Heat dissipation device of frequency converter and air conditioner

Abstract

The invention discloses a heat dissipation device of a frequency converter and an air conditioner, and the heat dissipation device of the frequency converter comprises a fan (4) which is configured to cool the frequency converter; the driving circuit (21) comprises a first current amplification device (V3) and an adjustable resistor (R2) electrically connected with a control current input end of the first current amplification device (V3), and one of an amplification current input end and an amplification current output end of the first current amplification device (V3) is electrically connected with the fan (4); a heat monitoring unit (3) configured to monitor a heat dissipation amount of the inverter; the controller (1) is electrically connected with the adjustable resistor (R2) so as to provide current for the control current input end of the first current amplification device (V3); the controller (1) is in signal connection with the heat monitoring part (3) and the adjustable resistor (R2) and is configured to reduce the resistance value of the adjustable resistor (R2) in response to the increase of the heat dissipating capacity of the frequency converter and / or increase the resistance value of the adjustable resistor (R2) in response to the decrease of the heat dissipating capacity of the frequency converter.

Description

Technical Field

[0001] The present invention relates to the technical field of frequency conversion, and in particular to a heat dissipation device of a frequency converter and an air conditioner. Background Art

[0002] Frequency conversion cabinet is mainly used for adjusting the speed of AC motor (asynchronous motor or synchronous motor). It is recognized as the most ideal and promising speed regulation scheme for AC motor. In addition to its excellent speed regulation performance, frequency conversion cabinet also has obvious energy-saving effect. It is an ideal speed regulation device for enterprise technological transformation and product upgrading. Frequency conversion cabinet plays an important role in the power, textile and chemical fiber, building materials, petroleum, chemical industry, metallurgy, municipal administration, papermaking, food and beverage, tobacco and other industries as well as public works (central air conditioning, water supply, water treatment, elevators, etc.).

[0003] The failure of the frequency converter cabinet will increase with the increase of the temperature inside the cabinet, and the service life of the frequency converter cabinet will decrease with the increase of temperature. In order to improve the application stability and service life of the frequency converter cabinet, the heat dissipation problem of the frequency converter cabinet environment must be solved. The existing air-cooled frequency converters in the industry use a cooling solution of cooling fans and fin heat sinks. The fans of this cooling solution all use ordinary DC cooling fans, and there is no fault feedback signal, and the speed cannot be adjusted. On the one hand, if the fan is damaged during the operation of the unit, it cannot be known in time, which further leads to a decrease in heat dissipation performance, which leads to an increase in the failure rate at the least, and directly causes the machine to explode at the worst; on the other hand, the fan speed cannot be adjusted, and it can only run at the specified speed all the time. The speed cannot be adjusted according to the actual operating power range, which is not conducive to the service life of the fan and the prototype. Summary of the invention

[0004] The present invention aims to provide a heat dissipation device for a frequency converter and an air conditioner, so as to improve the problem that the heat dissipation fan of the frequency converter in the prior art cannot adjust the rotation speed according to the actual power of the frequency converter, which is not conducive to the service life of the fan and the frequency converter.

[0005] According to one aspect of an embodiment of the present invention, the present invention provides a heat dissipation device for a frequency converter, the heat dissipation device comprising:

[0006] The fan is configured to cool the inverter;

[0007] The driving circuit includes a first current amplifying device and an adjustable resistor electrically connected to a control current input terminal of the first current amplifying device, wherein one of an amplified current input terminal and an amplified current output terminal of the first current amplifying device is electrically connected to the fan;

[0008] a heat monitoring unit configured to monitor heat dissipation of the inverter; and

[0009] A controller is electrically connected to the adjustable resistor to provide current to the control current input terminal of the first current amplifier device. The controller is signal-connected to the heat monitoring unit and the adjustable resistor respectively and is configured to: reduce the resistance value of the adjustable resistor in response to an increase in the heat dissipation of the inverter and / or increase the resistance value of the adjustable resistor in response to a decrease in the heat dissipation of the inverter.

[0010] In some embodiments, the driving circuit further includes an amplifier circuit connected between the control current input terminal of the first current amplifier device and the adjustable resistor.

[0011] In some embodiments, the adjustable resistance includes a programmable resistance.

[0012] In some embodiments, the heat dissipation device further includes a monitoring unit for monitoring the operating status of the fan, and the monitoring unit includes:

[0013] A voltage sampling circuit is configured to collect a sampled voltage that is positively correlated with a current of the fan;

[0014] The logic control circuit is electrically connected to the voltage sampling circuit and is configured to:

[0015] In response to the sampling voltage being less than the minimum current I for normal operation of the fan min The corresponding first voltage sends a first fault signal; and / or

[0016] In response to the sampling voltage being greater than the maximum current I MAX A second fault signal is issued according to a second voltage corresponding to the voltage; and / or

[0017] In response to the sampling voltage being greater than the fan stall current I stall A third fault signal is issued relative to a third voltage.

[0018] In some embodiments,

[0019] The logic control circuit issues a second fault signal in response to the sampling voltage being greater than the second voltage and less than the third voltage.

