CN114123749A - Soft start circuit, soft start control method, controller and air conditioner - Google Patents

Soft start circuit, soft start control method, controller and air conditioner Download PDF

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Publication number
CN114123749A
CN114123749A CN202111319185.9A CN202111319185A CN114123749A CN 114123749 A CN114123749 A CN 114123749A CN 202111319185 A CN202111319185 A CN 202111319185A CN 114123749 A CN114123749 A CN 114123749A
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Prior art keywords
voltage
bus capacitor
pfc
circuit
module
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Chinese (zh)
Inventor
焦斌刚
刘文斌
刘志辉
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/36—Means for starting or stopping converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208—Arrangements for improving power factor of AC input
    • H02M1/4225—Arrangements for improving power factor of AC input using a non-isolated boost converter
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The soft start circuit comprises a control module, a circuit switching module, a rectifying module, a PFC (power factor correction) switch tube and a bus capacitor, wherein the input end of the rectifying module is connected with an input alternating current power supply, the output end of the rectifying module is connected with the PFC switch tube, the control module switches the connection relation between the PFC switch tube and the bus capacitor through the circuit switching module, when the PFC switch tube is connected with the bus capacitor in series, the bus capacitor is charged, and the bus capacitor enters a soft start working state; when the PFC switch tube is connected with the bus capacitor in parallel, the bus capacitor is boosted, and the bus capacitor enters a boosting working state. The bus charging device can reduce current in a circuit in the bus charging process, reduces loss of impact current to rear-end electronic components, saves a plurality of cement resistors, and effectively saves space and reduces cost.

Description

Soft start circuit, soft start control method, controller and air conditioner
Technical Field
The application belongs to the technical field of soft start, and particularly relates to a soft start circuit, a soft start control method, a controller and an air conditioner.
Background
With the continuous improvement of the social living standard, the use of air-conditioning electrical appliances is gradually popularized, and the variable frequency air conditioner has been widely used due to the advantages of low cost, low noise, high performance and the like. The soft start control circuit as an important component of the variable frequency air conditioner is the key for improving the performance of the whole machine. The soft start charging circuit is used for inhibiting the impact of surge current on a power grid during starting, reducing current harmonic waves and improving the starting performance of the variable frequency air conditioner, so that the soft start charging circuit is widely applied to an outdoor unit of the variable frequency air conditioner. The common soft start charging scheme in the variable frequency air conditioner is mainly characterized in that a resistor is connected in series with an input end of a power supply and a relay is connected in parallel, but at the moment of power-on, the resistor and an inductor connected in series in a loop can only inhibit surge current but cannot inhibit impact current. With the increase of the service time of the air conditioner, the service life of the loop back-end component is shortened by the over-high impact current during the startup charging, and the reliability of the operation of the air conditioner is reduced.
In the related art, the loss of the impact current to rear-end electronic components is reduced by increasing the cement resistor in the bus pre-charging circuit, but too much space of a control panel is occupied, and the heat dissipation of the controller is not facilitated.
Disclosure of Invention
For at least overcoming traditional soft start circuit can not restrain impact current and lead to air conditioner operational reliability to reduce and increase cement resistance and can occupy the space of too many control panels when reducing impact current to a certain extent, be unfavorable for the radiating problem of controller, this application provides a soft start circuit, soft start control method, controller and air conditioner.
In a first aspect, the present application provides a soft-start circuit, comprising:
the control module, the circuit switching module, the rectifying module, the PFC switch tube and the bus capacitor;
the input end of the rectification module is connected with an input alternating current power supply;
the output end of the rectification module is connected with the PFC switching tube;
the control module switches the connection relation between the PFC switch tube and the bus capacitor through the circuit switching module, when the PFC switch tube is connected with the bus capacitor in series, the bus capacitor is charged, and the bus capacitor enters a soft start working state; when the PFC switch tube is connected with the bus capacitor in parallel, the bus capacitor is boosted, and the bus capacitor enters a boosting working state.
Further, the circuit switching module includes:
a first switch, a second switch, and a third switch;
the first switch is arranged between an emitter of the PFC switch tube and the anode of the bus capacitor;
the second switch is arranged between the collector of the PFC switch tube and the negative electrode of the bus circuit;
the third switch is arranged between the collector of the PFC switch tube and the anode of the bus circuit.
