CN113904579A - Control circuit and controller - Google Patents

Control circuit and controller Download PDF

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Publication number
CN113904579A
CN113904579A CN202111173471.9A CN202111173471A CN113904579A CN 113904579 A CN113904579 A CN 113904579A CN 202111173471 A CN202111173471 A CN 202111173471A CN 113904579 A CN113904579 A CN 113904579A
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CN
China
Prior art keywords
signal
module
resistor
electrically connected
sampling
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Pending
Application number
CN202111173471.9A
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Chinese (zh)
Inventor
王小洪
郑乐鹏
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Hangzhou Leaderway Electronics Co ltd
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Hangzhou Leaderway Electronics Co ltd
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Publication of CN113904579A publication Critical patent/CN113904579A/en
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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
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal 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
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal 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, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal 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, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal 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, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
    • 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
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H02M1/34—Snubber circuits
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
    • H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation
    • H02P27/085—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency

Abstract

The embodiment of the application provides a control circuit and a controller. The control circuit comprises a power module, a sampling module, a comparison module, a signal processing module, a control module, a power ground and a signal ground; the power module and the control module are electrically connected with a power ground, and the comparison module is electrically connected with the signal ground; the power ground and the signal ground are connected in common; the sampling module is electrically connected with the power module; the sampling module is electrically connected with the comparison module; the comparison module generates a first protection signal at least according to the sampling signal and the reference signal; the output end of the comparison module is electrically connected with the signal processing module; the signal processing module is electrically connected with both a power ground and a signal ground; the signal processing module generates a second protection signal at least according to the first protection signal; the output end of the signal processing module is electrically connected with the control module; the control module is connected with the power module and used for controlling the output current of the power module to be reduced at least according to the second protection signal. The control circuit has a reliable overcurrent protection function.

Description

Control circuit and controller
Technical Field
The present disclosure relates to circuit control, and more particularly to a control circuit and a controller for overcurrent protection.
Background
The circuit design not only needs to meet the electrical parameter requirements of the electric equipment, but also needs to be provided with a protection function, so that the reliability of the whole circuit design or the electric equipment is improved or the use risk is reduced; among them, overcurrent protection is a common protection function.
Disclosure of Invention
Based on this, the embodiment of the application provides a controller, can realize reliable overcurrent protection function.
In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:
a control circuit comprises a power module, a sampling module, a comparison module, a signal processing module, a control module, a power ground and a signal ground; the power module and the control module are electrically connected with the power ground, and the comparison module is electrically connected with the signal ground; the power ground and the signal ground are connected in common; the sampling module is electrically connected with the power module and is used for sampling to obtain a sampling signal, and the sampling signal represents the output current of the power module; the sampling module is electrically connected with the comparison module and is used for sending the sampling signal to the comparison module; the comparison module generates a first protection signal according to at least the sampling signal and a reference signal; the output end of the comparison module is electrically connected with the signal processing module and sends the first protection signal to the signal processing module; the signal processing module is electrically connected with both the power ground and the signal ground; the signal processing module generates a second protection signal at least according to the first protection signal; the output end of the signal processing module is electrically connected with the control module and is used for sending the second protection signal to the control module; the control module is electrically connected with the power module and used for controlling the output current of the power module to be reduced at least according to the second protection signal.
The embodiment of the application also provides a controller, which is used for controlling the motor and comprises the control circuit.
The application provides a control circuit, which comprises a power module, a sampling module, a comparison module, a signal processing module, a control module, a power ground and a signal ground; the power module and the control module are electrically connected with a power ground, and the comparison module is electrically connected with a signal ground; the sampling module samples to obtain a sampling signal representing the output current of the power module, and the comparison module outputs a first protection signal according to the sampling signal and a reference signal; the first protection signal which is generated by the comparison module and is used for representing the occurrence of overcurrent is subjected to signal conversion through the signal processing module, and a second protection signal which takes power ground as reference is generated; the control module executes protection according to the second protection signal, and the reliability of protection can be improved.