[0020] In some embodiments, the logic control circuit further comprises:

[0021] a first comparator, electrically connected to the voltage sampling circuit and configured to output a high level in response to the sampling voltage being less than the first voltage; and / or

[0022] a second comparator, electrically connected to the voltage sampling circuit and configured to output a high level in response to the sampling voltage being greater than the second voltage; and / or

[0023] The third comparator is electrically connected to the voltage sampling circuit and is configured to output a high level in response to the sampling voltage being greater than the third voltage.

[0024] In some embodiments, the logic control circuit includes a first AND gate logic circuit, which includes an output terminal for outputting a second fault signal, a first input terminal electrically connected to the output terminal of the second comparator, and a second input terminal electrically connected to the third comparator through an inverter.

[0025] In some embodiments, the heat dissipation device also includes a fault protection circuit, which includes a switching device and a relay. The switching device includes a control signal input terminal, a controlled current input terminal and a controlled current output terminal. The control signal input terminal of the switching device is respectively connected to the output terminals of the second comparator and the third amplifier, one of the controlled current input terminal and the controlled current output terminal of the switching device is connected to the control signal input terminal of the relay, and the terminals of the controlled loop of the relay are electrically connected to the fan to turn off the fan after one of the second comparator and the third amplifier outputs a high level.

[0026] In some embodiments, the fault protection circuit also includes a first time relay, a control signal input terminal of the first time relay is electrically connected to the second comparator, one end of the controlled circuit of the first time relay is electrically connected to the second comparator, and the other end is electrically connected to the control signal input terminal of the switching device.

[0027] In some embodiments, the first current amplifying device includes a transistor, the control current input terminal of the first current amplifying device is the base of the transistor, one of the amplified current input terminal and the amplified current output terminal of the first current amplifying device is the emitter of the transistor, and the other is the collector of the transistor, the monitoring unit also includes a differential voltage circuit for comparing the voltage difference between the base and the emitter of the transistor, the logic control circuit is electrically connected to the differential voltage circuit, and is configured to send a fourth fault signal in response to the voltage difference between the base and the emitter of the transistor being less than the conduction voltage difference of the transistor.

[0028] In some embodiments, the logic control circuit issues a first fault signal in response to a voltage difference between a base and an emitter of the transistor being greater than a conduction voltage difference of the transistor and a sampling voltage being less than a first voltage.

[0029] In some embodiments, the monitoring unit further comprises:

[0030] a first comparator, electrically connected to the voltage sampling circuit and configured to output a high level in response to the sampling voltage being less than the first voltage; and / or

[0031] The fourth comparator is electrically connected to the differential voltage circuit and is configured to output a high level in response to a voltage difference between the base and the emitter of the first current amplifying device being less than a conduction voltage difference.

[0032] In some embodiments, the logic control circuit also includes a second AND gate logic circuit, which includes an output terminal for outputting a first fault signal, a first input terminal electrically connected to the output terminal of the first comparator, and a second input terminal electrically connected to the fourth comparator through an inverter.

[0033] In some embodiments, the heat dissipation device also includes a second time relay, which includes a control signal input terminal electrically connected to the output terminal of the first comparator, a controlled signal input terminal electrically connected to the output terminal of the second AND gate logic circuit, and a controlled signal output terminal that outputs a first fault signal.

[0034] According to another aspect of the present invention, an air conditioner is provided. The air conditioner comprises the heat dissipation device of the inverter.

[0035] By applying the technical solution of the present invention, when the heat dissipation of the frequency converter increases, the control current of the first current amplifier device is increased by reducing the resistance of the adjustable resistor, thereby increasing the working current of the fan to increase the speed of the fan; when the heat dissipation of the frequency converter decreases, the control current of the first current amplifier device is reduced by increasing the resistance of the adjustable resistor, thereby reducing the working current of the fan to reduce the speed of the fan. The speed of the fan is adjusted according to the heat dissipation of the frequency converter so that the speed of the fan matches the heat dissipation of the frequency converter, which is beneficial to ensure the heat dissipation and cooling of the frequency converter to ensure the normal operation and service life of the frequency converter, and is also beneficial to prevent the fan from always maintaining the highest speed and affecting the life of the fan. Therefore, the problem in the prior art that the heat dissipation fan of the frequency converter cannot adjust the speed according to the actual power of the frequency converter, which is not conducive to the service life of the fan and the frequency converter, is improved.

[0036] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0038] Figure 1 A block diagram showing a heat dissipation device for a frequency converter according to an embodiment of the present invention is shown;

[0039] Figure 2 A circuit diagram of a heat sink for a frequency converter according to an embodiment of the present invention is shown;

[0040] Figure 3A fan status analysis flow chart of a bulk device of a frequency converter according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" in the specification and claims of the present invention and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0043] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0044] In the description of the present invention, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc. indicate positions or positional relationships only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0045] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of the present invention. In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0046] If there is no special explanation, the "include" and "comprising" mentioned in the present invention represent open-ended or closed-ended expressions. For example, the "include" and "comprising" may represent that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0047] If not specifically stated, in the present invention, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0048] like Figure 1 and 2 As shown, in an embodiment of the present invention, the heat dissipation device of the inverter includes a fan 4 for dissipating heat and cooling the inverter, a drive circuit 21 for controlling the start and stop and speed of the fan, a heat monitoring unit 3 for monitoring the heat dissipation of the inverter, and a controller 1.

[0049] The drive circuit 21 for controlling the start and stop and the rotation speed of the fan, the monitoring unit 22 for monitoring the operating status of the fan, and the fault protection circuit 23 for cutting off the power supply of the fan 4 when the fan fails (such as stalling) together constitute the monitoring circuit 2.

