Three-phase three-wire system converter open-phase control method and three-phase alternating current control system

Abstract

The invention discloses a three-phase three-wire system converter open-phase control method and a three-phase alternating current control system. A processor executes the following steps: receiving a power supply signal; judging whether the power supply signal is open-phase or not; if so, judging whether the power supply signal is open-phase at the previous moment; if no phase loss exists at the previous moment, switching from the second operation state to the first operation state, and outputting a first driving signal; if not, judging whether the power supply signal is open-phase at the previous moment or not; and if phase loss occurs at the previous moment, switching from the first operation state to the second operation state, and outputting a second driving signal. According to the open-phase judgment, the three-phase converter can be switched to the first operation state or the second operation state in time due to open-phase or no open-phase, the three-phase converter cannot be shut down, and the first operation state and the second operation state can share partial design, so that the switching of the operation states and the complexity of the system are greatly reduced, and therefore, the switching efficiency of the three-phase converter is improved. And the operation stability of the three-phase converter is greatly improved.

Description

Technical Field

[0001] This application relates to a control method, and more particularly to a control method and a three-phase AC control system for a phase loss in a three-phase three-wire converter, applicable to most three-phase topologies (such as: three-phase six-arm bridge rectifier circuit, Vienna rectifier circuit, T-Type rectifier circuit or ANPC, etc.). Background Technology

[0002] If one phase of a three-phase converter fails, the converter will need to be shut down for maintenance. Thus, whenever a phase is lost in a three-phase converter, the stability and reliability of the converter will be reduced due to the shutdown.

[0003] Therefore, there is indeed a need to provide further improvements to the existing technology. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the main purpose of this application is to provide a control method and system for phase loss in a three-phase three-wire converter. By judging the phase loss, the corresponding output drive signal is output according to different operating states, so as to improve the stability and reliability of the three-phase converter.

[0005] The main technical means to achieve the above objective is a control method that causes a phase loss in the aforementioned three-phase three-wire converter, which is executed by the processor and includes the following steps: Receive power signals; Determine whether the power signal is missing a phase; If a phase is missing, determine whether the power supply signal was missing a phase in the previous moment; If there was no phase loss in the previous moment, switch from the second operating state to the first operating state and output the first drive signal; If there is no phase loss, determine whether the power supply signal was missing a phase in the previous moment; If a phase is missing in the previous moment, the system switches from the first operating state to the second operating state and outputs a second drive signal.

[0006] Preferably, the step of "if there was no phase loss in the previous moment, switching from the second operating state to the first operating state and outputting the first drive signal" further includes the following sub-steps: If there was no phase loss in the previous moment, confirm the phase sequence of the missing phase of the power signal; After confirming the phase sequence of the missing phase of the power signal, the system switches from the second operating state to the first operating state and outputs the first drive signal.

[0007] Preferably, after the step of "if a phase is missing, determine whether the power supply signal was missing a phase in the previous moment", the following steps are also included: If a phase is missing in the previous moment, the first operating state is maintained.

[0008] Preferably, after the step of "if there is no phase loss, determine whether the power signal was missing a phase in the previous moment", the following steps are also included: If there was no phase loss in the previous moment, the second operating state is maintained.

[0009] By using the above method, and through the phase loss judgment of the three-phase three-wire converter phase loss control method, the system can immediately switch to the phase loss operation state when a phase is lost, without causing the three-phase converter to stop. When there is no phase loss, it can switch to the normal operation state. Furthermore, the design allows the phase loss operation state and the normal operation state to share some parts, which greatly reduces the complexity of the operation state switching and the system complexity, and significantly improves the operation stability of the three-phase converter.

[0010] Another major technical means to achieve the above objectives is to make the aforementioned three-phase AC control system, which includes: A three-phase converter that receives power signals; and The processor has an input terminal and an output terminal. The input terminal receives the power signal, and the output terminal is electrically connected to the three-phase converter. The processor determines whether the power signal is missing a phase: if a phase is missing, it determines whether the power signal was missing a phase at the previous moment; if a phase is missing and there was no phase loss at the previous moment, it switches from a second operating state to a first operating state and outputs a first drive signal; if the power signal is not missing a phase, it determines whether the power signal was missing a phase at the previous moment; if the power signal is not missing a phase and there was a phase loss at the previous moment, it switches from the first operating state to the second operating state and outputs a second drive signal.

[0011] Preferably, the processor includes: The voltage coordinate transformation and phase-locked loop module receives the voltage of the power supply signal and generates a first stationary coordinate system voltage, a second stationary coordinate system voltage, and a phase angle based on the voltage of the power supply signal. The phase loss detection module determines whether a phase is missing based on the voltage of the power signal, thereby determining whether the operating state is the first operating state or the second operating state, and outputs the first coordinate rotation voltage potential, the second coordinate rotation voltage potential and the phase angle. The current coordinate transformation module outputs a first coordinate rotation current and a second coordinate rotation current in response to the first operating state or the second operating state. The voltage loop module outputs a current control signal based on the error signal between DC voltages. The current loop module receives the first coordinate rotating voltage potential, the second coordinate rotating voltage potential and the phase angle from the phase loss judgment module, and receives the first coordinate rotating current and the second coordinate rotating current from the current coordinate transformation module, and receives the current control signal from the voltage loop module to generate the first stationary coordinate system voltage and the second stationary coordinate system voltage. The modulation wave generation module performs modulation wave processing on the first stationary coordinate system voltage according to the first operating state to output the first driving signal; and outputs the second driving signal according to the second operating state, the first stationary coordinate system voltage and the second stationary coordinate system voltage.

[0012] Preferably, the voltage coordinate transformation and phase-locked loop module includes a voltage coordinate transformation and phase-locked loop module under normal conditions and a voltage coordinate transformation and phase-locked loop module under phase loss conditions; the current coordinate transformation module includes a current coordinate transformation module under normal conditions, a current coordinate transformation module under phase loss conditions, a first switching module, and a current rotation transformation module; the modulation wave generation module includes a modulation wave generation module under normal conditions and a modulation wave generation module under phase loss conditions.

