Drive control circuit, air conditioner controller and air conditioner

Abstract

This invention provides a drive control circuit, an air conditioner controller, and an air conditioner. The drive control circuit includes: an inverter bridge for outputting drive signals, connected between a high-voltage bus and a low-voltage bus; a reactor for absorbing surge signals generated during the operation of the load driven by the drive control circuit, connected between the power grid and the load; a bus capacitor for filtering surge signals on the bus load, connected between the high-voltage bus and the low-voltage bus; and a capacitive absorption circuit for absorbing surge signals on the bus line, connected in parallel with the bus capacitor. The drive control circuit provided by this invention can effectively alleviate the poor surge signal absorption of the bus capacitor, thereby improving the stability and reliability of the bus voltage.

Description

[0001] This application claims priority to Chinese Patent Application No. 2019100417099, filed on January 16, 2019, entitled “Drive Control Circuit, Air Conditioner Controller and Air Conditioner”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of air conditioner technology, and more specifically, to a drive control circuit, an air conditioner controller, and an air conditioner. Background Technology

[0003] Currently, most variable frequency air conditioner controllers adopt an AC-DC-AC (alternating current-direct current-alternating current) topology, and its simplified structure is shown in the figure below. Figure 1 As shown, it mainly includes: AC power module 10', power filter module 12', rectifier module 14', filter module 16', inverter module 18' and load 20'.

[0004] Since the filter module 16' needs to smooth the rectified power frequency signal, it often uses a large-capacity electrolytic capacitor as the main filter element. However, the use of electrolytic capacitors will increase the THD (Total Harmonic Distortion) of the input AC current, and their short lifespan will affect the ultimate lifespan of the controller. In addition, the heat generated by the electrolytic capacitors will reduce the efficiency of the controller.

[0005] With increasing demands for cost and reliability, control schemes that reduce or even eliminate the capacity of electrolytic capacitors are becoming increasingly mature. For electrolytic capacitor-free control schemes, a smaller film capacitor is typically used instead of an electrolytic capacitor. Due to the reduced bus capacitor capacity, the surge absorption capability deteriorates, with the main drawbacks being in the following two aspects:

[0006] 1. Film capacitors or smaller electrolytic capacitors have limited surge absorption capabilities, leading to excessively high bus voltage and damage to components.

[0007] Second, film capacitors or smaller electrolytic capacitors have limited surge absorption capabilities. If a surge voltage is input during normal operation of the prototype, it will cause a sudden and drastic change in the bus voltage, affecting control stability. Summary of the Invention

[0008] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0009] Therefore, one aspect of the present invention is to provide a drive control circuit.

[0010] Another aspect of the present invention is to provide an air conditioner controller.

[0011] Another aspect of the present invention is to provide an air conditioner.

[0012] In view of this, one aspect of the present invention proposes a drive control circuit, comprising: an inverter bridge for driving and controlling the operation of a load, the inverter bridge being connected between a high-voltage bus and a low-voltage bus; a reactor for absorbing surge signals generated during the operation of the load by the drive control circuit, the reactor being connected between the power grid and the load; a bus capacitor for providing the starting voltage required for the load to be powered on, the bus capacitor also being used to absorb surge signals, the bus capacitor being connected in the bus line on the input side of the inverter bridge; the drive control circuit further comprises: a capacitive absorption circuit for absorbing surge signals on the bus line, the capacitive absorption circuit being connected in parallel with the bus capacitor.

[0013] The drive control circuit provided by this invention addresses surge energy primarily from power input, motor windings during prototype shutdown due to malfunction, AC / DC side inductor freewheeling current, and motor kinetic energy. When a surge signal arrives, the bus voltage rises rapidly due to the limited surge absorption capacity of the bus capacitor (such as a film capacitor or a small-capacity electrolytic capacitor). If the bus voltage exceeds the protection threshold, it may damage components. To protect components from high-voltage damage (mainly intelligent power modules and capacitors), a capacitive absorption circuit is connected in parallel with the bus capacitor. The capacitive absorption circuit assists the bus capacitor in absorbing the surge signal on the bus. Thus, when a surge signal arrives, the capacitive absorption circuit and the bus capacitor work simultaneously to absorb the surge signal. As the surge signal is absorbed by the capacitive absorption circuit, the voltage on the bus capacitor begins to decrease, thereby stabilizing the bus voltage. The drive control circuit provided by this invention effectively alleviates the poor surge signal absorption of the bus capacitor, thereby improving the stability and reliability of the bus voltage.

