Air conditioners and their control methods

Abstract

This invention discloses an air conditioner and its control method. The air conditioner includes a refrigerant circulation loop, a refrigeration system, an inverter, and a controller. The controller is configured to: determine a preset reference voltage vector boundary corresponding to each sector of a reference voltage vector circle; determine a simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary; compensate for the amplitude of the simplified reference voltage vector to obtain an overmodulated voltage vector. This allows for the elimination of the need to distinguish overmodulation regions during overmodulation, and enables uniform overmodulation processing when the actual output reference voltage vector exceeds the space vector hexagon. The method is simple, can quickly obtain the overmodulated voltage vector while ensuring the accuracy of the actual output reference voltage vector, and achieves a good balance between simplicity and accuracy.

Description

Technical Field

[0001] This invention relates to the field of air conditioner technology, and in particular to an air conditioner and its control method. Background Technology

[0002] Space vector modulation (SVM) generates pulse width modulation waves by adjusting the six switches of a three-phase inverter according to a specific switching pattern. Compared to sinusoidal pulse width modulation (PWM), SVM can increase the amplitude of the inverter's output line voltage by approximately 15%. Therefore, SVM is widely used in motor control systems.

[0003] In existing technologies, the overmodulation region needs to be partitioned when calculating the actual output reference voltage vector, and the calculation process is complex. Therefore, how to improve the speed and accuracy of calculating the actual output reference voltage vector while improving voltage utilization is an urgent problem to be solved. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the object of the present invention is to provide an air conditioner and a control method thereof.

[0005] This invention proposes an air conditioner comprising: a refrigerant circulation loop, in which refrigerant circulates within a loop consisting of a compressor, condenser, electronic expansion valve, evaporator, and four-way valve; a refrigeration system, which performs heat exchange between the refrigerant and indoor air in a compression refrigeration cycle within the refrigerant circulation loop, the refrigeration system including the compressor, which compresses low-temperature, low-pressure refrigerant gas into high-temperature, high-pressure refrigerant gas and discharges it to the condenser; a motor for driving the compressor; and an inverter for driving the motor based on an overmodulated voltage vector to expand the motor's speed range. The controller is configured to: determine a preset reference voltage vector boundary corresponding to each sector of the reference voltage vector circle; determine a simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary; the preset reference voltage vector boundary satisfies: AH⊥OA, BH⊥OB; where OA and OB are two adjacent basic voltage vectors in the space vector hexagon, AH is the boundary perpendicular to OA, and BH is the boundary perpendicular to OB; and compensate for the amplitude of the simplified reference voltage vector to obtain an overmodulated voltage vector.

[0006] In addition, the air conditioner according to embodiments of the present invention may also have the following additional technical features:

[0007] Furthermore, when determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the boundary of the preset reference voltage vector, the controller is specifically configured as follows: when the vector circle containing the actual output reference voltage vector exceeds the circumcircle of the space vector hexagon but does not exceed the boundary of the preset reference voltage vector, the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector; when the vector circle containing the actual output reference voltage vector exceeds the circumcircle of the space vector hexagon and exceeds the boundary of the preset reference voltage vector, the simplified reference voltage vector falls on the vertex of the nearest space vector hexagon.

[0008] Furthermore, when determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the boundary of the preset reference voltage vector, the controller is specifically configured such that: when the vector circle containing the actual output reference voltage vector exceeds the inscribed circle of the space vector hexagon but does not exceed the circumscribed circle of the space vector hexagon, and exceeds the boundary of the space vector hexagon, the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector.

[0009] Furthermore, when determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the boundary of the preset reference voltage vector, the controller is specifically configured such that: when the vector circle where the actual output reference voltage vector is located is the circumcircle of the space vector hexagon, the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector.

[0010] Furthermore, when determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the boundary of the preset reference voltage vector, the controller is specifically configured such that: when the vector circle containing the actual output reference voltage vector passes through point H, or when the radius of the vector circle containing the actual output reference voltage vector is greater than OH, the simplified reference voltage vector falls on the vertex of the nearest spatial vector hexagon.

[0011] Furthermore, the reference voltage vector on line AH satisfies:

[0012] T1 + T2 / 2 = T S1 ;

[0013] Where T1 is the duration of action of one of the two adjacent basic voltage vectors in the space vector hexagon; T2 is the duration of action of the other of the two adjacent basic voltage vectors in the space vector hexagon, T S1The duration of the reference voltage vector on line AH.

