Drive control circuit and air conditioner

Abstract

This invention provides a drive control circuit and an air conditioner. The drive control circuit includes: an inverter bridge for outputting drive signals, connected in series between a high-voltage bus and a low-voltage bus; the control circuit also includes: 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; and a bus capacitor for filtering surge signals on the bus line, connected in the bus line on the input side of the inverter bridge. By applying the technical solution provided by this invention, the use of a lower-cost film capacitor instead of an expensive electrolytic capacitor improves the lifespan of the drive control circuit, reduces the occurrence of reduced control efficiency due to bus capacitor heating, and improves the reliability and efficiency of the drive control circuit.

Description

[0001] This application claims priority to Chinese Patent Application No. 201910041294.5, filed on January 16, 2019, entitled "Drive Control Circuit and Air Conditioner", the entire contents of which are incorporated herein by reference. Technical Field

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

[0003] Generally, variable frequency air conditioner controllers widely adopt an AC-DC-AC (alternating current-direct current-alternating current) topology, such as... Figure 1 As shown, it mainly includes an AC power supply module 10', a power filter module 12', a rectifier module 14', a filter module 16', an inverter module 18', and a load 20'.

[0004] Generally, because the filtering module needs to smooth out the rectified power frequency signal, it often uses large-capacity electrolytic capacitors as the main filtering components, such as... Figure 2 and Figure 3 As shown, C2 to C7 are all electrolytic capacitors used for filtering.

[0005] However, the use of electrolytic capacitors can cause the following problems:

[0006] 1. The total harmonic distortion (THD) of the input AC current increases.

[0007] Second, electrolytic capacitors have a shorter lifespan, and using electrolytic capacitors will affect the maximum lifespan of the controller.

[0008] Third, electrolytic capacitors generate a lot of heat, which reduces the efficiency of the controller and increases the difficulty of thermal management of the controller.

[0009] Fourth, the extensive use of electrolytic capacitors can also lead to uneven stress distribution on the PCB (Printed Circuit Board) and increase the overall weight of the controller. Summary of the Invention

[0010] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0011] Therefore, a first aspect of the present invention provides a drive control circuit.

[0012] A second aspect of the present invention provides an air conditioner.

[0013] In view of the above, a first aspect of the present invention provides a drive control circuit, the drive control circuit comprising: an inverter bridge for outputting a drive signal, the inverter bridge being connected between a high-voltage bus and a low-voltage bus; the drive control circuit further comprising: a reactor for absorbing surge signals generated during the operation of the drive control circuit driving the load, the reactor being connected between the power grid and the load; and a bus capacitor for filtering out surge signals on the bus line, the bus capacitor being connected in the bus line on the input side of the inverter bridge.

[0014] In this technical solution, a reactor is installed in the drive control circuit. The reactor is used to absorb surge signals generated during the operation of the drive control circuit driving the load, thereby improving the surge resistance of the drive control circuit. The resonant frequency of the reactor and the bus capacitor is fixed at [value missing]. Where L is the inductance of the reactor and C is the capacitance of the bus capacitor, this effectively prevents the resonant frequency from being unstable due to distributed inductance and capacitance parameters. Simultaneously, a lower capacitance bus capacitor is selected instead of a traditional electrolytic capacitor; specifically, a film capacitor is chosen as the bus capacitor. The film capacitor is connected in parallel to the input side of the inverter bridge and in series between the high-voltage bus and the low-voltage bus to filter out surge signals on the bus. By applying the technical solution provided by this invention, the cost-effective use of low-cost film capacitors to replace expensive electrolytic capacitors effectively reduces production costs. The lifespan of the film capacitor can reach 6250 hours, far exceeding the 2000 hours of a typical electrolytic capacitor, thus effectively improving the lifespan of the drive control circuit. Furthermore, the film capacitor has a lower ESR (equivalent series resistance), and under the same ripple current, the heat generated by the film capacitor is much less than that of the electrolytic capacitor. Therefore, it can also effectively avoid the problem of reduced control efficiency due to bus capacitor heating, improving the reliability and efficiency of the drive control circuit.

[0015] Optionally, the drive control circuit also includes a current limiting circuit for limiting the charging current of the bus capacitor during initial power-on, the current limiting circuit being connected in series on the high-voltage bus.

[0016] Because the selected bus capacitor has a low capacitance value, when a surge voltage occurs, the small-capacity film capacitor cannot absorb too much energy. At this time, when the bus voltage is higher than the voltage at the surge absorption capacitor terminal, the current limiting circuit takes effect and limits the charging current of the bus capacitor when powered on, so as to prevent the bus capacitor from being broken down by overcurrent.

[0017] Optionally, the current limiting circuit includes: a thermistor for limiting the charging current of the bus capacitor during initial power-on, the thermistor being connected in series with the high-voltage bus; and a relay for controlling the connection of the first resistive element to limit current or short-circuiting the first resistive element to stop current limiting, the relay being connected in parallel across the thermistor.

[0018] When a surge signal occurs on the high-voltage bus, the thermistor limits the charging current of the bus capacitor during the initial power-on, thus ensuring that the bus capacitor is not damaged. Simultaneously, the resistance of the thermistor changes linearly with temperature, thereby limiting the rate of increase of the charging current. A relay is connected in parallel across the thermistor, forming a thermistor with switching characteristics. When the drive control circuit is initially powered on, the relay is in the open state, and the first thermistor and the bus capacitor absorb the surge signal from the AC power supply side. After the initial power-on, when the current on the high-voltage bus is not very large, the first relay closes, thereby reducing the current-limiting effect of the first thermistor on the high-voltage bus.

[0019] The drive control circuit according to the above embodiments of the present invention may further have the following technical features:

[0020] In any of the above technical solutions, the drive control circuit further includes: a first absorption circuit for absorbing surge signals on the bus line, the first absorption circuit being connected between the bus capacitor and the inverter bridge.