[0014] In addition, the drive control circuit according to the present invention may also have the following additional technical features:

[0015] In the above technical solution, preferably, the drive control circuit further includes: a unidirectional conducting element, used to regulate the process of the capacitive absorption circuit absorbing surge signals. The unidirectional conducting element is connected in series with the capacitive absorption circuit. When the unidirectional conducting element is turned on, the capacitive absorption circuit absorbs surge signals. When the unidirectional conducting element is turned off, the capacitive absorption circuit stops absorbing surge signals.

[0016] In this technical solution, the drive control circuit also includes a unidirectional conducting element, which is connected in series with a capacitive absorption circuit. Using the unidirectional conducting element as an isolation element between the capacitive absorption circuit and the bus capacitor can limit the absorption process of surge signals by the capacitive absorption circuit, resulting in low cost and high reliability. Specifically, the surge absorption circuit composed of the unidirectional conducting element and the capacitive absorption circuit is uncontrolled. When a surge signal higher than the maximum value of the bus voltage exists, the unidirectional conducting element conducts, and the capacitive absorption circuit and the bus capacitor work simultaneously to absorb the surge signal. The unidirectional conducting element is a component with unidirectional conducting characteristics, such as a diode.

[0017] In any of the above technical solutions, preferably, the drive control circuit further includes a switching element for regulating the process of the capacitive absorption circuit absorbing surge signals. The switching element is connected in series with the capacitive absorption circuit. When the switching element is turned on, the capacitive absorption circuit absorbs surge signals. When the switching element is turned off, the capacitive absorption circuit stops absorbing surge signals.

[0018] In this technical solution, switching elements are used as isolation components between the surge absorption capacitor and the bus capacitor. The resulting surge absorption circuit is controllable. When the current bus voltage exceeds a certain fixed value (e.g., 680V, ​​which can be set according to actual conditions), the switching elements are turned on, and the surge signal enters the capacitive absorption circuit as quickly as possible, thereby stabilizing the bus voltage. Furthermore, because it is a controllable absorption method, smaller absorption capacitors can be used, resulting in lower costs. Switching elements include transistors and relays.

[0019] In any of the above technical solutions, preferably, the capacitive absorption circuit includes: a first capacitive element for absorbing surge signals on the high-voltage bus and the low-voltage bus; a first resistive element for releasing the surge signal in the first capacitive element, wherein the first resistive element and the first capacitive element are connected in parallel.

[0020] In this technical solution, the capacitive absorption circuit includes a first capacitive element and a first resistive element connected in parallel, and the number of the first capacitive element and the first resistive element is one or more.

[0021] Optionally, the number of first resistive elements corresponds one-to-one with the number of first capacitive elements, and the first capacitive elements are connected in parallel with the first resistive elements. When there are multiple first capacitive elements, the first resistive elements play the role of balancing resistance and also serve as the discharge resistance of electrolytic capacitors.

[0022] Optionally, there may be multiple first resistive elements, which are connected in series and then in parallel with the first capacitive element.

[0023] In any of the above technical solutions, preferably, the capacitive absorption circuit further includes: a second capacitive element for absorbing surge signals on the high-voltage bus and the low-voltage bus, the second capacitive element being connected in series with the first capacitive element; and a second resistive element for releasing surge signals in the second capacitive element, the second resistive element being connected in parallel with the second capacitive element.

[0024] In this technical solution, the capacitive absorption circuit further includes a second capacitive element and a second resistive element connected in parallel, with one or more of each. The capacitance values ​​of the second capacitive element and the first capacitive element can be the same or different. Preferably, the resistance values ​​of the first resistive element and the second resistive element are the same to balance the voltage between the first and second capacitive elements, thus also serving as the discharge resistor of the electrolytic capacitor.

[0025] In any of the above technical solutions, preferably, the drive control circuit further includes: a third resistive element for limiting the current flowing through the capacitive absorption circuit, wherein the third resistive element is connected in series with the capacitive absorption circuit.

[0026] In this technical solution, the drive control circuit also includes a third resistive element, which limits the current flowing through the capacitive absorption circuit. The selection of the third resistive element varies depending on the capacitance values ​​of the first and second capacitive elements.

[0027] In any of the above technical solutions, preferably, the third resistive element includes: one or more resistors, wherein the resistors are connected in series and / or in parallel.

[0028] In any of the above technical solutions, preferably, the drive control circuit further includes: a control circuit connected to the switching element, the control circuit being used to detect the power supply signal of the drive control circuit, and to control the switching element to be turned on or off according to the power supply signal; wherein, the power supply signal includes a bus signal and / or an AC signal.