The embodiment of the application also provides a controller, which is used for controlling the motor and comprises the control circuit. The controller also has the advantage of reliable protection.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments or the background art of the present invention, the drawings needed to be used in the description of the embodiments or the background art will be briefly introduced below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a block diagram of a control circuit according to an embodiment of the present application;
fig. 2 is a circuit diagram of a signal processing module according to an embodiment of the present disclosure;
FIG. 3 is a circuit diagram of a control circuit according to another embodiment of the present disclosure;
fig. 4 is a circuit schematic diagram of a comparison module and a signal processing module according to another embodiment of the present application;
FIG. 5 is a schematic diagram of a control circuit for controlling a motor according to another embodiment of the present disclosure;
FIG. 6 is a block diagram of a control circuit for controlling a motor according to another embodiment of the present application;
fig. 7 is a schematic diagram of a signal processing module according to another embodiment of the present application;
FIG. 8 is a schematic circuit diagram of a comparison module and a signal processing module according to another embodiment of the present disclosure;
fig. 9 is a schematic circuit diagram of a comparison module and a signal processing module according to another embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. 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.
In this application, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
Some non-isolated control circuits often include a strong current portion and a weak current portion, the strong current portion is used for providing driving power of a load, and the weak current portion is used for controlling and providing a control signal for the strong current portion; common ground problems often exist in such non-isolated control circuits, particularly in variable frequency control driver circuit applications. In the design of a Printed Circuit Board (PCB), the signal ground of a weak portion and the power ground of a strong portion are commonly connected, for example, a single-point common ground connection is performed at a certain point, which sometimes causes certain design difficulty to the protection Circuit, and it is better to consider which ground is the reference. For example, a part of weak current part needs to execute corresponding protection action according to the protection signal, so as to control the working state of the strong current part. When the strong current part is in overcurrent, the weak current part needs to control the strong current part to reduce the output current according to an overcurrent signal; reducing the output current includes stopping the output current, i.e., reducing the output current to 0. In an actual product, if a Printed Circuit Board (PCB) of the controller is large, the power ground and the signal ground are far apart on the Printed Circuit Board, and even though the power ground and the signal ground are connected by copper plating or a wire, a potential difference still exists between the power ground and the signal ground, so that the same signal presents different potentials for the power ground and the signal ground, and further, protection false triggering may be caused. In larger panels, the potential difference between the grounds, which tends to be closer to the copper cladding or shorter wires, is smaller; conversely, the greater the potential difference between grounds with longer copper deposits or longer wires.
Based on this, the embodiment of the present application provides a control circuit, as shown in fig. 1, including a power module 11, a sampling module 12, a comparison module 13, a signal processing module 14, a control module 15, a power ground G1, and a signal ground G2. In the whole circuit or the cloth board, the power ground G1 and the signal ground G2 are electrically connected, and particularly, the power ground G1 and the signal ground G2 can be electrically connected by a connection mode of copper plating on a PCB and the like; however, due to the difference of the distribution plates, the potential difference between the grounds at close positions is often approximately 0, while the potential difference between the grounds at far positions exists; this is particularly the case for larger panel controllers or more powerful controllers or multi-load drive controllers. In this application, when a module or device terminal is connected to a ground, specifically, the module or device terminal is connected to the ground board in a close distance, and the module voltage or the device terminal voltage may be referenced to the ground; since the module is far from the other grounds, a certain potential difference exists between the module and the other grounds, and the far grounds are not suitable to be used as reference points of voltages of nodes of the module. In one embodiment, power module 11 and control module 15 are electrically connected to power ground G1, i.e., the reference grounds of power module 11 and control module 15 are closer to power ground G1 on the fabric, and the reference grounds of power module 11 and control module 15 are electrically connected to power ground G1. The comparison module 13 is electrically connected to the signal ground G2, i.e. the reference ground of the comparison module 13 is closer to the signal ground G2 on the board, and the reference ground of the comparison module 13 is electrically connected to the signal ground G2.