[0013] Preferably, the normal voltage coordinate transformation and phase-locked loop module includes: The voltage coordinate transformation module receives the voltage of the power supply signal and performs coordinate transformation on the voltage of the power supply signal to generate a first-axis coordinate transformation voltage, a second-axis coordinate transformation voltage, and three-phase phase angles. The rotation transformation and positive / negative sequence component module performs rotation transformation on the first axis coordinate transformation voltage and the second axis coordinate transformation voltage according to the three-phase phase angle, generating the first stationary coordinate system voltage and the second stationary coordinate system voltage, and performs positive and negative sequence component processing on the first stationary coordinate system voltage and the second stationary coordinate system voltage, generating a first coordinate rotation positive sequence voltage and a first coordinate rotation negative sequence voltage according to the first stationary coordinate system voltage, and generating a second coordinate rotation positive sequence voltage and a second coordinate rotation negative sequence voltage according to the second stationary coordinate system voltage; The three-phase phase-locked module performs digital direct frequency synthesis and phase-locked processing on the first coordinate rotation positive sequence voltage, the first coordinate rotation negative sequence voltage, the second coordinate rotation positive sequence voltage and the second coordinate rotation negative sequence voltage, and outputs the three-phase phase angle; The phase loss judgment module determines whether the operating state is normal based on the first coordinate rotation positive sequence voltage and the first coordinate rotation negative sequence voltage, and outputs the first coordinate rotation voltage potential, the second coordinate rotation voltage potential and the three-phase phase angle.

[0014] Preferably, the voltage coordinate transformation and phase-locked loop module for phase loss includes: The first voltage phase loss determination module receives the voltage of the power signal and determines the phase sequence of the missing phase in the power signal based on the line voltage of the power signal. The voltage second-order generalized integral module performs filtering processing on the line voltage of the power signal corresponding to the phase sequence without phase loss, and generates the single-phase voltage of the first axis coordinate transformation and the single-phase voltage of the second axis coordinate transformation. The voltage rotation transformation module performs rotation transformation based on the first axis coordinate transformed single-phase voltage and the second axis coordinate transformed single-phase voltage to generate the first coordinate rotated single-phase voltage, the second coordinate rotated single-phase voltage and the single-phase phase angle. The phase-locked module performs phase-locking processing on the first coordinate rotation single-phase voltage and the second coordinate rotation single-phase voltage, and outputs the single-phase phase angle; The phase loss judgment module determines that the operating state is a phase loss operating state based on the first coordinate rotation positive sequence voltage and the first coordinate rotation negative sequence voltage, and outputs the first coordinate rotation voltage potential, the second coordinate rotation voltage potential and the phase angle.

[0015] Preferably, the normal current coordinate transformation module includes: The current coordinate transformation module receives the current of the power supply signal and performs coordinate transformation on the current of the power supply signal to generate a first coordinate transformation current and a second coordinate transformation current.

[0016] Preferably, the current coordinate transformation module for phase loss includes: The second voltage phase loss determination module receives the line voltage of the power signal and determines the phase sequence of the missing phase in the power signal based on the line voltage of the power signal. The second-order generalized integrator module for current performs filtering on the line current of the power signal corresponding to the phase sequence without phase loss, generating a first coordinate transformed single-phase current and a second coordinate transformed single-phase current.

[0017] Preferably, the first switching module and the second switching module respectively receive the first coordinate rotation positive sequence voltage and the first coordinate rotation negative sequence voltage to switch to the phase loss operation state or the normal operation state; the current rotation transformation module performs rotation transformation on the first coordinate transformation current and the second coordinate transformation current according to the phase angle to generate the first coordinate rotation current and the second coordinate rotation current, or the current rotation transformation module performs rotation transformation on the first coordinate transformation single-phase current and the second coordinate transformation single-phase current according to the phase angle to generate the first coordinate rotation current and the second coordinate rotation current.

[0018] Preferably, the normal-time modulation wave generation module includes: The normal inverse coordinate transformation module receives the voltage of the first stationary coordinate system and the voltage of the second stationary coordinate system, and performs inverse coordinate transformation on the voltage of the first stationary coordinate system and the voltage of the second stationary coordinate system to generate a first inverse coordinate transformation voltage, a second inverse coordinate transformation voltage and a third inverse coordinate transformation voltage.

[0019] Preferably, the phase-loss modulation wave generation module includes: The phase loss inverse coordinate transformation module receives the voltage of the first stationary coordinate system and performs an inverse coordinate transformation on the voltage of the first stationary coordinate system to generate a first inverse coordinate transformation phase loss voltage, a second inverse coordinate transformation phase loss voltage and a third inverse coordinate transformation phase loss voltage. The third voltage phase loss detection module determines the phase sequence of the phase loss based on the line voltage of the power signal, and assigns the phase loss voltage corresponding to the first coordinate inverse transformation phase loss voltage, the second coordinate inverse transformation phase loss voltage, or the third coordinate inverse transformation phase loss voltage (V) to the phase sequence of the phase loss. c-single The output is zero, and there is no missing phase voltage (V) corresponding to the first coordinate inverse transformation phase sequence. a-single ), the second coordinate inverse transformation phase loss voltage (V) b-single ) or third coordinate inverse transformation phase loss voltage (V c-single Two of them are 180 degrees apart in phase angle.

[0020] Preferably, the voltage loop module receives the actual DC voltage and the desired DC voltage, calculates the error signal between them based on the actual DC voltage and the desired DC voltage, inputs the error signal into the proportional-integral module to generate the current control signal, and transmits the current control signal to the current loop module.