[0029] In this embodiment, the control circuit detects the power supply signal driving the control circuit, and controls the switching element to turn on or off based on the power supply signal, thereby controlling the absorption process of the capacitive element by the surge signal. The power supply signal includes a bus signal and / or an AC signal. Specifically, the AC signal is processed into a bus signal by a rectifier circuit, and both the bus signal and the AC signal can be used as conditions for determining whether the switching element is turned on or off.

[0030] In any of the above technical solutions, preferably, the bus capacitor is a thin-film capacitor.

[0031] In any of the above technical solutions, the capacitance value of the bus capacitor is less than the preset capacitance, which is calculated according to the following formula:

[0032]

[0033] Among them, C dc For the preset capacity, L S The total inductance value of the DC side of the equivalent drive control circuit, P L It is the load power of the drive control circuit, R S The total resistance on the DC side of the equivalent drive control circuit, v dc0 The average value of the bus voltage, for example, taking the 7P prototype as an example, is used to determine C according to this calculation formula. dc It must be greater than 840uF, the preset capacity is above 840uF, but 1230uF is used in the actual implementation.

[0034] Another aspect of the present invention provides an air conditioner controller, comprising: a drive control circuit as described in any of the above technical solutions.

[0035] The air conditioner controller according to the present invention includes the drive control circuit as described in any of the above technical solutions, and thus has all the technical effects of the drive control circuit, which will not be repeated here.

[0036] Another aspect of the present invention provides an air conditioner, comprising: a motor; and a drive control circuit as described in any of the above technical solutions; or an air conditioner controller as described in the above technical solutions; wherein the signal input terminal of the motor is connected to the drive control circuit or the air conditioner controller, and the drive signal output by the drive control circuit is used to drive the motor to run.

[0037] The air conditioner according to the present invention includes the drive control circuit as described in any of the above technical solutions, or the air conditioner controller as described in the above technical solutions, and thus has all the technical effects of the drive control circuit or the air conditioner controller, which will not be described again.

[0038] Additional aspects and advantages of the invention will become apparent in the following description or may be learned by practice of the invention. Attached Figure Description

[0039] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0040] Figure 1 A schematic diagram of the topology of a controller in a conventional inverter air conditioner is shown.

[0041] Figure 2 A schematic diagram of the drive control circuit according to a first embodiment of the present invention is shown;

[0042] Figure 3 A schematic diagram of the drive control circuit according to a second embodiment of the present invention is shown;

[0043] Figure 4 A schematic diagram of the drive control circuit according to a third embodiment of the present invention is shown;

[0044] Figure 5 A schematic diagram of the drive control circuit according to a fourth embodiment of the present invention is shown;

[0045] Figure 6 A schematic diagram of the drive control circuit according to a fifth embodiment of the present invention is shown;

[0046] Figure 7 A schematic diagram of the drive control circuit according to a sixth embodiment of the present invention is shown;

[0047] Figure 8 A schematic diagram of the drive control circuit according to a seventh embodiment of the present invention is shown;

[0048] Figure 9 A schematic diagram of the drive control circuit according to an eighth embodiment of the present invention is shown;

[0049] Figure 10 A schematic diagram of the drive control circuit according to the ninth embodiment of the present invention is shown.

[0050] Figure 11 A schematic diagram of the drive control circuit according to the tenth embodiment of the present invention is shown.

[0051] in, Figure 1 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0052] 10' AC power supply module, 12' power filter module, 14' rectifier module, 16' filter module, 18' inverter module, 20' load;

[0053] in, Figures 2 to 11 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0054] 10 Inverter bridge, 12 Reactor, 14 Bus capacitor, 16 Capacitive snubber circuit, 18 Unidirectional conducting element, 20 Switching element, 22 First capacitive element, 24 First resistive element, 26 Second capacitive element, 28 Second resistive element, 30 Third resistive element, 32 Thermistor, 34 Relay, 36 Rectifier circuit. Detailed Implementation

[0055] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0056] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0057] The following reference Figures 2 to 11 A drive control circuit, an air conditioning controller, and an air conditioner are described according to some embodiments of the present invention.

[0058] One embodiment of the present invention provides a drive control circuit.