[0014] Furthermore, when determining whether the vector circle containing the actual output reference voltage vector exceeds the preset reference voltage vector boundary, the controller is specifically configured such that: when T1 + T2 / 2 <= T S1 When the actual output reference voltage vector is located, the vector circle does not exceed the preset reference voltage vector boundary; when T1+T2 / 2>T S1 When the actual output reference voltage vector is located, the vector circle is determined to be outside the preset reference voltage vector boundary.

[0015] Furthermore, when the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector, the controller is specifically configured as follows:

[0016]

[0017] Where T1 is the duration of action of the actual output reference voltage vector in one of the two adjacent basic voltage vectors, as described before simplification; T2 is the duration of action of the actual output reference voltage vector in the other of the two adjacent basic voltage vectors, as described before simplification. S To simplify the actual output reference voltage vector's duration, T′1 is the duration of the simplified reference voltage vector's duration in one of the two adjacent basic voltage vectors, and T′2 is the duration of the simplified reference voltage vector's duration in the other of the two adjacent basic voltage vectors.

[0018] Furthermore, when compensating for the magnitude of the simplified reference voltage vector, the controller is specifically configured as follows:

[0019]

[0020] in, Let v be the overmodulated vector. ref Let k(m) be the simplified reference voltage vector, and k(m) be the modulation coefficient.

[0021] According to an embodiment of the present invention, the air conditioner determines a simplified reference voltage vector by defining a preset reference voltage vector boundary corresponding to each sector of the reference voltage vector circle, and by determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary. The preset reference voltage vector boundary satisfies: AH⊥OA, BH⊥OB; where OA and OB are two adjacent basic voltage vectors in the space vector hexagon, AH is the boundary perpendicular to OA, and BH is the boundary perpendicular to OB. The amplitude of the simplified reference voltage vector is compensated to obtain an overmodulated voltage vector. This allows for the elimination of the need to distinguish overmodulation regions during overmodulation, and enables uniform overmodulation processing when the actual output reference voltage vector exceeds the space vector hexagon. The method is simple, can quickly obtain the overmodulated voltage vector while ensuring the accuracy of the actual output reference voltage vector, and achieves a good balance between simplicity and accuracy.

[0022] To address the aforementioned problems, this invention also proposes a control method for an air conditioner, used in any of the above embodiments. The method includes the following steps: determining a preset reference voltage vector boundary corresponding to each sector of a reference voltage vector circle; determining a simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary; the preset reference voltage vector boundary satisfies: AH⊥OA, BH⊥OB; where OA and OB are two adjacent basic voltage vectors in a space vector hexagon, AH is the boundary perpendicular to OA, and BH is the boundary perpendicular to OB; compensating for the amplitude of the simplified reference voltage vector to obtain an overmodulated voltage vector.

[0023] According to the control method of the air conditioner of the present invention, a preset reference voltage vector boundary corresponding to each sector of the reference voltage vector circle is determined, and a simplified reference voltage vector is determined according to the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary. The preset reference voltage vector boundary satisfies: AH⊥OA, BH⊥OB; where OA and OB are two adjacent basic voltage vectors in the space vector hexagon, AH is the boundary perpendicular to OA, and BH is the boundary perpendicular to OB. The amplitude of the simplified reference voltage vector is compensated to obtain the overmodulated voltage vector, so that when overmodulation is performed, it is not necessary to distinguish the overmodulation region. When the actual output reference voltage vector exceeds the space vector hexagon, a unified overmodulation processing is performed. The method is simple, can quickly obtain the overmodulated voltage vector, and ensure the accuracy of the actual output reference voltage vector, achieving a good balance between simplicity and accuracy.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] 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:

[0026] Figure 1 This is a schematic diagram of the structure of an air conditioner according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of space vector voltage synthesis according to an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of a preset reference voltage vector boundary according to an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of determining a simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the boundary of a preset reference voltage vector, according to an embodiment of the present invention.

[0030] Figure 5 This is a schematic diagram of determining a simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the boundary of a preset reference voltage vector, according to another embodiment of the present invention.

[0031] Figure 6 This is a schematic diagram of determining a simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the boundary of a preset reference voltage vector, according to another embodiment of the present invention.

[0032] Figure 7 This is a flowchart of a control method for an air conditioner according to another embodiment of the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and 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 this invention.