Further, the control module switches the connection relationship between the PFC switch tube and the bus capacitor through the circuit switching module, including:
the control module controls the PFC switch tube to be connected with the bus capacitor in parallel by controlling the first switch and the second switch to be closed and the third switch to be opened;
the control module controls the PFC switch tube to be connected with the bus capacitor in series by controlling the first switch and the second switch to be switched off and the third switch to be switched on.
Further, the first switch, the second switch or the third switch is at least one of a relay, a circuit breaker, a contactor, a thyristor device and a controllable semiconductor device.
Further, the method also comprises the following steps:
the voltage sampling module is connected with the rectifying circuit;
the voltage sampling module comprises a first resistor and a second resistor, and the resistance value of the first resistor is greater than that of the second resistor;
the first resistor and the second resistor are used for dividing the direct-current voltage output by the rectifying module; the voltage sampling module is used for collecting a direct current voltage value on the second resistor;
the control module is further used for calculating the direct current voltage value output by the rectifying module according to the direct current voltage value on the second resistor collected by the voltage sampling module.
Further, the control module is further configured to:
setting a plurality of voltage intervals with the same voltage change amplitude;
taking a voltage interval with the minimum voltage mean value corresponding to the voltage interval as a charging voltage interval;
when the direct-current voltage value output by the rectifying module enters the charging voltage interval, controlling the conduction of a PFC (power factor correction) switching tube;
and when the maximum value of the charging voltage interval is reached, controlling the PFC switch tube to be cut off, and determining the voltage interval adjacent to the current charging voltage interval as the charging voltage interval until the voltage of the bus capacitor reaches the maximum value of the voltage.
Further, the maximum voltage value is
Figure BDA0003344607750000031
And U is the effective value of the voltage of the input alternating current power supply.
Further, the method also comprises the following steps:
and the PFC inductor is arranged between the positive output end of the rectifying module and the positive electrode of the bus capacitor and is used for charging or boosting the bus capacitor.
In a second aspect, the present application provides a soft start control method, including:
collecting a direct current voltage value in a soft start circuit;
controlling the connection relation between a PFC (power factor correction) switch tube and a bus capacitor according to the direct-current voltage value in the soft start circuit, and charging the bus capacitor when the PFC switch tube is connected with the bus capacitor in series, wherein the bus capacitor enters a soft start working state; when the PFC switch tube is connected with the bus capacitor in parallel, the bus capacitor is boosted, and the bus capacitor enters a boosting working state.
Further, the acquiring a dc voltage value in the soft start circuit includes:
dividing the direct-current voltage output by a rectifying module in the soft start circuit;
collecting a direct current voltage value on a divider resistor;
and calculating the direct current voltage value in the soft start circuit according to the direct current voltage value on the voltage dividing resistor.
Further, the controlling the operating state of the PFC switching tube according to the dc voltage value in the soft start circuit includes:
setting a plurality of voltage intervals with the same voltage change amplitude;
taking a voltage interval with the minimum voltage mean value corresponding to the voltage interval as a charging voltage interval;
when the direct-current voltage value in the soft start circuit enters the charging voltage interval, controlling the conduction of a PFC (power factor correction) switching tube;
and when the maximum value of the charging voltage interval is reached, controlling the PFC switch tube to be cut off, and determining the voltage interval adjacent to the current charging voltage interval as the charging voltage interval until the voltage of the bus capacitor reaches the maximum value of the voltage.
In a third aspect, the present application provides a controller comprising:
the soft start circuit of the first aspect.
In a fourth aspect, the present application provides an air conditioner comprising:
a controller as claimed in the third aspect.
The technical scheme provided by the embodiment of the application can have the following beneficial effects:
the soft start circuit comprises a control module, a circuit switching module, a rectifying module, a PFC (power factor correction) switch tube and a bus capacitor, wherein the input end of the rectifying module is connected with an input alternating current power supply, the output end of the rectifying module is connected with the PFC switch tube, the control module switches the connection relation between the PFC switch tube and the bus capacitor through the circuit switching module, when the PFC switch tube is connected with the bus capacitor in series, the bus capacitor is charged, and the bus capacitor enters a soft start working state; when the PFC switch tube is connected with the bus capacitor in parallel, the bus capacitor is boosted, and enters a boosting working state, so that the current in a circuit can be reduced in the bus charging process, the loss of impact current to rear-end electronic components is reduced, a plurality of cement resistors are omitted, and the space and the cost are effectively saved.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application.
