Three-vector model prediction direct power control method and system of doubly-fed asynchronous motor, and computer storage medium

Abstract

The invention provides a three-vector model prediction direct power control method and system for a doubly-fed asynchronous motor and a computer storage medium, and the method comprises the steps: calculating the negative conjugate of the complex power of a stator side according to the voltage and flux linkage equation of the doubly-fed asynchronous motor, and selecting three optimal voltage vectors on this basis to eliminate the power error; by adopting the constructed voltage vector relation graph, the difference value between the negative conjugate of the complex power at the next moment and the reference value of the complex power is calculated, a zero voltage vector correlation component and an effective voltage vector correlation component are defined, and then the action time and the duty ratio of each vector are calculated. And transmitting a switching signal corresponding to the action time and the duty ratio of each vector to a switching tube in the converter so as to control the power of the doubly-fed asynchronous motor. According to the method, the reasonable selection of the negative conjugate error component of the stator side complex power and the simplification of the calculation process of different voltage vector action time are realized, so that the prediction time is shortened.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor control, and in particular relates to a three-vector model prediction direct power control method, system and computer storage medium for a double-fed asynchronous motor. Background Art

[0002] In order to meet the ever-increasing demand for ship electricity, all-electric ships based on electric propulsion systems have gradually become the ship production standard of major shipyards around the world, which is also the development direction of future ships. All-electric ships represent a major shift in shipping propulsion systems from traditional, environmentally harmful fossil fuel energy to a cleaner electric propulsion paradigm. All-electric ship propulsion systems are equipped with a large number of power electronic devices, which not only enhance the convenience and reliability of operation, but also simplify the system architecture, while providing a more efficient and quieter electric drive system. However, during long voyages, high-frequency switching actions may bring a large number of potential failure risks to power electronic converters, thereby increasing the failure rate and maintenance costs, which may affect the reliability of the entire system.

[0003] To address these challenges, a doubly-fed asynchronous motor-based ship propulsion system is proposed that uses AC transmission lines and back-to-back power converters to build a bidirectional power flow path. This approach effectively mitigates the impact of power converter faults, utilizes reasonably priced and mature AC circuit breakers, and reduces the ship propulsion system's reliance on the DC bus, thereby improving the simplicity and effectiveness of fault protection.

[0004] Direct power control is a commonly used motor system control method. It is based on a table lookup method to reduce dependence on motor parameters. It has a simple control structure and fast dynamic performance, but it will cause the switching frequency to be unstable and the system to have large power ripple. Some scholars have combined the fast response of direct power control with the constant switching frequency of vector control, which has improved the steady-state performance to a certain extent. However, there are a large number of control parameters that need to be adjusted, making it difficult to achieve the optimal control effect. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a three-vector model predictive direct power control method, system and computer storage medium for a double-fed asynchronous motor.

[0006] In a first aspect, the present invention provides a three-vector model predictive direct power control method for a doubly-fed asynchronous motor, comprising:

[0007] Determine the voltage and flux relationship between the stator and rotor sides of the doubly-fed asynchronous motor in the dq coordinate system;

[0008] Determine the stator side dq current based on the voltage and flux relationship on the stator and rotor sides;

[0009] Determine the stator-side complex power of the double-fed asynchronous motor according to the stator-side dq current and the stator-side dq voltage;

[0010] In the synchronous speed rotating dq coordinate system, the d axis is used as the positioning axis of the voltage vector to determine the rate of change of the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor;

[0011] According to the negative conjugate change rate of the complex power on the stator side of the doubly-fed asynchronous motor at the current moment, the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at the next moment is determined;

[0012] In the case where only the zero voltage vector acts in a control cycle, the difference between the negative conjugate of the complex power on the stator side of the double-fed asynchronous motor at the next moment and the reference value is determined;

[0013] According to the negative conjugate vector of the stator complex power of the doubly-fed asynchronous motor related to the zero voltage vector and the effective voltage vector in the same direction, a voltage vector relationship diagram is constructed to determine the difference between the negative conjugate vector of the stator side complex power of the doubly-fed asynchronous motor at the next moment and a reference value to select three optimal voltage vectors;

[0014] Construct three optimal voltage vector relationship diagrams to determine the action time and duty cycle of each vector;

[0015] The switching signal corresponding to the action time and duty cycle of each vector is transmitted to the switch tube in the converter to control the power of the doubly-fed asynchronous motor.