[0021] Preferably, upon receiving the current control signal, the current loop module calculates a first error signal between itself and the first coordinate rotation current based on the current control signal and the first coordinate rotation current, and calculates a second error signal between itself and the second coordinate rotation current based on the second coordinate rotation current and a constant value. The first and second error signals are then transmitted to the proportional-integral module to generate a first error voltage and a second error voltage, respectively. After receiving the first and second coordinate rotation currents, the module transmits them to the decoupling module for decoupling processing, generating a first decoupling voltage on the first axis and a second decoupling voltage on the second axis. A first rotational error voltage is calculated based on the second decoupling voltage, the first coordinate rotation voltage potential, and the first error voltage. The first rotational error voltage is summed with the actual DC voltage based on the phase angle, and an inverse rotation transformation is performed to generate the first stationary coordinate system voltage. A second rotational error voltage is calculated based on the first decoupling voltage, the second coordinate rotation voltage potential, and the second error voltage. The second rotational error voltage is summed with the actual DC voltage based on the phase angle, and an inverse rotation transformation is performed to generate the second stationary coordinate system voltage.

[0022] Through the above-described structure and the phase loss detection of the three-phase AC control system, the system can immediately switch to the phase loss operation state when a phase is lost, without causing the three-phase converter to shut down. When there is no phase loss, it can switch to the normal operation state. Furthermore, the design allows the phase loss operation state and the normal operation state to share some parts, which greatly reduces the switching of operation states and the system complexity, and significantly improves the operation stability of the three-phase converter. Attached Figure Description

[0023] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0024] Figure 1 This is a block diagram of the three-phase AC control system of this application.

[0025] Figure 2 This is a block diagram of the processor of this application.

[0026] Figure 3 This is a block diagram of the voltage coordinate transformation and phase-locked loop module and the phase loss judgment module of this application.

[0027] Figure 4 This is a block diagram of the current coordinate transformation module of this application.

[0028] Figure 5This is a block diagram of the voltage loop module of this application.

[0029] Figure 6 This is a block diagram of the current loop module of this application.

[0030] Figure 7 This is a block diagram of the modulation wave generation module of this application.

[0031] Figure 8 This is a flowchart of the phase loss control method for a three-phase three-wire converter according to this application. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] Figure 1 This relates to an embodiment of the three-phase AC control system of this application, such as... Figure 1 As shown, the three-phase AC control system includes a three-phase converter 11 and a processor 12. The three-phase converter 11 is connected to the three-phase power supply e. a e b e c Electrically connected, the processor 12 includes an input terminal (Input) and an output terminal (Output). The input terminal (Input) receives a three-phase power supply e. a e b e c Three-phase power supply e a e b e c It includes three-phase voltage and / or three-phase current, and the output terminal is electrically connected to the three-phase converter 11, wherein the processor 12 is based on the three-phase power supply e a e b e c The system determines whether the current three-phase voltage state is the same as the previous voltage state. If they are the same, the three-phase converter 11 maintains its current operating state. If they are different, the three-phase converter 11 switches its operating state and outputs a drive signal through the output terminal Output. In this embodiment, the operating state includes normal operation and phase loss operation.

[0034] Specifically, processor 12 is based on three-phase power supply e a e b e cThe system determines whether a phase is missing based on the voltage readings. If a phase is missing in the current voltage, it further determines whether a phase was missing in the previous voltage. If a phase is missing in the current voltage but not in the previous voltage, the system switches from the second operating state to the first operating state and outputs a first drive signal. If no phase is missing in the current voltage, the system further determines whether a phase was missing in the previous voltage. If a phase is missing in the current voltage but not in the previous voltage, the system switches from the first operating state to the second operating state and outputs a second drive signal. In this embodiment, the first operating state is a phase-missing operating state; the second operating state is a normal operating state.

[0035] In one embodiment, Figure 2 This is a block diagram of the processor of this application. For example... Figure 2 As shown, the processor 12 includes a voltage coordinate transformation and phase-locked loop module 13, a phase loss detection module 14, a current coordinate transformation module 15, a voltage loop module 16, a current loop module 17, a modulation wave generation module 18, and a pulse width modulation module 19. First, the voltage coordinate transformation and phase-locked loop module 13 receives the three-phase power supply e. a e b e c The phase loss detection module 14 is based on the three-phase power supply e a e b e c The system determines whether a phase is missing. If a phase is missing, a first control signal is generated; if no phase is missing, a second control signal is generated. After generating either the first or second control signal, these signals are transmitted to the current coordinate transformation module 15 and the modulation wave generation module 18. This allows the current coordinate transformation module 15 and the modulation wave generation module 18 to execute the corresponding first or second operating state in response to the first or second control signal. Furthermore, the voltage loop module 16 and the current loop module 17 serve as signal inputs to the modulation wave generation module 18, enabling the pulse width modulation module 19 to output a corresponding drive signal, thereby driving the three-phase converter 11 to switch operating states. This prevents the three-phase converter 11 from shutting down due to phase loss. The detailed explanations of each module in normal operation and phase-loss operation states are then provided in separate sections below.

[0036] In one embodiment, the voltage coordinate transformation and phase-locked loop (PLL) module 13 includes a normal voltage coordinate transformation and PLL module 131 and a phase-loss voltage coordinate transformation and PLL module 132. The current coordinate transformation module 15 includes a normal current coordinate transformation module 151, a phase-loss current coordinate transformation module 152, a first switching module 153, and a current rotation transformation module 154. The current loop module 17 includes an inverse rotation transformation module 171. The modulation wave generation module 18 includes a normal modulation wave generation module 181, a phase-loss modulation wave generation module 182, and a second switching module 183.

[0037] The detailed description of the normal operating status is as follows.

