An air conditioner power supply system and method

Abstract

The application discloses an air conditioner power supply system and method, relates to the technical field of household appliances, and can reduce three-phase alternating current power supply current harmonics in an air conditioner system. The system comprises a sampling circuit configured as a controller, a phase of a grid voltage locked to supply power to a three-phase VIENNA topology circuit, three-phase alternating current power supply sampling voltage in an abc coordinate system being converted into three-phase alternating current power supply sampling voltage in a dq coordinate system according to the locked grid voltage phase, three-phase alternating current power supply sampling current in the abc coordinate system being converted into three-phase alternating current power supply sampling voltage in the dq coordinate system, a voltage control quantity being obtained according to the three-phase alternating current power supply sampling voltage in the dq coordinate system, the three-phase alternating current power supply sampling current in the dq coordinate system and a sampling capacitor voltage, and the voltage control quantity being used to control the duty cycle of a switch tube in a rectifier circuit of the three-phase VIENNA topology circuit. The embodiment of the application is used for controlling an air conditioner power supply.

Description

Technical Field

[0001] This invention relates to the field of home appliance technology, and more particularly to an air conditioner power supply system and method. Background Technology

[0002] Currently, in three-phase AC power air conditioning systems, due to cost considerations, the common approach is to add an uncontrolled rectifier circuit to the three-phase AC power supply circuit as the power input. This method results in a larger inductor and more capacitors, and generates harmonics that fail to meet standard requirements. While some methods employ single-switch or six-switch current harmonic mitigation, these are less effective. Summary of the Invention

[0003] Embodiments of the present invention provide an air conditioning power supply system and method that can reduce current harmonics generated by the three-phase AC power supply in the air conditioning system.

[0004] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0005] Firstly, this application provides an air conditioning power supply system, comprising a sampling circuit, a controller, and a power supply circuit. The sampling circuit and the controller are at least coupled to a rectifier in the power supply circuit. The rectifier is a three-phase VIENNA topology circuit. The sampling circuit is also at least coupled to the controller. The air conditioning power supply system includes: a sampling circuit configured to sample the voltage and current of a three-phase AC power supply in the power supply circuit to obtain a sampled voltage and a sampled current of the three-phase AC power supply, and to sample the voltage of a capacitor in the three-phase VIENNA topology circuit to obtain a sampled capacitor voltage. A controller configured to lock the phase of the grid voltage supplying power to the power supply circuit, perform coordinate transformation on the sampled voltage and sampled current of the three-phase AC power supply according to the locked grid voltage phase, and obtain a voltage control quantity based on the coordinate-transformed sampled voltage, sampled current, and sampled capacitor voltage of the three-phase AC power supply. The voltage control quantity is used to control the duty cycle of the switching transistors in the three-phase VIENNA topology circuit.

[0006] Therefore, this application rectifies the three-phase AC power supply of the power circuit in the three-phase air conditioning power supply system through a three-phase VIENNA topology circuit, and converts the sampled three-phase AC power supply voltage and current in the stationary abc coordinate system into the sampled three-phase AC power supply voltage and current in the rotating dq coordinate system, so that the AC quantity in the three-phase VIENNA topology circuit is converted into DC quantity, thereby better filtering out the harmonics generated in the three-phase VIENNA topology circuit and improving the power factor of the three-phase VIENNA topology circuit.

[0007] In some embodiments, the capacitor includes a first capacitor and a second capacitor, both coupled to the switching transistor. The sampled capacitor voltage includes a first capacitor sampled voltage corresponding to the first capacitor and a second capacitor sampled voltage corresponding to the second capacitor.

[0008] In some embodiments, the controller includes: a voltage loop calculation module, a current loop calculation module, a phase-locked loop (PLL) module, a pulse width modulation (PWM) module, and a coordinate transformation module, wherein: the PLL module is configured to lock the phase of the grid voltage. The coordinate transformation module is used to perform coordinate transformation from the abc coordinate system to the dq coordinate system based on the locked phase of the grid voltage, using the sampled voltage and sampled current of the three-phase AC power supply in the abc coordinate system. The voltage loop calculation module is used to perform voltage following control on the first capacitor sampled voltage and the second capacitor sampled voltage to obtain a first current reference value corresponding to the d-axis in the dq coordinate system. The current loop calculation module is used to perform current following control based on the first current reference value to obtain a first voltage standard value corresponding to the d-axis in the dq coordinate system, and to perform current following control based on a preset second current reference value corresponding to the q-axis in the dq coordinate system to obtain a second voltage reference value corresponding to the q-axis in the dq coordinate system. The PWM module is used to obtain the voltage control quantity based on the first voltage reference value, the second voltage reference value, and the voltage deviation between the first capacitor sampled voltage and the second capacitor sampled voltage.

[0009] In some embodiments, the controller further includes a voltage balancing module. The voltage balancing module is configured to obtain a voltage deviation between the first capacitor sampling voltage and the second capacitor sampling voltage based on the first capacitor sampling voltage and the second capacitor sampling voltage. Voltage balancing correction is performed on the voltage deviation between the first capacitor sampling voltage and the second capacitor sampling voltage to obtain a voltage adjustment value, which is used to obtain a voltage control value.

[0010] In some embodiments, the phase-locked loop (PLL) module includes a PLL and a second-order generalized integrator. The PLL is configured to acquire the angular frequency of the grid output voltage. The second-order generalized integrator is configured to extract the positive-sequence component of the grid voltage based on the voltage angular frequency. The PLL is also configured to lock the phase of the grid voltage based on the positive-sequence component of the grid voltage.

[0011] In some embodiments, the voltage loop calculation module is configured to: obtain a third voltage reference value in the dq coordinate system, and obtain the accumulated value of the first capacitor sample voltage and the second capacitor sample voltage. The first current reference value is obtained based on the difference between the third voltage reference value and the accumulated value.