[0050] The driving circuit 21 includes a first current amplifier V3 and an adjustable resistor R2 electrically connected to a control current input terminal of the first current amplifier V3 . One of an amplified current input terminal and an amplified current output terminal of the first current amplifier V3 is electrically connected to the fan 4 .

[0051] The controller 1 is electrically connected to the adjustable resistor R2 to provide current to the control current input terminal of the first current amplifier device V3. The controller 1 is signal-connected to the heat monitoring unit 3 and the adjustable resistor R2 respectively and is configured to: reduce the resistance value of the adjustable resistor R2 in response to an increase in the heat dissipation of the inverter and / or increase the resistance value of the adjustable resistor R2 in response to a decrease in the heat dissipation of the inverter.

[0052] In this embodiment, when the heat dissipation of the inverter increases, the control current of the first current amplifier device V3 is increased by reducing the resistance of the adjustable resistor R2, thereby increasing the working current of the fan 4 to increase the speed of the fan; when the heat dissipation of the inverter decreases, the control current of the first current amplifier device V3 is reduced by increasing the resistance of the adjustable resistor R2, thereby reducing the working current of the fan 4 to reduce the speed of the fan. The speed of the fan is adjusted according to the heat dissipation of the inverter so that the speed of the fan 4 matches the heat dissipation of the inverter, which is conducive to ensuring the heat dissipation and cooling of the inverter to ensure the normal operation and service life of the inverter, and is also conducive to preventing the fan 4 from always maintaining the highest speed and affecting the life of the fan 4. Therefore, the problem that the heat dissipation fan of the inverter cannot adjust the speed according to the actual power of the inverter in the prior art, which is not conducive to the service life of the fan and the inverter, is improved.

[0053] Furthermore, the existing air-cooled heat dissipation inverter uses a heat dissipation fan that can only run at a fixed full speed, which is not conducive to the service life of the fan 4, is noisy, and causes unnecessary energy loss under certain working conditions. This embodiment can solve the above problems by calculating the heat dissipation requirements of the actual operating conditions and further adaptively adjusting the speed of the fan 4.

[0054] In this embodiment, the controller 1 is electrically connected to the adjustable resistor R2 to output current to the adjustable resistor R2, and is signal-connected to the adjustable resistor R2 to output a signal for controlling the change of resistance to the adjustable resistor R2. Optionally, the adjustable resistor R2 includes a programmable resistor so that the resistance can be adjusted under the control of the controller 1, thereby adjusting the operating current and speed of the fan 4 to match the heat dissipation of the inverter.

[0055] The driving circuit 21 also includes an amplifier circuit 211 connected between the control current input terminal of the first current amplifier device V3 and the adjustable resistor R2. The amplifier circuit 211 is used to adjust the current in the driving circuit 21 to the current range required by the control current input terminal of the first current amplifier device V3 to ensure that the first current amplifier device V3 can efficiently adjust the working current of the fan 4 according to the input current.

[0056] In some embodiments, the controller 1 includes a microprocessor (DSP). The microprocessor DSP includes a motor drive module (DSP-drive) that outputs current to the resistor R2.

[0057] The heat dissipation device further includes a monitoring unit 22 for monitoring the operating status of the fan 4 . The monitoring unit 22 includes a voltage sampling circuit 223 and a logic control circuit 222 .

[0058] The voltage sampling circuit 223 is configured to collect a sampling voltage Vr1 that is positively correlated with the current of the fan 4. One of the amplified current input terminal and the amplified current output terminal of the first current amplifying device V3 is electrically connected to the ground terminal GND, and a resistor R1 is provided in the circuit between the first current amplifying device V3 and the ground terminal GND. The logic control circuit 222 is electrically connected to one end of the resistor R1 that is away from the ground terminal GND to introduce the sampling voltage Vr1.

[0059] The logic control circuit 222 is electrically connected to the voltage sampling circuit 223 and is configured as follows:

[0060] In response to the sampling voltage Vr1 being less than the minimum current I for normal operation of the fan 4 min The corresponding first voltage Vref3 generates a first fault signal fault1. The minimum operating current I of the fan 4 is min The product of the sampling voltage Vr1 and the resistor R1 is the first voltage Vref3. When the sampling voltage Vr1 is less than the first voltage Vref3, the working current of the fan 4 is less than the minimum current I min , indicating that the fan 4 is in a damaged state and cannot operate normally. At this time, the logic control circuit 222 sends a first fault signal fault1, which is helpful for the operator to find the state of the fan 4 in time for maintenance to prevent the inverter from overheating and damage.

[0061] In response to the sampling voltage Vr1 being greater than the maximum current I of the fan 4 in normal operation MAX The corresponding second voltage Vref1 sends a second fault signal fault2. The maximum current I MAX The product of the sampling voltage Vr1 and the resistor R1 is the second voltage Vref1. When the sampling voltage Vr1 is greater than the second voltage Vref1, the working current of the fan 4 is greater than the maximum current I MAX , indicating that the fan 4 is in an overloaded state. At this time, the logic control circuit 222 sends a second fault signal fault2, which is helpful for the operator to find the state of the fan 4 in time for maintenance to prevent the inverter from being damaged due to overheating.

