, and the direct current load can not be electrified under the condition that the phase sequence of the three-phase power is abnormal, thereby not only protecting a switching power supply bus, but also protecting the direct current load bus.

According to an embodiment of the present invention, there is also provided a method for controlling a dc power supply corresponding to an air conditioner, as shown in fig. 5, which is a schematic flow chart of an embodiment of the method of the present invention. The direct current power supply includes: the switching power supply, the first switching unit, the first rectifying unit and the first bus capacitor unit. The direct current power supply further comprises: the second switch unit, the second rectification unit and the second bus capacitor unit. Fig. 3 is a schematic structural diagram of another dc power supply circuit. A first switching unit, such as relay K1. A second switching unit, such as relay K2. A first rectifying unit, such as a rectifier bridge DB 1. A second rectifying unit, such as a rectifier bridge DB 2. A first bus capacitor unit, such as capacitor C2. And a second bus capacitor unit, such as a capacitor C3 and a capacitor C4. And a control unit, such as an MCU. The control method of the direct current power supply comprises the following steps: step S110 to step S130.

At step S110, a first switching instruction (e.g., control signal START2) is initiated by the control unit after the three-phase ac power source is powered up, in the event that the control unit itself has been powered by the switching power source, in the event that no error has occurred in the wiring of the input of the three-phase ac power source. The first switching instruction is used for controlling the second switching unit to be changed from an open state to a closed state. And determining the power-on time of the control unit itself, and initiating a second switch command (such as a control signal START1) when the power-on time of the control unit itself reaches a set time. The second switching instruction is used for controlling the first switching unit to be changed from an open state to a closed state. And determining the self-energizing time of the control unit, for example, timing the control unit by using an external timer or a self-clock module of the control unit to obtain the self-energizing time of the control unit.

At step S120, the first switch unit is controlled to switch from the normally open state to the closed state when the second switch instruction is received.

And at the step S130, controlling the second switch unit to switch from the normally open state to the closed state under the condition of receiving the first switch instruction.

In addition, in order to solve the high-voltage problem of the bus capacitor (namely, the problem that the high-voltage bus capacitor is damaged due to overvoltage), when four high-voltage capacitors are used in series-parallel connection (namely, in series connection and/or in parallel connection), the high-voltage capacitors are high in cost, large in occupied area, uneven in voltage division and the like. According to the scheme of the utility model, four electrolytic capacitors can be connected in series and parallel (namely connected in series and/or in parallel), then two capacitors with small capacity are connected in series (such as the capacitor C3 and the capacitor C4 in the figure 3) to supply power to the MCU, and the direct current load power supply capacitor (such as the capacitor C2 in the figure 3) is controlled by the MCU, so that the problems of high cost, large space occupied by a PCB (printed circuit board), uneven voltage division and the like existing when the capacitors are connected in series and parallel for power supply by four direct current loads are solved, the cost can be reduced, the area of the PCB can be reduced, and even voltage division can be realized. That is to say, compared with the scheme that four electrolytic capacitors are connected in series and in parallel, the scheme of the utility model can reduce the cost, reduce the area of the PCB and realize uniform voltage division.

In some embodiments, the control device of the dc power supply further includes: and a phase sequence detection unit. And the input end of the three-phase alternating current power supply is connected to the control unit after passing through the phase sequence detection unit. And a phase sequence detection unit, such as a phase sequence control circuit.

In step S120, when no error occurs in the connection of the input terminal of the three-phase ac power supply, a specific process of a first switching command is initiated by the control unit, which is described in the following exemplary description.

The following further describes, with reference to a flowchart of an embodiment of initiating the first switch command in the method of the present invention shown in fig. 6, a specific process of initiating the first switch command in step S120, including: step S210 and step S220.

And step S210, detecting the current phase sequence of the three-phase alternating current power supply through a phase sequence detection unit.

Step S220, determining, by a control unit, whether the current phase sequence of the three-phase ac power supply meets a preset phase sequence, so as to determine that no error occurs in the wiring of the input terminal of the three-phase ac power supply when the current phase sequence of the three-phase ac power supply meets the preset phase sequence, and initiating a first switching instruction. In order to make the phase sequence detection result more accurate, it may be determined that the current phase sequence of the three-phase ac power supply meets the preset phase sequence only when the current phase sequence of the three-phase ac power supply is detected within a certain time (for example, a first set time a seconds). And determining the self-energizing time of the control unit under the condition that the second switch unit is switched from the normally-open state to the closed state, and initiating a second switch instruction under the condition that the self-energizing time of the control unit reaches a set time (such as a second set time B seconds). Of course, when the current phase sequence of the three-phase ac power supply does not satisfy the preset phase sequence, it is determined that an error has occurred in the connection of the input terminal of the three-phase ac power supply, and the first switching instruction is not initiated.

Since the processing and functions implemented by the method of this embodiment substantially correspond to the embodiments, principles and examples of the air conditioner, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.