[0035] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] In this invention, the air conditioner performs a refrigeration cycle by using a compressor, a condenser, an electronic expansion valve, and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation, and supplies refrigerant to the conditioned and heat-exchanged air.

[0038] The compressor compresses refrigerant gas under high temperature and pressure and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process.

[0039] The electronic expansion valve expands the high-temperature, high-pressure liquid refrigerant condensed in the condenser into a low-pressure liquid refrigerant. The evaporator evaporates the expanded refrigerant in the electronic expansion valve, returning the low-temperature, low-pressure refrigerant gas to the compressor. The evaporator achieves its cooling effect by utilizing the latent heat of refrigerant evaporation to exchange heat with the material being cooled. Throughout the cycle, the air conditioner regulates the temperature of the indoor space.

[0040] The outdoor unit of an air conditioner refers to the part of the refrigeration cycle that includes the compressor and the outdoor heat exchanger. The indoor unit of an air conditioner includes the indoor heat exchanger, and an electronic expansion valve can be provided in either the indoor or outdoor unit.

[0041] The indoor and outdoor heat exchangers function as either condensers or evaporators. When the indoor heat exchanger is used as a condenser, the air conditioner functions as a heater in heating mode; when the indoor heat exchanger is used as an evaporator, the air conditioner functions as a cooler in cooling mode.

[0042] The following is for reference. Figures 1-7 An air conditioner and its control method according to embodiments of the present invention are described.

[0043] Figure 1 This is a schematic diagram of the structure of an air conditioner according to an embodiment of the present invention. Figure 1 As shown, an air conditioner includes: a refrigerant circulation loop 10, a refrigeration system 20, an inverter 30, a controller 40, and a motor 50. The refrigerant circulation loop 10 circulates the refrigerant within a loop consisting of a compressor, condenser, electronic expansion valve, evaporator, and four-way valve. The refrigeration system 20 performs heat exchange between the refrigerant and indoor air within a compression refrigeration cycle of the refrigerant circulation loop. The refrigeration system 20 includes a compressor that compresses low-temperature, low-pressure refrigerant gas into high-temperature, high-pressure refrigerant gas and discharges it to the condenser. A motor 50 drives the compressor. An inverter 30 drives the motor 50 based on an overmodulated voltage vector to expand the speed range of the motor 50. The controller 40 is configured to: determine a preset reference voltage vector boundary corresponding to each sector of the reference voltage vector circle; determine a simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary; the preset reference voltage vector boundary satisfies: AH⊥OA, BH⊥OB; where OA and OB are two adjacent basic voltage vectors in a space vector hexagon, AH is the boundary perpendicular to OA, and BH is the boundary perpendicular to OB; and compensate for the amplitude of the simplified reference voltage vector to obtain the overmodulated voltage vector.

[0044] Specifically, such as Figure 2 The diagram shows a schematic of Space Vector Pulse Width Modulation (SVPWM) voltage synthesis. The amplitude of the voltage vector output by SVPWM is limited to the boundary of a space vector hexagon with its six basic voltage vector endpoints as vertices, and the limit is within the six vertices of the space vector hexagon. When the motor 50 is driven, it controls the voltage vector to operate within the range of the space vector hexagon; the larger the operating range, the higher the voltage utilization rate. Figure 2 As shown, the basic voltage vectors within the space vector hexagon include V1, V2, V3, V4, V5, and V6, and the actual output reference voltage vector V... ref It can be synthesized from two adjacent basic voltage vectors V1 and V2, where the arrows represent vectors, i.e.:

[0045]

[0046]

[0047] Where T1 is the duration of action of one of the two adjacent fundamental voltage vectors, T2 is the duration of action of the other of the two adjacent fundamental voltage vectors, and T... s The actual output reference voltage vector V ref The duration of action.

[0048] In a specific embodiment, the trajectory of the reference voltage vector is circular, forming a reference voltage vector circle, which is divided into six sectors by a space vector hexagon. Since the maximum system boundary is a hexagon, the actual output reference voltage vector may be limited. Traditional overmodulation methods involve numerous divisions and trigonometric function operations when calculating the output reference voltage, making the calculation process very complex and placing a heavy burden on the chip's computation. Therefore, in product applications, higher-end chips are required to meet the requirements, undoubtedly increasing costs. This invention determines a simplified reference voltage vector by pre-setting a reference voltage vector boundary and determining the simplified reference voltage vector boundary based on the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary. It eliminates the need to distinguish overmodulation regions and performs uniform overmodulation processing when the actual output reference voltage vector exceeds the spatial vector hexagon. The method is simple. Since the amplitude of the actual output reference voltage vector is reduced after simplification in this embodiment, the amplitude of the simplified reference voltage vector is compensated to obtain the overmodulated voltage vector, thereby improving the accuracy of the overmodulated voltage vector. Thus, this embodiment of the invention achieves a good balance between simplicity and accuracy by quickly obtaining the overmodulated voltage vector without complex calculations, while ensuring the accuracy of the actual output reference voltage vector. It is understood that due to its simple calculation, this embodiment of the invention is applicable to low-cost controllers, thereby reducing the overall cost of the air conditioner.