[0038] Under normal operating conditions Figure 3 This is a block diagram of the voltage coordinate transformation and phase-locked loop module and the phase loss detection module of this application. Figure 3 As shown, under normal conditions, the voltage coordinate transformation and phase-locked loop module 131 includes a voltage coordinate transformation module 1311, a rotation transformation and positive / negative sequence component module 1312, and a three-phase phase-locked loop module 1313. The voltage coordinate transformation module 1311 receives the three-phase power supply e. a e b e c Subsequently, the voltage coordinate transformation module 1311 will transform the three-phase power supply e a e b e c line voltage V a V b V c Perform coordinate transformation to convert the three-phase power supply e a e b e c line voltage V a V b V c The voltage e is generated by transforming to two coordinate axes, resulting in the first axis coordinate transformation voltage. α-three Second axis coordinate transformation voltage e β-three With the three-phase phase angle θ PLL-three Next, the rotation transformation and positive / negative sequence component module 1312 performs the transformation based on the three-phase phase angle θ. PLL-three Transform the voltage e along the first axis coordinate respectively α-three Voltage e transformed with the second axis coordinate β-three Perform a rotational transformation to transform the voltage e of the first axis coordinate. α-three Voltage e transformed with the second axis coordinate β-three The voltage e in the first stationary coordinate system is generated by performing a rotational transformation. d-three With respect to the voltage e in the second stationary coordinate system q-three Subsequently, the rotation transformation and positive / negative sequence component module 1312 respectively applied the voltage e in the first stationary coordinate system. d-three With respect to the voltage e in the second stationary coordinate system q-three Perform positive and negative sequence component processing to rotate the first coordinate voltage e d-three Generate the first coordinate rotation positive sequence voltage e d-three+ Rotation of negative sequence voltage e with the first coordinate d-three- ; and make the voltage e in the second stationary coordinate system q-three Generate the second coordinate rotation positive sequence voltage e q-three+ Rotation of negative sequence voltage e with second coordinate q-three-Next, the three-phase phase-locked module 1313 rotates the positive sequence voltage e of the first coordinate. d-three+ First coordinate rotation negative sequence voltage e d-three- Second coordinate rotation positive sequence voltage e q-three+ Rotation of negative sequence voltage e with second coordinate q-three- It performs Direct Digital Synthesizer with Rotating Frame-Phase Locked Loop (DDSRF-PLL) and outputs the three-phase phase angle θ. PLL-three Subsequently, the phase loss detection module 14 rotates the positive sequence voltage e according to the first coordinate. d-three+ Rotation of negative sequence voltage e with the first coordinate d-three- Determine if the operating status is normal, and output the first coordinate rotating voltage potential ed, the second coordinate rotating voltage potential eq, and the output phase angle θ. PLL .

[0039] In one embodiment, Figure 4 This is a block diagram of the current coordinate transformation module of this application. (See diagram below.) Figure 4 As shown, the current coordinate transformation module 151 normally includes a current coordinate transformation module 1511. When the phase loss judgment module 14 determines that the operating state is the normal operating state, the first switching module 153 will receive the first coordinate rotation positive sequence voltage e. d-three+ Rotation of negative sequence voltage e with the first coordinate d-three- To rotate the positive sequence voltage e according to the first coordinate d-three+ Rotation of negative sequence voltage e with the first coordinate d-three- Switching to normal operation mode. With the first switching module 153 already switched to normal operation mode, when the current coordinate transformation module 1511 receives the three-phase power supply e... a e b e c The current coordinate transformation module 1511 also transforms the three-phase power supply e. a e b e c The line current i in a i b i c Perform coordinate transformation, and convert the three-phase power supply e a e b e c The line current i in a i b i c Transformed into the first coordinate transformation current i α-three With the second coordinate transformation current i β-three Subsequently, the current rotation conversion module 154, based on the phase angle θ, PLLFor the first coordinate transformation current i α-three With the second coordinate transformation current i β-three Perform a rotation transformation to change the first coordinate transformation current i α-three With the second coordinate transformation current i β-three The transformation is into the first coordinate rotating current id and the second coordinate rotating current iq.

[0040] Figure 5 This is a block diagram of the voltage loop module, such as... Figure 5 As shown, voltage loop module 16 is used to receive the actual DC voltage V. dc With the desired DC voltage V dc* And based on the actual DC voltage V dc With the desired DC voltage V dc* The error signal between them is calculated. Then, the error signal is input into the proportional-integral (PI) module to generate a current control signal id*, and the current control signal id* is transmitted to the current loop module 17.

[0041] Figure 6 This is a block diagram of the current loop module, such as... Figure 6 As shown, when the current loop module 17 receives the current control signal id*, it calculates the first error signal e1 between the current control signal id* and the first coordinate rotation current id; and calculates the second error signal e2 between the second coordinate rotation current iq and the constant value iq* (in this embodiment, the constant value is zero). Subsequently, the first error signal e1 and the second error signal e2 are transmitted to the proportional-integral module PI, respectively, generating a first error voltage V1 and a second error voltage V2. After receiving the first coordinate rotation current id and the second coordinate rotation current iq, the current loop module 17 transmits the first coordinate rotation current id and the second coordinate rotation current iq to the decoupling module wL for decoupling processing, generating a first decoupling voltage V on the first axis. de1 With the second decoupling voltage V on the second axis de2 Specifically, the decoupling process involves transmitting the first coordinate rotational current id and the second coordinate rotational current iq to the decoupling module wL, respectively. Through the angular frequency and inductor in the decoupling module wL, a first decoupling voltage V on the first axis is generated. de1 With the second decoupling voltage V on the second axis de2 Next, the current loop module 17, based on the second decoupling voltage V, de2 The first rotational error voltage vd is calculated based on the first coordinate rotational voltage potential ed and the first error voltage V1; the second decoupling voltage V is used to calculate the first rotational error voltage vd. de2The second rotational error voltage vq is calculated from the second coordinate rotational voltage potential eq and the second error voltage V2. Specifically, the first rotational error voltage vd and the second rotational error voltage vq are calculated according to the following formulas (1) and (2), respectively.