[0062] In some embodiments, the logic control circuit 222 is configured to issue the second fault signal fault1 after the sampling voltage Vr1 is less than the first voltage Vref3 for a duration T1. Although the fan 4 starts quickly, it takes a certain amount of time to start the fan 4. The value of T1 should be greater than the start-up time of the fan 4 to prevent a false fault alarm during the startup phase because the fan 4 has not reached the start-up point.

[0063] In response to the sampling voltage Vr1 being greater than the current I when the fan 4 is stalled stallA third fault signal fault3 is generated relative to the third voltage Vref2. The current I of the fan 4 when it is stalled stall The product of the sampling voltage Vr1 and the resistor R1 is the third voltage Vref2. When the sampling voltage Vr1 is greater than the third voltage Vref2, the working current of the fan 4 is greater than the current I when the fan 4 is blocked. stall , indicating that the fan 4 is in a blocked state and cannot rotate normally. At this time, the logic control circuit 222 sends a third fault signal fault3, which is helpful for the operator to find the state of the fan 4 in time for maintenance to prevent the inverter from overheating and damage.

[0064] In this embodiment, the logic control circuit 222 can determine the operating state of the fan 4 by determining the size of the sampled voltage Vr1, and send different fault signals according to different operating states of the fan 4, so that the operator can find the fault of the fan in time, so as to prevent the inverter from malfunctioning or being damaged due to overheating caused by the malfunction of the fan 4.

[0065] Existing air-cooled inverters do not use cooling fans with fault feedback signals, and the quality of the fan can only be determined by sampling and analyzing the ambient temperature or the radiator temperature. When the inverter is started with load, the instantaneous current is very large. If the cooling fan is damaged, the module temperature will rise sharply instantly because the heat dissipation performance does not meet the requirements. The ambient temperature and radiator temperature response time is long, and the user's mainboard has not yet taken protective action, and the power module explodes due to overheating. The bulk device of this embodiment has its own fault feedback signal, which can quickly and timely feedback the fault signal to the user's mainboard, avoiding the problem of power module overheating due to fan failure.

[0066] In some embodiments, the logic control circuit 222 sends a second fault signal fault2 in response to the sampling voltage Vr1 being greater than the second voltage Vref1 and less than the third voltage Vref2, and classifies the fault of the fan. Specifically, the second fault signal fault2 is sent when the sampling voltage Vr1 is greater than the second voltage Vref1 and less than the third voltage Vref2, and the third fault signal fault3 is sent when the sampling voltage Vr1 is greater than the third voltage Vref2, thereby achieving classification of the fault of the fan 4, so that the operator can take corresponding measures according to different faults, which is conducive to improving maintenance efficiency.

[0067] Specifically, see Figure 2 , the logic control circuit 222 also includes a first comparator A1, a second comparator A2 and a third comparator A3.

[0068] The first comparator A1 is electrically connected to the voltage sampling circuit 223, and is configured to output a high level in response to the sampling voltage Vr1 being less than the first voltage Vref3. Optionally, one input terminal of the first comparator A1 is electrically connected to the voltage sampling circuit 223 to introduce the sampling voltage Vr1, and the other input terminal introduces the first voltage Vref3. When the sampling voltage Vr1 is less than the first voltage Vref3, the first comparator A1 outputs a high level. The high level output by the first comparator A1 is used to trigger a high level representing the first fault signal fault1, which is beneficial for the operator to find the state of the fan 4 in time for maintenance, so as to prevent the inverter from being damaged due to overheating.

[0069] The second comparator A2 is electrically connected to the voltage sampling circuit 223, and is configured to output a high level in response to the sampling voltage Vr1 being greater than the second voltage Vref1. Optionally, one input terminal of the second comparator A2 is electrically connected to the voltage sampling circuit 223 to introduce the sampling voltage Vr1, and the other input terminal introduces the second voltage Vref1. When the sampling voltage Vr1 is greater than the second voltage Vref1, the second comparator A2 outputs a high level. The high level output by the second comparator A2 is used to trigger a high level representing the second fault signal fault2, which is helpful for the operator to find the state of the fan 4 in time for maintenance, so as to prevent the inverter from being damaged due to overheating.

[0070] The third comparator A3 is electrically connected to the voltage sampling circuit 223, and is configured to output a high level in response to the sampling voltage Vr1 being greater than the third voltage Vref2. Optionally, one input terminal of the third comparator A1 is electrically connected to the voltage sampling circuit 223 to introduce the sampling voltage Vr1, and the other input terminal introduces the third voltage Vref2. When the sampling voltage Vr1 is greater than the third voltage Vref2, the third comparator A3 outputs a high level. The high level output by the third comparator A3 is used to trigger a high level representing the third fault signal fault3, which is helpful for the operator to find the state of the fan 4 in time for maintenance, so as to prevent the inverter from being damaged due to overheating.