[0049] Furthermore, in this embodiment of the invention, the preset reference voltage vector boundary is the same across the six sectors, meaning each sector corresponds to a sub-boundary. Taking the first sector as an example, where AB is a side of the space vector hexagon, as shown... Figure 3As shown, if AH is not perpendicular to OA, and the actual output reference voltage vector is, for example, OK, then to determine whether OK is inside or outside the preset reference voltage vector boundary, point K needs to be calculated first before making the judgment. However, the calculation of point K is very large and not suitable for engineering applications. Therefore, to further simplify the calculation, this embodiment of the invention stipulates that point H in the sub-boundary OAHB in the first sector satisfies: AH⊥OA, BH⊥OB, to easily determine whether the actual output reference voltage vector is inside OAHB. It can be understood that the preset reference voltage vector boundary in the other sectors of the reference voltage vector circle has the same shape as OAHB in the first sector, which will not be elaborated here.

[0050] In one embodiment of the present invention, when determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary, the controller 40 is specifically configured as follows: when the vector circle where the actual output reference voltage vector is located exceeds the circumcircle of the space vector hexagon but does not exceed the preset reference voltage vector boundary, the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector; when the vector circle where the actual output reference voltage vector is located exceeds the circumcircle of the space vector hexagon and exceeds the preset reference voltage vector boundary, the simplified reference voltage vector falls on the vertex of the nearest space vector hexagon.

[0051] In a specific embodiment, such as Figure 4 As shown, taking the first sector as an example, if the actual output reference voltage vector is, for example, on arc JK, since arc JK exceeds the circumcircle of the space vector hexagon but does not exceed the preset reference voltage vector boundary OAHB, the simplified reference voltage vector shrinks to the boundary AB of the space vector hexagon within the sector. If the actual output reference voltage vector is, for example, on arc PJ, since arc PJ exceeds the circumcircle of the space vector hexagon and exceeds the preset reference voltage vector boundary OAHB, the simplified reference voltage vector falls on the vertex B of the nearest space vector hexagon, that is, the simplified reference voltage vector is OB. Similarly, if the actual output reference voltage vector is, for example, on arc KQ, since arc KQ exceeds the circumcircle of the space vector hexagon and exceeds the preset reference voltage vector boundary OAHB, the simplified reference voltage vector falls on the vertex A of the nearest space vector hexagon, that is, the simplified reference voltage vector is OA. It should be noted that in the remaining sectors of the reference voltage vector circle, when the vector circle where the actual output reference voltage vector is located exceeds the outer circle of the space vector hexagon but does not exceed the corresponding sub-boundary in the remaining sectors, or when the vector circle where the actual output reference voltage vector is located exceeds the outer circle of the space vector hexagon and exceeds the corresponding sub-boundary in the remaining sectors, the method for determining the simplified reference voltage vector is similar to that in the first sector, and will not be elaborated here.

[0052] In one embodiment of the present invention, when determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary, the controller 40 is specifically configured such that: when the vector circle where the actual output reference voltage vector is located exceeds the inscribed circle of the space vector hexagon but does not exceed the circumscribed circle of the space vector hexagon, and exceeds the boundary of the space vector hexagon, the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector.

[0053] In a specific embodiment, such as Figure 4 As shown, taking the first sector as an example, if the actual output reference voltage vector is, for example, on the arc ED, since the arc ED exceeds the incircle of the spatial vector hexagon but not the circumcircle, and exceeds the boundary AB of the spatial vector hexagon, the simplified reference voltage vector shrinks to the boundary of the spatial vector hexagon within the sector, i.e., on the line segment ED. It should be noted that in the other sectors where the reference voltage vector circle is located, when the vector circle containing the actual output reference voltage vector exceeds the incircle of the spatial vector hexagon but not the circumcircle, and exceeds the boundary of the spatial vector hexagon within the corresponding sector, the method for determining the simplified reference voltage vector is similar to that in the first sector, and will not be elaborated here.