[0042] vd=-PI×(id*-id)+ed+ωL×iq Formula (1)

[0043] vq=-PI×(iq*-iq)+eq+ωL×id Formula (2)

[0044] In the above formulas (1) and (2), PI refers to the proportional-integral module PI processing; ω refers to the angular frequency; L refers to the inductor; id* is the current control signal; id is the first coordinate rotating current; ed is the first coordinate rotating voltage potential; iq* is a constant value; iq is the second coordinate rotating current; eq is the second coordinate rotating voltage potential.

[0045] Subsequently, the first rotational error voltage vd and the second rotational error voltage vq were compared with the actual DC voltage V. dc The summation is then performed, followed by the inverse rotation transformation module 171 of the current loop module 17 based on the phase angle θ. PLL Perform inverse rotation transformations on the summed first rotation error voltage vd and the summed second rotation error voltage vq, respectively, to generate the corresponding first stationary coordinate system voltage V. α Voltage V in the second stationary coordinate system β .

[0046] In some embodiments, Figure 7 This is a block diagram of the modulation wave generation module of this application. (See diagram below.) Figure 7 As shown, the modulation wave generation module 181 under normal conditions includes a normal inverse coordinate transformation module 1811. When the phase loss judgment module 14 determines that the operating state is the normal operating state, the second switching module 181 will receive the first coordinate rotation positive sequence voltage e. d-three+ Rotation of negative sequence voltage e with the first coordinate d-three- To rotate the positive sequence voltage e according to the first coordinate d-three+ Rotation of negative sequence voltage e with the first coordinate d-three- Switch to normal operation mode. In normal operation mode, the normal inverse coordinate transformation module 1811 receives the voltage V from the first stationary coordinate system. α Voltage V in the second stationary coordinate system β And for the voltage V in the first stationary coordinate system α Voltage V in the second stationary coordinate system β Perform an inverse coordinate transformation to generate the first inverse coordinate transformation voltage V. a-three Second coordinate inverse transformation voltage V b-three Inverse transformation voltage V with third coordinatec-three .

[0047] Next, under normal operating conditions, the pulse width modulation module 19 performs voltage V inverse transformation according to the first coordinate. a-three Second coordinate inverse transformation voltage V b-three Inverse transformation voltage V with third coordinate c-three Output drive signals Sa, Sb, Sc.

[0048] The detailed description of the phase loss operation state is as follows.

[0049] In a phase-deficient operating state, such as Figure 3 As shown, the first voltage phase loss judgment module 1321 receives the three-phase power supply e a e b e c Subsequently, the first voltage phase loss judgment module 1321 judges the voltage based on the three-phase power supply e. a e b e c line voltage V a V b V c Determine the three-phase power supply e a e b e c The phase sequence of the missing phase is determined by the first voltage phase loss judgment module 1321, which outputs the line voltage V. a V b V c Only after determining the phase sequence of the missing phase can the line voltage V corresponding to the phase sequence without missing phases be determined. a V b V c The voltage second-order generalized integrator module 1322 performs filtering processing and generates the first-axis coordinate transformation single-phase voltage e accordingly. α-single Single-phase voltage e transformed with second axis coordinates β-single Next, the first axis coordinates are transformed to represent the single-phase voltage e. α-single Second axis coordinate transformation single-phase voltage e β-single Phase angle θ of a single phase PLL-single The voltage is transmitted to the voltage rotation transformation module 1323 for rotation transformation, so that the first axis coordinate transformation single-phase voltage e is performed. α-single Single-phase voltage e transformed with second axis coordinates β-single The first coordinate rotation single-phase voltage e is generated by rotation. d-single Rotating single-phase voltage e with the second coordinate q-single Subsequently, the first coordinate is rotated by the single-phase voltage e. d-single Rotating single-phase voltage e with the second coordinate q-single The data is transmitted to the phase-locked module 1324 for phase-locking processing, and the single-phase phase angle θ is output. PLL-singleNext, the phase loss detection module 14 rotates the positive sequence voltage e according to the first coordinate. d-three+ Rotation of negative sequence voltage e with the first coordinate d-three- Determine if the operating state is a phase loss state, and output the first coordinate rotating voltage potential ed, the second coordinate rotating voltage potential eq, and the phase angle θ. PLL In this embodiment, the filtering process involves passing the line voltages corresponding to the phase sequences without phase loss through a second-order general integrator (SOGI) to generate the corresponding first-axis coordinate transformed single-phase voltage e. α-single Single-phase voltage e transformed with second axis coordinates β-single .

[0050] like Figure 4 As shown, when the phase loss judgment module 14 determines that the operating state is a phase loss operating state, the first switching module 153 will receive the first coordinate rotation positive sequence voltage e d-three+ Rotation of negative sequence voltage e with the first coordinate d-three- To rotate the positive sequence voltage e according to the first coordinate d-three+ Rotation of negative sequence voltage e with the first coordinate d-three- Switch to single-phase operation mode. In single-phase operation mode, the second voltage single-phase detection module 1521 receives the three-phase power supply e... a e b e c The second voltage phase loss judgment module 1521, based on the three-phase power supply e a e b e c line voltage V a V b V c Determine the three-phase power supply e a e b e c The phase sequence of the missing phase can only be determined by the second voltage phase sequence determination module 1521 after the missing phase sequence is determined. Only then can the line current i corresponding to the phase sequence without missing phase be determined. a i b i c The current is filtered by the second-order generalized integrator module 1522, which generates the first coordinate transformation single-phase current i. α-single Single-phase current i transformed with the second coordinate system β-single Subsequently, the current rotation conversion module 154, based on the phase angle θ, PLL For the first coordinate transformation, the single-phase current i α-single Single-phase current i transformed with the second coordinate system β-single Perform a rotational transformation to change the first coordinates of the single-phase current i. α-single Single-phase current i transformed with the second coordinate system β-singleThe transformation results in a first coordinate rotating current id and a second coordinate rotating current iq. In this embodiment, the filtering process involves passing the line currents corresponding to phase sequences without phase loss through a second-order generalized integrator (SOGI) to generate the corresponding first coordinate transformed single-phase current i. α-single Single-phase current i transformed with the second coordinate system β-single .