[0071] In some embodiments, the logic control circuit 222 includes a first AND gate logic circuit Q2, which includes an output terminal for outputting a second fault signal fault2, a first input terminal electrically connected to the output terminal of the second comparator A2, and a second input terminal electrically connected to the third comparator A3 via an inverter. Figure 2When the sampling voltage Vr1 is greater than the second voltage Vref1 and less than the third voltage Vref2, the second comparator A2 outputs a high level and the third comparator A3 outputs a low level. Since the third comparator A3 is electrically connected to the second input terminal of the first AND gate logic circuit Q2 through an inverter, the first input terminal and the second input terminal of the first AND gate logic circuit Q2 both introduce a high level. Accordingly, the first AND gate logic circuit Q2 outputs a high level representing the second fault signal fault2. When the sampling voltage Vr1 is greater than the second voltage Vref1 and less than the third voltage Vref2, the second fault signal fault2 is issued. When the sampling voltage Vr1 is greater than the third voltage Vref2, the third fault signal fault3 is issued, thereby realizing the classification of the faults of the fan 4, so that the operator can take corresponding measures according to different faults, which is conducive to improving the maintenance efficiency.

[0072] In some embodiments, the heat dissipation device further includes a fault protection circuit 23, which includes a switch device 231 and a relay KM. The switch device 231 includes a control signal input terminal, a controlled current input terminal and a controlled current output terminal. The control signal input terminal of the switch device 231 is respectively connected to the output terminals of the second comparator A2 and the third amplifier A3, and one of the controlled current input terminal and the controlled current output terminal of the switch device 231 is connected to the control signal input terminal of the relay KM. The terminal of the controlled circuit of the relay KM is electrically connected to the fan 4 to turn off the fan 4 after one of the second comparator A2 and the third amplifier A3 outputs a high level. When the sampling voltage Vr1 is greater than the third voltage Vref2 corresponding to the current Istall when the fan 4 is stalled, the logic control circuit 222 sends a third fault signal fault3, and immediately controls the relay KM to be energized to cut off the power supply of the fan, so that the fan stops working, and avoids direct damage to the fan due to stalling.

[0073] When one of the second comparator A2 and the third amplifier A3 outputs a high level, the controlled current input terminal and the controlled current output terminal of the switch device 213 are connected, thereby triggering the relay KM to turn off the fan 4. After the sampling voltage Vr1 is greater than the second voltage Vref1 and less than the third voltage Vref2, or after the sampling voltage Vr1 is greater than the third voltage Vref2, the fan 4 is turned off to prevent the fan 4 from operating at the maximum current I MAX Or it is damaged due to stalling, which is helpful to protect the fan 4 from being damaged. The heat dissipation device of this embodiment has stalling detection and protection functions, which can provide corresponding protection for stalling and feed back relevant signals to the user's mainboard, making it convenient for the user to troubleshoot and repair.

[0074] In some embodiments, the switch device 231 includes a transistor. The control signal input terminal of the switch device 231 is the base of the transistor 231, one of the controlled current input terminal and the controlled current output terminal of the switch component 231 is the collector of the transistor, and the other is the emitter of the transistor.

[0075] In some embodiments, the fan 4 is turned off after the sampling voltage Vr1 is greater than the second voltage Vref1 and less than the third voltage Vref2 for a duration T. The value of T is set according to the fan current overload time, and T should be less than the current overload time provided by the fan manufacturer.

[0076] Specifically, the fault protection circuit 23 also includes a first time relay KT, a control signal input end of the first time relay KT is electrically connected to the second comparator A2, one end of the controlled loop of the first time relay KT is electrically connected to the second comparator A2, and the other end is electrically connected to the control signal input end of the switching device 231.

[0077] After the sampling voltage Vr1 is greater than the second voltage Vref1 and less than the third voltage Vref2, the second comparator A2 outputs a high level. After a duration of T, the controlled circuit of the first time relay KT is turned on. The high level output by the second comparator A2 acts on the switch device 231 including the control signal input terminal, thereby making the controlled current input terminal and the controlled current output terminal of the switch device 231 conductive, and then shutting down the fan 4 through the relay TM to protect the fan 4 from being damaged by overload.

[0078] In some embodiments, the first current amplifier device V3 includes a transistor, the control current input terminal of the first current amplifier device V3 is the base of the transistor, one of the amplified current input terminal and the amplified current output terminal of the first current amplifier device V3 is the emitter of the transistor, and the other is the collector of the transistor, the monitoring unit 22 also includes a differential voltage circuit 221 for comparing the voltage difference between the base and the emitter of the transistor, and the logic control circuit 222 is electrically connected to the differential voltage circuit 221 and is configured to respond to the voltage difference between the base and the emitter of the transistor being less than the conduction voltage difference V of the transistor. BES A fourth fault signal fault4 is issued.

[0079] By comparing the voltage difference between the base and emitter of the transistor, it is determined whether the driving circuit 21 is faulty, thereby increasing the types of fault monitoring, making it easier for operators to perform corresponding maintenance, and helping to improve maintenance efficiency.

[0080] In some embodiments, the logic control circuit 222 responds to the voltage difference between the base and the emitter of the transistor being greater than the conduction voltage difference V of the transistor. BES, and the sampling voltage Vr1 is less than the first voltage Vref3, a first fault signal fault1 is issued. Subdividing the faults into subdivided categories is helpful for operators to take targeted measures and improve maintenance efficiency.

[0081] In some embodiments, the monitoring unit A2 further includes a first comparator A1 and a fourth comparator A4.

[0082] The first comparator A1 is electrically connected to the voltage sampling circuit 223, and is configured to output a high level in response to the sampling voltage Vr1 being less than the first voltage Vref3; the fourth comparator A4 is electrically connected to the differential voltage circuit 221, and is configured to output a high level in response to the voltage difference between the base and the emitter of the first current amplifier device V3 being less than the conduction voltage difference V BES Output high level.