[0054] In one embodiment of the present invention, when determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector and the preset reference voltage vector boundary in each sector, the controller 40 is specifically configured such that: when the vector circle where the actual output reference voltage vector is located is the circumcircle of the space vector hexagon, the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector.

[0055] In a specific embodiment, such as Figure 5 As shown, when the vector circle containing the actual output reference voltage vector is the circumcircle of the space vector hexagon, taking the first sector as an example, if the actual output reference voltage vector is, for example, on arc AB, then the simplified reference voltage vector shrinks to the boundary AB of the space vector hexagon within the sector. It should be noted that in the other sectors where the vector circle containing the actual output reference voltage vector is the circumcircle of the space vector hexagon, the method for determining the simplified reference voltage vector is similar to that in the first sector, and will not be elaborated here.

[0056] In one embodiment of the present invention, when determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector and the preset reference voltage vector boundary in each sector, the controller 40 is specifically configured such that: when the vector circle containing the actual output reference voltage vector passes through point H, or when the radius of the vector circle containing the actual output reference voltage vector is greater than OH, the simplified reference voltage vector falls on the vertex of the nearest spatial vector hexagon.

[0057] In a specific embodiment, such as Figure 6 As shown, when the vector circle containing the actual output reference voltage vector passes through point H, taking the first sector as an example, if the actual output reference voltage vector is, for example, on the arc MH, then the simplified reference voltage vector falls on the vertex B of the nearest spatial vector hexagon, that is, the simplified reference voltage vector is OB. It should be noted that when the radius of the vector circle containing the actual output reference voltage vector is greater than OH, the simplified reference voltage vector is the same as when the vector circle containing the actual output reference voltage vector passes through point H, that is, it falls on the vertex of the nearest spatial vector hexagon; this will not be elaborated here. In the other sectors of the reference voltage vector circle, when the vector circle containing the actual output reference voltage vector passes through point H, or when the radius of the vector circle containing the actual output reference voltage vector is greater than OH, the method for determining the simplified reference voltage vector is similar to that in the first sector, and will not be elaborated here.

[0058] In one embodiment of the present invention, the reference voltage vector on line AH satisfies:

[0059] T1 + T2 / 2 = T S1 ;

[0060] Where T1 is the duration of action of one of the two adjacent fundamental voltage vectors in the space vector hexagon; T2 is the duration of action of the other of the two adjacent fundamental voltage vectors in the space vector hexagon, T S1 The duration of the reference voltage vector on line AH.

[0061] Specifically, such as Figure 3 As shown above, when AH⊥OA and BH⊥OB, the reference voltage vector on line AH, for example OK, satisfies T1+T2 / 2=T S1 Therefore, it is possible to simply use T1+T2 / 2 to determine whether the actual output reference voltage vector is within OAHB, which further simplifies the calculation of the simplified reference voltage vector.

[0062] In one embodiment of the present invention, when determining whether the vector circle containing the actual output reference voltage vector exceeds the preset reference voltage vector boundary, the controller 40 is specifically configured such that: when T1+T2 / 2<=T S1When the actual output reference voltage vector is located, the vector circle does not exceed the preset reference voltage vector boundary; when T1+T2 / 2>T S1 When the actual output reference voltage vector is located, the vector circle is determined to be outside the preset reference voltage vector boundary.

[0063] In a specific embodiment, taking the first sector as an example, such as... Figure 3 As shown, when T1 + T2 / 2 <= T S1 When the actual output reference voltage vector is located, the vector circle does not exceed the preset reference voltage vector boundary OAHB, that is, it is within OAHB; when T1+T2 / 2>T S1 When the actual output reference voltage vector is located, the vector circle is determined to be outside the preset reference voltage vector boundary OAHB, i.e., outside OAHB.

[0064] In one embodiment of the present invention, when the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector, the controller 40 is specifically configured as follows:

[0065]

[0066] Where T1 is the duration of the actual output reference voltage vector before simplification, which is the duration of action of one of the two adjacent basic voltage vectors; T2 is the duration of action of the actual output reference voltage vector before simplification, which is the duration of action of the other of the two adjacent basic voltage vectors. S To simplify the actual output reference voltage vector's duration of action, T′1 is the duration of action of the simplified reference voltage vector over one of the two adjacent basic voltage vectors, and T′2 is the duration of action of the simplified reference voltage vector over the other of the two adjacent basic voltage vectors.