[0059] like Figures 2 to 4 The diagram shows a schematic of the drive control circuit according to a first embodiment of the present invention. The drive control circuit includes: an inverter bridge 10 for driving and controlling the load operation, the inverter bridge 10 being connected between the high-voltage bus and the low-voltage bus; a reactor 12 for absorbing surge signals generated during the drive control circuit's operation of the load, connected between the power grid and the load; a bus capacitor 14 for providing the starting voltage required for the load to be powered on, the bus capacitor 14 also being used to absorb surge signals, the bus capacitor 14 being connected in parallel with the bus line on the input side of the inverter bridge 10; the drive control circuit further includes: a capacitive absorption circuit 16 for absorbing surge signals on the high-voltage bus and the low-voltage bus, the capacitive absorption circuit 16 being connected in parallel with the bus capacitor 14.

[0060] The drive control circuit provided by this invention addresses surge energy primarily from power input, motor windings during prototype shutdown due to malfunction, AC / DC side inductor freewheeling current, and motor kinetic energy. When a surge signal arrives, the bus capacitor 14 (such as a film capacitor or a small-capacity electrolytic capacitor) has limited surge absorption capacity, causing the bus voltage to rise rapidly. If the bus voltage exceeds the protection threshold, it may damage components. To protect components from high-voltage damage (mainly intelligent power modules and capacitors), a capacitive absorption circuit 16 is connected in parallel with the bus capacitor 14. The capacitive absorption circuit 16 assists the bus capacitor 14 in absorbing the surge signal on the bus. Thus, when a surge signal arrives, the capacitive absorption circuit 16 and the bus capacitor 14 work simultaneously to absorb the surge signal. As the surge signal is absorbed by the capacitive absorption circuit 16, the voltage on the bus capacitor 14 begins to decrease, thereby stabilizing the bus voltage. The drive control circuit provided by this invention effectively alleviates the poor surge signal absorption of the bus capacitor, thereby improving the stability and reliability of the bus voltage.

[0061] In one embodiment of the present invention, preferably, the drive control circuit further includes: a unidirectional conducting element 18, used to limit the absorption process of the surge signal by the capacitive absorption circuit 16. The unidirectional conducting element 18 is connected in series with the capacitive absorption circuit 16. When the unidirectional conducting element 18 is turned on, the capacitive absorption circuit 16 absorbs the surge signal; when the unidirectional conducting element 18 is turned off, the capacitive absorption circuit 16 stops absorbing the surge signal. Specifically, as shown... Figures 2 to 4 As shown, the unidirectional conducting element 18 is a diode.

[0062] In this embodiment, the drive control circuit further includes a unidirectional conducting element 18, which is connected in series with the capacitive absorption circuit 16. Using the unidirectional conducting element 18 as an isolation element between the capacitive absorption circuit 16 and the bus capacitor 14 can limit the absorption process of the surge signal by the capacitive absorption circuit 16. Specifically, the surge absorption circuit composed of the unidirectional conducting element 18 and the capacitive absorption circuit 16 is uncontrolled. When a surge signal higher than the maximum value of the bus voltage exists, the unidirectional conducting element 18 conducts, and the capacitive absorption circuit 16 and the bus capacitor 14 work simultaneously to absorb the surge signal.

[0063] In another embodiment of the present invention, preferably, the drive control circuit further includes a switching element 20 for regulating the process of the capacitive absorption circuit 16 absorbing surge signals. The switching element 20 is connected in series with the capacitive absorption circuit 16. When the switching element 20 is turned on, the capacitive absorption circuit 16 absorbs surge signals; when the switching element 20 is turned off, the capacitive absorption circuit 16 stops absorbing surge signals. Specifically, as shown... Figures 5 to 9 As shown, the switching element 20 is a relay switch.

[0064] In this embodiment, the switching element 20 is used as an isolation element between the surge absorption capacitor and the bus capacitor. The surge absorption circuit is controllable. When the current bus voltage is greater than a certain fixed value (e.g., 680V, ​​which can be set according to the actual situation), the switching element 20 is turned on, and the surge signal will enter the capacitive absorption circuit 16 as quickly as possible, thereby stabilizing the bus voltage. In addition, since it is a controllable absorption form, a smaller capacity absorption capacitor can be used, resulting in low cost.

[0065] In one embodiment of the present invention, preferably, the capacitive absorption circuit 16 includes: a first capacitive element 22 for absorbing surge signals on the high-voltage bus and the low-voltage bus; and a first resistive element 24 for releasing the surge signals in the first capacitive element 22, wherein the first resistive element 24 is connected in parallel with the first capacitive element 22.

[0066] In this embodiment, the capacitive absorption circuit 16 includes a first capacitive element 22 and a first resistive element 24 connected in parallel, and the number of both the first capacitive element 22 and the first resistive element 24 is one or more. Specifically, as shown... Figure 2As shown, the number of the first capacitive element 22 and the first resistive element 24 is one.