Fig. 1 is a circuit diagram of a soft start circuit according to an embodiment of the present application.
Fig. 2 is a functional block diagram of a soft start circuit according to another embodiment of the present application.
Fig. 3 is a graph of a switching tube on-time and bus voltage waveform according to an embodiment of the present application.
Fig. 4 is a flowchart of a soft start control method according to an embodiment of the present application.
Fig. 5 is a flowchart of another soft-start control method according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail below. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without making any creative effort, shall fall within the protection scope of the present application.
Fig. 1 is a functional block diagram of a soft-start circuit according to an embodiment of the present application, and as shown in fig. 1, the soft-start circuit includes:
the circuit comprises a control module 1, a circuit switching module 2, a rectifying module 3, a PFC (Power Factor Correction) switch tube 5 and a bus capacitor 4;
the input end of the rectification module 3 is connected with an input alternating current power supply;
the output end of the rectification module 3 is connected with the PFC switching tube 5;
the control module 1 switches the connection relation between the PFC switch tube 5 and the bus capacitor 4 through the circuit switching module 2, when the PFC switch tube 5 is connected with the bus capacitor 4 in series, the bus capacitor 4 is charged, and the bus capacitor 4 enters a soft start working state; when the PFC switch tube 5 is connected in parallel with the bus capacitor 4, the bus capacitor 4 is boosted, and the bus capacitor 4 enters a boosting working state.
In this embodiment, the method further includes:
and the PFC inductor 6 is arranged between the positive electrode output end of the rectifier module 3 and the positive electrode of the bus capacitor 4 and is used for charging or boosting the bus capacitor 4.
In this embodiment, the method further includes:
the voltage sampling module 7 is connected with the rectifying circuit 3, and the voltage sampling module 7 is connected with the rectifying circuit 3;
the voltage sampling module 7 comprises a first resistor and a second resistor, and the resistance value of the first resistor is greater than that of the second resistor;
the first resistor and the second resistor are used for dividing the direct-current voltage output by the rectifying module; the voltage sampling module 7 is used for collecting a direct-current voltage value on the second resistor;
the control module 1 is further configured to calculate a dc voltage value output by the rectifying module 3 according to the dc voltage value on the second resistor collected by the voltage sampling module 7.
Because the direct current voltage value of rectifier module 3 output is higher, through gather again after carrying out the partial pressure to the direct current voltage of rectifier module 3 output can reduce the influence of big voltage to the controller, because the second resistance value is less than first resistance value far away, therefore the second resistance corresponds the partial pressure value less, goes to calculate the direct current voltage value of rectifier module 1 output again with less partial pressure value input controller, can improve system reliability.
Through increase cement resistance in bus pre-charge circuit in order to reduce impulse current to rear end electronic components's loss among traditional soft start circuit, nevertheless can occupy the space of too many control panels, extravagant cost just is unfavorable for the controller heat dissipation.
In this embodiment, the soft start circuit includes a control module, a circuit switching module, a rectifying module, a PFC switching tube, and a bus capacitor, an input end of the rectifying module is connected to the input ac power supply, an output end of the rectifying module is connected to the PFC switching tube, the control module switches a connection relationship between the PFC switching tube and the bus capacitor through the circuit switching module, when the PFC switching tube is connected in series with the bus capacitor, the bus capacitor is charged, and the bus capacitor enters a soft start operating state; when the PFC switch tube is connected with the bus capacitor in parallel, the bus capacitor is boosted, and enters a boosting working state, so that the current in a circuit can be reduced in the bus charging process, the loss of impact current to rear-end electronic components is reduced, a plurality of cement resistors are omitted, and the space and the cost are effectively saved.
Fig. 2 is a circuit diagram of a soft-start circuit according to another embodiment of the present application, and as shown in fig. 2, based on the previous embodiment, a circuit switching module in the soft-start circuit includes:
first switch K1A second switch K2And a third switch K3；
First switch K1The power supply is arranged between the emitting electrode of the PFC switching tube Q and the positive electrode of the bus capacitor C;
second switch K2The voltage regulator is arranged between the collector of the PFC switching tube Q and the negative electrode of the bus circuit C;
third switch K3And is arranged between the collector of the PFC switch tube Q and the anode of the bus circuit C.