[0016] Optionally, determining the relationship between voltage and flux linkage on the stator and rotor sides of the doubly-fed asynchronous motor in a dq coordinate system includes:

[0017] Calculate the stator side dq voltage U according to the following formula sdq and rotor side dq voltage U rdq :

[0018]

[0019] Among them, R s is the resistance on the stator side; I sdq is the stator side dq current; ψ sdq is the stator side flux; t is time; j is the imaginary unit; ω1 is the system angular frequency; R r is the resistance on the rotor side; I rdq is the dq current on the rotor side; ψ rdq is the magnetic flux on the rotor side; ω slip is the rotor slip angular frequency; represents a differential operator;

[0020] The stator side flux and rotor side flux are calculated according to the following formula:

[0021]

[0022] Among them, L s is the stator side inductance; L m is the mutual inductance between the stator and the rotor; L r is the rotor side inductance.

[0023] Optionally, determining the stator-side dq current according to the voltage and flux relationship on the stator-rotor side includes:

[0024] Calculate the stator side dq current I according to the following formula sdq :

[0025]

[0026] Among them, L r is the rotor side inductance; L m is the mutual inductance between the stator and the rotor; L s is the stator side inductance; ψ sdq is the stator side flux; ψ rdq is the rotor side flux.

[0027] Optionally, determining the stator-side complex power of the double-fed asynchronous motor according to the stator-side dq current and the stator-side dq voltage comprises:

[0028] The stator-side complex power S of the double-fed asynchronous motor is calculated according to the following formula:

[0029]

[0030] in, is the stator side dq current I sdq The conjugate value of sdq is the stator side dq voltage.

[0031] Optionally, in the synchronous speed rotating dq coordinate system, the d-axis is used as the positioning axis of the voltage vector to determine the rate of change of the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor, including:

[0032] The rate of change of the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor is calculated according to the following formula

[0033]

[0034] Among them, -S * is the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor; L m is the mutual inductance between the stator and the rotor; L r is the rotor side inductance; L s is the stator side inductance; U rdqis the dq voltage on the rotor side; is the conjugate of the dq voltage on the stator side; j is the imaginary unit; ω slip is the rotor slip angular frequency; S * is the conjugate of the complex power on the stator side of the doubly fed asynchronous motor.

[0035] Optionally, determining the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at the next moment according to the negative conjugate change rate of the complex power on the stator side of the doubly-fed asynchronous motor at the current moment comprises:

[0036] The negative conjugate of the stator-side complex power of the doubly-fed asynchronous motor at the next moment is calculated according to the following formula:

[0037]

[0038] Among them, (-S * ) t+1 is the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at time t+1; (-S * ) t is the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at time t; T s is the sampling time; It is the rate of change of the negative conjugate complex power on the stator side of the doubly fed asynchronous motor.

[0039] Optionally, in the case where only the zero voltage vector acts in one control cycle, determining the difference between the negative conjugate of the stator-side complex power of the doubly-fed asynchronous motor at the next moment and a reference value comprises:

[0040] According to the following formula, the negative conjugate of the stator side complex power at the next moment is calculated when only the zero voltage vector acts in a control cycle:

[0041]

[0042] in, is the negative conjugate of the stator side complex power at time t+1 when only the zero voltage vector acts in a control cycle; (-S * ) t is the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at time t; T s is the sampling time; j is the imaginary unit; ω1 is the system angular frequency; ω slip is the rotor slip angular frequency; L s is the stator side inductance; L m is the mutual inductance between the stator and the rotor; L r is the rotor side inductance; U sdq is the stator side dq voltage;

[0043] The difference between the negative conjugate of the stator-side complex power of the doubly-fed asynchronous motor at the next moment and the reference value is calculated according to the following formula:

[0044]

[0045] Among them, Δ(-S * ) t+1 is the difference between the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor at time t+1 and the reference value; (-S * ) ref is the reference value of the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor; U rdq is the dq voltage on the rotor side.

[0046] Optionally, the voltage vector relationship diagram is constructed according to the negative conjugate vector of the stator complex power of the doubly-fed asynchronous motor related to the zero voltage vector and the effective voltage vector in the same direction, and the difference between the negative conjugate vector of the stator side complex power of the doubly-fed asynchronous motor at the next moment and the reference value is determined to select three optimal voltage vectors, including:

[0047] Construct the negative conjugate vector expression of the stator side complex power associated with the zero voltage vector:

[0048]

[0049] n is the negative conjugate vector of the stator-side complex power associated with the zero voltage vector;

[0050] Construct the negative conjugate vector expression of the stator side complex power related to the effective voltage vector in the same direction:

[0051]

[0052] Among them, T i is the action time of the i-th effective voltage vector;

[0053] A voltage vector relationship diagram is constructed according to the negative conjugate vector of the stator complex power of the doubly-fed asynchronous motor related to the zero voltage vector and the effective voltage vector in the same direction;

[0054] The difference between the negative conjugate vector of the complex power on the stator side of the double-fed asynchronous motor at the next moment and the reference value is determined according to the voltage vector relationship diagram to select three optimal voltage vectors.