The sampling module 12 is electrically connected to the power module 11 and configured to sample to obtain a sampling signal Vs, where the sampling signal Vs represents an output current of the power module 11. The sampling module 12 is electrically connected to the comparing module 13, and is configured to send the sampling signal Vs to the comparing module 13. The comparison module 13 generates a first protection signal P1 according to the sampling signal 12 and the reference signal; the reference signal can be built in the comparison module or generated in an external connection mode; if the comparison module 13 is programmable, the preset can also be programmed. The output end of the comparing module 13 is electrically connected to the signal processing module 14, and sends the first protection signal P1 to the signal processing module 14.
The signal processing module 14 generates a second protection signal P2 according to the first protection signal P1; the output end of the signal processing module 14 is electrically connected to the control module 15, and is configured to send the second protection signal P2 to the control module 15. In this embodiment, the signal processing module 14 is electrically connected to both the power ground G1 and the signal ground G2, i.e., the signal processing module 14 is connected across the power ground G1 and the signal ground G2, and the reference point of the potential of the first protection signal P1 is the signal ground G2; after the first protection signal P1 is processed by the signal processing module, a second protection signal P2 with the power ground G1 as a reference point is generated, and the second protection signal P2 is the same as the reference ground of the control unit 15, so that false triggering is avoided. Further, the control module 15 is connected to the power module 11 for controlling the output current of the power module 15 to decrease according to the second protection signal P2. It should be noted that, in the present application, controlling the output current of the power module to decrease includes decreasing the output current of the power module to 0, that is, the control module stops outputting the control signal to the power module, and the power module no longer provides the drive for the load.
Further, the protection is suitable for high-level protection, that is, the protection mechanism of the control module 15 is to execute a protection action when receiving a high-level protection signal; in other words, if the second protection signal P2 input to the control module 15 is at a high level, the overcurrent protection is triggered, and the control module 15 controls the output current of the power module 11 to decrease.
When the protection mechanism of the control module is high-level protection, as shown in fig. 2, the signal processing module may be configured to include a first switch Q1, a first resistor R1, a second resistor R2 and a third resistor R3; the output end of the comparison module is electrically connected with the control end of the first switch tube Q1, and the first protection signal P1 is sent to the control end of the first switch tube Q1; a first end of the first switch tube Q1 is electrically connected with the power supply terminal VCC, a second end of the first switch tube Q1 is electrically connected with a first end of the first resistor R1, and a second end of the first resistor R1 is electrically connected with the signal ground G2; a second end of the first switch tube Q1 is electrically connected with a first end of a second resistor R2, a second end of the second resistor R2 is electrically connected with a first end of a third resistor R3, and a second end of the third resistor R3 is electrically connected with a power ground G1; the second end of the second resistor R2 is the output end of the signal processing module, is electrically connected with the control module and sends a second protection signal P2 to the control module; the first switching tube Q1 is configured to: when the control end of the first switch tube Q1 receives the first protection signal P1, the first switch tube Q1 is closed and conducted, the second resistor R2 and the third resistor R3 divide the voltage of the power supply VCC, and the voltage at the common point of the second resistor R2 and the third resistor R3 is made to be at a high level with respect to the power ground G1 by setting the resistance values of the second resistor R2 and the third resistor R3, that is, the second protection signal output by the signal processing module is also guaranteed to be at a high level with respect to the reference ground (the power ground G1) of the control module.
Further, as shown in fig. 3, in one embodiment, the comparing module is as described at 131, and includes a comparator M; in this embodiment, the sampling signal Vs is output to the inverting input (-) of the comparator M, and the reference signal Vref is output to the non-inverting input (+) of the comparator M; at this time, the first switch Q1 of the signal processing module 141 is set to be a PNP transistor Q11; in this embodiment, when the output current of the power module is greater than the overcurrent value, the sampling signal Vs is greater than the reference signal Vref, and at this time, the comparator outputs a low level, and the first switch tube Q11 is turned on, so as to generate a second protection signal with a high level;
in another embodiment, as shown in fig. 4, the sampling signal Vs is output to the non-inverting input (+) of the comparator M, and the reference signal Vref is output to the inverting input (-) of the comparator M; at this time, the first switch Q1 of the signal processing module 142 is set to be an NPN transistor Q12; in this embodiment, when the output current of the power module is greater than the overcurrent value, the sampling signal Vs is greater than the reference signal Vref, and at this time, the comparator outputs a high level, and when the comparator outputs a high level, the first switch Q12 is turned on, and a second protection signal of the high level is generated.