[0083] In some embodiments, the logic control circuit 222 also includes a second AND gate logic circuit Q1, which includes an output terminal for outputting a first fault signal fault1, a first input terminal electrically connected to the output terminal of the first comparator A1, and a second input terminal electrically connected to the fourth comparator A4 through an inverter.

[0084] After the sampling voltage Vr1 is less than the first voltage Vref3, the first comparator A1 outputs a high level, and the voltage difference between the base and the emitter of the first current amplifier V3 is greater than the conduction voltage difference V BES After that, the fourth comparator A4 outputs a low level. Since the fourth comparator A4 is electrically connected to the second input terminal of the second AND gate logic circuit Q1 through an inverter, a high level is introduced into the second input terminal. Therefore, the second AND gate logic circuit Q1 of this embodiment can distinguish the first fault signal fault1 from the fourth fault signal fault4, and classify the faults in detail, which is beneficial for operators to take targeted measures and improve maintenance efficiency.

[0085] In order to further distinguish various faults, the second AND gate logic circuit Q1 also includes a third input terminal electrically connected to the output terminal of the second comparator A2 through an inverter and a fourth input terminal electrically connected to the output terminal of the third comparator A3 through an inverter. Since the second comparator A2, the third comparator A3 and the fourth comparator A4 are electrically connected to the second AND gate logic circuit Q1 through inverters, when any one of the second comparator A2, the third comparator A3 and the fourth comparator A4 outputs a high level, the second AND gate logic circuit Q1 has a low level input, so the second AND gate logic circuit Q1 will not input a high level representing the first fault signal fault1 to distinguish various faults.

[0086] In some embodiments, the heat dissipation device further includes a second time relay KT1, which includes a control signal input terminal electrically connected to the output terminal of the first comparator A1, a controlled signal input terminal electrically connected to the output terminal of the second AND gate logic circuit Q1, and a controlled signal output terminal outputting a first fault signal fault1. It takes a certain amount of time for the fan 4 to start, and the value of T1 should be greater than the start-up time of the fan 4 to prevent a false fault alarm during the startup phase because the fan 4 has not reached the start-up point.

[0087] The fault code table of this embodiment is as follows:

[0088]

[0089] Existing air-cooled heat dissipation inverters use cooling fans that do not have fault feedback signals, and can only judge the quality of the fan by sampling and analyzing the ambient temperature or the radiator temperature. However, there are many factors that affect the ambient temperature and the radiator temperature, and the source of the fault cannot be accurately located. The present invention can clearly locate the fault point of the cooling fan.

[0090] See also Figure 3 In this embodiment, the minimum current I of the fan for normal operation is min Determine the first Vref3 = I min *R1, under the condition that the second fault signal fault2, the third fault signal fault3, and the fourth fault signal fault4 are not triggered, the collected sampled voltage Vr1 is compared with the reference first voltage Vref3. If the sampled voltage Vr1 is less than the first voltage Vref3, it means that the working current of the cooling fan circuit has not reached the minimum current I that can maintain the fan operation. min , the fan cannot start, the cooling fan 4 itself is damaged, and the fault signal is delayed for a certain time T1 (although the fan starts quickly, it takes a certain amount of time to start the fan, and the T1 value should be greater than the fan start-up time to prevent false alarms during the startup phase because the fan has not reached the starting point) to the user; the above functions are realized through the logic circuit Q1 and the second time relay KT1. During normal operation, fault1=0 (0 represents a low level); when it is detected that the sampling voltage Vr1 is less than the first Vref3, the first fault signal fault1 is set to 1 (1 represents a high level) after a delay of T1 period.

[0091] According to the maximum current I of the normal operation of the fan 4 MAX Determine the second voltage Vref1=I MAX *R1, according to the fan stall current I stall Determine the third voltage Vref2=I stall*R1. Compare the collected sampled voltage Vr1 with the second voltage Vref1 and the third voltage Vref2. If the sampled voltage Vr1 is less than the second voltage Vref1, it indicates that the fan is operating normally. If the second voltage Vref1≤sampled voltage Vr1≤third voltage Vref2, it indicates that the current of the fan 4 is higher than the maximum current I allowed for normal operation of the fan. MAX But it is not blocked, and the fault signal is fed back to the user at this time. At the same time, the fan power supply is cut off after a delay of T time (the value of T is set according to the fan current overload time, and T should be less than the current overload time provided by the fan manufacturer) through the time relay KT to prevent the fan from being damaged due to overcurrent. If the sampling voltage Vr1 is greater than the third Vref2, it means that the fan 4 is blocked; the system immediately cuts off the fan power supply to protect the fan, and feeds back the fault signal to the user. The above functions are realized by the first comparator A1 and the second comparator A2 voltage comparator, combined with the first AND gate logic circuit Q2, the second time relay KT and the relay KM.