[0055] In a second aspect, the present invention provides a three-vector model predictive direct power control system for a doubly-fed asynchronous motor, comprising:

[0056] The first determination module is used to determine the voltage and flux relationship between the stator and rotor sides of the double-fed asynchronous motor in the dq coordinate system;

[0057] A second determination module is used to determine the stator side dq current according to the voltage and flux relationship between the stator and rotor sides;

[0058] A third determination module is used to determine the stator-side complex power of the double-fed asynchronous motor according to the stator-side dq current and the stator-side dq voltage;

[0059] A fourth determination module is used to determine the rate of change of the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor by using the d-axis as the positioning axis of the voltage vector in a synchronous speed rotating dq coordinate system;

[0060] A fifth determination module, used to determine the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at the next moment according to the negative conjugate change rate of the complex power on the stator side of the doubly-fed asynchronous motor at the current moment;

[0061] A sixth determination module, used for determining the difference between the negative conjugate of the complex power on the stator side of the double-fed asynchronous motor at the next moment and the reference value when only the zero voltage vector acts in a control cycle;

[0062] A seventh determination module is used to construct a voltage vector relationship diagram according to the negative conjugate vector of the stator complex power of the doubly-fed asynchronous motor related to the zero voltage vector and the effective voltage vector in the same direction, and determine the difference between the negative conjugate vector of the stator side complex power of the doubly-fed asynchronous motor at the next moment and the reference value to select three optimal voltage vectors;

[0063] An eighth determination module is used to construct three optimal voltage vector relationship diagrams to determine the action time and duty cycle of each vector;

[0064] The control module is used to transmit the switching signal corresponding to the action time and duty cycle of each vector to the switch tube in the converter to control the power of the double-fed asynchronous motor.

[0065] In a third aspect, the present invention provides a computer-readable storage medium for storing a computer program; when the computer program is executed by a processor, the steps of the three-vector model predictive direct power control method for a doubly-fed asynchronous motor described in the first aspect are implemented.

[0066] The present invention provides a three-vector model prediction direct power control method, system and computer storage medium for a doubly fed asynchronous motor. In the method, the three-vector model prediction control technology is combined with the direct power control method, a voltage vector relationship diagram is constructed, the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor is calculated, and the difference between the negative conjugate vector of the complex power at the next moment and its reference value is calculated, three optimal voltage vectors are selected to eliminate the power error, and the negative conjugate error component of the complex power on the stator side is reasonably selected and the calculation process of the action time of different voltage vectors is simplified. Only one-step prediction is required, so that the prediction time is shortened. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0068] Figure 1 A flowchart of a three-vector model predictive direct power control method for a doubly-fed asynchronous motor provided by an embodiment of the present invention;

[0069] Figure 2 A schematic diagram of the topological structure of a double-fed asynchronous motor and its control system provided in an embodiment of the present invention;

[0070] Figure 3 An equivalent circuit diagram of a doubly-fed asynchronous motor in a synchronous speed rotating coordinate system provided by an embodiment of the present invention;

[0071] Figure 4 A voltage and power vector relationship diagram taking sector 1 as an example provided in an embodiment of the present invention;

[0072] Figure 5 A block diagram of a three-vector optimization selection model predictive direct power control of a doubly-fed asynchronous motor provided by an embodiment of the present invention;

[0073] Figure 6 A schematic structural diagram of a three-vector model predictive direct power control system for a doubly-fed asynchronous motor provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0074] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0075] The purpose of the present invention is to provide a three-vector model predictive direct power control method for a doubly-fed asynchronous motor, aiming to improve the reliability and control system response speed of a doubly-fed asynchronous all-electric ship propulsion system. Figure 2 shown. Figure 2 Medium S1-S 12 Both are switch tubes; C1 and C2 are DC bus capacitors; U dc1 and U dc2 are the upper and lower DC bus voltages respectively; L g and Rg are the inductance and resistance of the source side converter respectively; i sa 、i sb and i sc are the A-phase, B-phase and C-phase currents on the stator side respectively; i ga 、i gb and i gc are the A-phase, B-phase and C-phase currents of the source-side converter respectively; i ra 、i rb and i rc They are the A-phase, B-phase and C-phase currents on the rotor side respectively.