In the above two embodiments, the reference ground of the high/low level (the first protection signal P1) output by the comparator M is the signal ground G2, and the reference ground of the base voltage of the first switch tube is also the signal ground G2, so that the first protection signal P1 output by the comparator M can correctly drive the first switch tube. The reference ground of the second protection signal P2 is the power ground G1, and the reference ground of the control module performing the protection action is also the power ground G1, so the second protection signal P2 can correctly trigger the protection mechanism of the control module. In this embodiment, a sufficiently high protection signal with respect to both signal ground and power ground can be generated by the power supply terminal VCC and the first switching tube.
Further, in an embodiment, the signal ground may generate interference, that is, an electrical signal enters from the signal ground, as shown in fig. 2, when the interference signal may form a path in the signal ground G2, the first resistor R1, the second resistor R2, the third resistor R3 and the power ground G1, in order to prevent the interference signal from causing false triggering of overcurrent protection, the sum of the resistances of the first resistor and the second resistor may be set to be greater than or equal to 10 times of the resistance of the third resistor, that is, (R1+ R2)/R3 ≧ 10, so that it is ensured that even if there is the interference signal, the voltage division of the interference signal on the third resistor R3 is low, a high level signal relative to the power ground G1 is not generated, and the control module is not subject to false triggering protection due to the interference signal. Further, as shown in fig. 4, in practical applications, the signal processing module is often further provided with a first capacitor C1, and the first capacitor C1 is connected in parallel with the third resistor R31, at this time, in order to prevent the interference signal on the signal ground from generating the false trigger signal and to achieve the fast response of the overcurrent protection, the resistance value of the first resistor R1 may be set to be greater than or equal to 10 times of the sum of the resistance values of the second resistor R2 and the third resistor R3, that is, R1/(R2+ R3) ≧ 10.
In some embodiments, if the protection mechanism of the control module is low-level protection, that is, the protection mechanism of the control module 15 is to execute a protection action when receiving a low-level protection signal; in other words, if the second protection signal P2 input to the control module 15 is at a low level, the overcurrent protection is triggered, and the control module 15 controls the output current of the power module 11 to decrease. At this time, the signal processing module 14 may be configured as shown in fig. 7, where the signal processing module 14 includes a second switching tube Q2, a third switching tube Q3, a zeroth first resistor R01, a zeroth second resistor R02, a zeroth third resistor R03, and a zeroth fourth resistor R04; the output end of the comparison module is electrically connected with the control end of a second switch tube Q2, and a first protection signal P1 is sent to the control end of a second switch tube Q2; a first end of a second switch tube Q2 is electrically connected with a power supply terminal VCC, and a second end of a second switch tube Q2 is electrically connected with a first end of a zero first resistor R01; a second end of the zeroth resistor R01 is electrically connected with a signal ground G2; a second end of the second switch tube Q2 is electrically connected with a first end of a second zero resistor R02, a second end of a second zero resistor R02 is electrically connected with a first end of a third zero resistor R03, and a second end of the third zero resistor R03 is electrically connected with a power ground G1; the second end of the second zero resistor R02 is electrically connected to the control end of the third switch Q3, the first end of the third switch Q3 is electrically connected to the power supply VCC, the second end of the third switch Q3 is electrically connected to the first end of the fourth zero resistor R04, the second end of the fourth zero resistor R04 is electrically connected to the power ground G1, the first end of the fourth zero resistor R04 is the output end of the signal processing module 14, and is electrically connected to the control module, and outputs a second protection signal P2 to the control module; specifically, when the third switch Q3 receives the first protection signal P1, the operating state is switched such that the fourth switch Q4 is turned off and the second protection signal generated at the first end of the zeroth fourth resistor R04 is at a low level. When the control module receives the second protection signal P2 with low level, the output current of the control power module decreases.