In this embodiment, the control module switches the operating condition of the PFC switching tube through the circuit switching module, including:
the control module controls the first switch K1And a second switch K2Closed, third switch K3Disconnecting and controlling the PFC switch tube Q to be connected with the bus capacitor C in parallel;
the control module 1 controlsA switch K1And a second switch K2Open, third switch K3And closing the switch tube to control the PFC switch tube Q to be connected with the bus capacitor C in series.
In some embodiments, the first switch K1A second switch K2Or a third switch K3Is at least one of a relay, a circuit breaker, a contactor, a thyristor device and a controllable semiconductor device.
It should be noted that, the soft start system with the controllable switch tube around the bus circuit can use the soft start circuit of the present application, and the switch device is used to switch the controllable switch tube between the buck-boost state and the bus pre-charge state, so that the bus voltage soft start can be completed by using the controllable switch tube of the system itself and adding the switch device.
In some embodiments, the control module 1 is further configured to:
setting a plurality of voltage intervals with the same voltage change amplitude;
taking a voltage interval with the minimum voltage mean value corresponding to the voltage interval as a charging voltage interval;
when the direct-current voltage value output by the rectifying module enters a charging voltage interval, controlling the conduction of a PFC (power factor correction) switching tube Q; and when the maximum value of the charging voltage interval is reached, controlling the PFC switch tube Q to be cut off, and determining the voltage interval adjacent to the current charging voltage interval as the charging voltage interval until the voltage of the bus capacitor reaches the maximum value of the voltage.
In this embodiment, the maximum voltage is
Figure BDA0003344607750000071
Wherein, U is the effective value of the voltage of the input alternating current power supply.
In this embodiment, an input ac power source generates a dc power through a rectifier module, and the dc power is divided by a resistor (resistor R)1、R2) Obtaining a DC sampled value Vin(ii) a The inductor L, the switching tube Q and the capacitor C form a boost circuit; relay K1、K2、K3The control circuit is used for controlling the whole circuit to work between a boosting state and a bus voltage soft start state; MCU controllerGenerating switching signals for respectively controlling the relays K1、K2、K3The switch state of (1).
In a relay K1、K2、K3When all the circuits are disconnected, the whole circuit is in a disconnected state and is marked as an initial state; relay K1、K2Disconnection, K3When closed, the power supply passes through the inductor L, the switch tube Q and the relay K3Charging a bus capacitor C, wherein the circuit works in a bus voltage soft start charging state; relay K1、K2Closure, K3When the circuit is disconnected, the switching tube Q is connected with the bus capacitor C in parallel to form a boost circuit, and the circuit works in a PFC boost state.
Upon power-up, relay K1、K2、K3When the system receives a working instruction, the bus capacitor needs to be charged, and the MCU control unit processes and judges the sampling signal of the input direct current voltage and inputs the direct current voltage VinFrom
Figure BDA0003344607750000081
(where U is an effective value of the voltage of the input AC power) are sequentially divided into k (k) having the same voltage variation>Segment 1), defining an interval
Figure BDA0003344607750000082
Figure BDA0003344607750000083
It should be noted that the larger k is, the better the soft start effect is, and those skilled in the art can set the value of k according to the time requirement.
MCU detects VinIn the nth interval
Figure BDA0003344607750000084
During the process, the MCU controls the switch tube Q to be in an on state and in an off state at other times, and the cycle is repeated for a plurality of periods to ensure that the bus voltage is charged to
Figure BDA0003344607750000085
So on, go straightFinish V to MCU onceinUnder the control of all the intervals, the bus voltage is correspondingly increased
Figure BDA0003344607750000086
Taking 220V power frequency AC input voltage as an example, under ideal conditions, after rectification, DC voltage peak value V is obtained by samplinginIs in the range of 0V to 311V, according to the formula:
Figure BDA0003344607750000087
it can be known that the smaller the voltage change Δ u is for the same time change Δ t or the larger the time change Δ t is for the same voltage change Δ u, the smaller the current i is.