[0021] In this technical solution, when a film capacitor is selected as the bus capacitor, if a surge voltage exists in the circuit, the film capacitor cannot absorb too much surge energy. Therefore, a first absorption circuit is set between the bus capacitor and the inverter bridge to assist the bus capacitor in absorbing the surge signal on the bus line of the inverter bridge side, so as to prevent the bus capacitor from being broken down by the surge signal.

[0022] In any of the above technical solutions, the first absorption circuit further includes: a resistive absorption element for absorbing surge signals, the resistive absorption element being connected in parallel with the bus capacitor; and a switching element for regulating the process of the resistive absorption element absorbing surge signals, the switching element being connected in series with the resistive absorption element, the resistive absorption element absorbing surge signals when the switching element is turned on, and the resistive absorption element stopping absorbing surge signals when the switching element is turned off.

[0023] In this technical solution, the first absorption circuit includes a resistive absorption element, which is used to absorb surge signals from the bus capacitor near the inverter bridge. Specifically, when the switching element is turned on, the resistive absorption element is connected to the drive control circuit and absorbs the surge signal. Specifically, the resistive absorption element converts the electrical energy of the surge signal into heat energy and releases it to dissipate the surge signal, preventing damage to the bus capacitor caused by the surge signal due to the replacement of a smaller-value film capacitor. When the surge signal on the bus decreases or disappears, the switching element is turned off, and the resistive absorption element is disconnected from the drive control circuit to avoid affecting the normal electrical signals in the absorption control circuit.

[0024] In any of the above technical solutions, the resistive absorption element further includes: a first resistor for absorbing surge signals, the first resistor being connected in series with a switching element, the resistance value of the first resistor corresponding to a preset bus voltage protection threshold; and / or the resistance value of the first resistor corresponding to a preset overcurrent protection threshold of the switching element.

[0025] In this technical solution, the resistive absorption element includes a first resistor connected in series with a switching element. When the switching element is turned on, the first absorption circuit is turned on, and the surge signal is absorbed by the first resistor. When the switching element is turned off, the first absorption circuit is turned off, and the first resistor no longer absorbs electrical signals from the drive control circuit. Specifically, the resistance value and power of the first resistor correspond to the preset bus voltage protection threshold and the preset overcurrent value and power absorption requirement of the switching element to ensure the surge absorption effect of the resistive absorption element. The voltage protection threshold and current protection threshold are related to the voltage and current values ​​that each component in the drive circuit can withstand, as specified by the manufacturer.

[0026] In any of the above technical solutions, the resistive absorption element further includes: a first single-phase conducting element connected in parallel with the first resistor, wherein the conducting direction of the first single-phase conducting element is opposite to the direction of the current flowing through the first resistor.

[0027] In this technical solution, a first unidirectional conducting element is connected in parallel across the first resistor. Specifically, the first unidirectional conducting element is a diode, which is used to form a self-induced voltage release circuit for the first resistor to prevent the self-induced voltage generated on the first resistor from affecting the reliability of the switching element.

[0028] Optionally, the first resistor is an inductive resistor.

[0029] Optionally, the conduction direction of the first single-phase conducting element is opposite to the current direction in the first resistor.

[0030] In any of the above technical solutions, the drive control circuit further includes: a second absorption circuit for absorbing surge signals on the high-voltage bus and the low-voltage bus. The second absorption circuit includes: a capacitive absorption element for absorbing surge signals, the capacitive absorption element being connected in parallel with the bus capacitor; and a second unidirectional conducting element for regulating the absorption process of the surge signals by the capacitive absorption element, the second unidirectional conducting element being connected in series with the capacitive absorption element.

[0031] In this technical solution, the second absorption circuit includes a capacitive absorption element connected in parallel with the bus capacitor to absorb surge signals on the bus. It also includes a second unidirectional conducting element connected in series with the capacitive absorption element. Specifically, the capacitive absorption element is capacitive and is used to limit the absorption process of the surge signal, ensuring that it can only absorb surge signals from the high-voltage bus. That is, by using the unidirectional conducting element, the bus capacitor and the capacitive absorption element are distinguished, preventing the capacitive absorption element from being used as a bus capacitor, reducing its usage frequency, and improving the lifespan of the second absorption circuit.

[0032] In any of the above technical solutions, the capacitive absorption element further includes at least one capacitor, or multiple capacitors connected in series and / or in parallel, and the second absorption circuit further includes: a second resistor for absorbing the surge signal in the first capacitive element, the second resistor being connected in parallel with the capacitor.

[0033] In this technical solution, the capacitive absorption element includes one or more capacitors for absorbing surge signals. The multiple capacitors are connected in series and / or in parallel with each other, and a second resistor is provided in parallel with the capacitors. The surge signal in the capacitors is absorbed by the second resistor in parallel with the capacitors. The setting of the second resistor improves the reliability of the drive control circuit.

[0034] Optionally, the second absorption circuit and the first absorption circuit can be set simultaneously or one of them can be set separately. When the second absorption circuit and the first absorption circuit are set simultaneously, the second absorption circuit and the first absorption circuit are connected in parallel.

[0035] In any of the above technical solutions, the second absorption circuit further includes: a current-limiting resistor, used to limit the current flowing through the capacitive absorption element, the current-limiting resistor being connected in series with the capacitive absorption element.

[0036] In this technical solution, the second absorption circuit is equipped with a current-limiting resistor, which is connected in series with the capacitive absorption element to limit the current flowing through the capacitive absorption element when powered on, thereby limiting the charging current of the capacitive absorption element within a specified range and preventing the capacitive absorption element from being overcurrent-damaged.