[0076] Example 1

[0077] like Figure 1 As shown, this embodiment provides a three-vector model prediction direct power control method for a doubly-fed asynchronous motor, comprising:

[0078] Step 101, determining the relationship between the voltage and flux linkage on the stator and rotor sides of the doubly-fed asynchronous motor in a dq coordinate system.

[0079] The equivalent circuit diagram of the dq mathematical model of the double-fed asynchronous motor is as follows: Figure 3 shown. Figure 3 Medium ls and L lr are the stator side and rotor side self-inductance, respectively, and their expressions are L ls =L s –L m , L lr =L r -L m , the superscript s indicates that the variables on the rotor side are equivalent to the variables on the stator side.

[0080] Exemplarily, the stator side dq (on-axis) voltage U is calculated according to the following formula: sdq and the rotor side dq (on-axis) voltage U rdq :

[0081]

[0082] Among them, R s is the resistance on the stator side; I sdq is the stator side dq (axis) current; ψ sdq is the flux on the stator side (on the dq axis); t is time; j is an imaginary unit; ω1 is the system angular frequency; R r is the resistance on the rotor side; I rdq is the rotor side dq (shaft) current; ψ rdq is the magnetic flux on the rotor side (on the dq axis); ω slip is the rotor slip angular frequency; represents a differential operator.

[0083] The stator side flux and rotor side flux are calculated according to the following formula:

[0084]

[0085] Among them, L s is the stator side inductance; L m is the mutual inductance between the stator and the rotor; L r is the rotor side inductance.

[0086] Step 102, determining the stator side dq current according to the relationship between the voltage and the flux linkage on the stator and rotor sides.

[0087] Exemplarily, the stator side dq current I is calculated according to the following formula: sdq :

[0088]

[0089] Among them, L r is the rotor side inductance; L m is the mutual inductance between the stator and the rotor; L s is the stator side inductance; ψ sdq is the stator side flux; ψ rdq is the rotor side flux.

[0090] Step 103, determining the stator-side complex power of the doubly-fed asynchronous motor according to the stator-side dq current and the stator-side dq voltage.

[0091] Exemplarily, the stator-side complex power S of the double-fed asynchronous motor is calculated according to the following formula:

[0092]

[0093] in, is the stator side dq current I sdq The conjugate value of sdq is the stator side dq voltage; P and Q are active power and reactive power respectively.

[0094] Step 104, in the synchronous speed rotating dq coordinate system, the d-axis is used as the positioning axis of the voltage vector to determine the rate of change of the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor.

[0095] In order to eliminate the influence of the rotor side voltage conjugate value, the negative conjugate of the stator side complex power and its derivative value are calculated, and the relationship between the negative conjugate values ​​of the complex power at two adjacent moments is obtained according to the Euler discrete formula. Therefore, the rate of change of the complex power is calculated as follows:

[0096]

[0097] In the synchronous speed rotating dq coordinate system, the d-axis is selected as the positioning axis of the voltage vector, then U sdq is a time-invariant vector, that is

[0098]

[0099] In a doubly-fed asynchronous motor, the stator-rotor resistor R s and R r are small, so they can be ignored in the calculation of the complex power derivative, resulting in the following expression:

[0100]

[0101] in,

[0102] The rate of change of the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor is calculated according to the following formula

[0103]

[0104] Among them, -S * is the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor; L m is the mutual inductance between the stator and the rotor; L r is the rotor side inductance; L s is the stator side inductance; U rdq is the dq voltage on the rotor side; is the conjugate of the dq voltage on the stator side; j is the imaginary unit; ω slip is the rotor slip angular frequency; S * It is the conjugate of the complex power on the stator side of the doubly fed asynchronous motor.

[0105] Step 105, determining the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor at the next moment according to the negative conjugate change rate of the complex power on the stator side of the doubly fed asynchronous motor at the current moment.

[0106] Will After the expression of is discretized, the relationship between the complex power at time t+1 and the complex power at time t can be obtained, that is, the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor at the next moment is calculated according to the following formula:

[0107]

[0108] Among them, (-S * ) t+1 is the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at time t+1; (-S * ) t is the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at time t; Ts is the sampling time; It is the rate of change of the negative conjugate complex power on the stator side of the doubly fed asynchronous motor.