As can be seen from fig. 7, the reference ground of the high/low level (the first protection signal P1) outputted by the comparing module is the signal ground G2, and the reference ground of the control terminal voltage of the second switch tube is also the signal ground G2, so that the first protection signal P1 outputted by the comparing module can correctly drive the first switch tube. The ground reference of the third switch tube is the power ground G1, the ground reference of the second protection signal P2 is the power ground G1, and the ground reference of the control module performing the protection action is also the power ground G1, so the second protection signal P2 can correctly trigger the protection mechanism of the control module.
As shown in fig. 8, in an embodiment, the second switch Q2 is an NPN transistor Q21, the third switch is a PNP transistor Q31, and the sampling signal Vs of the sampling module is input to the non-inverting input terminal of the comparator M. When the output current of the power module is greater than the overcurrent value, the sampling signal Vs is greater than the reference signal Vref, and at this time, the comparator M outputs a high level, when the comparator outputs a high level, the second switch Q21 is turned on, the second end of the zeroth second resistor R02 is at a high level, the third switch Q31 is turned off, the voltage at the first end of the zeroth fourth resistor R04 is at a low level with respect to the power ground G1, that is, the signal processing module outputs the second protection signal P2 at a low level.
In another embodiment, as shown in fig. 9, the second switching transistor Q2 is a PNP transistor Q22, the third switching transistor is a PNP transistor Q32, and the sampling signal Vs of the sampling module is input to the inverting input terminal of the comparator M. When the output current of the power module is greater than the overcurrent value, the sampling signal Vs is greater than the reference signal Vref, and at this time, the comparator M outputs a low level, and when the comparator outputs a low level, the second switch Q22 is turned on, the second end of the zeroth second resistor R02 is at a high level, the third switch Q33 is turned off, and the voltage at the first end of the zeroth fourth resistor R04 is at a low level with respect to the power ground G1, that is, the signal processing module outputs the second protection signal P2 at a low level.
In the embodiment of the low-level protection mechanism, the signal ground may also have interference, that is, an electrical signal enters from the signal ground, as shown in fig. 8, at this time, the interference signal may form a path in the signal ground G2, the first resistor R01, the second resistor R02, the third resistor R03 and the power ground G1, in order to prevent the interference signal from causing the over-current protection false triggering, the sum of the resistances of the first resistor and the second resistor may be set to be greater than or equal to 10 times of the resistance of the third resistor, that is, (R01+ R02)/R03 ≧ 10, so that it is ensured that even if there is an interference signal, the voltage division of the interference signal on the third resistor R3 is low, a high-level signal with respect to the power ground G1 is not generated, Q31 is not turned on, and the control module is not over-current protected by the false triggering of the interference signal. Further, as shown in fig. 9, in practical applications, the signal processing module often further includes a zeroth capacitor C01, and the first capacitor C01 is connected in parallel with the zeroth third resistor R03, in this case, in order to prevent the interference signal on the signal ground from generating a false trigger signal and to achieve a fast response of the overcurrent protection, it may be configured that: the resistance value of the first zero resistor is more than or equal to 10 times of the sum of the resistance values of the second zero resistor and the third zero resistor, namely R01/(R02+ R03) ≧ 10.
In the signal processing module of the above embodiment, regardless of the type settings of the first switch tube, the second switch tube and the third switch tube, and the sampling signal is input to the equidirectional input end/the inverse input end of the comparator, the optimal setting is that the control signal transmitted from the signal ground to the power ground is a high-level signal, and the high-level signal is generated by level conversion and resistance voltage division through the triode, and the high-level signal generated by this way can ensure that the relative power ground is also a high level, so that the protection function cannot be triggered by mistake.