[0037] In any of the above technical solutions, the drive control circuit further includes: a fourth resistor for absorbing the oscillation signal generated on the reactor, the fourth resistor being connected in parallel with the reactor.

[0038] In this technical solution, a fourth resistor is connected in parallel across the reactor to absorb the oscillation signal generated on the reactor. Specifically, the fourth resistor increases the system damping, and its resistance is less than 200 ohms. When the bus capacitor is a film capacitor, setting the fourth resistor can improve the system stability.

[0039] In any of the above technical solutions, the drive control circuit further includes: a sampling control circuit connected to the switching element, the sampling control circuit being used to acquire 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; wherein, the power supply signal includes the AC power supply signal of the drive control circuit and the power supply signal of the bus line.

[0040] In this technical solution, the drive control circuit is equipped with a sampling circuit. The sampling circuit collects the power supply signal measured by the circuit AC and / or the power supply signal of the bus line. Based on the voltage amplitude of the power supply signal, it controls the switching element to be turned on or off, thereby controlling the first absorption circuit to absorb the surge signal.

[0041] A second 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, wherein the signal input terminal of the motor is connected to the drive control circuit, and the drive signal output by the drive control circuit is used to drive the motor to operate. Therefore, this air conditioner possesses all the beneficial effects of the drive control circuit described in any of the above embodiments, which will not be elaborated further here. Attached Figure Description

[0042] 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:

[0043] Figure 1 A schematic diagram of a typical AC-DC-AC topology is shown.

[0044] Figure 2 This shows a schematic diagram of a typical drive control circuit;

[0045] Figure 3 This diagram shows another drive control circuit in a typical case;

[0046] Figure 4 A schematic diagram of a drive control circuit according to an embodiment of the present invention is shown;

[0047] Figure 5 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0048] Figure 6 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0049] Figure 6.1 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0050] Figure 7 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0051] Figure 8 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0052] Figure 9 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0053] Figure 10 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0054] Figure 11 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0055] Figure 12 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0056] Figure 13 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0057] Figure 14 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0058] Figure 15 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0059] Figure 16 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0060] Figure 17 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0061] Figure 18 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0062] Figure 19 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0063] Figure 20 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0064] Figure 21 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0065] Figure 22 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0066] Figure 23 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0067] Figure 24 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0068] Figure 25 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0069] Figure 26 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0070] Figure 27 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0071] Figure 28 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0072] Figure 29 A schematic diagram of a drive control circuit according to another embodiment of the present invention is shown;

[0073] Figure 30 A schematic diagram of the topology of a drive control circuit according to an embodiment of the present invention is shown. Detailed Implementation

[0074] 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.

[0075] 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.

[0076] The following reference Figures 4 to 30 This describes a drive control circuit and an air conditioner according to some embodiments of the present invention. For example... Figure 4 As shown, in an embodiment of the first aspect of the present invention, a drive control circuit is provided, comprising: an inverter bridge for outputting a drive signal, the inverter bridge being connected between a high-voltage bus and a low-voltage bus; the control circuit further comprising: a reactor for absorbing surge signals generated during the operation of the drive control circuit driving the load, the reactor being connected between the power grid and the load; and a bus capacitor for filtering out surge signals on the bus line, the bus capacitor being connected in the bus line on the input side of the inverter bridge.

[0077] In this embodiment, a reactor is included in the drive control circuit. The reactor is used to absorb surge signals generated by the AC input side and the inverter bridge to improve the surge immunity of the drive control circuit. The resonant frequency of the reactor and the bus capacitor is fixed at [value missing]. Where L is the inductance of the reactor and C is the capacitance of the bus capacitor, this effectively prevents the resonant frequency from being unstable due to distributed inductance and capacitance parameters. Simultaneously, a lower capacitance bus capacitor is used instead of a traditional electrolytic capacitor; specifically, a film capacitor is selected as the bus capacitor. The film capacitor is connected in parallel to the input side of the inverter bridge and in series between the high-voltage bus and the low-voltage bus to filter out surge signals on the bus. By applying the technical solution provided by this invention, the cost-effective use of low-cost film capacitors to replace expensive electrolytic capacitors effectively reduces production costs. The lifespan of the film capacitor can reach 6250 hours, far exceeding the 2000 hours of a typical electrolytic capacitor, thus effectively improving the lifespan of the drive control circuit. Furthermore, the film capacitor has a lower ESR (equivalent series resistance), and under the same ripple current, the heat generated by the film capacitor is much less than that of the electrolytic capacitor. Therefore, it can also effectively avoid the problem of reduced control efficiency due to bus capacitor heating, improving the reliability and efficiency of the drive control circuit.

[0078] Preferably, the capacitance value of the bus capacitor is less than the preset capacitance. Specifically, the preset capacitance is calculated according to the following formula:

[0079]

[0080] Among them, C dc For the preset capacity, L S It is the total inductance value on 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, can be determined using this calculation formula. dc It must be greater than 840uF, the preset capacity is above 840uF, but 1230uF is used in the actual implementation.

[0081] Optionally, the bus capacitor is a film capacitor, and the film capacitor is a single 900V, 30uF capacitor.

[0082] Optionally, a current-limiting resistor R0 is provided between the reactor Ldc2 and the rectifier bridge. The resistor R0 can be a general resistor.

[0083] Optionally, such as Figure 5As shown, the drive control circuit also includes a current limiting circuit, which is used to limit the charging current of the bus capacitor when it is first powered on. The current limiting circuit is connected in series on the high voltage bus.

[0084] Because the selected bus capacitor has a low capacitance value, when a surge voltage occurs, the small-capacity film capacitor cannot absorb too much energy. At this time, when the bus voltage is higher than the voltage at the surge absorption capacitor terminal, the current limiting circuit takes effect and limits the charging current of the bus capacitor when powered on, so as to prevent the bus capacitor from being broken down by overcurrent.