[0109] Step 106, when only the zero voltage vector acts in a control cycle, determine the difference between the negative conjugate of the complex power on the stator side of the double-fed asynchronous motor at the next moment and the reference value.

[0110] When only the zero voltage vector acts in a control cycle, the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor at the next moment is obtained. The expression is as follows:

[0111]

[0112] in, is the negative conjugate of the stator side complex power at time t+1 when only the zero voltage vector acts in a control cycle; (-S * ) t is the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at time t; T s is the sampling time; j is the imaginary unit; ω1 is the system angular frequency; ω slip is the rotor slip angular frequency; L s is the stator side inductance; L m is the mutual inductance between the stator and the rotor; L r is the rotor side inductance; U sdq is the stator side dq voltage.

[0113] Depend on The expression and The expression of can be obtained:

[0114]

[0115] The difference between the negative conjugate of the stator-side complex power of the doubly-fed asynchronous motor at the next moment and the reference value is calculated according to the following formula:

[0116]

[0117] Among them, Δ(-S * ) t+1 is the difference between the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor at time t+1 and the reference value; (-S * ) ref is the reference value of the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor; U rdq is the dq voltage on the rotor side.

[0118] Step 107, constructing a voltage vector relationship diagram based on the negative conjugate vector of the stator complex power of the doubly fed asynchronous motor related to the zero voltage vector and the effective voltage vector in the same direction, determining the difference between the negative conjugate vector of the stator side complex power of the doubly fed asynchronous motor at the next moment and the reference value, so as to select three optimal voltage vectors.

[0119] In Δ(-S * ) t+1 Based on the expression of , vector n is defined as the negative conjugate vector of the stator side complex power associated with the zero voltage vector; vector m is defined as the negative conjugate vector of the stator side complex power associated with the effective voltage vector in the same direction.

[0120] Exemplarily, this step includes:

[0121] Construct the negative conjugate vector expression of the stator side complex power associated with the zero voltage vector:

[0122]

[0123] Construct the negative conjugate vector expression of the stator side complex power related to the effective voltage vector in the same direction:

[0124]

[0125] Among them, T i is the action time of the i-th effective voltage vector.

[0126] A voltage vector relationship diagram is constructed according to the negative conjugate vector of the stator complex power of the doubly-fed asynchronous motor related to the zero voltage vector and the effective voltage vector in the same direction.

[0127] The difference between the negative conjugate vector of the complex power on the stator side of the double-fed asynchronous motor at the next moment and the reference value is determined according to the voltage vector relationship diagram to select three optimal voltage vectors.

[0128] By using the constructed voltage vector relationship diagram, the (-S * ) and reference value (-S * ) ref The difference between Δ(-S * ), and define the zero voltage vector related component n and the vector m corresponding to the effective voltage vector, on this basis, three optimal voltage vectors are selected to eliminate the power error.

[0129] Taking the case where n is in sector 1 as an example, the relationship between voltage and power vector is as follows: Figure 4 As shown, the vector corresponding to the selected effective voltage vector is m V4 and m V6 In order to make the negative conjugate value of the complex power at time t+1 zero,

[0130] n=m v4 +m v6 .

[0131] Then the action time and duty ratio of each vector are calculated as follows:

[0132]

[0133] Where θ is n and m V4 The angle between them, V4 and V6 respectively represent the two effective voltage vectors corresponding to the sector where n is located.

[0134] Step 108 : construct three optimal voltage vector relationship diagrams to determine the action time and duty cycle of each vector.

[0135] Step 109, transmitting the switching signal corresponding to the action time and duty cycle of each vector to the switch tube in the converter to control the power of the double-fed asynchronous motor.

[0136] In step 108-109, after calculating the action time T and duty cycle d of each vector based on the relationship diagram formed by the three voltage vectors, the corresponding action time is proportionally adjusted in consideration of the situation that the effective voltage vector action time exceeds one control cycle. Figure 5 shown. Figure 5 Middle I gdq is the dq current of the source side converter; U dc is the DC bus voltage; U ref is the reference voltage value; P g and Q g are the active and reactive power of the source side converter respectively; P s and Q s are stator active and reactive power respectively; P ref and Q ref are active and reactive power reference values ​​respectively; u g is the control signal; s g and l are the switching signals of the converter on the source side and the load side respectively; ω r is the rotor electrical angular velocity; n p is the number of rotor pole pairs; θ r is the rotor electrical angle.