[0051] like Figure 5 and Figure 6 As shown, the signal transmission of the voltage loop module 16 and the current loop module 17 in the phase loss operation state is the same as the signal transmission in the normal operation state, so it will not be described again here.

[0052] like Figure 7 As shown, when the phase loss judgment module 14 determines that the operating state is a phase loss operating state, the second switching module 183 will receive the first coordinate rotation positive sequence voltage e d-three+ Rotation of negative sequence voltage e with the first coordinate d-three- To rotate the positive sequence voltage e according to the first coordinate d-three+ Rotation of negative sequence voltage e with the first coordinate d-three- Switch to single-phase operation mode. In single-phase operation mode, the single-phase inverse coordinate transformation module 1821 receives the voltage V from the first stationary coordinate system. α The phase-deficient inverse coordinate transformation module 1821 transforms the voltage V in the first stationary coordinate system. α Perform an inverse coordinate transformation to generate the first inverse coordinate transformation voltage V. a-single Second coordinate inverse transformation voltage V b-single Inverse transformation voltage V with third coordinate c-single The third voltage phase loss detection module 1822 determines the voltage based on the three-phase power supply e. a e b e c line voltage V a V b V c Determine the three-phase power supply e a e b e c In the case of a phase loss in the three-phase power supply, when the third voltage phase loss judgment module 1822 determines that the phase loss is in the three-phase power supply... a e b e c Line voltage V in a V b V c After the phase sequence is lost, the third voltage phase loss judgment module 1822 will determine the line voltage V corresponding to the phase sequence loss. a V b V cThe output is zero, and there is no line voltage V corresponding to the phase sequence without a missing phase. a V b V c The phase angles between them differ by 180 degrees. For example, when the second coordinate inverse transformation voltage V... b-single The line voltage of the phase sequence determined to be missing a phase is then the voltage V of the second coordinate inverse transformation. b-single The output will be zero; while the first coordinate inverse transformation voltage V a-single The inverse transformation voltage V of the third coordinate ahead c-single The line voltage is 180 degrees.

[0053] Please refer to Figure 2 As shown, in the phase-loss operation state, the pulse width modulation module 19 performs inverse transformation of the phase-loss voltage V according to the first coordinate. a-single Second coordinate inverse transformation phase loss voltage V b-single Phase loss voltage V under inverse transformation of the third coordinate c-single Output drive signals Sa, Sb, and Sc, and output the drive signals Sa, Sb, and Sc to the three-phase converter 11 through the output terminal Output.

[0054] In the above embodiments, coordinate transformation is to transform the three-phase power supply e a e b e c Perform a Clark transformation (or α-β transformation) to make the three-phase power supply e a e b e c It is projected onto the α and β axes.

[0055] In the above embodiments, the rotation transformation is based on the aforementioned phase angle θ. PLL Three-phase phase angle θ PLL-three Or single-phase phase angle θ PLL-single For three-phase power supply e a e b e c Perform a PARK transformation (or dq transformation) to make the three-phase power supply e a e b e c It is projected onto the d and q axes. The inverse rotation transformation described above is based on the phase angle θ mentioned above. PLL Perform the inverse PARK transformation.

[0056] The above embodiments are applicable to most three-phase topologies, such as three-phase six-arm bridge rectifier circuits, Vienna rectifier circuits, T-Type rectifier circuits, or ANPCs.

[0057] By normalizing the normal operation state and the phase loss operation state in the dq axis coordinate system as described above, the two modes can be treated as a single controlled object. This allows the voltage loop and current loop designs to be identical in both modes, thus achieving the same dynamic performance.

[0058] Furthermore, since the two modes achieve normalized control in the dq coordinate system, the complexity of the design and the occupation of interrupt resources are simplified in practical system applications. This can greatly simplify the design of digital systems and achieve the effect of significantly reducing the difficulty of control.

[0059] Moreover, through the above design, the switching between the two modes can be completed in a short time (measured at 10 milliseconds), enabling the three-phase converter 11 to achieve stable operation.

[0060] In addition, this application provides a method for controlling phase loss in a three-phase three-wire converter, such as... Figure 8 As shown, the main steps performed by the processor include: Receive power signal (S1); Determine if the power signal is missing a phase (S2); If a phase is missing, determine whether the power supply signal was missing a phase in the previous moment (S21); If there was no phase loss in the previous moment, switch from the second operating state to the first operating state and output the first drive signal (S211); If there is no phase loss, determine whether the power supply signal was missing a phase in the previous moment (S22); If a phase is missing in the previous moment, switch from the first operating state to the second operating state and output the second drive signal (S221).

[0061] In one embodiment, the step of "if there was no phase loss in the previous moment, switching from the second operating state to the first operating state and outputting the first drive signal (S211)" further includes the following sub-step: If there was no phase loss in the previous moment, confirm the phase sequence of the missing phase of the power signal (S2111); specifically, in this step, it is determined whether the power signal is missing the first phase sequence, the second phase sequence, or the third phase sequence. After confirming the phase sequence of the missing phase of the power signal, the system switches from the second operating state to the first operating state and outputs the first drive signal (S2112).

[0062] In one embodiment, after the aforementioned step of "if a phase is missing, determine whether the power supply signal was missing a phase in the previous moment (S21)", the following step is further included: If a phase is missing in the previous moment, the first operating state is maintained (S212). Specifically, if it is determined that the power signal received at the current moment is missing a phase, and further determined that the power signal at the previous moment was also missing a phase, the first operating state is maintained. In this embodiment, the first operating state is the phase-missing operating state.

[0063] In one embodiment, after the aforementioned step of "if there is no phase loss, determine whether the power supply signal was missing a phase in the previous moment (S22)", the following step is further included: If there was no phase loss in the previous moment, the second operating state is maintained (S222). Specifically, if it is determined that the power signal received at the current moment has no phase loss, and further determined that the power signal at the previous moment also had no phase loss, then the second operating state is maintained. In this embodiment, the second operating state is the normal operating state.