[0012] In some embodiments, the current loop calculation module includes a first PI control circuit, a first decoupling circuit, a second PI control circuit, and a second decoupling circuit, wherein: the first PI control circuit is configured to perform current following control based on a first current reference value and the sampled current of the three-phase AC power supply to obtain a fourth voltage reference value corresponding to the d-axis in the dq coordinate system. The first decoupling circuit is configured to perform decoupling calculation based on the fourth voltage reference value, the sampled current of the three-phase AC power supply, and the sampled voltage of the three-phase AC power supply as feedforward to obtain a first voltage reference value. The second PI control circuit is configured to perform current following control based on a second current reference value and the sampled current of the three-phase AC power supply to obtain a fifth voltage reference value corresponding to the q-axis in the dq coordinate system. The second decoupling circuit is configured to perform decoupling calculation based on the fifth voltage reference value, the sampled current of the three-phase AC power supply, and the sampled voltage of the three-phase AC power supply as feedforward to obtain a second voltage reference value.

[0013] In some embodiments, the coordinate transformation module is further configured to perform an inverse coordinate transformation based on a first voltage reference value, a second voltage reference value, and a voltage adjustment value, and convert the result of the inverse coordinate transformation into an AC voltage quantity, which is then output as a voltage control quantity to the pulse width modulation module. The pulse width modulation module is further configured to determine the duty cycle of the switching transistors in the three-phase VIENNA topology circuit based on the voltage control quantity, and to send a pulse width modulation signal to the three-phase VIENNA topology circuit based on the duty cycle to control the switching transistors in the three-phase VIENNA topology circuit. The coordinate transformation includes a transformation from the abc coordinate system to the αβ coordinate system, and then a transformation from the αβ coordinate system to the dq coordinate system. The inverse coordinate transformation includes an inverse transformation from the dq coordinate system to the αβ coordinate system.

[0014] Secondly, this application provides a control method for an air conditioner power supply. The method is used in an air conditioner power supply system, which includes a power supply circuit, a sampling circuit, and a controller. The sampling circuit and the controller are at least coupled to a rectifier in the power supply circuit. The rectifier is a three-phase VIENNA topology circuit. The sampling circuit is also at least coupled to the controller. The method includes: locking the phase of the grid voltage supplying power to the power supply circuit; performing coordinate transformation on the three-phase AC power supply sampling voltage and the three-phase AC power supply sampling current based on the locked phase of the grid voltage; obtaining a voltage control quantity based on the coordinate-transformed three-phase AC power supply sampling voltage, the three-phase AC power supply sampling current, and the sampling capacitor voltage; and using the voltage control quantity to control the duty cycle of the switching transistors in the rectifier circuit of the three-phase VIENNA topology circuit.

[0015] For the benefits of the second aspect, please refer to the explanation of the first aspect.

[0016] In some embodiments, the capacitor includes a first capacitor and a second capacitor. The sampling capacitor voltage includes a first capacitor sampling voltage corresponding to the first capacitor and a second capacitor sampling voltage corresponding to the second capacitor. The phase-locked module is configured to lock the phase of the grid voltage. The coordinate transformation module is used to perform coordinate transformation from the abc coordinate system to the dq coordinate system based on the locked grid voltage phase, the sampled voltage of the three-phase AC power supply, the sampled current of the three-phase AC power supply, and the difference between the first capacitor sampling voltage and the second capacitor sampling voltage. The voltage loop calculation module is used to perform voltage balance control on the first capacitor sampling voltage and the second capacitor sampling voltage to obtain a first current reference value corresponding to the d-axis in the dq coordinate system. The current loop calculation module is used to perform current following control based on the first current reference value to obtain a first voltage standard value corresponding to the d-axis in the dq coordinate system, and to perform current following control based on a preset second current reference value corresponding to the q-axis in the dq coordinate system to obtain a second voltage reference value corresponding to the q-axis in the dq coordinate system.

[0017] The pulse width modulation module is used to obtain the voltage control quantity based on the voltage deviation between the first voltage reference value, the second voltage reference value, and the first capacitor sampling voltage and the second capacitor sampling voltage. Attached Figure Description

[0018] Figure 1 A schematic diagram of a three-phase air conditioner power supply circuit provided for this application;

[0019] Figure 2 A schematic diagram of an air conditioning power supply system provided in this application;

[0020] Figure 3 A schematic diagram of an air conditioning power supply system provided in this application;

[0021] Figure 4 A schematic diagram of an air conditioning power supply system provided in this application;

[0022] Figure 5 A schematic diagram of an air conditioning power supply system provided in this application;

[0023] Figure 6 A schematic diagram of a software phase-locked loop for a second-order generalized integrator provided in this application;

[0024] Figure 7 A schematic diagram of a second-order generalized second-order integrator is provided for this application;

[0025] Figure 8 Bode plots of the closed-loop transfer functions of D(s) and Q(s) provided in this application;

[0026] Figure 9 A schematic diagram of an air conditioning power supply system provided in this application;

[0027] Figure 10 A schematic diagram of the internal structure of a controller provided in this application;

[0028] Figure 11 This is a schematic diagram of an air conditioner power control method provided in this application. Detailed Implementation

[0029] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0030] In the description of this invention, it should be understood that 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 indicated technical features. Therefore, 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.

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the term "coupled" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a mechanical connection or an electrical connection; it can refer to a direct connection or an indirect connection through an intermediate medium; it 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. Furthermore, when describing pipelines or channels, the terms "connected" and "coupled" used in this application have the meaning of conducting electricity. The specific meaning needs to be understood in conjunction with the context.

[0032] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0033] In the home appliance industry, the power grid typically supplies power to electronic devices in home appliances through rectifiers. A common rectifier is a non-linear circuit composed of diodes, inductors, and capacitors. In actual power supply processes, this circuit generates harmonics and reactive power pollution that fail to meet standard requirements, increasing circuit losses and resulting in a low power factor for home appliances.