Taking the division into 3 segments as an example, as shown in FIG. 3, the peak value of the DC voltage is VdcAnd the z input period is T, the switching tube on time and the bus voltage waveform refer to FIG. 3, the switching tube on time in the interval 1 corresponds to the bus voltage waveform, the waveform is initial until the voltage value corresponding to the waveform reaches 103V, then the switching tube is controlled to be cut off, and when the voltage value corresponding to the bus voltage waveform falls back to 103V, the switching tube is controlled to be switched on. The specific control mode is as follows: after the system receives the working instruction, the direct current voltage V is inputinIs divided into 3 sections from 0V to 311V, and defines an interval 1[0V to 103V ]]And interval 2[ 103V-206V ]]And interval 3[ 206V-311V ]](ii) a The MCU detects the DC voltage VinIn the interval 1[ 0V-103V ]]During the process, the MCU controls the switching tube Q to be in an on state and in an off state at other times, and the process is repeated for a plurality of periods to ensure that the bus voltage is charged to 103V; the MCU then detects the DC input voltage VinIn the interval 2[ 103V-206V]During the process, the MCU controls the switching tube Q to be in an on state and in an off state at other times, and the process is repeated for a plurality of cycles to ensure that the bus voltage is charged to 206V; finally, the MCU detects the DC input voltage VinIn the interval 3[ 206V-311V]During the charging, the MCU controls the switching tube Q to be in an on state and be in an off state at other times, and the cycle is repeated for a plurality of periods to ensure that the bus voltage is charged to 311V, and then the bus voltage can correspondingly rise to 311V; then the MCU controls the relay to work in a state IIIAnd at this point, completing the soft start process of the whole bus voltage. Compared with the traditional bus voltage starting mode, the process is more stable in a resistance buffering mode. Therefore, the bus voltage is controllable in the whole soft start process, the on and off of the controllable switch tube are controlled by synchronously acquiring the input voltage value, the bus voltage is stably raised, the impact current in the charging process of the traditional charging circuit is reduced, and the reliability and the service life of electronic components are improved.
In the embodiment, the peak value of the input voltage passing through the rectifying module is sampled in real time, the working state of the controllable switch tube of the PFC is controlled by the relay, so that the controllable switch tube is switched between the direct-current bus voltage soft start working state and the boost state, when the controllable switch tube works in the bus voltage soft start state, the direct-current voltage value at the rear end of the rectifying bridge is detected in real time, the MCU controls the switch tube to be switched on from the lowest point of the direct-current voltage peak value and to be switched on when the direct-current voltage gradually changes to the highest point, and the on-off time and the on-off duration time of the switch tube are adjusted in real time and accurately in the process, so that the charging current during bus charging is effectively controlled, the impact on elements at the rear end of a loop is reduced, the starting reliability of the air conditioner is improved, and the service life of the air conditioner is prolonged; meanwhile, a plurality of cement resistors are omitted, so that the space is effectively saved and the cost is reduced.
Fig. 4 is a flowchart of a soft-start control method according to an embodiment of the present application, and as shown in fig. 3, the soft-start control method includes:
s41: collecting a direct current voltage value in a soft start circuit;
in this embodiment, the dc voltage value in the soft start circuit is collected, including:
s411: dividing the direct-current voltage output by a rectifying module in the soft start circuit;
s412: collecting a direct current voltage value on a divider resistor;
s413: and calculating the direct current voltage value in the soft start circuit according to the direct current voltage value on the voltage dividing resistor.
S42: controlling the connection relation between a PFC switch tube and a bus capacitor according to a direct-current voltage value in the soft start circuit, and charging the bus capacitor when the PFC switch tube is connected with the bus capacitor in series, so that the bus capacitor enters a soft start working state; when the PFC switch tube is connected with the bus capacitor in parallel, the bus capacitor is boosted, and the bus capacitor enters a boosting working state.
In this embodiment, controlling the operating state of the PFC switching tube according to the dc voltage value in the soft start circuit includes:
s421: setting a plurality of voltage intervals with the same voltage change amplitude;
s422: taking a voltage interval with the minimum voltage mean value corresponding to the voltage interval as a charging voltage interval;
s423: when the direct-current voltage value in the soft start circuit enters a charging voltage interval, controlling a PFC (power factor correction) switching tube to be conducted;
s424: and when the maximum value of the charging voltage interval is reached, controlling the PFC switching tube to be cut off, and determining the voltage interval adjacent to the current charging voltage interval as the charging voltage interval until the voltage of the bus capacitor reaches the maximum value of the voltage.