[0085] Optionally, such as Figure 5 As shown, the current limiting circuit includes: a thermistor, used to limit the charging current of the bus capacitor when it is first powered on, the thermistor being connected in series on the high-voltage bus; and a relay, used to control the connection of the first resistive element to limit the current or to short-circuit the first resistive element to stop the current limiting, the relay being connected in parallel across the thermistor.

[0086] In this embodiment, when a surge signal occurs on the high-voltage bus, the thermistor limits the charging current of the bus capacitor during the initial power-on, thereby ensuring that the bus capacitor is not broken down. Simultaneously, the resistance of the thermistor changes linearly with temperature, limiting the rate of increase of the charging current. A relay is connected in parallel across the thermistor, forming a thermistor with switching characteristics. When the drive control circuit is initially powered on, the relay is in the open state, and the first thermistor and the bus capacitor absorb the surge signal from the AC power supply side. After the initial power-on, when the current on the high-voltage bus is not very large, the first relay closes, thereby reducing the current-limiting effect of the first thermistor on the high-voltage bus.

[0087] In one embodiment of the present invention, further, as Figure 6 As shown, the drive control circuit also includes a first absorption circuit for absorbing surge signals on the bus line. The first absorption circuit is connected between the bus capacitor and the inverter bridge.

[0088] In this embodiment, when a film capacitor is selected as the bus capacitor, if a surge voltage exists in the circuit, the film capacitor cannot absorb too much surge energy. Therefore, a first absorption circuit is set between the bus capacitor and the inverter bridge to assist the bus capacitor in absorbing the surge signal on the bus line of the inverter bridge side, so as to prevent the bus capacitor from being broken down by the surge signal.

[0089] In one embodiment of the present invention, further, as Figure 6As shown, the first absorption circuit includes: a resistive absorption element for absorbing surge signals, the resistive absorption element being connected in parallel with the bus capacitor; and a switching element for regulating the process of the resistive absorption element absorbing surge signals, the switching element being connected in series with the resistive absorption element, the resistive absorption element absorbing surge signals when the switching element is turned on, and the resistive absorption element stopping absorbing surge signals when the switching element is turned off.

[0090] In this embodiment, the first absorption circuit includes a resistive absorption element, which is used to absorb surge signals from the bus capacitor near the inverter bridge. Specifically, when the switching element is turned on, the resistive absorption element is connected to the drive control circuit and absorbs the surge signal. Specifically, the resistive absorption element converts the electrical energy of the surge signal into heat energy and releases it to dissipate the surge signal, preventing damage to the bus capacitor caused by the surge signal due to the replacement of a film capacitor with a smaller capacitance value. When the surge signal on the bus decreases or disappears, the switching element is turned off, and the resistive absorption element is disconnected from the drive control circuit to avoid affecting the normal electrical signals in the absorption control circuit.

[0091] In one embodiment of the present invention, further, as Figure 6 As shown, the resistive absorption element includes: a first resistor for absorbing surge signals, the first resistor being connected in series with a switching element, the resistance value of the first resistor corresponding to a preset bus voltage protection threshold; and / or the resistance value of the first resistor corresponding to a preset overcurrent protection threshold of the switching element.

[0092] In this embodiment, the resistive absorption element includes a first resistor connected in series with a switching element. When the switching element is turned on, the first absorption circuit is turned on, and the surge signal is absorbed by the first resistor. When the switching element is turned off, the first absorption circuit is turned off, and the first resistor no longer absorbs electrical signals in the drive control circuit. Specifically, the resistance value of the first resistor corresponds to a preset bus voltage protection threshold and a preset overcurrent protection threshold of the switching element to ensure the surge absorption effect of the resistive absorption element. The voltage protection threshold and the current protection threshold are related to the voltage and current values ​​that each component in the drive circuit can withstand, as specified by the manufacturer.

[0093] Furthermore, such as Figure 6 As shown, when the first resistor is a non-inductive resistor, the resistive absorption element also includes a diode connected in reverse parallel to the first resistor to form an induced voltage release circuit.

[0094] Furthermore, such as Figure 6.1 As shown, when the first resistor is a non-inductive resistor, the resistive absorption element also includes a capacitor C1 and a resistor R1. C1 and R1 are connected in series and then connected in parallel across the two ends of the first resistor to form an induced voltage release circuit.

[0095] In one embodiment of the present invention, further, as Figure 6 As shown, the resistive absorption element includes: a first single-phase conducting element connected in parallel with a first resistor, wherein the conducting direction of the first single-phase conducting element is opposite to the direction of the current flowing through the first resistor.

[0096] In this embodiment, a first unidirectional conducting element is connected in parallel across the first resistor. Specifically, the first unidirectional conducting element is a diode, which is used to form a self-induced voltage release circuit for the first resistor to prevent the self-induced voltage generated on the first resistor from affecting the reliability of the switching element.

[0097] Optionally, the first resistor is an inductive resistor.

[0098] Optionally, the conduction direction of the first single-phase conducting element is opposite to the current direction in the first resistor.

[0099] In one embodiment of the present invention, further, as Figure 7 As shown, the drive control circuit also includes: a second absorption circuit for absorbing surge signals on the high-voltage bus and the low-voltage bus. The second absorption circuit includes: a capacitive absorption element for absorbing surge signals, which is connected in parallel with the bus capacitor; and a second unidirectional conducting element for regulating the absorption process of the surge signal by the capacitive absorption element, which is connected in series with the capacitive absorption element.