[0034] Currently, in air conditioning systems using single-phase AC power, power factor correction (PFC) circuits are typically used to suppress harmonics generated in the circuit that fail to meet standard requirements. However, in air conditioning systems using three-phase AC power, there is no PFC circuit that can effectively reduce the non-compliant current harmonics generated by the three-phase AC power supply in three-phase air conditioning systems.

[0035] Therefore, this application provides a method for reducing unacceptable harmonics generated by three-phase AC power supply in the power circuit of a three-phase air conditioning power supply system by using a three-phase Vienna rectifier.

[0036] Figure 1 This application provides a schematic diagram of a three-phase air conditioner power supply circuit. The power supply circuit includes: a three-phase AC power supply, resistors R1, R2, and R3, inductors L1, L2, and L3, and a rectifier 101. The three-phase voltages of the three-phase AC power supply are Ea, Eb, and Ec. The rectifier 101 includes: diodes D1, D2, D3, D4, D5, and D6, switching transistors Q1, Q2, Q3, Q4, Q5, and Q6, and capacitors C1 and C2.

[0037] The three-phase AC power supply consists of three AC circuits with the same frequency, equal potential amplitude, and a phase difference of 120 degrees, which are used as the power input for the rectifier 101.

[0038] Diodes D1, D2, D3, D4, D5, and D6 form the uncontrolled rectifier section of the power supply circuit, used to convert the AC power output from the three-phase AC power supply into DC power.

[0039] Resistors R1, R2 and R3, inductors L1, L2 and L3, and capacitors C1 and C2 constitute the passive part of the power supply circuit.

[0040] The switching transistors Q1, Q2, Q3, Q4, Q5, and Q6 constitute the active part of the circuit.

[0041] like Figure 2 The diagram shown is a schematic of an air conditioning power supply system provided in this application. The air conditioning power supply system includes a sampling circuit 201, a controller 202, and a power supply circuit 203. The sampling circuit 201 and the controller 202 are at least coupled to the rectifier 101 in the power supply circuit 203. The rectifier 101 is a three-phase VIENNA topology circuit. The sampling circuit 201 is also at least coupled to the controller 202.

[0042] It is understood that the rectifier 101 can be a three-phase VIENNA topology circuit, and this application does not limit it. The internal structure of the power supply circuit 203 is as follows: Figure 1 As shown.

[0043] In some embodiments, the sampling circuit 201 is configured to sample the voltage and current of the three-phase AC power supply in the power supply circuit 203 to obtain the sampled voltage and sampled current of the three-phase AC power supply, and to sample the voltage of the capacitors in the three-phase VIENNA topology circuit to obtain the sampled capacitor voltage. The capacitors in the three-phase VIENNA topology circuit include at least a first capacitor and a second capacitor coupled to a switching transistor. The sampled capacitor voltage includes a first capacitor sampled voltage corresponding to the first capacitor and a second capacitor sampled voltage corresponding to the second capacitor.

[0044] The first capacitor here can be understood as... Figure 1 The capacitor C1 in the middle, the second capacitor can be understood as Figure 1 Capacitor C2 in the first capacitor. The sampling voltage of the first capacitor corresponding to the first capacitor is... Figure 1 V in dcp The sampling voltage of the second capacitor corresponding to the second capacitor is Figure 1 V in dcn .

[0045] That is, the sampling circuit 201 samples the voltage output of the three-phase AC power supply in the power supply circuit 203 to obtain the three-phase AC power supply sampling voltage E. a E b and E c The sampling current i of the three-phase AC power supply output from the three-phase AC power supply in power supply circuit 203 is obtained by sampling the three-phase AC power supply. a i b and i c The voltage of the first capacitor C1 is sampled to obtain V. dcp The voltage of the second capacitor C2 is sampled to obtain V. dcn Among them, the sampling circuit 201 samples the three-phase AC sampling voltage E. a E b and E c and three-phase AC sampling current i a i b and i c It is the amount of communication, V dcp and V dcn It is a DC current, three-phase AC sampling voltage E a E b and E c Sampling current i a i b and i c V dcp and V dcn The output is sent to controller 202 for processing.

[0046] In some embodiments, the controller 202 is configured to lock the phase of the mains voltage supplying power to the power supply circuit 203, and to sample the voltage (E) of the three-phase AC power supply according to the locked mains voltage phase. a E b and E c ) and the sampling current of the three-phase AC power supply (i a i b and i c Perform coordinate transformation, and then use the sampled voltage (E) of the three-phase AC power supply after coordinate transformation. a E b and E c ), the current sampled from the three-phase AC power supply (i a i b and i c ) and sampling capacitor voltage (V dcp and V dcn This yields a voltage control quantity, which is used to control the duty cycle of the switching transistors in the three-phase VIENNA topology circuit. The grid voltage here is used to supply power to the three-phase AC power source. The grid voltage is alternating current, and its magnitude and direction change with time. For example, the formula for a sinusoidal AC voltage in trigonometric functions can be described as u = Usin2πft. In trigonometric functions, 2πft corresponds to an angle, therefore 2πft is called the voltage phase.

[0047] In some embodiments, the coordinate transformation includes transforming from the abc coordinate system to the αβ coordinate system, and then from the αβ coordinate system to the dq coordinate system. It is understood that the three-phase AC power supply sampling voltages (Ea, Eb, and Ec), the three-phase AC power supply sampling currents (ia, ib, and ic), and the sampling capacitor voltages (Vdcp and Vdcn) are all described based on the abc coordinate system.

[0048] The voltage and current of a three-phase AC power supply are typically represented by vectors in the complex plane; these vectors are spatial vectors. In field-oriented control (FOC), there are two coordinate transformations: one is from a stationary abc coordinate system to a stationary αβ coordinate system, and the other is the inverse transformation from the stationary αβ coordinate system to a rotating dq coordinate system. Three-phase voltage E a E b and E c The direction of the space voltage vector can be described using the reference direction of the stationary abc coordinate system. This is achieved by considering the three-phase voltage E... a E b and E cThe spatial voltage vectors are summed to synthesize a uniformly rotating spatial composite voltage vector. Since this composite spatial voltage vector is a rotating vector, it is difficult to describe using a three-phase stationary abc coordinate system. Therefore, a two-phase stationary αβ coordinate system is introduced, where the α and β axes are orthogonal, and the α axis is chosen to coincide with the direction of A. It can be understood that the spatial composite voltage vector is still rotating in this two-phase stationary αβ coordinate system.