[0067] In a specific embodiment, taking the first sector as an example, when the actual output reference voltage vector exceeds the inverter's output area OAB, based on the above formula, the phase angle of the reference voltage vector can be kept unchanged, and the amplitude of the reference voltage vector can be proportionally contracted to the edge AB, so that it runs along the hexagonal boundary.

[0068] In one embodiment of the present invention, when compensating for the magnitude of the simplified reference voltage vector, the controller 40 is specifically configured as follows:

[0069]

[0070] in, v is the overmodulated vector. ref The simplified reference voltage vector is given by k(m), which is the modulation coefficient.

[0071] Specifically, in this embodiment of the invention, the calculation of the reference voltage vector is simplified based on the positional relationship between the actual output reference voltage vector and the preset reference voltage vector boundary in each sector, greatly reducing the computational load. However, this method reduces the amplitude of the reference voltage vector, resulting in a large deviation between the reference amplitude and the actual output amplitude in the overmodulation region. For example, as... Figure 4 As shown, when the actual output reference voltage vector is located on the arc MHN, the reference amplitude is At that time, the actual output amplitude was 2V. dc Therefore, the magnitude of the simplified reference voltage vector also needs to be compensated.

[0072] In a specific embodiment, the simplified voltage fundamental amplitude, for example, A1, can be calculated based on the simplified reference voltage vector. The unsimplified voltage fundamental amplitude, for example, A2, can be calculated using conventional methods. Since the conventional method does not simplify the amplitude, A2 is an accurate value. Therefore, the ratio of A2 to A1 is taken as k(m), i.e., k(m) = A2(m) / A1(m), where m is the modulation ratio. It should be noted that the calculation of k(m) is quite complex. In practical applications, it can be calculated offline, and the result stored in the chip. During actual control, the result can be directly retrieved from a table to avoid complex real-time calculations and improve the calculation speed. It should also be noted that calculating the unsimplified voltage fundamental amplitude using conventional methods is prior art and will not be elaborated upon here.

[0073] According to an embodiment of the present invention, the air conditioner determines a simplified reference voltage vector by defining a preset reference voltage vector boundary corresponding to each sector of the reference voltage vector circle, and by determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary. The preset reference voltage vector boundary satisfies: AH⊥OA, BH⊥OB; where OA and OB are two adjacent basic voltage vectors in the space vector hexagon, AH is the boundary perpendicular to OA, and BH is the boundary perpendicular to OB. The amplitude of the simplified reference voltage vector is compensated to obtain an overmodulated voltage vector. This allows for the elimination of the need to distinguish overmodulation regions during overmodulation, and enables uniform overmodulation processing when the actual output reference voltage vector exceeds the space vector hexagon. The method is simple, can quickly obtain the overmodulated voltage vector while ensuring the accuracy of the actual output reference voltage vector, and achieves a good balance between simplicity and accuracy.

[0074] Further embodiments of the present invention disclose a control method for an air conditioner, used in any of the above embodiments, such as... Figure 7 As shown, the method includes the following steps:

[0075] Step S1: Determine the preset reference voltage vector boundary corresponding to each sector of the reference voltage vector circle.

[0076] Step S2: Determine the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary; the preset reference voltage vector boundary satisfies: AH⊥OA, BH⊥OB; where OA and OB are two adjacent basic voltage vectors in the space vector hexagon, AH is the boundary perpendicular to OA, and BH is the boundary perpendicular to OB.

[0077] Step S3: Compensate the amplitude of the simplified reference voltage vector to obtain the overmodulated voltage vector.

[0078] In one embodiment of the present invention, when determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary, the controller is specifically configured as follows: when the vector circle where the actual output reference voltage vector is located exceeds the circumcircle of the space vector hexagon but does not exceed the preset reference voltage vector boundary, the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector; when the vector circle where the actual output reference voltage vector is located exceeds the circumcircle of the space vector hexagon and exceeds the preset reference voltage vector boundary, the simplified reference voltage vector falls on the vertex of the nearest space vector hexagon.

[0079] In one embodiment of the present invention, when determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary, the controller is specifically configured such that: when the vector circle where the actual output reference voltage vector is located exceeds the inscribed circle of the space vector hexagon but does not exceed the circumscribed circle of the space vector hexagon, and exceeds the boundary of the space vector hexagon, the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector.