[0064] In summary, by employing the aforementioned control method for phase loss in a three-phase three-wire converter and the phase loss detection method in a three-phase AC control system, the system can immediately switch to the phase loss operation state when a phase is lost, without causing the three-phase converter to shut down. Conversely, when there is no phase loss, the system can switch to normal operation. Furthermore, by allowing the phase loss operation state and normal operation state to share some design elements, the switching between operation states and system complexity are significantly reduced, thereby greatly improving the operational stability of the three-phase converter.

[0065] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0066] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms fall within the scope of protection of this application.

Claims

1. A method for controlling phase loss in a three-phase three-wire converter, characterized in that, The phase loss control method for the three-phase three-wire converter is executed by the processor and includes the following steps: Receive power signals; Determine whether the power signal is missing a phase; If a phase is missing, determine whether the power supply signal was missing a phase in the previous moment; If there was no phase loss in the previous moment, switch from the second operating state to the first operating state and output the first drive signal; If there is no phase loss, determine whether the power supply signal was missing a phase in the previous moment; If a phase is missing in the previous moment, the system switches from the first operating state to the second operating state and outputs a second drive signal.

2. The method for controlling phase loss in a three-phase three-wire converter as described in claim 1, characterized in that, The step of "if there was no phase loss in the previous moment, switch from the second operating state to the first operating state and output the first drive signal" also includes the following sub-steps: If there was no phase loss in the previous moment, confirm the phase sequence of the missing phase of the power signal; After confirming the phase sequence of the missing phase of the power signal, the system switches from the second operating state to the first operating state and outputs the first drive signal.

3. The method for controlling phase loss in a three-phase three-wire converter as described in claim 1, characterized in that, After the step of "if a phase is missing, determine whether the power signal was missing a phase in the previous moment", the following steps are also included: If a phase is missing in the previous moment, the first operating state is maintained.

4. The method for controlling phase loss in a three-phase three-wire converter as described in claim 1, characterized in that, After the step of "if there is no phase loss, determine whether the power signal was missing a phase in the previous moment", the following steps are also included: If there was no phase loss in the previous moment, the second operating state is maintained.

5. A three-phase AC control system, characterized in that, include: Three-phase converter, receiving power signals; as well as The processor has an input terminal and an output terminal. The input terminal receives the power signal, and the output terminal is electrically connected to the three-phase converter. The processor determines whether the power signal is missing a phase: if a phase is missing, it determines whether the power signal was missing a phase at the previous moment; if a phase is missing and there was no phase loss at the previous moment, it switches from a second operating state to a first operating state and outputs a first drive signal; if the power signal is not missing a phase, it determines whether the power signal was missing a phase at the previous moment; if the power signal is not missing a phase and there was a phase loss at the previous moment, it switches from the first operating state to the second operating state and outputs a second drive signal.

6. The three-phase AC control system as described in claim 5, characterized in that, The processor includes: The voltage coordinate transformation and phase-locked loop module receives the voltage of the power supply signal and generates a first stationary coordinate system voltage, a second stationary coordinate system voltage, and a phase angle based on the voltage of the power supply signal. The phase loss detection module determines whether a phase is missing based on the voltage of the power signal, thereby determining whether the operating state is the first operating state or the second operating state, and outputs the first coordinate rotation voltage potential, the second coordinate rotation voltage potential and the phase angle. The current coordinate transformation module outputs a first coordinate rotation current and a second coordinate rotation current in response to the first operating state or the second operating state. The voltage loop module outputs a current control signal based on the error signal between DC voltages. The current loop module receives the first coordinate rotating voltage potential, the second coordinate rotating voltage potential and the phase angle from the phase loss judgment module, and receives the first coordinate rotating current and the second coordinate rotating current from the current coordinate transformation module, and receives the current control signal from the voltage loop module to generate the first stationary coordinate system voltage and the second stationary coordinate system voltage. The modulation wave generation module performs modulation wave processing on the first stationary coordinate system voltage according to the first operating state to output the first driving signal; and outputs the second driving signal according to the second operating state, the first stationary coordinate system voltage and the second stationary coordinate system voltage.

7. The three-phase AC control system as described in claim 6, characterized in that, The voltage coordinate transformation and phase-locked loop module includes a voltage coordinate transformation and phase-locked loop module under normal conditions and a voltage coordinate transformation and phase-locked loop module under phase loss conditions; the current coordinate transformation module includes a current coordinate transformation module under normal conditions, a current coordinate transformation module under phase loss conditions, a first switching module, and a current rotation transformation module; the modulation wave generation module includes a modulation wave generation module under normal conditions and a modulation wave generation module under phase loss conditions.

8. The three-phase AC control system as described in claim 7, characterized in that, The normal voltage coordinate transformation and phase-locked loop module includes: The voltage coordinate transformation module receives the voltage of the power supply signal and performs coordinate transformation on the voltage of the power supply signal to generate a first-axis coordinate transformation voltage, a second-axis coordinate transformation voltage, and three-phase phase angles. The rotation transformation and positive / negative sequence component module performs rotation transformation on the first axis coordinate transformation voltage and the second axis coordinate transformation voltage according to the three-phase phase angle, generating the first stationary coordinate system voltage and the second stationary coordinate system voltage, and performs positive and negative sequence component processing on the first stationary coordinate system voltage and the second stationary coordinate system voltage, generating a first coordinate rotation positive sequence voltage and a first coordinate rotation negative sequence voltage according to the first stationary coordinate system voltage, and generating a second coordinate rotation positive sequence voltage and a second coordinate rotation negative sequence voltage according to the second stationary coordinate system voltage; The three-phase phase-locked module performs digital direct frequency synthesis and phase-locked processing on the first coordinate rotation positive sequence voltage, the first coordinate rotation negative sequence voltage, the second coordinate rotation positive sequence voltage and the second coordinate rotation negative sequence voltage, and outputs the three-phase phase angle; The phase loss judgment module determines whether the operating state is normal based on the first coordinate rotation positive sequence voltage and the first coordinate rotation negative sequence voltage, and outputs the first coordinate rotation voltage potential, the second coordinate rotation voltage potential and the phase angle.