Through a large number of tests, the technical scheme of the embodiment is adopted, the switching power supply and the direct-current load are respectively powered after being rectified and filtered by two different groups of rectification and filtering units (such as a rectifier bridge and a filter) aiming at the switching power supply and the direct-current load, the MCU is powered by the switching power supply, whether the direct-current load is powered or not is controlled by the MCU, the direct-current load can be powered under the condition that the phase sequence of three-phase electricity is normal, the direct-current load cannot be powered under the condition that the phase sequence of the three-phase electricity is abnormal, and high reliability and high-voltage direct-current load protection are achieved.

In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.

The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A control device for a dc power supply, characterized in that the dc power supply comprises: the switching power supply, the first switching unit, the first rectifying unit and the first bus capacitor unit; the direct current power supply further comprises: the second switch unit, the second rectifying unit and the second bus capacitor unit; the control device of the direct current power supply comprises: a control unit; wherein the content of the first and second substances,

the single-phase alternating-current power supply led out from the input end of the three-phase alternating-current power supply can provide a first bus voltage after passing through the first switch unit, the second switch unit, the first rectifying unit and the first bus capacitor unit so as to supply power to a first direct-current bus load; the first switch unit and the second switch unit are both in a normally open state;

the single-phase alternating-current power supply led out from the input end of the three-phase alternating-current power supply can provide a second bus voltage after passing through the second rectifying unit and the second bus capacitor unit so as to supply power to the switching power supply; the switching power supply can supply power to the control unit and the second direct current bus load;

wherein the content of the first and second substances,

the control unit is configured to initiate a first switching instruction in the case that no error occurs in the wiring of the input end of the three-phase alternating current power supply in the case that the control unit itself has been powered by the switching power supply after the three-phase alternating current power supply is powered on; determining the self-energizing time of the control unit, and initiating a second switch instruction when the self-energizing time of the control unit reaches the set time;

the first switch unit is configured to be switched from a normally open state to a closed state under the condition that the second switch instruction is received;

2. The control device for a dc power supply according to claim 1, wherein the first bus capacitor unit includes: a first capacitor; the second bus capacitor unit includes: the second capacitor and the third capacitor are connected in series; wherein the content of the first and second substances,

the capacitance of the first capacitor is larger than that of the second capacitor; the capacitance of the first capacitor is larger than that of the third capacitor.

3. The control device of a dc power supply according to claim 1, wherein the dc power supply further comprises: at least one of a filtering unit and a protection unit; wherein the content of the first and second substances,

under the condition that the direct-current power supply further comprises a filtering unit, the filtering unit is arranged between the single-phase alternating-current power supply and the second rectifying unit; the single-phase alternating current power supply is connected to the second rectifying unit after passing through the filtering unit; the single-phase alternating-current power supply is connected to the first switching unit and the first rectifying unit after passing through the filtering unit;

under the condition that the direct-current power supply further comprises a protection unit, the protection unit is arranged between the single-phase alternating-current power supply and the second rectification unit; and the single-phase alternating current power supply is connected to the second rectifying unit after passing through the protection unit.

4. The control device of a DC power supply according to claim 3, wherein in case that the DC power supply further comprises a filtering unit and a protection unit,

the zero line of the single-phase alternating-current power supply is connected to the input end of the first switch unit after passing through the filtering unit; the output end of the first switching unit is connected to the second input end of the first rectifying unit after passing through the second switching unit;

the zero line of the single-phase alternating-current power supply is connected to the first input end of the second rectifying unit after passing through the filtering unit and the protection unit;

and the phase line of the single-phase alternating-current power supply is connected to the first input end of the first rectifying unit and the second input end of the second rectifying unit after passing through the filtering unit.

5. The control device of the dc power supply according to claim 3, wherein the protection unit includes: an NTC resistance.

6. The control device of a dc power supply according to claim 1, wherein the first switching unit includes: a first relay and a first resistance module;

the second switching unit includes: a second relay;

wherein the content of the first and second substances,

the normally open contact of the first relay is connected with the first resistance module in parallel; and the normally open contact of the first relay and the normally open contact of the second relay are arranged between the zero line of the single-phase alternating-current power supply and the second input end of the first rectifying unit in series.

7. The control device of the dc power supply according to any one of claims 1 to 6, further comprising: a phase sequence detection unit; the input end of the three-phase alternating current power supply is connected to the control unit after passing through the phase sequence detection unit; wherein the content of the first and second substances,

the phase sequence detection unit is configured to detect a current phase sequence of the three-phase alternating current power supply;

determining whether the current phase sequence of the three-phase alternating-current power supply meets a preset phase sequence or not, determining that no error occurs in the wiring of the input end of the three-phase alternating-current power supply under the condition that the current phase sequence of the three-phase alternating-current power supply meets the preset phase sequence, and initiating a first switching instruction; and determining the self-energizing time of the control unit under the condition that the second switch unit is switched from a normally open state to a closed state, and initiating a second switch instruction under the condition that the self-energizing time of the control unit reaches a set time.

8. An air conditioner, comprising: the control device of a direct current power supply according to any one of claims 1 to 7.