The circuit design of the outdoor controller of the air conditioner is often a non-isolated design; in the air conditioner controller, a power module is equivalent to a PFC module and/or an inversion module, and the PFC module and the inversion module controllably transmit power of a power grid to an air conditioner compressor and/or a fan under the control of the control module. When the controller is distributed, the positions of the PFC module and the PFC control module are close, and the positions of the inversion module and the inversion control module are close, namely the reference ground of the PFC module and the reference ground of the PFC control module are the same, and the reference ground of the inversion module and the inversion control module is the same, namely the power ground G1 in the embodiment; the supply voltage for the protection module for some protection functions is often supplied by a switching power supply, whose reference ground is also the signal ground of the switching power supply, such as the signal ground G2 in the above-described embodiment; because there is a positional difference between signal ground and power ground, the voltages are not exactly the same. When the air conditioner controller is designed to be thermally grounded, i.e., the opposite ground terminal of the controller with weak current and the opposite ground terminal of the controller with strong current are connected together, especially for a high-power outdoor air conditioner controller and a multi-motor (compressor and fan) controlled outdoor air conditioner controller, because the circuit board is large, the thermal design may cause the difference between the reference ground voltages of the module levels far away, i.e., the potential difference between the signal ground and the power ground.
Therefore, the control circuit provided by the embodiment of the application is suitable for the controller, and the controller is used for controlling the motor, such as the compressor or the fan, and can also be used for controlling the compressor and the fan at the same time. In this embodiment, as shown in fig. 5, the power module of the control circuit includes an inverter unit 111; the inversion unit comprises an inversion bridge consisting of 6 IGBTs. The output end of the inversion unit 111 can be electrically connected with a motor and is used for driving the motor M to work; the output end of the control module is electrically connected with the control end of the inverter unit 111, that is, electrically connected with the control ends of the 6 IGBTs, and is configured to send a control signal to the inverter unit 111; the inverter unit 111 generates a driving signal for driving the motor M to operate according to the control signal.
The sampling module is electrically connected to the inverter unit 111, and is configured to sample a current signal representing an output current of the inverter unit and generate a sampling signal. Specifically, the sampling unit may include a sampling resistor Rs; the sampling resistor Rs is connected in series in an output current loop of the inverter unit 111 or at least connected in series in a phase current loop of the inverter unit; as shown in FIG. 3, the Rs position and the sampling resistor Rs can also be connected in series at any position in the A/B/C/D/E/F/G. The current at any point of A/B/C/D/E/F/G can be used for representing the output current of the inverter unit 111.
Further, in the above embodiment, as shown in fig. 5, the embodiment takes a phase current control manner as an example of motor control, and each phase current loop is provided with a sampling resistor, as shown in Rs1/Rs2/Rs3, and the current on the sampling resistor Rs1 of the W phase is used to represent the output current of the inverter unit 111. The control circuit is further provided with a differential amplification module 16, two input ends of the differential amplification module 16 are respectively connected to two ends of the sampling resistor, such as two ends of Rs1, or two ends of the sampling resistor at any position of a/B/C/D/E/F/G/Rs; the differential amplification module 16 is used for performing differential amplification on the voltages at the two ends of the sampling resistor to obtain a sampling signal; the output end of the differential amplifying module 16 is electrically connected with the same-direction input end or the reverse-direction input end of the comparator M.
Specifically, the output current of the power module can be calculated by the voltage of the sampling resistor Rs1, the voltage difference between the two ends of the sampling resistor is amplified by the differential amplification module, the amplified output voltage enters the reverse input end of the comparator M, and the reference signal of the comparator M is connected to the same-direction input end. Specifically, the reference signal is a reference voltage, and the reference signal Vref is obtained by dividing the power supply terminal voltage VCC by a resistor R7 and a resistor R8. The first protection signal P1 can be accurately detected by the circuit, and the level conversion is carried out through R11 and Q11 to generate a second protection signal P2. The second protection signal P2 is further transmitted to the control module, and the control module performs overcurrent protection according to the second protection signal P2. This circuit has two ground designations, G1 and G2.G1 are power grounds, and G2 is signal ground. G1 and G2 are electrically connected together, but G1 and G2 are at a distance above the PCB LAYOUT where a potential difference exists, and G1 and G2 are likely to interact with each other. By setting R11> > (R21& R31), the interference signal generated at G2 can be prevented, the second protection signal is output and sent to the control module to generate false triggering, and meanwhile, in order to pass the EMC test, the resistance value of R1 can be made to be larger than (R2+ R3) as much as possible.