[0067] In another embodiment of the present invention, preferably, the number of first resistive elements 24 corresponds one-to-one with the number of first capacitive elements 22, and the first capacitive elements 22 and the first resistive elements 24 are connected in parallel. When there are multiple first capacitive elements 22, the first resistive elements 24 serve as balancing resistors and also as discharge resistors for electrolytic capacitors.

[0068] In another embodiment of the present invention, preferably, there are multiple first resistive elements 24, and the multiple first resistive elements 24 are connected in series and then connected in parallel with the first capacitive element 22.

[0069] In one embodiment of the present invention, preferably, the capacitive absorption circuit 16 further includes: a second capacitive element 26 for absorbing surge signals on the high-voltage bus and the low-voltage bus, the second capacitive element 26 being connected in series with the first capacitive element 22; and a second resistive element 28 for releasing the surge signal in the second capacitive element 26, the second resistive element 28 being connected in parallel with the second capacitive element 26.

[0070] In this embodiment, the capacitive absorption circuit 16 further includes a second capacitive element 26 and a second resistive element 28 connected in parallel, and the number of both the second capacitive element 26 and the second resistive element 28 is one or more. Specifically, as shown... Figure 2 As shown, the number of the second capacitive element 26 and the second resistive element 28 is one. The capacitance value of the second capacitive element 26 and the first capacitive element 22 can be the same or different. Preferably, the resistance value of the first resistive element 24 and the second resistive element 28 is the same, so as to balance the voltage of the first capacitive element 22 and the second capacitive element 26, and also serve as the discharge resistor of the electrolytic capacitor.

[0071] In one embodiment of the present invention, preferably, the drive control circuit further includes: a third resistive element 30 for limiting the current flowing through the capacitive absorption circuit 16, wherein the third resistive element 30 is connected in series in the branch where the capacitive absorption circuit 16 and the unidirectional conduction element 18 are located.

[0072] In this embodiment, the drive control circuit further includes a third resistive element 30, which limits the current flowing through the capacitive absorption circuit 16. The selection of the third resistive element 30 varies depending on the capacitance values ​​of the first capacitive element 22 and the second capacitive element 26.

[0073] In another embodiment of the invention, preferably, the third resistive element includes one or more resistors, which are connected in series and / or in parallel.

[0074] In another embodiment of the invention, such as Figure 8As shown, preferably, the drive control circuit further includes a thermistor 32, used to limit the current on the first capacitive element 22 and the second capacitive element 26, and the thermistor 32 is connected to the high-voltage bus.

[0075] In this embodiment, PTC is an abbreviation for Positive Temperature Coefficient, meaning a positive temperature coefficient, generally referring to semiconductor materials or components with a large positive temperature coefficient. Usually, when we mention PTC, we mean a positive temperature coefficient thermistor, or simply a thermistor. By connecting the thermistor 32 to the high-voltage bus, it mainly functions at the moment of power-on, limiting the instantaneous current on the absorption capacitor, and is short-circuited after charging is complete. Of course, any device with a positive temperature coefficient resistance can replace the thermistor 32.

[0076] In one embodiment of the present invention, preferably, the energy released from the first capacitive element 22 and the second capacitive element 26 can have different forms, such as... Figure 10 and Figure 11 These two forms.

[0077] like Figure 10 As shown, the drive control circuit has an output terminal located between the first capacitive element 22 and the second capacitive element 26. The electrical signal on the high-voltage bus passes through the diode and charges the first capacitive element 22 and the second capacitive element 26, forming a relatively low voltage output signal at the output terminal. The capacitance ratio of the first capacitive element 22 and the second capacitive element 26 can be adjusted according to the load requirements connected to the output terminal to provide a suitable voltage output signal to the load requiring low voltage.

[0078] like Figure 11 As shown, the drive control circuit has another output terminal, which is located between the unidirectional conducting element 18 and the first capacitive element 22. The electrical signal on the high-voltage bus passes through the unidirectional conducting element 18 and charges the first capacitive element 22 and the second capacitive element 26. At this time, there will be a high voltage difference between the output terminal between the unidirectional conducting element 18 and the first capacitive element 22 and the low-voltage bus. That is, the output terminal provides the output electrical signal with a higher voltage for use by loads that require high voltage.