[0100] In this embodiment, the second absorption circuit includes a capacitive absorption element connected in parallel with the bus capacitor to absorb surge signals on the bus. It also includes a second unidirectional conducting element connected in series with the capacitive absorption element. Specifically, the capacitive absorption element is capacitive, and the second capacitive absorption element limits the absorption process of the surge signal by the capacitive absorption element, ensuring that it can only absorb surge signals on the high-voltage bus. That is, by using the unidirectional conducting element, the bus capacitor and the capacitive absorption element are distinguished, preventing the capacitive absorption element from being used as a bus capacitor, reducing the frequency of use of the capacitive absorption element, and improving the lifespan of the second absorption circuit.

[0101] In one embodiment of the present invention, further, as Figure 7 As shown, the capacitive absorption element includes at least one capacitor, or multiple capacitors connected in series and / or in parallel. The second absorption circuit further includes a second resistor for absorbing surge signals in the first capacitive element, and the second resistor is connected in parallel with the capacitor.

[0102] In this embodiment, the capacitive absorption element includes one or more capacitors for absorbing surge signals. The multiple capacitors are connected in series and / or in parallel, and a second resistor is provided in parallel with the capacitors. The surge signal in the capacitors is absorbed by the second resistor in parallel with the capacitors. The provision of the second resistor improves the reliability of the drive control circuit.

[0103] Optionally, the second absorption circuit and the first absorption circuit can be set simultaneously or one of them can be set separately. When the second absorption circuit and the first absorption circuit are set simultaneously, the second absorption circuit and the first absorption circuit are connected in parallel.

[0104] In one embodiment of the present invention, further, as Figure 7 As shown, the second absorption circuit also includes a current-limiting resistor, which is used to limit the current flowing through the capacitive absorption element, and the current-limiting resistor is connected in series with the capacitive absorption element.

[0105] In this embodiment, the second absorption circuit is provided with a current-limiting resistor, which is connected in series with the capacitive absorption element to limit the current flowing through the capacitive absorption element when powered on, thereby limiting the charging current of the capacitive absorption element within a specified range and preventing the capacitive absorption element from being overcurrent-damaged.

[0106] In one embodiment of the present invention, the drive control circuit further includes a fourth resistor for absorbing the oscillation signal generated on the reactor, the fourth resistor being connected in parallel with the reactor.

[0107] In this embodiment, a fourth resistor is connected in parallel across the reactor to absorb the oscillation signal generated on the reactor. Specifically, the fourth resistor increases the system damping, and its resistance is less than 200 ohms. When the bus capacitor is a film capacitor, setting the fourth resistor can improve the system stability.

[0108] In one embodiment of the present invention, further, as Figure 8 As shown, the current limiting circuit can be set to three or two, specifically PTC1, PTC2 and PTC3, or any two of PTC1, PTC2 and PTC3, such as PTC1 and PTC2, which are located on the three-phase or any two-phase input lines on the AC input source side, specifically between the filter circuit and the rectifier bridge. When powered on for the first time, the relay is disconnected so that the temperature-sensitive resistor is connected to the circuit, thereby limiting the charging current of the bus capacitor.

[0109] In one embodiment of the present invention, further, as Figure 9 As shown, three current-limiting circuits are configured, specifically PTC1, PTC2, and PTC3, located on the three-phase busbar of the AC input source side, specifically between the filter circuit and the rectifier bridge. Upon initial power-on, the relay disconnects to allow the thermistor to enter the circuit, thereby limiting the charging current of the busbar capacitor. Simultaneously, a first absorption circuit is included in the drive control circuit.

[0110] In one embodiment of the present invention, further, as Figure 10 and Figure 11As shown, three current-limiting circuits are configured, specifically PTC1, PTC2, and PTC3, located on the three-phase busbar of the AC input source side, specifically between the filter circuit and the rectifier bridge. Upon initial power-up, the relay disconnects, allowing the thermistor to connect to the circuit, thereby limiting the charging current of the busbar capacitor. Simultaneously, the drive control circuit includes both a first absorption circuit and a second absorption circuit, as shown... Figure 10 As shown, the first absorption circuit is located between the bus capacitor C and the inverter bridge, and the second absorption circuit is located between the rectifier bridge and the reactor; or as shown... Figure 11 As shown, the first absorption circuit is located between the bus capacitor C and the inverter bridge, and the second absorption circuit is located between the reactor and the bus capacitor C.

[0111] by Figure 11 Taking the illustrated scheme as an example, during normal system operation, the voltage on the capacitive absorption element of the second absorption circuit is maintained at the maximum value of the DC bus voltage. At this time, the switching element corresponding to the resistive absorption element is disconnected. Since surge energy mainly comes from power input, compressor windings during system failure shutdown, AC / DC side inductor freewheeling current, and compressor kinetic energy, when a surge voltage exists, the small-capacity film capacitor cannot absorb too much energy. When the bus voltage is higher than the voltage at the surge absorption capacitor terminal, the capacitive absorption element takes effect, and the remaining energy flows into the film capacitor and surge absorption capacitor module. As the surge energy is absorbed, the DC bus voltage rises slowly (the larger the surge absorption capacitor, the slower the DC bus voltage rises). When the DC bus voltage is higher than a certain set value (such as 720V, which can be adjusted in practice), the resistive absorption element intervenes, and the switching element starts to turn on in pulse width modulation (PWM) form or fixed form to ensure that the bus voltage is as stable as possible when a surge voltage occurs.

[0112] In one embodiment of the present invention, further, as Figure 12 As shown, the current-limiting circuit is located on the high-voltage bus. Upon initial power-on, the relay disconnects, allowing the thermistor to connect to the circuit, thereby limiting the charging current of the bus capacitor. Simultaneously, the drive control circuit includes a second absorption circuit, which absorbs surge signals through capacitive absorption elements.