As shown in FIG. 5, upon power-up, relay K1、K2、K3When the system receives a working instruction, the bus capacitor needs to be charged, and the MCU control unit processes and judges the sampling signal of the input direct current voltage and inputs the direct current voltage VinFrom
Figure BDA0003344607750000101
(where U is an effective value of the voltage of the input AC power) are sequentially divided into k (k) having the same voltage variation>Segment 1), defining an interval
Figure BDA0003344607750000102
Figure BDA0003344607750000103
It should be noted that the larger k is, the better the soft start effect is, and those skilled in the art can set the value of k according to the time requirement.
MCU detects VinIn the nth interval
Figure BDA0003344607750000111
During the process, the MCU controls the switch tube Q to be in an on state and in an off state at other times, and the cycle is repeated for a plurality of periods to ensure that the bus voltage is charged to
Figure BDA0003344607750000112
So on until the MCU completes V onceinUnder the control of all the intervals, the bus voltage is correspondingly increased
Figure BDA0003344607750000113
It should be noted that the present application is applicable to a rectifying-boosting circuit, and is applicable to a scenario with bus charging.
In the embodiment, the peak value of the input voltage passing through the rectifying module is sampled in real time, the working state of the controllable switch tube of the PFC is controlled by the relay, so that the controllable switch tube is switched between the direct-current bus voltage soft start working state and the boost state, when the controllable switch tube works in the bus voltage soft start state, the direct-current voltage value at the rear end of the rectifying bridge is detected in real time, the MCU controls the switch tube to be switched on from the lowest point of the direct-current voltage peak value and to be switched on when the direct-current voltage gradually changes to the highest point, and the on-off time and the on-off duration time of the switch tube are adjusted in real time and accurately in the process, so that the charging current during bus charging is effectively controlled, the impact on elements at the rear end of a loop is reduced, the starting reliability of the air conditioner is improved, and the service life of the air conditioner is prolonged; meanwhile, a plurality of cement resistors are omitted, so that the space is effectively saved and the cost is reduced.
An embodiment of the present invention provides a controller, including: a soft start circuit as described in the previous embodiments.
An embodiment of the present invention further provides an air conditioner, including: a controller as described in the previous embodiments.
It is understood that the same or similar parts in the above embodiments may be mutually referred to, and the same or similar parts in other embodiments may be referred to for the content which is not described in detail in some embodiments.
It should be noted that, in the description of the present application, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Further, in the description of the present application, the meaning of "a plurality" means at least two unless otherwise specified.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and the scope of the preferred embodiments of the present application includes other implementations in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present application.
It should be understood that portions of the present application may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.
In addition, functional units in the embodiments of the present application may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.
The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc.
In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.
It should be noted that the present invention is not limited to the above-mentioned preferred embodiments, and those skilled in the art can obtain other products in various forms without departing from the spirit of the present invention, but any changes in shape or structure can be made within the scope of the present invention with the same or similar technical solutions as those of the present invention.

Claims (13)

1. A soft start circuit, comprising:
the control module, the circuit switching module, the rectifying module, the PFC switch tube and the bus capacitor;
the input end of the rectification module is connected with an input alternating current power supply;
the output end of the rectification module is connected with the PFC switching tube;
the control module switches the connection relation between the PFC switch tube and the bus capacitor through the circuit switching module, when the PFC switch tube is connected with the bus capacitor in series, the bus capacitor is charged, and the bus capacitor enters a soft start working state; when the PFC switch tube is connected with the bus capacitor in parallel, the bus capacitor is boosted, and the bus capacitor enters a boosting working state.
2. The soft-start circuit of claim 1, wherein the circuit switching module comprises:
a first switch, a second switch, and a third switch;
the first switch is arranged between an emitter of the PFC switch tube and the anode of the bus capacitor;
the second switch is arranged between the collector of the PFC switch tube and the negative electrode of the bus circuit;
the third switch is arranged between the collector of the PFC switch tube and the anode of the bus circuit.