Further, in an embodiment, as shown in fig. 6, the control Module of the air conditioner controller may include an MCU (Microcontroller Unit) 151, where the MCU is configured to generate PWM signals for driving the 6 switching tubes of the inverter Unit 111; further, in order to improve the driving capability, the control module may further include a driving unit, and at this time, the second protection signal may also be input to the driving unit, and after the driving unit receives the second protection signal, the driving unit pulls down or raises the signal input by the MCU, so as to prevent the PWM signal from being output to the inverter unit.
When MCU does not have protect function, for the convenience of protection or improve the driving capability, can also be provided with: the MCU is connected to the inverter unit 141 sequentially through the buffer unit 152 and the driving unit 153, and at this time, the second protection signal may be input to the buffer unit and/or the driving unit; and after receiving the second protection signal, the buffer unit and/or the driving unit stops outputting the PWM control signal to the inverter unit, so that the overcurrent protection effect is realized.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the system or system embodiments are substantially similar to the method embodiments and therefore are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described system and system embodiments are only illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A control circuit is characterized by comprising a power module, a sampling module, a comparison module, a signal processing module, a control module, a power ground and a signal ground; the power module and the control module are electrically connected with the power ground, and the comparison module is electrically connected with the signal ground; the power ground and the signal ground are connected in common; the sampling module is electrically connected with the power module and is used for sampling to obtain a sampling signal, and the sampling signal represents the output current of the power module; the sampling module is electrically connected with the comparison module and is used for sending the sampling signal to the comparison module; the comparison module generates a first protection signal according to at least the sampling signal and a reference signal; the output end of the comparison module is electrically connected with the signal processing module and sends the first protection signal to the signal processing module; the signal processing module is electrically connected with both the power ground and the signal ground; the signal processing module generates a second protection signal at least according to the first protection signal; the output end of the signal processing module is electrically connected with the control module and is used for sending the second protection signal to the control module; the control module is electrically connected with the power module and used for controlling the output current of the power module to be reduced at least according to the second protection signal.
2. The control circuit of claim 1, wherein the protection mechanism of the control module is that if the second protection signal is at a high level, overcurrent protection is triggered, and the output current of the power module is controlled to be reduced;
the signal processing module comprises a first switching tube, a first resistor, a second resistor and a third resistor; the output end of the comparison module is electrically connected with the control end of the first switch tube, and the first protection signal is sent to the control end of the first switch tube; the first end of the first switch tube is electrically connected with a power supply end, the second end of the first switch tube is electrically connected with the first end of the first resistor, and the second end of the first resistor is electrically connected with the signal ground; the second end of the first switch tube is electrically connected with the first end of the second resistor, the second end of the second resistor is electrically connected with the first end of the third resistor, and the second end of the third resistor is electrically connected with the power ground; the second end of the second resistor is the output end of the signal processing module and is electrically connected with the control module; when the first switch tube control end receives the first protection signal, the first switch tube is closed, and the signal processing module outputs a high-level second protection signal.
3. The control circuit of claim 2, wherein the sum of the resistances of the first and second resistors is greater than or equal to 10 times the resistance of the third resistor;
or the resistance value of the first resistor is greater than or equal to 10 times of the sum of the resistance values of the second resistor and the third resistor.
4. The control circuit of claim 3, wherein the comparison module comprises a comparator;
the sampling signal is output to an inverting input end of the comparator, and the reference signal is output to a homodromous input end of the comparator; the first switch tube is a PNP triode;
alternatively, the first and second electrodes may be,
the sampling signal is output to the same-direction input end of the comparator, and the reference signal is output to the reverse-direction input end of the comparator; the first switch tube is an NPN triode.