[0113] In one embodiment of the present invention, further, as Figure 13 and Figure 14 As shown, the current-limiting circuit is located on the high-voltage bus. Upon initial power-on, the relay disconnects, allowing the thermistor to connect to the circuit, thereby limiting the charging current of the bus capacitor. Simultaneously, the drive control circuit includes both a first absorption circuit and a second absorption circuit, as shown... Figure 13 As shown, the first absorption circuit is located between the bus capacitor C and the inverter bridge, and the second absorption circuit is located between the current limiting circuit and the reactor; or as shown... Figure 14As shown, the first absorption circuit is located between the bus capacitor C and the inverter bridge, and the second absorption circuit is located between the reactor and the bus capacitor C.

[0114] In one embodiment of the present invention, further, as Figure 15 As shown, three current-limiting circuits are configured, specifically PTC1, PTC2, and PTC3, located on the three-phase busbars of the AC input source side. Upon initial power-up, the relays disconnect, allowing the thermistors to connect to the circuit, thereby limiting the charging current of the busbar capacitors. Simultaneously, the drive control circuit includes a second absorption circuit, which incorporates a switching element. When the surge signal in the system is weak, the switching element disconnects, absorbing the surge signal through the busbar capacitors. When the surge signal in the system is strong, the switching element closes, and the second absorption circuit connects between the high-voltage and low-voltage busbars to assist in absorbing the surge signal.

[0115] In one embodiment of the present invention, further, as Figure 16 As shown, the current-limiting circuit is located on the high-voltage bus. Upon initial power-on, the relay disconnects, allowing the thermistor to connect to the circuit, thereby limiting the charging current of the bus capacitor. Simultaneously, the drive control circuit includes a second absorption circuit, which contains a conducting element, specifically a switching element. When the surge signal in the system is weak, the switching element opens, absorbing the electrophoretic signal through the bus capacitor. When the surge signal in the system is strong, the switching element closes, and the second absorption circuit connects between the high-voltage and low-voltage bus to assist in absorbing the surge signal.

[0116] In one embodiment of the present invention, further, as Figure 17 As shown, the current-limiting circuit is located on the high-voltage bus. Upon initial power-on, the relay disconnects, allowing the thermistor to connect to the circuit, thereby limiting the charging current of the bus capacitor. Simultaneously, the drive control circuit includes a first absorption circuit and a second absorption circuit, located on opposite sides of the bus capacitor. The second absorption circuit contains a conducting element, specifically a switching element, while the first absorption circuit also contains a switching element. When the surge signal in the system is weak, the switching elements of both the first and second absorption circuits disconnect, allowing the bus capacitor to absorb the surge signal. When the surge signal is strong, the corresponding switching element closes, connecting the first and / or second absorption circuits between the high-voltage and low-voltage bus to assist in absorbing the surge signal.

[0117] In one embodiment of the present invention, further, as Figure 18As shown, three current-limiting circuits are configured, specifically PTC1, PTC2, and PTC3, located on the three-phase busbars of the AC input source side. Upon initial power-on, the relay disconnects to allow the thermistor to connect to the circuit, thereby limiting the charging current of the busbar capacitor. Simultaneously, the drive control circuit includes a first absorption circuit and a second absorption circuit, located on opposite sides of the busbar capacitor. The second absorption circuit contains a conducting element, specifically a switching element, while the first absorption circuit also contains a switching element. When the surge signal in the system is weak, the switching elements of the first and second absorption circuits disconnect, allowing the busbar capacitor to absorb the surge signal. When the surge signal in the system is strong, the corresponding switching element is closed, connecting the first and / or second absorption circuits between the high-voltage and low-voltage busbars to assist in absorbing the surge signal.

[0118] In one embodiment of the present invention, further, as Figure 19 As shown, three current-limiting circuits are configured, specifically PTC1, PTC2, and PTC3, located on the three-phase busbars of the AC input source side. Upon initial power-up, the relay disconnects, allowing the thermistor to connect to the circuit, thereby limiting the charging current of the busbar capacitor. Simultaneously, the drive control circuit includes a first absorption circuit and a second absorption circuit, located on opposite sides of the busbar capacitor. The second absorption circuit incorporates a conducting element, specifically a diode, allowing surge signals on the busbar to pass through the diode into the second absorption circuit. The discharge current of the capacitive absorption element in the second absorption circuit is blocked by the diode, preventing any impact on the electrical signal on the busbar. Furthermore, a fourth resistor R4 is connected in parallel with the reactor to reduce the oscillation signal between the reactor and the busbar capacitor, preventing system fluctuations caused by the LC oscillation effect between the reactor and the busbar capacitor, thus improving system stability.

[0119] In one embodiment of the present invention, further, as Figure 20 As shown, the current-limiting circuit is located on the high-voltage bus. Upon initial power-on, the relay disconnects, allowing the thermistor to enter the circuit, thereby limiting the charging current of the bus capacitor. Simultaneously, the drive control circuit includes a first absorption circuit and a second absorption circuit, located on opposite sides of the bus capacitor. The second absorption circuit incorporates a conducting element, specifically a diode, allowing surge signals from the bus to pass through and enter the second absorption circuit. The discharge current of the capacitive absorption element in the second absorption circuit is blocked by the diode, preventing any impact on the electrical signal on the bus. Furthermore, a fourth resistor R4 is connected in parallel with the reactor to reduce oscillation signals between the reactor and the bus capacitor, preventing system fluctuations caused by the LC oscillation effect between the reactor and the bus capacitor, thus improving system stability.