[0049] The rotating dq coordinate system can rotate synchronously with the spatially synthesized voltage vector, with the coordinate axes being the d-axis and q-axis, where the d-axis and q-axis are orthogonal. By decomposing the components of the spatially synthesized voltage vector along the d-axis and q-axis into the α-axis and β-axis, we can obtain the transformation from the two-phase stationary αβ coordinate system to the rotating dq coordinate system. Furthermore, the component of the spatially synthesized voltage vector in the rotating dq coordinate system is a constant value.

[0050] The following example illustrates the transformation of the three-phase voltage of a three-phase AC power supply from the stationary abc coordinate system to the rotating dq coordinate system. The three-phase voltage E of the three-phase AC power supply... a E b and E c The mathematical model in the stationary abc coordinate system is represented by equation (1-1):

[0051]

[0052] Among them, i a i b and i c This can be understood as the sampling current i of a three-phase AC power supply. a i b and i c .

[0053] R represents Figure 1 The resistors are R1, R2, and R3.

[0054] V aN express Figure 1 China V a The voltage between point N and point N, V bN express Figure 1 China V b The voltage between point N and point N, V cN express Figure 1 China V c The voltage between point N and point 203. The three-phase voltages in the stationary abc coordinate system of power supply circuit 203 are obtained as the three-phase voltages E in the rotating dq coordinate system after coordinate transformation. d and E q The mathematical model is shown in equation (1-2):

[0055]

[0056] In equation (1-2), θ is the angle between the d-axis of the rotating dq coordinate system and the α-axis of the two stationary αβ coordinate systems during the rotation process.

[0057] Because the current in a three-phase VIENNA topology in a stationary abc coordinate system is an alternating current, the Proportional-Integral Controller (PI) in the three-phase VIENNA topology cannot eliminate steady-state errors. Furthermore, the harmonic suppression effect of the three-phase VIENNA topology circuit in the stationary abc coordinate system needs improvement. Therefore, the implementation of the three-phase VIENNA topology circuit in this application is mainly based on the rotating dq coordinate system.

[0058] In this application, the controller 202 can sample the three-phase AC power supply voltage (E) in the stationary abc coordinate system obtained by the sampling circuit 201 based on the locked grid voltage phase. a E b and E c Three-phase AC power supply sampling current (i) a i b and i c ) and sampling capacitor voltage (V dcp and V dcn Converted to a three-phase AC power supply sampling voltage (E) in a rotating dq coordinate system d and E q ), three-phase AC power supply sampling current (i d and i q ) and sampling capacitor voltage (V dcp and V dcn The controller 202 samples the voltage (E) of the three-phase AC power supply in the transformed rotating dq coordinate system. d and E q ), three-phase AC power supply sampling current (i d and i q ) and sampling capacitor voltage (V dcp and V dcn The voltage control quantity is obtained through calculation, and this quantity controls the duty cycle of the switches Q1, Q2, Q3, Q4, Q5, and Q6 in the three-phase VIENNA topology circuit. The sampled voltage (E) of the three-phase AC power supply in the rotated dq coordinate system after coordinate transformation is then used. d and E q ), three-phase AC power supply sampling current (i d and i q The duty cycle is a direct current device. Here, the duty cycle can be understood as the proportion of a high-level signal within a pulse cycle, and it can be used to control the on-time of the switching transistor. For example, a 1-second high-level signal followed by a 1-second low-level signal results in a 50% duty cycle.

[0059] Therefore, this application rectifies the three-phase AC power supply of the power circuit in the three-phase air conditioning power supply system through a three-phase VIENNA topology circuit, and samples the three-phase AC power supply sampling voltage (E) in the stationary abc coordinate system. a E b and E c ), three-phase AC power supply sampling current (i a i b and i c Converted to a three-phase AC power supply sampling voltage (E) in a rotating dq coordinate system d and E q ), three-phase AC power supply sampling current (i d and i q This converts the AC quantities in the three-phase VIENNA topology circuit into DC quantities, thereby better filtering out the harmonics generated in the three-phase VIENNA topology circuit and improving the power factor of the three-phase VIENNA topology circuit.

[0060] like Figure 3 The diagram shown is a schematic of an air conditioning power supply system provided in this application, wherein the controller 202 includes: a voltage loop calculation module 301, a current loop calculation module 302, a phase-locked loop module 303, a coordinate transformation module 304, and a pulse width modulation module 305.

[0061] Among them, the phase-locked module 303 is configured to lock the phase θ1 of the grid voltage.

[0062] In some embodiments, the phase-locked module 303 employs a software phase-locked loop (PLL) with a second-order generalized integrator (SOGI) to lock the phase of the grid voltage. When the grid voltage is unbalanced, harmonics are typically generated. The SOGI can shift the voltage signal input to the power supply circuit 203 by 90 degrees and filter out high-order harmonics generated during grid imbalance. Therefore, even when the grid voltage is unbalanced, the PLL can stably lock the phase θ1 of the grid voltage.

[0063] The coordinate transformation module 304 is configured to measure the sampled voltage (E) of the three-phase AC power supply in the abc coordinate system based on the phase of the locked grid voltage. a E b and E c ), sampling current of three-phase AC power supply (i a i b and i c Perform coordinate transformation from the abc coordinate system to the dq coordinate system.

[0064] In some embodiments, the coordinate transformation module 304 can sample the voltage (E) of the three-phase AC power supply according to the locked grid voltage phase. a E b and E c ) and three-phase AC power supply sampling current (i a i b and i c Perform coordinate transformation.