[0137] In summary, the three-vector model predictive direct power control method for the doubly fed asynchronous motor provided in this embodiment combines the three-vector model predictive control technology with the direct power control method, constructs a voltage vector relationship diagram, calculates the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor, and calculates the difference between the negative conjugate vector of the complex power at the next moment and its reference value, selects three optimal voltage vectors to eliminate the power error, realizes the reasonable selection of the negative conjugate error component of the complex power on the stator side and the simplification of the calculation process of the action time of different voltage vectors, and only requires one-step prediction, so that the prediction time is shortened.

[0138] Example 2

[0139] Based on the same inventive concept as Example 1, this embodiment provides a three-vector model prediction direct power control system for a doubly-fed asynchronous motor. Since the principle of solving the problem by this system is similar to the aforementioned three-vector model prediction direct power control method for a doubly-fed asynchronous motor, the implementation of this system can refer to the implementation of the three-vector model prediction direct power control method for a doubly-fed asynchronous motor.

[0140] like Figure 6 As shown, the three-vector model prediction direct power control system of the doubly-fed asynchronous motor includes:

[0141] The first determination module 10 is used to determine the voltage and flux relationship between the stator and rotor sides of the doubly-fed asynchronous motor in a dq coordinate system.

[0142] The second determination module 20 is used to determine the stator-side dq current according to the voltage and flux relationship on the stator-rotor side.

[0143] The third determination module 30 is used to determine the stator-side complex power of the double-fed asynchronous motor according to the stator-side dq current and the stator-side dq voltage.

[0144] The fourth determination module 40 is used to determine the rate of change of the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor by using the d-axis as the positioning axis of the voltage vector in the synchronous speed rotating dq coordinate system.

[0145] The fifth determination module 50 is used to determine the negative conjugate of the stator-side complex power of the doubly-fed asynchronous motor at the next moment according to the negative conjugate change rate of the stator-side complex power of the doubly-fed asynchronous motor at the current moment.

[0146] The sixth determination module 60 is used to determine the difference between the negative conjugate of the stator-side complex power of the double-fed asynchronous motor at the next moment and the reference value when only the zero voltage vector acts in a control cycle.

[0147] The seventh determination module 70 is used to construct a voltage vector relationship diagram based on the negative conjugate vector of the stator complex power of the doubly fed asynchronous motor related to the zero voltage vector and the effective voltage vector in the same direction, and determine the difference between the negative conjugate vector of the stator side complex power of the doubly fed asynchronous motor at the next moment and the reference value to select three optimal voltage vectors.

[0148] The eighth determination module 80 is used to construct three optimal voltage vector relationship diagrams to determine the action time and duty cycle of each vector.

[0149] The control module 90 is used to transmit the switching signal corresponding to the action time and duty cycle of each vector to the switch tube in the converter to control the power of the double-fed asynchronous motor.

[0150] For more specific working processes of the above modules, please refer to the corresponding contents disclosed in Example 1, which will not be repeated here.

[0151] Example 3

[0152] This embodiment provides a computer device, including a processor and a memory; wherein, when the processor executes the computer program stored in the memory, the steps of the three-vector model predictive direct power control method for the doubly-fed asynchronous motor described in Example 1 are implemented.

[0153] For more specific details of the above method, please refer to the corresponding contents disclosed in Example 1, which will not be repeated here.

[0154] Example 4

[0155] This embodiment provides a computer-readable storage medium for storing a computer program; when the computer program is executed by a processor, the steps of the three-vector model predictive direct power control method for a doubly-fed asynchronous motor described in Embodiment 1 are implemented.

[0156] For more specific details of the above method, please refer to the corresponding contents disclosed in Example 1, which will not be repeated here.

[0157] Example 5

[0158] This embodiment provides a computer program product, including computer executable instructions or a computer program. When the computer executable instructions or the computer program are executed by a processor, the steps of the three-vector model predictive direct power control method for a doubly-fed asynchronous motor described in Example 1 are implemented.

[0159] For more specific details of the above method, please refer to the corresponding contents disclosed in Example 1, which will not be repeated here.

[0160] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the systems, devices, storage media, and computer program products disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0161] Those skilled in the art can clearly understand that the technology in the embodiments of the present invention can be implemented by means of software plus a necessary general hardware platform. Based on this understanding, the technical solution in the embodiments of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a disk, an optical disk, etc., and includes a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention or some parts of the embodiments.

[0162] In some embodiments, computer executable instructions may be in the form of a program, software, software module, script or code, written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and may be deployed in any form, including as a stand-alone program or as a module, component, subroutine or other unit suitable for use in a computing environment.