[0120] In one embodiment of the present invention, further, as Figures 21 to 26 As shown, the drive control circuit includes a third absorption circuit, which includes a current limiting element, a capacitive absorption element, and a unidirectional conduction element. The current limiting element can be a temperature-sensitive resistor (PTC) or a current-limiting resistor (R), and a switching element connected in parallel across the PTC or R. Specifically, surge energy mainly originates from power input, compressor windings during prototype shutdown due to malfunction, AC / DC side inductor freewheeling current, and compressor kinetic energy. When a surge voltage exists, because the small-capacity film capacitor cannot absorb too much energy, when the bus voltage is higher than the terminal voltage of the capacitive absorption elements (specifically capacitors C2 and C3) in the third absorption circuit, the third absorption circuit takes effect, and the remaining energy flows into the bus capacitor and the third absorption circuit. At this time, the switching element closes, and the temperature-sensitive resistor PTC or current-limiting resistor R is short-circuited, allowing the surge energy to be quickly absorbed. When the power supply is disconnected or the DC bus voltage is lower than a fixed value (preferably set to 200V), it is determined that no current flows through the switching element, so the switching element is controlled to open (only when using an AC relay as the switching element is it necessary to determine whether no current flows through the switching element; normal IGBTs or DC relays can be opened at any time). That is, when powered on, the temperature-sensitive resistor PTC or current-limiting resistor R is connected in series in the circuit of the capacitive absorption element to achieve the purpose of current limiting. Afterward, the switching element is closed to short-circuit the temperature-sensitive resistor PTC or current-limiting resistor R, achieving the purpose of quickly absorbing surge energy.

[0121] Furthermore, such as Figure 21 As shown, the current-limiting element is located between the single-phase conducting element and the capacitive absorption element; or as... Figure 22 As shown, the current-limiting element is located between the high-voltage busbar and the single-phase conducting element; or as... Figure 23 As shown, the current-limiting element is located between the capacitive absorption element and the low-voltage bus.

[0122] Furthermore, such as Figures 24 to 26 As shown, the current-limiting resistor R1 (PTC thermistor or current-limiting resistor R) can be implemented by connecting two resistors R4 and R5 in series, where the sum of the resistances of R4 and R5 is equal to the resistance of R1. The switching element is connected in parallel across resistor R4. When the system is powered on, resistors R4 and R5 are simultaneously connected in series into the third current-limiting circuit for current limiting. During the surge absorption phase after power-on, the switching element closes to short-circuit resistor R4, at which point resistor R5 performs the current-limiting function independently.

[0123] In one embodiment of the present invention, further, as Figure 27As shown, the drive control circuit includes both a first absorption circuit and a third absorption circuit. Each circuit includes a current-limiting element, a capacitive absorption element, and a unidirectional conducting element. The current-limiting element comprises current-limiting resistors R4 and R5, with R5 located between the unidirectional conducting element and the capacitive absorption element. R4 is located between the capacitive absorption element and the low-voltage busbar. A switching element is connected in parallel across resistor R4. When the system is powered on, resistors R4 and R5 are simultaneously connected in series in the third current-limiting circuit for current limiting. During the surge absorption phase after power-on, the switching element closes to short-circuit resistor R4, at which point resistor R5 performs current limiting independently.

[0124] In one embodiment of the present invention, further, as Figure 28 and Figure 29 As shown, the drive control circuit includes a fourth absorption circuit. The fourth absorption circuit comprises a capacitive absorption element, a resistive absorption element, and a current-limiting element; the capacitive absorption element and the current-limiting element are connected in series. The capacitive absorption element includes a conducting element, an absorption capacitor, a current-limiting resistor R1, and a discharge resistor. Two absorption capacitors are provided, C2 and C3, and the discharge resistors R2 and R3 are connected in parallel across C2 and C3, respectively. The conducting element is specifically a single-phase conducting element or a switching element. The resistive absorption element includes an absorption resistor, a freewheeling circuit connected in parallel across the absorption resistor, a switching element, and a current-measuring element. The freewheeling circuit preferably uses a diode connected in reverse parallel. When the power supply is disconnected or the DC bus voltage is lower than a fixed value, if the current-measuring element determines that no current flows through the switching element, it controls the switching element to open.

[0125] Furthermore, such as Figure 28 As shown, the input terminal of the resistive element is connected between the conducting element and the current-limiting resistor R1, and the output terminal of the resistive element is connected to the low-voltage bus.

[0126] Furthermore, such as Figure 29 As shown, the input terminal of the resistive element is connected between the current-limiting resistor R1 and the absorption capacitor C2, and the output terminal of the resistive element is connected to the low-voltage bus.

[0127] In the above Figures 4 to 29In the corresponding embodiment, Lac refers to the inductance of the actual AC inductance model and the input power line, which includes inductance and resistance. The AC side inductance value used in the existing model is 25mH, 500 milliohms, and the inductance value of the input power line is less than or equal to 10mH (numerical amplification), and the resistance value is not less than 0.5 ohms (the actual resistance of the wire used is approximately 1.2 ohms); Ldc refers to the actual DC side inductance model, which includes inductance and resistance. The inductance value of Ldc is 4.5mH, 120 milliohms; R4 is a damping resistor. The damping resistor R4 is not set when the inductance value of Ldc is selected as 4.5mH. Ldc is not set on the 6KW prototype, and R4 can also be omitted; Lac and Ldc exist for EMC harmonic requirements. If there are EMX harmonic requirements, Lac or Ldc may be present on the prototype, or Lac and Ldc may coexist. In regions where harmonics are not required, neither Lac nor Ldc exists. However, to address the issue of high-frequency harmonics (where the Ldc inductor can be omitted if the problem is ignored), a smaller inductance Ldc2 is used at the Ldc location in the circuit topology, and a small damping resistor R4 is connected in parallel with this smaller Ldc2 to improve system stability.

[0128] In one embodiment of the present invention, the drive control circuit further includes a sampling control circuit (not shown in the figure), which is used to acquire 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; wherein, the power supply signal includes the AC power supply signal of the drive control circuit and the power supply signal of the bus line.