9. The three-phase AC control system as described in claim 8, characterized in that, The voltage coordinate transformation and phase-locked loop module for phase loss includes: The first voltage phase loss determination module receives the voltage of the power signal and determines the phase sequence of the missing phase in the power signal based on the line voltage of the power signal. The voltage second-order generalized integral module performs filtering processing on the line voltage of the power signal corresponding to the phase sequence without phase loss, and generates the single-phase voltage of the first axis coordinate transformation and the single-phase voltage of the second axis coordinate transformation. The voltage rotation transformation module performs rotation transformation based on the first axis coordinate transformation single-phase voltage and the second axis coordinate transformation single-phase voltage and single-phase phase angle to generate the first coordinate rotation single-phase voltage and the second coordinate rotation single-phase voltage. The phase-locked module performs phase-locking processing on the first coordinate rotation single-phase voltage and the second coordinate rotation single-phase voltage, and outputs the single-phase phase angle; The phase loss judgment module determines that the operating state is a phase loss operating state based on the first coordinate rotation positive sequence voltage and the first coordinate rotation negative sequence voltage, and outputs the first coordinate rotation voltage potential, the second coordinate rotation voltage potential and the phase angle.

10. The three-phase AC control system as described in claim 9, characterized in that, The normal current coordinate transformation module includes: The current coordinate transformation module receives the current of the power supply signal and performs coordinate transformation on the current of the power supply signal to generate a first coordinate transformation current and a second coordinate transformation current.

11. The three-phase AC control system as described in claim 10, characterized in that, The current coordinate transformation module during phase loss includes: The second voltage phase loss determination module receives the line voltage of the power signal and determines the phase sequence of the missing phase in the power signal based on the voltage of the line voltage of the power signal. The second-order generalized integrator module for current performs filtering processing on the current of the power supply signal corresponding to the phase sequence without phase loss, generating a first coordinate transformed single-phase current and a second coordinate transformed single-phase current.

12. The three-phase AC control system as described in claim 11, characterized in that, The first switching module and the second switching module respectively receive the first coordinate rotation positive sequence voltage and the first coordinate rotation negative sequence voltage to switch to the phase loss operation state or the normal operation state; the current rotation transformation module performs rotation transformation on the first coordinate transformation current and the second coordinate transformation current according to the phase angle to generate the first coordinate rotation current and the second coordinate rotation current, or the current rotation transformation module performs rotation transformation on the first coordinate transformation single-phase current and the second coordinate transformation single-phase current according to the phase angle to generate the first coordinate rotation current and the second coordinate rotation current.

13. The three-phase AC control system as described in claim 12, characterized in that, The normal time modulation wave generation module includes: The normal inverse coordinate transformation module receives the voltage of the first stationary coordinate system and the voltage of the second stationary coordinate system, and performs inverse coordinate transformation on the voltage of the first stationary coordinate system and the voltage of the second stationary coordinate system to generate a first inverse coordinate transformation voltage, a second inverse coordinate transformation voltage and a third inverse coordinate transformation voltage.

14. The three-phase AC control system as described in claim 13, characterized in that, The phase-loss modulation wave generation module includes: The phase loss inverse coordinate transformation module receives the voltage of the first stationary coordinate system and performs an inverse coordinate transformation on the voltage of the first stationary coordinate system to generate a first inverse coordinate transformation phase loss voltage, a second inverse coordinate transformation phase loss voltage and a third inverse coordinate transformation phase loss voltage. The third voltage phase loss judgment module determines the phase sequence of the phase loss based on the line voltage of the power signal, and outputs the first coordinate inverse transformation phase loss voltage, the second coordinate inverse transformation phase loss voltage, or the third coordinate inverse transformation phase loss voltage corresponding to the phase loss phase sequence as zero. For phase sequences without phase loss, the phase angle between any two of the first coordinate inverse transformation phase loss voltage, the second coordinate inverse transformation phase loss voltage, or the third coordinate inverse transformation phase loss voltage is 180 degrees.

15. The three-phase AC control system as described in claim 14, characterized in that, The voltage loop module receives the actual DC voltage and the desired DC voltage, calculates the error signal between them based on the actual DC voltage and the desired DC voltage, inputs the error signal into the proportional-integral module to generate the current control signal, and transmits the current control signal to the current loop module.

16. The three-phase AC control system as described in claim 15, characterized in that, The current loop module receives the current control signal, calculates a first error signal between itself and the first coordinate rotation current based on the current control signal and the first coordinate rotation current, and calculates a second error signal between itself and the second coordinate rotation current based on the second coordinate rotation current and a constant value; transmits the first error signal and the second error signal to the proportional-integral module respectively, generating a first error voltage and a second error voltage accordingly; after receiving the first coordinate rotation current and the second coordinate rotation current, transmits the first coordinate rotation current and the second coordinate rotation current to the decoupling module for decoupling processing, generating a first decoupling voltage on the first axis and a second decoupling voltage on the second axis; calculates a first rotation error voltage based on the second decoupling voltage, the first coordinate rotation voltage potential, and the first error voltage; performs an inverse rotation transformation after summing the first rotation error voltage and the actual DC voltage based on the phase angle, generating a first stationary coordinate system voltage; and calculates a second rotation error voltage based on the first decoupling voltage, the second coordinate rotation voltage potential, and the second error voltage; performs an inverse rotation transformation after summing the second rotation error voltage and the actual DC voltage based on the phase angle, generating a second stationary coordinate system voltage.

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