[0065] Voltage loop calculation module 301 is configured to sample the voltage (V) of the first capacitor. dcp ) and second capacitor sampling voltage (V dcn Voltage follower control is performed to obtain the first current reference value corresponding to the d-axis in the dq coordinate system.

[0066] In some embodiments, the voltage loop calculation module 301 controls the power supply circuit 203 to stabilize the output voltage and outputs a first current reference value I. d *To the current loop calculation module 302. It is understandable that the first current reference value I... d * is a reference value for the active component of the current loop calculation module 302.

[0067] The current loop calculation module 302 is configured to calculate based on the first current reference value I. d * Perform current-following control to obtain the first standard voltage value V corresponding to the d-axis in the dq coordinate system. d **, and based on the second current reference value I corresponding to the preset q-axis in the dq coordinate system. q * Perform current-following control to obtain the second voltage reference value V corresponding to the q-axis in the dq coordinate system. q **.

[0068] In some implementations, the current loop calculation module 302 can control the amplitude and phase of the power supply circuit 203, thereby correcting the input power factor of the power supply circuit 203. For example, when correcting the input power factor of the power supply circuit 203, the input component of the d-axis in the current loop calculation module 302 is the first current reference value I. d * The q-axis input component is typically 0. After calculation by the current loop calculation module 302, the first voltage reference value V is obtained. d ** and second voltage reference value V q **.

[0069] The pulse width modulation module 305 is configured to adjust the pulse width according to the first voltage reference value V. d **, the second voltage reference value and V q **First capacitor sampling voltage (V) dcp ) and second capacitor sampling voltage (V dcnThe voltage deviation is used to obtain the voltage control quantity.

[0070] In some embodiments, the pulse width modulation module 305 determines the voltage reference value V based on the received first voltage reference value V. d ** and second voltage reference value V q The voltage deviation is transformed using coordinate transformation module 304 to obtain the voltage control quantity, which controls the duty cycle of the switching transistors in the three-phase VIENNA topology circuit. The control of the duty cycle of the switching transistors in the rectifier circuit of the three-phase VIENNA topology circuit by the voltage control quantity will be described below.

[0071] like Figure 4 The diagram shown is a schematic of an air conditioning power supply system provided in this application, based on... Figure 3 Based on this, the controller 202 also includes a voltage balancing module 401.

[0072] Voltage balancing module 401 is configured to sample the voltage (V) of the first capacitor in the abc coordinate system. dcp ) and second capacitor sampling voltage (V dcn The voltage deviation between the first and second capacitor sampling voltages in the abc coordinate system is obtained. Voltage equalization correction is then performed on the voltage deviation between the first and second capacitor sampling voltages in the abc coordinate system to obtain the voltage adjustment value, which is used to obtain the voltage control value.

[0073] In some embodiments, capacitors C1 and C2 may experience voltage imbalance due to inconsistencies in parasitic parameters and input voltage imbalance. This output voltage imbalance leads to different stresses on capacitors C1 and C2, increasing the stress on switching transistors Q1, Q2, Q3, Q4, Q5, and Q6. If this stress exceeds a certain range, it can cause the switching transistors in the three-phase VIENNA topology to fail. The voltage balancing module 401 performs linear calculations on the sampled voltage (V) of the first capacitor using a PI controller. dcp ) and second capacitor sampling voltage (V dcn Perform equalization correction to make the sampling voltage of the first capacitor (V) equalize. dcp ) and second capacitor sampling voltage (V dcn The difference (V) dcp -V dcn The voltage is within a normal range. This results in a voltage adjustment value V0, which is then transmitted to the coordinate transformation module 304 for inverse coordinate transformation.

[0074] like Figure 5 The diagram shown is a schematic of an air conditioning power supply system provided in this application. Figure 4 Based on this, the phase-locked module 303 includes a phase-locked loop 501 and a second-order generalized integrator 502.

[0075] Phase-locked loop 501 is configured to acquire the angular frequency of the grid output voltage. Second-order generalized integrator 502 is configured to extract the positive-sequence component of the grid voltage based on the voltage angular frequency. Phase-locked loop 501 is also configured to lock the phase of the grid voltage based on the positive-sequence component of the three-phase AC power supply voltage.

[0076] The phase-locked loop 501 here can be understood as the PLL mentioned above, and the second-order generalized integrator 502 can be understood as the SOGI mentioned above.

[0077] In some embodiments, such as Figure 6 The diagram shows a software phase-locked loop (PLL) for a second-order generalized integrator provided in this application. Here, k represents the damping coefficient, and ω0 represents the resonant frequency of the second-order generalized integrator. ω0 can be understood as the angular frequency of the grid output voltage obtained by the PLL. It is understood that the grid output voltage angular frequency changes in real time.

[0078] The three-phase AC power supply voltages (Ea, Eb, and Ec) sampled by sampling circuit 201 in the stationary abc coordinate system are converted into a two-phase stationary αβ coordinate system to obtain orthogonal output signals Eα and Eβ. After linear combination of the orthogonal output signals Eα and Eβ by SOGI, the positive-sequence components Eα+ and Eβ+ in the grid voltage can be obtained. These positive-sequence components Eα+ and Eβ+ are then subjected to single-synchronous phase-locked loop (SLL) to obtain the locked grid voltage phase θ1. Even under grid voltage distortion, the SOGI system still exhibits good steady-state and dynamic performance, and can also filter the input signal. It can be understood that the grid voltage phase θ1 is the same angle as θ in equation (1-2).

[0079] The second-order generalized second-order integrator will be introduced below.

[0080] like Figure 7 The diagram shown is a schematic of a second-order generalized second-order integrator provided in this application. Figure 7 The closed-loop transfer function in the equation is given by equation (1-3):

[0081]

[0082] Here, S can be understood as the expression of the original function after the Laplace transform.

[0083] Combination Figure 8 The figure shows a Bode plot of the closed-loop transfer functions of D(s) and Q(s) provided in this application.