[0079] In another embodiment of the invention, such as Figure 8 As shown, preferably, the drive control circuit further includes a relay 34, configured to control the current limiting process of the thermistor 32 on the first capacitive element 22 and the second capacitive element 26, the relay 34 being connected in parallel with the thermistor 32.

[0080] In this embodiment, the relay 34 is configured to control the current limiting process of the thermistor 32 on the first capacitive element 22 and the second capacitive element 26. The relay 34 is normally open so that the thermistor 32 can act at the moment of power-on to limit the instantaneous current on the absorption capacitor. After charging is completed, the relay 34 is closed so that the thermistor 32 is short-circuited.

[0081] In another embodiment of the invention, such as Figure 9 As shown, preferably, the drive control circuit also includes multiple thermistors 32 for limiting the current on the first capacitive element 22 and the second capacitive element 26. Specifically, there are three thermistors 32, namely PTC1, PTC2 and PTC3, which are respectively installed on each of the three-phase three-wire AC lines.

[0082] Preferably, the drive control circuit further includes multiple relays 34, the number of relays 34 corresponding one-to-one with the thermistors 32. Specifically, there are three relays 34, which are connected in parallel with PTC1, PTC2, and PTC3 respectively, and are configured to control the process of limiting the current on the first capacitive element 22 and the second capacitive element 26 by the thermistors 32.

[0083] Regarding the above embodiments, it should be noted that: Figure 2 , Figure 3 , Figure 4 The results achieved are exactly the same, but Figure 4 The time required for voltage balancing on the first capacitive element 22 and the second capacitive element 26 is greater than Figure 2 and Figure 3 . Figure 5 , Figure 6 , Figure 7 Using a switching element 20 instead of a diode as the isolation element between the first capacitive element 22, the second capacitive element 26, and the bus capacitor 14, a smaller capacitive element can be used due to the controllable absorption form. However, since a large amount of energy is injected from the power supply side at the moment of conduction, a thermistor 32 is added to the power supply side. Figure 8 , Figure 9 As shown, the thermistor 32 is used to absorb the surge energy caused by the inductor, compressor kinetic energy, and compressor inductance. At the same time, the thermistor 32 is also used to limit the instantaneous current on the first capacitive element 22 and the second capacitive element 26, thereby making the circuit more stable.

[0084] In another embodiment of the present invention, preferably, the drive control circuit further includes: a control circuit (not shown in the figure), connected to the switching element 20, the control circuit being used to detect the power supply signal of the drive control circuit, and to control the switching element 20 to be turned on or off according to the power supply signal; wherein, the power supply signal includes a bus signal and / or an AC signal.

[0085] In this embodiment, the control circuit detects the power supply signal driving the control circuit, and controls the switching element 20 to turn on or off based on the power supply signal, thereby controlling the absorption process of the surge signal by the capacitive element. The power supply signal includes a bus signal and / or an AC signal. Specifically, the AC signal is processed into a bus signal by the rectifier circuit 36, and both the bus signal and the AC signal can be used as conditions for determining whether the switching element 20 is turned on or off.

[0086] The bus signal can be obtained by detecting the voltage before the reactor 12 after the rectifier circuit 36 ​​and / or the voltage before the inverter bridge 10 after the reactor 12; the AC signal is the peak value of the AC input voltage and / or the voltage before the rectifier circuit 36.

[0087] A power amplifier circuit (not shown in the figure) is connected in series between the control circuit and the switching element 20. The power amplifier circuit amplifies the control signal output by the control circuit so that the control circuit can drive the switching element 20.

[0088] In any of the above embodiments, preferably, the bus capacitor 14 is a thin-film capacitor.

[0089] In any of the above embodiments, the capacitance value of the bus capacitor 14 is less than the preset capacitance, which is calculated according to the following formula:

[0090]

[0091] Among them, C dc For the preset capacity, L S The total inductance value of the DC side of the equivalent drive control circuit, P L It is the load power of the drive control circuit, R S The total resistance on the DC side of the equivalent drive control circuit, v dc0 The average value of the bus voltage, for example, taking the 7P prototype as an example, is used to determine C according to this calculation formula. dc It must be greater than 840uF, the preset capacity is above 840uF, but 1230uF is used in the actual implementation.

[0092] To better illustrate the present invention, as Figures 2 to 11 As shown, the actual operating parameters for the 6KW prototype are as follows:

[0093] The reactor Lac refers to the actual AC side inductance model and the input power line inductance, which includes inductance and resistance. Existing models use an AC side inductance of 25mH and 500 milliohms, and the inductance of the input power line is less than or equal to 10mH (numerical amplification) and the resistance is not less than 0.5 ohms (the actual wire resistance is about 1.2 ohms).