[0163] As an example, computer-executable instructions may, but need not, correspond to a file in a file system, may be stored as part of a file that stores other programs or data, such as in one or more scripts in a HyperText Markup Language (HTML) document, in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files storing one or more modules, subroutines, or code portions).

[0164] As an example, computer executable instructions may be deployed to be executed on one electronic device, or on multiple electronic devices located at one site, or on multiple electronic devices distributed at multiple sites and interconnected by a communication network.

[0165] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A three-vector model predictive direct power control method for a doubly-fed asynchronous motor, characterized in that: include: Determine the voltage and flux relationship between the stator and rotor sides of the doubly-fed asynchronous motor in the dq coordinate system; Determine the stator side dq current based on the voltage and flux relationship on the stator and rotor sides; Determine the stator-side complex power of the double-fed asynchronous motor according to the stator-side dq current and the stator-side dq voltage; In the synchronous speed rotating dq coordinate system, the d axis is used as the positioning axis of the voltage vector to determine the rate of change of the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor; According to the negative conjugate change rate of the complex power on the stator side of the doubly-fed asynchronous motor at the current moment, the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at the next moment is determined; In the case where only the zero voltage vector acts in a control cycle, the difference between the negative conjugate of the complex power on the stator side of the double-fed asynchronous motor at the next moment and the reference value is determined; According to the negative conjugate vector of the stator complex power of the doubly-fed asynchronous motor related to the zero voltage vector and the effective voltage vector in the same direction, a voltage vector relationship diagram is constructed to determine the difference between the negative conjugate vector of the stator side complex power of the doubly-fed asynchronous motor at the next moment and a reference value to select three optimal voltage vectors; Construct three optimal voltage vector relationship diagrams to determine the action time and duty cycle of each vector; The switching signal corresponding to the action time and duty cycle of each vector is transmitted to the switch tube in the converter to control the power of the doubly-fed asynchronous motor.

2. The three-vector model predictive direct power control method for a doubly-fed asynchronous motor according to claim 1, characterized in that: The method of determining the relationship between the voltage and flux linkage of the stator and rotor sides of the doubly-fed asynchronous motor in the dq coordinate system includes: Calculate the stator side dq voltage U according to the following formula sdq and rotor side dq voltage U rdq : Among them, R s is the resistance on the stator side; I sdq is the stator side dq current; ψ sdq is the stator side flux; t is time; j is the imaginary unit; ω1 is the system angular frequency; R r is the resistance on the rotor side; I rdq is the dq current on the rotor side; ψ rdq is the magnetic flux on the rotor side; ω slip is the rotor slip angular frequency; represents a differential operator; The stator side flux and rotor side flux are calculated according to the following formula: Among them, L s is the stator side inductance; L m is the mutual inductance between the stator and the rotor; L r is the rotor side inductance.

3. The three-vector model predictive direct power control method for a doubly-fed asynchronous motor according to claim 1, characterized in that: Determining the stator-side dq current according to the voltage and flux relationship on the stator-rotor side includes: Calculate the stator side dq current I according to the following formula sdq : Among them, L r is the rotor side inductance; L m is the mutual inductance between the stator and the rotor; L s is the stator side inductance; ψ sdq is the stator side flux; ψ rdq is the rotor side flux.

4. The three-vector model predictive direct power control method for a doubly-fed asynchronous motor according to claim 1, characterized in that: Determining the stator-side complex power of the double-fed asynchronous motor according to the stator-side dq current and the stator-side dq voltage comprises: The stator-side complex power S of the double-fed asynchronous motor is calculated according to the following formula: in, is the stator side dq current I sdq The conjugate value of sdq is the stator side dq voltage.

5. The three-vector model predictive direct power control method for a doubly-fed asynchronous motor according to claim 1, characterized in that: The method uses the d-axis as the positioning axis of the voltage vector in the synchronous speed rotating dq coordinate system to determine the rate of change of the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor, including: The rate of change of the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor is calculated according to the following formula Among them, -S * is the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor; L m is the mutual inductance between the stator and the rotor; L r is the rotor side inductance; L s is the stator side inductance; U rdq is the dq voltage on the rotor side; is the conjugate of the dq voltage on the stator side; j is the imaginary unit; ω slip is the rotor slip angular frequency; S * is the conjugate of the complex power on the stator side of the doubly fed asynchronous motor.