[0084] D(S) can be understood as a bandpass filter, Q(S) as a lowpass filter, and E is obtained through a second-order generalized integrator. α *E α * After a 90° phase shift, qE can be obtained. α Therefore, SOGI has certain filtering characteristics.

[0085] In some embodiments, the voltage loop calculation module is configured to: obtain the third voltage reference value V in the dq coordinate system. dc * and obtain the sum of the first capacitor sampling voltage and the second capacitor sampling voltage. Based on the difference between the third voltage reference value and the sum of the values, a PI controller is used to obtain the first current reference value I. d *

[0086] That is, the first current reference value Id* = (V dc *-(Vdcp+Vdcn))*(kp+ki / s). Where kp represents the proportional control of the PI controller, and Ki represents the integral control of the PI controller.

[0087] like Figure 9 The diagram shown is a schematic of an air conditioning power supply system provided in this application. The current loop calculation module 302 includes a first PI control circuit 901, a first decoupling circuit 902, a second PI control circuit 903, and a second decoupling circuit 904.

[0088] The first PI control circuit 901 and the second PI control circuit 903 here can be understood as PI controllers.

[0089] The first PI control circuit 901 is configured to perform current balancing control based on the first current reference value and the three-phase AC power supply sampling current corresponding to the d-axis in the dq coordinate system, so as to obtain the fourth voltage reference value corresponding to the d-axis.

[0090] In some embodiments, the first current reference value I d *Sampling current I of three-phase AC power supply d The difference is used by the first PI control circuit 901 to obtain the fourth voltage reference value V corresponding to the d-axis. d *. Fourth voltage reference value V d *Input is given to the first decoupling circuit 902.

[0091] The first decoupling circuit 902 is configured to sample the current I of the three-phase AC power supply based on the fourth voltage reference value and the q-axis corresponding to the three-phase AC power supply. q The first voltage reference value V is obtained by decoupling the sampling voltage Ed of the three-phase AC power supply corresponding to the d-axis as feedforward. d The first voltage reference value Vd is transmitted to the coordinate transformation module 304 for coordinate transformation.

[0092] In some embodiments, the three-phase AC power supply sampling voltage E d-(Fourth voltage reference value V) d *+i q ×ωL)=First voltage reference value V d **. ω can be understood as a constant, depending on the specific situation, while L can be understood as... Figure 1 The inductances of L1, L2 and L3.

[0093] The second PI control circuit 903 is configured to perform current balancing control based on the second current reference value and the three-phase AC power supply sampling current corresponding to the q-axis in the dq coordinate system, so as to obtain the fifth voltage reference value corresponding to the q-axis.

[0094] In some embodiments, the second current reference value I q *Sampling current I of three-phase AC power supply q The difference is used by the second PI control circuit 903 to obtain the fourth voltage reference value V corresponding to the q-axis. q *. Fifth voltage reference value V q *Input is given to the second decoupling circuit 904.

[0095] The second decoupling circuit 904 is configured to operate according to the fifth voltage reference value V. q * The three-phase AC power supply sampling current I corresponding to the d-axis d And the three-phase AC power supply sampling voltage E corresponding to the q-axis as feedforward. q Decoupling calculations are performed to obtain the second voltage reference value V. q **, Second voltage reference value V q The data is transmitted to the coordinate transformation module 304 for coordinate transformation.

[0096] In some embodiments, the three-phase AC power supply sampling voltage E q -(Fifth voltage reference value V) q *+id×ω)=Second voltage reference value V q In some implementations, the coordinate transformation module 304 is also configured to transform the coordinates according to a first voltage reference value V. d The second voltage reference value Vq and the voltage adjustment value V0 are subjected to an inverse coordinate transformation, and the result of the inverse coordinate transformation is converted into an AC voltage quantity. The AC voltage quantity is then output as a voltage control quantity to the pulse width modulation module 305. The inverse coordinate transformation includes an inverse transformation from the dq coordinate system to the αβ coordinate system.

[0097] The first voltage reference value Vd** and the second voltage reference value Vq** are output to the coordinate transformation module 304. The coordinate transformation module 304 performs an inverse coordinate transformation based on the received first voltage reference value Vd**, second voltage reference value Vq**, and the difference (Vdcp-Vdcn) between the first capacitor sampling voltage (Vdcp) and the second capacitor sampling voltage (Vdcn). This transforms the first voltage reference value Vd**, the second voltage reference value Vq**, and the difference (Vdcp-Vdcn) between the first capacitor sampling voltage (Vdcp) and the second capacitor sampling voltage (Vdcn) in the dq coordinate system into reference voltages Vα and Vβ in the two-phase stationary αβ coordinate system. The coordinate transformation module 304 then transmits the reference voltages Vα and Vβ in the two-phase stationary αβ coordinate system to the pulse width modulation module 305. Here, the power factor can be understood as the ratio of effective power to apparent power.

[0098] The mathematical model for the inverse coordinate transformation from the dq coordinate system to the αβ coordinate system is shown in equation (1-4):

[0099]

[0100] like Figure 10 The diagram shown is a schematic diagram of the internal structure of a controller 202 provided in this application.

[0101] In some embodiments, the pulse width modulation module 305 is further configured to control the voltage amount (V) according to the voltage control quantity (V) α V β Determine the duty cycle of the switching transistors in the three-phase VIENNA topology circuit, and send a pulse width modulation signal to the three-phase VIENNA topology circuit according to the duty cycle to control the switching transistors in the three-phase VIENNA topology circuit.

[0102] The pulse width modulation module 305 can be understood as Space Vector Pulse Width Modulation (SVPWM). The pulse width modulation signal can be understood as a high or low level drive signal. The duty cycle of the switching transistor can be understood as the ratio of the switching transistor's on-time to its operating cycle.