[0094] The reactor 12 refers to the actual DC-side inductor model, which includes inductance and resistance, 4.5mH, 120 milliohms;

[0095] R4 is the system damping resistor (not greater than 200 ohms; 68 ohms is used on the 16KW prototype, but it can be omitted in practice). The damping resistor R4 was not increased when reactor 12 was selected as 4.5mH. On the 6KW prototype, there is no reactor 12, so R4 can also be omitted.

[0096] It should be noted that reactors Lac and 12 exist for EMC harmonic requirements. In areas with harmonic requirements, the prototype may have both reactor Lac and reactor 12, or even both. In areas without harmonic requirements, neither reactor Lac nor reactor 12 exists. However, to address high-frequency harmonic issues (if this issue is ignored, reactor 12 can be omitted), a smaller reactor Ldc will be used at the location of reactor 12 in the circuit topology. A small inductance, such as less than 2mH, is preferred. A small damping resistor is connected in parallel with this smaller Ldc to improve system stability.

[0097] The unidirectional conducting element 18 is a diode with high withstand voltage and instantaneous overcurrent greater than 100A. The third resistive element 30 is a current-limiting resistor. The first capacitive element 22 and the second capacitive element 26 are the first capacitor and the second capacitor, respectively. The current-limiting resistor is selected differently depending on the capacitance values ​​of the first capacitor and the second capacitor. For a 6KW 230V (phase voltage) powered prototype, the first capacitor and the second capacitor are selected as 450V / 820uF, and the current-limiting resistor is selected as 4.7 ohms.

[0098] Bus capacitor 14 is a film capacitor, selected as 30uF, with a withstand voltage of 900V (less than 100uF; in practice, the larger the capacitance of the film capacitor, the easier it is to control, but the cost is higher).

[0099] The first resistive element 24 and the second resistive element 28 are balancing resistors, which also serve as discharge resistors for electrolytic capacitors. A value of 150K is selected.

[0100] Operating instructions:

[0101] When the prototype is powered on, the input voltage is rectified by rectifier circuit 36 ​​and simultaneously charges the surge absorption capacitor (the first capacitor and the second capacitor in series) and the bus capacitor 14. During normal operation of the prototype, the voltage on the bus capacitor 14 fluctuates at a frequency 6 times that of the AC input power supply frequency. Only a small current flows through the first capacitor and the second capacitor, and the terminal voltages of the first capacitor and the second capacitor are stable at the maximum value of the bus voltage.

[0102] Surge energy mainly originates from the power input, the compressor windings during prototype shutdown due to malfunction, the freewheeling current of the AC / DC side inductors, and the compressor's kinetic energy; if it is an uncontrolled surge absorption circuit, such as Figure 2 , Figure 3 , Figure 4 When a surge voltage exceeding the current maximum bus voltage exists, the first and second capacitors, along with bus capacitor 14, function simultaneously to absorb the surge energy. If it is a controlled surge absorption circuit, as shown in the example... Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 When the current bus voltage exceeds a certain fixed value (e.g., 680V), surge energy will quickly enter the first and second capacitors to stabilize the bus voltage and stop the motor. As the surge energy is absorbed by the capacitors, the voltage on bus capacitor 14 begins to drop. When the main control chip detects that the voltage on bus capacitor 14 is stable (normally it should be Vac×1.414×1.732), the surge absorption process is complete, and the switching element is disconnected. In practice, when using an AC relay as the switching element, it is only necessary to consider disconnecting the relay only when there is no current in the relay contacts; a DC relay can disconnect the relay as soon as the surge absorption process is completed, i.e., when the voltage on bus capacitor 14 begins to drop.

[0103] Another embodiment of the present invention provides an air conditioner controller, including: a drive control circuit as described in any of the above embodiments.

[0104] The air conditioner controller provided in this embodiment includes the drive control circuit as described in any of the above embodiments, and therefore has all the technical effects of the drive control circuit, which will not be repeated here.

[0105] Another aspect of the present invention provides an air conditioner, comprising: a motor; a drive control circuit as in any of the above embodiments, or an air conditioner controller as in the above embodiments; wherein the signal input terminal of the motor is connected to the drive control circuit or the air conditioner controller, and the drive signal output by the drive control circuit is used to drive the motor to run.

[0106] The air conditioner provided by the embodiments of the present invention includes the drive control circuit as described in any of the above embodiments, or the air conditioner controller as described in the above embodiments. Therefore, it can effectively solve the problem of surge energy absorption after using a small-capacity capacitor for the DC bus capacitor, stabilize the bus voltage, protect the components and ensure control stability, thereby ensuring the stable operation of the air conditioner.