3. The soft-start circuit of claim 2, wherein the control module switches the connection relationship between the PFC switch tube and the bus capacitor through the circuit switching module, and the circuit switching module comprises:
the control module controls the PFC switch tube to be connected with the bus capacitor in parallel by controlling the first switch and the second switch to be closed and the third switch to be opened;
the control module controls the PFC switch tube to be connected with the bus capacitor in series by controlling the first switch and the second switch to be switched off and the third switch to be switched on.
4. A soft start circuit according to claim 2 or 3, wherein the first, second or third switch is at least one of a relay, a circuit breaker, a contactor, a thyristor, a controllable semiconductor device.
5. The soft-start circuit of claim 1, further comprising:
the voltage sampling module is connected with the rectifying circuit;
the voltage sampling module comprises a first resistor and a second resistor, and the resistance value of the first resistor is greater than that of the second resistor;
the first resistor and the second resistor are used for dividing the direct-current voltage output by the rectifying module; the voltage sampling module is used for collecting a direct current voltage value on the second resistor;
the control module is further used for calculating the direct current voltage value output by the rectifying module according to the direct current voltage value on the second resistor collected by the voltage sampling module.
6. The soft-start circuit of claim 5, wherein the control module is further configured to:
setting a plurality of voltage intervals with the same voltage change amplitude;
taking a voltage interval with the minimum voltage mean value corresponding to the voltage interval as a charging voltage interval;
when the direct-current voltage value output by the rectifying module enters the charging voltage interval, controlling the conduction of a PFC (power factor correction) switching tube;
and when the maximum value of the charging voltage interval is reached, controlling the PFC switch tube to be cut off, and determining the voltage interval adjacent to the current charging voltage interval as the charging voltage interval until the voltage of the bus capacitor reaches the maximum value of the voltage.
7. A soft start circuit as claimed in claim 5 or 6 wherein the voltage maximum is
Figure FDA0003344607740000021
Wherein, U is the effective value of the voltage of the input alternating current power supply.
8. The soft-start circuit of claim 1, further comprising:
and the PFC inductor is arranged between the positive output end of the rectifying module and the positive electrode of the bus capacitor and is used for charging or boosting the bus capacitor.
9. A soft start control method, comprising:
collecting a direct current voltage value in a soft start circuit;
controlling the connection relation between a PFC (power factor correction) switch tube and a bus capacitor according to the direct-current voltage value in the soft start circuit, and charging the bus capacitor when the PFC switch tube is connected with the bus capacitor in series, wherein the bus capacitor enters a soft start working state; when the PFC switch tube is connected with the bus capacitor in parallel, the bus capacitor is boosted, and the bus capacitor enters a boosting working state.
10. The soft-start control method of claim 9, wherein the acquiring the dc voltage value in the soft-start circuit comprises:
dividing the direct-current voltage output by a rectifying module in the soft start circuit;
collecting a direct current voltage value on a divider resistor;
and calculating the direct current voltage value in the soft start circuit according to the direct current voltage value on the voltage dividing resistor.
11. The soft-start control method according to claim 9 or 10, wherein the controlling the connection relationship between the PFC switching tube and the bus capacitor according to the dc voltage value in the soft-start circuit comprises:
setting a plurality of voltage intervals with the same voltage change amplitude;
taking a voltage interval with the minimum voltage mean value corresponding to the voltage interval as a charging voltage interval;
when the direct-current voltage value in the soft start circuit enters the charging voltage interval, controlling the conduction of a PFC (power factor correction) switching tube;
and when the maximum value of the charging voltage interval is reached, controlling the PFC switch tube to be cut off, and determining the voltage interval adjacent to the current charging voltage interval as the charging voltage interval until the voltage of the bus capacitor reaches the maximum value of the voltage.
12. A controller, comprising:
a soft start circuit as claimed in any one of claims 1 to 8.
13. An air conditioner, comprising:
the controller of claim 12.
CN202111319185.9A 2021-11-09 2021-11-09 Soft start circuit, soft start control method, controller and air conditioner Pending CN114123749A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114709499A (en) * 2022-05-10 2022-07-05 深圳市海雷新能源有限公司 Lithium battery monitoring system and method based on fire-fighting parameters

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114709499A (en) * 2022-05-10 2022-07-05 深圳市海雷新能源有限公司 Lithium battery monitoring system and method based on fire-fighting parameters

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