5. The control circuit according to claim 1, wherein the protection mechanism of the control module is that if the second protection signal is low level, overcurrent protection is triggered, and the output current of the power module is controlled to decrease;
the signal processing module comprises a second switching tube, a third switching tube, a zeroth first resistor, a zeroth second resistor, a zeroth third resistor and a zeroth fourth resistor; the output end of the comparison module is electrically connected with the control end of the second switch tube, and the first protection signal is sent to the control end of the second switch tube; the first end of the second switch tube is electrically connected with the power supply end, and the second end of the second switch tube is electrically connected with the first end of the zeroth resistor; the second end of the zero first resistor is electrically connected with the signal ground; the second end of the second switch tube is electrically connected with the first end of the second zero resistor, the second end of the second zero resistor is electrically connected with the first end of the third zero resistor, and the second end of the third zero resistor is electrically connected with the power ground; the second end of the second zero resistor is electrically connected with the control end of the third switching tube, the first end of the third switching tube is electrically connected with the power supply end, the second end of the third switching tube is electrically connected with the first end of the fourth zero resistor, the second end of the fourth zero resistor is electrically connected with the power ground, and the first end of the fourth zero resistor is the output end of the signal processing module and is electrically connected with the control module; when the third switch tube receives the first protection signal, the working state is switched, so that the fourth switch tube is disconnected, and a second protection signal with low level is generated at the first end of the zeroth fourth resistor.
6. The control circuit of claim 5, wherein the sum of the resistances of the first zero resistor and the second zero resistor is greater than or equal to 10 times the resistance of the third zero resistor;
or the resistance value of the first zero resistor is greater than or equal to 10 times of the sum of the resistance values of the second zero resistor and the third zero resistor.
7. The control circuit of any of claims 1-6, wherein the power module comprises an inverter unit; the output end of the inversion unit can be electrically connected with a motor and is used for driving the motor to work; the output end of the control module is electrically connected with the control end of the inversion unit and is used for sending a control signal to the inversion unit; the inverter unit generates a driving signal for driving the motor to work according to the control signal;
the sampling module is electrically connected with the inversion unit and is used for sampling a current signal representing the output current of the inversion unit and generating a sampling signal.
8. The control circuit of claim 7, wherein the sampling module comprises a sampling resistor; the sampling resistor is connected in series in an output current loop of the inversion unit or the sampling resistor is connected in series in at least one phase current loop of the inversion unit;
the control circuit further comprises a differential amplification module, and the input ends of the differential amplification module are respectively connected to the two ends of the sampling resistor; the differential amplification module is used for amplifying the voltages at two ends of the sampling resistor to obtain a sampling signal; and the output end of the differential amplification module is electrically connected with the homodromous input end or the reverse input end of the comparator.
9. The control circuit according to claim 8, wherein the control module comprises an MCU and/or a buffer unit and/or a driving unit, and the second protection signal is input to the MCU and/or the buffer unit and/or the driving unit; and after the MCU and/or the buffer unit and/or the driving unit receives the second protection signal, stopping outputting a control signal to the inversion unit.
10. A controller for controlling an electric machine, comprising a control circuit according to any of claims 1-9.
CN202111173471.9A 2021-07-19 2021-10-05 Control circuit and controller Pending CN113904579A (en)

Applications Claiming Priority (2)

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CN2021108172345 2021-07-19

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106961095A (en) * 2017-05-12 2017-07-18 广东美的制冷设备有限公司 Current foldback circuit and air-conditioner
CN209860581U (en) * 2019-04-24 2019-12-27 浙江鲲悟科技有限公司 Overcurrent protection circuit of PFC converter
CN213341632U (en) * 2020-10-30 2021-06-01 上海易咖智车科技有限公司 Switching power supply protection circuit

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106961095A (en) * 2017-05-12 2017-07-18 广东美的制冷设备有限公司 Current foldback circuit and air-conditioner
CN209860581U (en) * 2019-04-24 2019-12-27 浙江鲲悟科技有限公司 Overcurrent protection circuit of PFC converter
CN213341632U (en) * 2020-10-30 2021-06-01 上海易咖智车科技有限公司 Switching power supply protection circuit

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