[0080] In one embodiment of the present invention, when determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector and the preset reference voltage vector boundary in each sector, the controller is specifically configured such that: when the vector circle where the actual output reference voltage vector is located is the circumcircle of the space vector hexagon, the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector.

[0081] In one embodiment of the present invention, when determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector and the preset reference voltage vector boundary in each sector, the controller is specifically configured such that: when the vector circle containing the actual output reference voltage vector passes through point H, or when the radius of the vector circle containing the actual output reference voltage vector is greater than OH, the simplified reference voltage vector falls on the vertex of the nearest spatial vector hexagon.

[0082] In one embodiment of the present invention, the reference voltage vector on line AH satisfies:

[0083] T1 + T2 / 2 = T S1 ;

[0084] Where T1 is the duration of action of one of the two adjacent fundamental voltage vectors in the space vector hexagon; T2 is the duration of action of the other of the two adjacent fundamental voltage vectors in the space vector hexagon, T S1 The duration of the reference voltage vector on line AH.

[0085] In one embodiment of the present invention, when determining whether the vector circle containing the actual output reference voltage vector exceeds the preset reference voltage vector boundary, the controller is specifically configured such that: when T1+T2 / 2<=T S1 When the actual output reference voltage vector is located, the vector circle does not exceed the preset reference voltage vector boundary; when T1+T2 / 2>T S1 When the actual output reference voltage vector is located, the vector circle is determined to be outside the preset reference voltage vector boundary.

[0086] In one embodiment of the present invention, when the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector, the controller is specifically configured as follows:

[0087]

[0088] Where T1 is the duration of the actual output reference voltage vector before simplification, which is the duration of action of one of the two adjacent basic voltage vectors; T2 is the duration of action of the actual output reference voltage vector before simplification, which is the duration of action of the other of the two adjacent basic voltage vectors. S To simplify the actual output reference voltage vector's duration of action, T′1 is the duration of action of the simplified reference voltage vector over one of the two adjacent basic voltage vectors, and T′2 is the duration of action of the simplified reference voltage vector over the other of the two adjacent basic voltage vectors.

[0089] In one embodiment of the present invention, when compensating for the magnitude of the simplified reference voltage vector, the controller is specifically configured as follows:

[0090]

[0091] in, v is the overmodulated vector. ref The simplified reference voltage vector is given by k(m), which is the modulation coefficient.

[0092] It should be noted that the specific implementation of the air conditioner in the embodiments of the present invention is similar to the specific implementation of the control method of the air conditioner controller in the embodiments of the present invention. For details, please refer to the description in the method section. In order to reduce redundancy, it will not be repeated here.

[0093] According to the control method of the air conditioner of the present invention, a preset reference voltage vector boundary corresponding to each sector of the reference voltage vector circle is determined, and a simplified reference voltage vector is determined according to the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary. The preset reference voltage vector boundary satisfies: AH⊥OA, BH⊥OB; where OA and OB are two adjacent basic voltage vectors in the space vector hexagon, AH is the boundary perpendicular to OA, and BH is the boundary perpendicular to OB. The amplitude of the simplified reference voltage vector is compensated to obtain the overmodulated voltage vector, so that when overmodulation is performed, it is not necessary to distinguish the overmodulation region. When the actual output reference voltage vector exceeds the space vector hexagon, a unified overmodulation processing is performed. The method is simple, can quickly obtain the overmodulated voltage vector, and ensure the accuracy of the actual output reference voltage vector, achieving a good balance between simplicity and accuracy.

[0094] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are 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.

[0095] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An air conditioner, characterized in that, include: The refrigerant circulation loop allows the refrigerant to circulate within a circuit consisting of the compressor, condenser, electronic expansion valve, evaporator, and four-way valve. A refrigeration system that performs heat exchange between refrigerant and indoor air in a compression refrigeration cycle of the refrigerant circulation loop, the refrigeration system including the compressor, the compressor being used to compress low-temperature, low-pressure refrigerant gas into high-temperature, high-pressure refrigerant gas and discharge it to the condenser; An electric motor is used to drive the compressor. An inverter for driving a motor based on an overmodulated voltage vector to extend the speed range of the motor; The controller is configured as follows: Determine the preset reference voltage vector boundary corresponding to each sector of the reference voltage vector circle; The simplified reference voltage vector is determined based on the positional relationship between the actual output reference voltage vector in each sector and the boundary of the preset reference voltage vector. The preset reference voltage vector boundary satisfies: AH⊥OA, BH⊥OB; where OA and OB are two adjacent basic voltage vectors in the space vector hexagon, AH is the boundary perpendicular to OA, and BH is the boundary perpendicular to OB. The simplified reference voltage vector is compensated for to obtain an overmodulated voltage vector. Specifically, the controller is configured to: ， in, The overmodulated vector, Let A be the simplified reference voltage vector, k(m) be the modulation coefficient, k(m) = A2(m) / A1(m), A1(m) is the simplified voltage base amplitude calculated based on the simplified reference voltage vector, and A2(m) is the voltage base amplitude calculated by the traditional method without simplification.