[0092] When it is detected that the sampling voltage Vr1 is less than the second voltage Vref1, the fan 4 operates normally, and the second fault signal fault2 and the third fault signal fault3 are both equal to 0; when it is detected that the second voltage Vref1≤sampling voltage Vr1≤third voltage Vref2, the operating current of the fan 4 is higher than the maximum current I of normal operation. MAX At this time, the second fault signal fault2=1, the third fault signal fault3=0, and the power supply of the fan 4 is cut off through the relay KM after a delay of T time; when it is detected that the sampling voltage Vr1 is greater than the third voltage Vref2, the fan 4 is blocked. At this time, the second fault signal fault2=0, the third fault signal fault3=1, and the power supply of the fan is immediately cut off through the relay KM.

[0093] The heat monitoring unit 3 of this embodiment includes a voltage sampling module 31 that feeds back the voltage of the inverter to the controller 1 and a current sampling module 32 that feeds back the current of the inverter to the controller 1. The controller 1 is used to calculate the heat consumption of the power device and the air volume and speed corresponding to the fan 4 according to the values ​​collected by the current collection module 32 and the voltage sampling module 31, and according to the calculated speed, control and adjust the value of the driving adjustable resistor R2 in the fan control and fault detection circuit to further realize the speed adjustment of the fan 4.

[0094] The current collected by the current sampling circuit is recorded as I A ,I B , I dc ,I U ,I V , according to the three-phase current vector sum is 0, calculate the C phase input current I C , W phase output current I WCurrent value.

[0095] Combined with the value of Mode and the collected DC bus current I C Calculate the heat consumption of the power devices on the rectifier side; if Mode=0, it means that the product used is a three-phase diode rectifier, and the heat consumption P1 of the power devices on the rectifier side is calculated according to the diode heat consumption calculation method; if Mode=1, it means that the product used is a three-phase controlled rectifier; take the maximum value of the three-phase input current as the input current value, and calculate the heat consumption P3 of the power devices on the rectifier side according to the IGBT heat consumption calculation method.

[0096] Take the three-phase output current I U ,I V , I W The maximum value among them is taken as the output current value, and the inverter side heat consumption P2 is calculated according to the IGBT heat consumption calculation method.

[0097] The total heat consumption Ptotal of the power devices is calculated based on the heat consumption of the rectifier side and the inverter side (Ptotal=P1+P2 for diode rectification, Ptotal=P2+P3 for controllable rectification). The required air volume is calculated based on the relationship between the total heat consumption and the air volume, and then converted into the required speed. The fan operating current can be obtained based on the relationship between the fan operating current and the speed. The required driving resistance value can be obtained based on the relationship between the driving resistance value and the fan operating current and the amplification factor. The fan speed can be adjusted by controlling the resistance value of the driving resistor R2 through DSP.

[0098] The resistance value of R1 is fixed. From U=IR, we know that when the fan operating current changes, the sampling voltage Vr1 applied to both ends of R1 will change linearly. By detecting the sampling voltage Vr1 of R1, the size of the fan operating current can be known.

[0099] From the above, it can be seen that the heat dissipation device of the inverter of this embodiment achieves the following technical effects:

[0100] 1. The intelligent cooling fan module of the heat dissipation device of the inverter of this embodiment has built-in fault detection, fault feedback and protection functions, which can timely detect the fault of the fan 4 and feed back the fault signal to the mainboard to take protective action, thereby avoiding damage to the power module due to overheating and explosion of the machine due to the fan 4, improving the reliability and safety of the product system, and being more conducive to the service life of the product;

[0101] 2. The intelligent cooling fan module designed by the present invention can provide differentiated feedback on fan blockage and other faults, which is more conducive to locating the problem point when a fault occurs;

[0102] 3. The intelligent cooling fan module designed in the present invention can adaptively adjust the air volume according to the requirements of the cooling system for the actual operating conditions of the product, so that the fan is not in a full-load working state for a long time. This not only extends the service life of the cooling fan, but also avoids unnecessary energy loss when the load is small and reduces noise.

[0103] According to another aspect of the present invention, an air conditioner is provided. The air conditioner comprises the heat dissipation device of the inverter.

[0104] The above description is only an exemplary embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A heat dissipation device for a frequency converter, characterized in that: include: A fan (4) is configured to cool the inverter; A drive circuit (21) comprising a first current amplifying device (V3) and an adjustable resistor (R2) electrically connected to a control current input terminal of the first current amplifying device (V3), wherein one of an amplified current input terminal and an amplified current output terminal of the first current amplifying device (V3) is electrically connected to the fan (4); A heat monitoring unit (3) configured to monitor the heat dissipation of the inverter; as well as A controller (1) is electrically connected to the adjustable resistor (R2) to provide current to a control current input terminal of the first current amplifier (V3); the controller (1) is signal-connected to the heat monitoring unit (3) and the adjustable resistor (R2) respectively and is configured to: reduce the resistance value of the adjustable resistor (R2) in response to an increase in the heat dissipation of the inverter and / or increase the resistance value of the adjustable resistor (R2) in response to a decrease in the heat dissipation of the inverter.

2. The heat dissipation device according to claim 1, characterized in that: The driving circuit (21) further comprises an amplifier circuit (211) connected between a control current input terminal of the first current amplifier device (V3) and the adjustable resistor (R2).

3. The heat dissipation device according to claim 1, characterized in that: The adjustable resistor (R2) includes a programmable resistor.