[0103] For example, the pulse width modulation module 305 controls the voltage amount V according to the received voltage control quantity. α and V β The drive signals PWM1-PWM6 are sent to the switching transistors Q1, Q2, Q3, Q4, Q5 and Q6 in the three-phase VIENNA topology circuit to control the switching on and off of the switching transistors Q1, Q2, Q3, Q4, Q5 and Q6. When the drive signal is high, the switching transistor is turned on, and when the drive signal is low, the switching transistor is turned off.

[0104] Based on the air conditioning power supply system 20 provided in this application, the embodiments of this application will be described below.

[0105] like Figure 11 The diagram shown is a schematic of an air conditioner power control method provided in this application. The method includes:

[0106] 1101. Controller 202 samples the voltage and current of the three-phase AC power supply in the power supply circuit to obtain the sampled voltage and sampled current of the three-phase AC power supply, and samples the voltage of the capacitor in the three-phase VIENNA topology circuit to obtain the sampled capacitor voltage.

[0107] The sampling of voltage and current of the three-phase AC power supply in the power supply circuit and the sampling of voltage of capacitors in the three-phase VIENNA topology circuit have been described above and will not be repeated here.

[0108] 1102. Controller 202 locks the phase of the grid voltage supplying power to the power circuit. Based on the locked grid voltage phase, it performs coordinate transformation on the sampled voltage and sampled current of the three-phase AC power supply. Based on the coordinate-transformed sampled voltage, sampled current, and sampled capacitor voltage of the three-phase AC power supply, it obtains the voltage quantity. This voltage control quantity is used to control the duty cycle of the switching transistors in the three-phase VIENNA topology circuit. In other words, controller 202, based on the locked grid voltage phase, converts the three-phase AC voltage and current of the three-phase AC power supply in the abc coordinate system, as well as the voltage across the capacitors in the three-phase VIENNA topology circuit, acquired in step 1101, into the voltage and current of the three-phase AC power supply and the voltage across the capacitors in the three-phase VIENNA topology circuit in the dq coordinate system. The controller 202 obtains the voltage control quantity based on the three-phase AC voltage and three-phase AC current of the three-phase AC power supply in the transformed dq coordinate system and the voltage of the capacitor in the three-phase VIENNA topology circuit. This quantity is used to control the duty cycle of the switching transistor in the rectifier circuit of the three-phase VIENNA topology circuit.

[0109] The use of voltage control quantities to control the duty cycle of the switching transistors in the rectifier circuit of a three-phase VIENNA topology has been introduced previously and will not be repeated here.

[0110] Therefore, this application rectifies the three-phase AC power supply of the power circuit in the three-phase air conditioning power supply system through a three-phase VIENNA topology circuit, and samples the three-phase AC power supply sampling voltage (E) in the stationary abc coordinate system. a E b and E c ), three-phase AC power supply sampling current (i a i b and i cConverted to a three-phase AC power supply sampling voltage (E) in a rotating dq coordinate system d and E q ), three-phase AC power supply sampling current (i d and i q This converts the AC quantities in the three-phase VIENNA topology circuit into DC quantities, thereby better filtering out the harmonics generated in the three-phase VIENNA topology circuit and improving the power factor of the three-phase VIENNA topology circuit.

[0111] In some embodiments, step 1102 can be implemented as follows: Controller 202 locks the phase of the grid voltage supplying the three-phase VIENNA topology circuit. Based on the locked grid voltage phase, the three-phase AC power supply sampling voltage in the abc coordinate system is transformed into the three-phase AC power supply sampling voltage in the dq coordinate system, and the three-phase AC power supply sampling current is transformed into the three-phase AC power supply sampling voltage in the dq coordinate system. The first capacitor sampling voltage (V) in the abc coordinate system is then converted... dcp ) and the second capacitor sampling voltage (V) in the abc coordinate system dcn Voltage deviation (V) dcp -V dcn The voltage deviation (V) of the first capacitor sampling voltage and the second capacitor sampling voltage transformed into the dq coordinate system. dcp -V dcn Based on the first capacitor sampling voltage (V) in the dq coordinate system. dcp ) and the second capacitor sampling voltage (V) in the dq coordinate system dcn Voltage balance control is performed to obtain the first current reference value Id* corresponding to the d-axis in the dq coordinate system. Current following control is then performed based on the first current reference value Id* to obtain the first voltage standard value V corresponding to the d-axis in the dq coordinate system. d **, and according to the second current reference value (I) corresponding to the preset q-axis in the dq coordinate system. q (*=0) Perform current following control to obtain the second voltage reference value V corresponding to the q-axis in the dq coordinate system. q **. Based on the first voltage reference value corresponding to the d-axis and the second voltage reference value V corresponding to the q-axis. q The voltage control quantity is obtained by measuring the voltage deviation between the first capacitor sampling voltage and the second capacitor sampling voltage in the ** and dq coordinate systems.

[0112] The specific implementation method has been described above and will not be repeated here.

[0113] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, the disclosure, and the appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple instances. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0114] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and modifications.