[0107] The drive control circuit, air conditioner controller, and air conditioner provided by this invention can effectively solve the problem of surge energy absorption after using small-capacity capacitors in the DC bus, stabilize the bus voltage, protect components, and ensure control stability.

[0108] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance, unless otherwise expressly specified and limited. The terms "connection," "installation," and "fixing," etc., should be interpreted broadly. For example, "connection" can mean a fixed connection, a detachable connection, or an integral connection; it can mean a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0109] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0110] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A drive control circuit, comprising: An inverter bridge is used to drive and control a load, the inverter bridge being connected between a high-voltage bus and a low-voltage bus; characterized in that the drive control circuit further includes: a reactor for absorbing surge signals generated during the operation of the load by the drive control circuit, the reactor being connected between the power grid and the load; a bus capacitor for providing the starting voltage required for the load to be powered on, the bus capacitor also being used to absorb the surge signals, the bus capacitor being connected in the bus line on the input side of the inverter bridge; and the drive control circuit further includes: A capacitive absorption circuit is used to absorb surge signals on the bus line, and the capacitive absorption circuit is connected in parallel with the bus capacitor; The capacitive absorption circuit includes: A first capacitive element is used to absorb surge signals on the high-voltage bus and the low-voltage bus; A first resistive element is used to release the surge signal in the first capacitive element, and the first resistive element is connected in parallel with the first capacitive element; The second capacitive element is used to absorb surge signals on the high-voltage bus and the low-voltage bus, and the second capacitive element is connected in series with the first capacitive element. The second resistive element is used to release the surge signal in the second capacitive element, and the second resistive element is connected in parallel with the second capacitive element; Wherein, the resistance values ​​of the first resistive element and the second resistive element are the same; The bus capacitor is a film capacitor, and its capacitance value is less than a preset capacitance. The preset capacitance is calculated as follows: Among them, C dc For the preset capacity, L S P is the total inductance value on the DC side of the equivalent drive control circuit. L R is the load power of the drive control circuit. S V is the total resistance on the DC side of the equivalent drive control circuit. dc0 This represents the average value of the bus voltage. The drive control circuit also includes multiple thermistors and multiple relays. The thermistors are used to limit the current on the first capacitive element and the second capacitive element. There are three thermistors, which are respectively set on each line of the three-phase AC power supply. The number of relays is the same as the number of thermistors, and they are set in parallel with the thermistors. The relays are configured to control the process of the thermistors limiting the current on the first capacitive element and the second capacitive element.

2. The drive control circuit according to claim 1, characterized in that, Also includes: A unidirectional conducting element is used to regulate the process of the capacitive absorption circuit absorbing the surge signal. The unidirectional conducting element is connected in series with the capacitive absorption circuit. When the unidirectional conducting element is turned on, the capacitive absorption circuit absorbs the surge signal. When the unidirectional conducting element is turned off, the capacitive absorption circuit stops absorbing the surge signal.

3. The drive control circuit according to claim 1, characterized in that, Also includes: A switching element is used to regulate the process of the capacitive absorption circuit absorbing the surge signal. The switching element is connected in series with the capacitive absorption circuit. When the switching element is turned on, the capacitive absorption circuit absorbs the surge signal. When the switching element is turned off, the capacitive absorption circuit stops absorbing the surge signal.

4. The drive control circuit according to any one of claims 1 to 3, characterized in that, Also includes: A third resistive element is used to limit the current flowing through the capacitive absorption circuit, and the third resistive element is connected in series with the capacitive absorption circuit.

5. The drive control circuit according to claim 4, characterized in that, The third resistive element includes one or more resistors, which are connected in series and / or in parallel.

6. The drive control circuit according to claim 3, characterized in that, Also includes: A control circuit is connected to the switching element. The control circuit is used to detect the power supply signal of the drive control circuit and control the switching element to be turned on or off according to the power supply signal. The power supply signals include bus signals and / or AC signals.

7. An air conditioner controller, characterized in that, include: The drive control circuit as described in any one of claims 1 to 6.

8. An air conditioner, characterized in that, include: Electric motor; as well as The drive control circuit as described in any one of claims 1 to 6; or The air conditioner controller as described in claim 7; in, The signal input terminal of the motor is connected to the drive control circuit or the air conditioner controller, and the drive signal output by the drive control circuit is used to drive the motor to run.

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