4. The heat dissipation device according to claim 1, characterized in that: It also includes a monitoring unit (22) for monitoring the operating state of the fan (4), wherein the monitoring unit (22) includes: A voltage sampling circuit (223) configured to collect a sampled voltage (Vr1) that is positively correlated with the current of the fan (4); The logic control circuit (222) is electrically connected to the voltage sampling circuit (223) and is configured to: In response to the sampling voltage (Vr1) being less than the minimum current I for normal operation of the fan (4), min The corresponding first voltage (Vref3) sends a first fault signal (fault1); and / or In response to the sampling voltage (Vr1) being greater than the maximum current I of the fan (4) for normal operation MAX A second fault signal (fault2) is issued by a corresponding second voltage (Vref1); and / or In response to the sampling voltage (Vr1) being greater than the current I when the fan (4) is stalled stall A third fault signal (fault3) is issued relative to the third voltage (Vref2).

5. The heat dissipation device according to claim 4, characterized in that: The logic control circuit (222) generates a second fault signal (fault2) in response to the sampling voltage (Vr1) being greater than the second voltage (Vref1) and less than the third voltage (Vref2).

6. The heat dissipation device according to claim 4 or 5, characterized in that: The logic control circuit (222) further includes: a first comparator (A1), electrically connected to the voltage sampling circuit (223), and configured to output a high level in response to the sampling voltage (Vr1) being less than the first voltage (Vref3); and / or a second comparator (A2), electrically connected to the voltage sampling circuit (223), and configured to output a high level in response to the sampling voltage (Vr1) being greater than the second voltage (Vref1); and / or The third comparator (A3) is electrically connected to the voltage sampling circuit (223) and is configured to output a high level in response to the sampling voltage (Vr1) being greater than the third voltage (Vref2).

7. The heat dissipation device according to claim 6, characterized in that: The logic control circuit (222) comprises a first AND gate logic circuit (Q2), wherein the first AND gate logic circuit (Q2) comprises an output terminal for outputting the second fault signal (fault2), a first input terminal electrically connected to the output terminal of the second comparator (A2), and a second input terminal electrically connected to the third comparator (A3) via an inverter.

8. The heat dissipation device according to claim 6, characterized in that: The invention also comprises a fault protection circuit (23), wherein the fault protection circuit (23) comprises a switch device (231) and a relay (KM), wherein the switch device (231) comprises a control signal input terminal, a controlled current input terminal and a controlled current output terminal, wherein the control signal input terminal of the switch device (231) is respectively connected to the output terminal of the second comparator (A2) and the output terminal of the third amplifier (A3), wherein one of the controlled current input terminal and the controlled current output terminal of the switch device (231) is connected to the control signal input terminal of the relay (KM), and a terminal of the controlled circuit of the relay (KM) is electrically connected to the fan (4) so ​​as to turn off the fan (4) after one of the second comparator (A2) and the third amplifier (A3) outputs a high level.

9. The heat dissipation device according to claim 7, characterized in that: The fault protection circuit (23) further comprises a first time relay (KT), wherein a control signal input terminal of the first time relay (KT) is electrically connected to the second comparator (A2), one end of a controlled circuit of the first time relay (KT) is electrically connected to the second comparator (A2), and the other end is electrically connected to the control signal input terminal of the switch device (231).

10. The heat dissipation device according to claim 4, characterized in that: The first current amplifier device (V3) comprises a transistor, the control current input terminal of the first current amplifier device (V3) is the base of the transistor, one of the amplified current input terminal and the amplified current output terminal of the first current amplifier device (V3) is the emitter of the transistor, and the other is the collector of the transistor, the monitoring unit (22) further comprises a differential voltage circuit (221) for comparing the voltage difference between the base and the emitter of the transistor, the logic control circuit (222) is electrically connected to the differential voltage circuit (221), and is configured to respond to the voltage difference between the base and the emitter of the transistor being less than the conduction voltage difference (V BES ) issues a fourth fault signal (fault4).

11. The heat dissipation device according to claim 10, characterized in that: The logic control circuit (222) responds to the voltage difference between the base and the emitter of the transistor being greater than the conduction voltage difference (V BES ), and the sampling voltage (Vr1) is less than the first voltage (Vref3), a first fault signal (fault1) is issued.

12. The heat dissipation device according to claim 11, characterized in that: The monitoring unit (A2) further includes: a first comparator (A1), electrically connected to the voltage sampling circuit (223), and configured to output a high level in response to the sampling voltage (Vr1) being less than the first voltage (Vref3); and / or A fourth comparator (A4) is electrically connected to the differential voltage circuit (221) and is configured to respond to the voltage difference between the base and the emitter of the first current amplifier (V3) being less than the conduction voltage difference (V BES ) outputs high level.

13. The heat dissipation device according to claim 11, characterized in that: The logic control circuit (222) further comprises a second AND gate logic circuit (Q1), wherein the second AND gate logic circuit (Q1) comprises an output terminal for outputting the first fault signal (fault1), a first input terminal electrically connected to the output terminal of the first comparator (A1), and a second input terminal electrically connected to the fourth comparator (A4) via an inverter.

14. The heat dissipation device according to claim 13, characterized in that: It also includes a second time relay (KT1), which includes a control signal input end electrically connected to the output end of the first comparator (A1), a controlled signal input end electrically connected to the output end of the second AND gate logic circuit (Q1), and a controlled signal output end outputting the first fault signal (fault1).

15. An air conditioner, characterized in that: A heat dissipation device for a frequency converter comprising any one of claims 1 to 14.

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