[0129] In this embodiment, such as Figure 30 As shown, the drive control circuit is equipped with a sampling control circuit 20. The sampling control circuit 20 collects the power supply signal measured by the circuit AC and / or the power supply signal of the bus line, and controls the switching element to be turned on or off according to the voltage amplitude of the power supply signal, thereby controlling the first absorption circuit to absorb the surge signal.

[0130] Optionally, the power supply signal for AC measurement is specifically the electrical signal between the AC power module 10 and the filter circuit 12.

[0131] Optionally, the power supply signal for AC measurement is specifically the electrical signal between the filter circuit 12 and the rectifier bridge 14.

[0132] Optionally, the power supply signal of the bus line includes the electrical signal between the rectifier bridge 14 and the absorption circuit 16, specifically the electrical signal between the rectifier bridge 14 and the reactor.

[0133] Optionally, the power supply signal for the bus line includes the electrical signal between the snubber circuit 16 and the inverter bridge 18.

[0134] In a second aspect of the present invention, an air conditioner is provided, comprising: a motor; and a drive control circuit as described in any of the above embodiments, wherein the signal input terminal of the motor is connected to the drive control circuit, and the drive signal output by the drive control circuit is used to drive the motor to operate. Therefore, this air conditioner possesses all the beneficial effects of the drive control circuit described in any of the above embodiments, which will not be elaborated further here.

[0135] In the description of this invention, the term "multiple" refers to two or more. Unless otherwise explicitly defined, the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "connection," "installation," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be 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.

[0136] In the description of this invention, 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 invention. In this invention, the illustrative use of the above terms does 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.

[0137] 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, the drive control circuit comprising: An inverter bridge, used to output a drive signal, is connected between a high-voltage bus and a low-voltage bus; characterized in that the drive control circuit further includes: A reactor is used to absorb surge signals generated during the operation of the drive control circuit driving the load. The reactor is connected between the power grid and the load. Bus capacitors are used to filter out surge signals on the bus line, and the bus capacitors are connected to the bus line on the input side of the inverter bridge. The second absorption circuit is used to absorb surge signals from the high-voltage bus and the low-voltage bus. The second absorption circuit includes: A capacitive absorption element is used to absorb the surge signal, and the capacitive absorption element is connected in parallel with the bus capacitor; The second unidirectional conducting element is used to regulate the absorption process of the surge signal by the capacitive absorption element, and the second unidirectional conducting element is connected in series with the capacitive absorption element; The capacitive absorption element includes: At least one capacitor, or multiple capacitors connected in series and / or parallel, The second absorption circuit also includes: The second resistor is used to absorb surge signals in the capacitor, and the second resistor is connected in parallel with the capacitor. The bus capacitor is a thin-film capacitor; The capacitance value of the bus capacitor is less than the preset capacitance, which is calculated according to the following formula: Among them, C dc For the preset capacity, L S It is the total inductance value on 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 This represents the average value of the bus voltage. The drive control circuit also includes a fourth resistor for absorbing the oscillation signal generated on the reactor, and the fourth resistor is connected in parallel with the reactor. The drive control circuit also includes a current limiting circuit for limiting the charging current of the bus capacitor during the first power-on, and the current limiting circuit is connected in series on the high-voltage bus. The current limiting circuit includes a thermistor and a relay; The temperature-sensitive resistor is used to limit the charging current of the bus capacitor when it is first powered on, and the temperature-sensitive resistor is connected in series on the high-voltage bus. The relay is used to control the connection of the first resistive element to limit current or to short-circuit the first resistive element to stop current limiting. The relay is connected in parallel across the two ends of the thermistor. The current limiting circuit is configured as three or two, located between the filter circuit and the rectifier bridge. Upon initial power-on, the relay is disconnected to allow the temperature-sensitive resistor to enter the circuit, thereby limiting the charging current of the bus capacitor. The drive control circuit also includes a first absorption circuit, which is used to absorb surge signals on the bus line. The first absorption circuit includes a resistive absorption element and a switching element, wherein the resistive absorption element is used to absorb the surge signal; The switching element is used to regulate the process by which the resistive absorption element absorbs the surge signal; The resistive absorption element includes a first resistor, which is used to absorb the surge signal. The first resistor is connected in series with the switching element. The resistance value of the first resistor corresponds to a preset bus voltage protection threshold; and the resistance value of the first resistor corresponds to a preset overcurrent protection threshold of the switching element. The resistive absorption element includes a first unidirectional conducting element, which is connected in parallel with the first resistor, and the conducting direction of the first unidirectional conducting element is opposite to the direction of the current flowing through the first resistor. The first unidirectional conducting element is a diode, which is used to form a self-induced voltage release circuit for the first resistor.

2. The drive control circuit according to claim 1, characterized in that, The first absorption circuit is connected between the bus capacitor and the inverter bridge.

3. The drive control circuit according to claim 2, characterized in that, The resistive absorption element is connected in parallel with the bus capacitor; The switching element is connected in series with the resistive absorption element. When the switching element is turned on, the resistive absorption element absorbs the surge signal. When the switching element is turned off, the resistive absorption element stops absorbing the surge signal.

4. The drive control circuit according to claim 1, characterized in that, The second absorption circuit also includes: A current-limiting resistor is used to limit the current flowing through the capacitive absorption element, and the current-limiting resistor is connected in series with the capacitive absorption element.

5. The drive control circuit according to claim 3, characterized in that, Also includes: A sampling control circuit is connected to the switching element. The sampling control circuit is used to collect 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 signal includes the AC power supply signal of the drive control circuit and the power supply signal of the bus line.

6. An air conditioner, characterized in that, The air conditioner includes: Electric motor; and According to any one of claims 1 to 5, the signal input terminal of the motor is connected to the drive control circuit, and the drive signal output by the drive control circuit is used to drive the motor to run.

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