[0115] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An air conditioning power supply system, characterized in that, The air conditioning power supply system includes a sampling circuit, a controller, and a power supply circuit. The sampling circuit and the controller are at least coupled to a rectifier in the power supply circuit. The rectifier is a three-phase VIENNA topology circuit. The sampling circuit is also at least coupled to the controller. The air conditioning power supply system includes: The sampling circuit is configured to sample the voltage and current of the three-phase AC power supply in the power supply circuit to obtain the sampled voltage and sampled current of the three-phase AC power supply, and to sample the voltage of the capacitor in the three-phase VIENNA topology circuit to obtain the sampled capacitor voltage. The capacitor includes at least a first capacitor and a second capacitor coupled to the switching transistor; The sampling capacitor voltage includes a first capacitor sampling voltage corresponding to the first capacitor and a second capacitor sampling voltage corresponding to the second capacitor; The controller includes a phase-locked loop module, a voltage loop calculation module, a current loop calculation module, a voltage balance module, a coordinate transformation module, and a pulse width modulation module; The phase-locked module is configured to lock the phase of the mains voltage supplying power to the power supply circuit; The coordinate transformation module is configured to perform coordinate transformation from the abc coordinate system to the dq coordinate system based on the phase of the locked grid voltage and the sampled current of the three-phase AC power supply in the abc coordinate system; the coordinate transformation includes transforming from the abc coordinate system to the αβ coordinate system, and then transforming from the αβ coordinate system to the dq coordinate system. The voltage loop calculation module is configured to perform voltage following control on the first capacitor sampling voltage and the second capacitor sampling voltage to obtain the first current reference value corresponding to the d-axis in the dq coordinate system; The current loop calculation module is configured to perform current following control based on the first current reference value to obtain the first voltage reference value corresponding to the d-axis in the dq coordinate system, and to perform current following control based on the second current reference value corresponding to the preset q-axis in the dq coordinate system to obtain the second voltage reference value corresponding to the q-axis in the dq coordinate system. The voltage balancing module is configured to obtain the voltage deviation between the first capacitor sampling voltage and the second capacitor sampling voltage based on the first capacitor sampling voltage and the second capacitor sampling voltage, perform voltage equalization correction on the voltage deviation to obtain a voltage adjustment value, and transmit the voltage adjustment value to the coordinate transformation module; The coordinate transformation module is further configured to perform an inverse coordinate transformation based on the first voltage reference value, the second voltage reference value, and the voltage adjustment value, and convert the result of the inverse coordinate transformation into an AC voltage quantity, and output the AC voltage quantity as a voltage control quantity to the pulse width modulation module; the inverse coordinate transformation includes an inverse transformation from the dq coordinate system to the αβ coordinate system; The pulse width modulation module is configured to determine the duty cycle of the switching transistors in the three-phase VIENNA topology circuit based on the voltage control quantity, and to send a pulse width modulation signal to the three-phase VIENNA topology circuit based on the duty cycle to control the switching transistors in the three-phase VIENNA topology circuit.

2. The air conditioning power supply system according to claim 1, characterized in that, The phase-locked module includes a phase-locked loop and a second-order generalized integrator; The phase-locked loop is configured to acquire the voltage angular frequency output by the power grid; The second-order generalized integrator is configured to extract the positive-sequence component of the grid voltage based on the voltage angular frequency. The phase-locked loop is also configured to lock the phase of the grid voltage based on the positive-sequence component of the grid voltage.

3. The air conditioning power supply system according to claim 1, characterized in that, The voltage loop calculation module is configured as follows: Obtain the third voltage reference value in the dq coordinate system, and obtain the sum of the first capacitor sampling voltage and the second capacitor sampling voltage; The first current reference value is obtained based on the difference between the third voltage reference value and the accumulated value.

4. The air conditioning power supply system according to claim 1, characterized in that, The current loop calculation module includes a first PI control circuit, a first decoupling circuit, a second PI control circuit, and a second decoupling circuit, wherein: The first PI control circuit is configured to perform current following control based on the first current reference value and the sampled current of the three-phase AC power supply to obtain the fourth voltage reference value corresponding to the d-axis in the dq coordinate system. The first decoupling circuit is configured to perform decoupling calculations based on the fourth voltage reference value, the sampling current of the three-phase AC power supply, and the sampling voltage of the three-phase AC power supply as a feedforward to obtain the first voltage reference value. The second PI control circuit is configured to perform current following control based on the second current reference value and the sampled current of the three-phase AC power supply to obtain the fifth voltage reference value corresponding to the q axis in the dq coordinate system. The second decoupling circuit is configured to perform decoupling calculations based on the fifth voltage reference value, the sampling current of the three-phase AC power supply, and the sampling voltage of the three-phase AC power supply as a feedforward to obtain the second voltage reference value.

5. A method for controlling an air conditioner power supply, characterized in that, The method is applied to an air conditioning power supply system, which includes a sampling circuit, a controller, and a power supply circuit. The sampling circuit and the controller are at least coupled to a rectifier in the power supply circuit. The rectifier is a three-phase VIENNA topology circuit. The sampling circuit is also at least coupled to the controller. The method includes: The voltage and current of the three-phase AC power supply in the power supply circuit are sampled to obtain the sampled voltage and sampled current of the three-phase AC power supply, and the voltage of the capacitor in the three-phase VIENNA topology circuit is sampled to obtain the sampled capacitor voltage. The capacitor includes at least a first capacitor and a second capacitor coupled to the switching transistor; The sampling capacitor voltage includes a first capacitor sampling voltage corresponding to the first capacitor and a second capacitor sampling voltage corresponding to the second capacitor; Lock the phase of the mains voltage supplying power to the power circuit; Based on the phase of the locked grid voltage, the sampled voltage and sampled current of the three-phase AC power supply in the abc coordinate system are transformed from the abc coordinate system to the dq coordinate system; the coordinate transformation includes transforming from the abc coordinate system to the αβ coordinate system, and then transforming from the αβ coordinate system to the dq coordinate system. Voltage follower control is performed on the first capacitor sampling voltage and the second capacitor sampling voltage to obtain the first current reference value corresponding to the d-axis in the dq coordinate system; Current following control is performed based on the first current reference value to obtain the first voltage reference value corresponding to the d-axis in the dq coordinate system, and current following control is performed based on the second current reference value corresponding to the preset q-axis in the dq coordinate system to obtain the second voltage reference value corresponding to the q-axis in the dq coordinate system. The voltage deviation between the first capacitor sampling voltage and the second capacitor sampling voltage is obtained based on the first capacitor sampling voltage and the second capacitor sampling voltage. Voltage equalization correction is performed on the voltage deviation to obtain the voltage adjustment value. A coordinate inverse transformation is performed based on the first voltage reference value, the second voltage reference value, and the voltage adjustment value to obtain the voltage control quantity; wherein, the coordinate inverse transformation is a transformation from the dq coordinate system to the αβ coordinate system; the duty cycle of the switching transistor in the three-phase VIENNA topology circuit is determined based on the voltage control quantity to control the switching transistor in the three-phase VIENNA topology circuit.

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