2. The air conditioner according to claim 1, characterized in that, When determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the boundary of the preset reference voltage vector, the controller is specifically configured as follows: When the vector circle containing the actual output reference voltage vector exceeds the circumcircle of the space vector hexagon but does not exceed the preset reference voltage vector boundary, the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector; When the vector circle containing the actual output reference voltage vector exceeds the circumcircle of the space vector hexagon and also exceeds the preset reference voltage vector boundary, the simplified reference voltage vector falls on the vertex of the nearest space vector hexagon.

3. The air conditioner according to claim 1, characterized in that, When determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the boundary of the preset reference voltage vector, the controller is specifically configured as follows: When the vector circle containing the actual output reference voltage vector exceeds the inscribed circle of the space vector hexagon but does not exceed the circumscribed circle of the space vector hexagon, and exceeds the boundary of the space vector hexagon, the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector.

4. The air conditioner according to claim 1, characterized in that, When determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the boundary of the preset reference voltage vector, the controller is specifically configured as follows: When the vector circle containing the actual output reference voltage vector is the circumcircle of the space vector hexagon, the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector.

5. The air conditioner according to claim 1, characterized in that, When determining the simplified reference voltage vector based on the positional relationship between the actual output reference voltage vector in each sector and the boundary of the preset reference voltage vector, the controller is specifically configured as follows: When the vector circle containing the actual output reference voltage vector passes through point H, or when the radius of the vector circle containing the actual output reference voltage vector is greater than OH, the simplified reference voltage vector falls on the vertex of the nearest spatial vector hexagon.

6. The air conditioner according to claim 2, characterized in that, The reference voltage vector on line AH satisfies: T1+T2 / 2 = T S1 ; Where T1 is the duration of action of one of the two adjacent basic voltage vectors in the space vector hexagon; T2 is the duration of action of the other of the two adjacent basic voltage vectors in the space vector hexagon, T S1 The duration of the reference voltage vector on line AH.

7. The air conditioner according to claim 6, characterized in that, When determining whether the vector circle containing the actual output reference voltage vector exceeds the preset reference voltage vector boundary, the controller is specifically configured as follows: When T1 + T2 / 2 <= T S1 When the actual output reference voltage vector is located, the vector circle does not exceed the preset reference voltage vector boundary. When T1 + T2 / 2 > T S1 When the actual output reference voltage vector is located, the vector circle is determined to be outside the preset reference voltage vector boundary.

8. The air conditioner according to any one of claims 4-6, characterized in that, When the simplified reference voltage vector shrinks to the boundary of the space vector hexagon within the sector, the controller is specifically configured as follows: Where T1 is the duration of action of the actual output reference voltage vector in one of the two adjacent basic voltage vectors, as described before simplification; T2 is the duration of action of the actual output reference voltage vector in the other of the two adjacent basic voltage vectors, as described before simplification. S To simplify the application time of the actual output reference voltage vector mentioned above, The simplified reference voltage vector is the duration of action of one of the two adjacent fundamental voltage vectors. The simplified reference voltage vector is applied for the duration of another fundamental voltage vector among two adjacent fundamental voltage vectors.

9. A control method for an air conditioner, characterized in that: For use in an air conditioner as described in any one of claims 1-8, the method comprises the following steps: Determine the preset reference voltage vector boundary corresponding to each sector of the reference voltage vector circle; Based on the positional relationship between the actual output reference voltage vector in each sector and the preset reference voltage vector boundary, the simplified reference voltage vector is determined; the preset reference voltage vector boundary satisfies: AH⊥OA, BH⊥OB; where OA and OB are two adjacent basic voltage vectors in the space vector hexagon, AH is the boundary perpendicular to OA, and BH is the boundary perpendicular to OB. The amplitude of the simplified reference voltage vector is compensated to obtain the overmodulated voltage vector.

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