6. The three-vector model predictive direct power control method for a doubly-fed asynchronous motor according to claim 1, characterized in that: The method of determining the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at the next moment according to the negative conjugate change rate of the complex power on the stator side of the doubly-fed asynchronous motor at the current moment comprises: The negative conjugate of the stator-side complex power of the doubly-fed asynchronous motor at the next moment is calculated according to the following formula: Among them, (-S * ) t+1 is the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at time t+1; (-S * ) t is the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at time t; T s is the sampling time; It is the rate of change of the negative conjugate complex power on the stator side of the doubly fed asynchronous motor.

7. The three-vector model predictive direct power control method for a doubly-fed asynchronous motor according to claim 1, characterized in that: The method of determining the difference between the negative conjugate of the stator-side complex power of the double-fed asynchronous motor at the next moment and a reference value when only the zero voltage vector acts in a control cycle includes: According to the following formula, the negative conjugate of the stator side complex power at the next moment is calculated when only the zero voltage vector acts in a control cycle: in, is the negative conjugate of the stator side complex power at time t+1 when only the zero voltage vector acts in a control cycle; (-S * ) t is the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at time t; T s is the sampling time; j is the imaginary unit; ω1 is the system angular frequency; ω slip is the rotor slip angular frequency; L s is the stator side inductance; L m is the mutual inductance between the stator and the rotor; L r is the rotor side inductance; U sdq is the stator side dq voltage; The difference between the negative conjugate of the stator-side complex power of the doubly-fed asynchronous motor at the next moment and the reference value is calculated according to the following formula: Among them, Δ(-S * ) t+1 is the difference between the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor at time t+1 and the reference value; (-S * ) ref is the reference value of the negative conjugate of the complex power on the stator side of the doubly fed asynchronous motor; U rdq is the dq voltage on the rotor side.

8. The three-vector model predictive direct power control method for a doubly-fed asynchronous motor according to claim 7, characterized in that: The method constructs a voltage vector relationship diagram according to the negative conjugate vector of the stator complex power of the doubly-fed asynchronous motor related to the zero voltage vector and the effective voltage vector in the same direction, determines the difference between the negative conjugate vector of the stator side complex power of the doubly-fed asynchronous motor at the next moment and the reference value, so as to select three optimal voltage vectors, including: Construct the negative conjugate vector expression of the stator side complex power associated with the zero voltage vector: n is the negative conjugate vector of the stator-side complex power associated with the zero voltage vector; Construct the negative conjugate vector expression of the stator side complex power related to the effective voltage vector in the same direction: Among them, T i is the action time of the i-th effective voltage vector; A voltage vector relationship diagram is constructed according to the negative conjugate vector of the stator complex power of the doubly-fed asynchronous motor related to the zero voltage vector and the effective voltage vector in the same direction; The difference between the negative conjugate vector of the complex power on the stator side of the double-fed asynchronous motor at the next moment and the reference value is determined according to the voltage vector relationship diagram to select three optimal voltage vectors.

9. A three-vector model predictive direct power control system for a doubly-fed asynchronous motor, characterized in that: include: The first determination module is used to determine the voltage and flux relationship between the stator and rotor sides of the double-fed asynchronous motor in the dq coordinate system; A second determination module is used to determine the stator side dq current according to the voltage and flux relationship between the stator and rotor sides; A third determination module is used to determine the stator-side complex power of the double-fed asynchronous motor according to the stator-side dq current and the stator-side dq voltage; A fourth determination module is used to determine the rate of change of the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor by using the d-axis as the positioning axis of the voltage vector in a synchronous speed rotating dq coordinate system; A fifth determination module, used to determine the negative conjugate of the complex power on the stator side of the doubly-fed asynchronous motor at the next moment according to the negative conjugate change rate of the complex power on the stator side of the doubly-fed asynchronous motor at the current moment; A sixth determination module, used for determining the difference between the negative conjugate of the complex power on the stator side of the double-fed asynchronous motor at the next moment and the reference value when only the zero voltage vector acts in a control cycle; A seventh determination module is used to construct a voltage vector relationship diagram according to the negative conjugate vector of the stator complex power of the doubly-fed asynchronous motor related to the zero voltage vector and the effective voltage vector in the same direction, and determine the difference between the negative conjugate vector of the stator side complex power of the doubly-fed asynchronous motor at the next moment and the reference value to select three optimal voltage vectors; An eighth determination module is used to construct three optimal voltage vector relationship diagrams to determine the action time and duty cycle of each vector; The control module is used to transmit the switching signal corresponding to the action time and duty cycle of each vector to the switch tube in the converter to control the power of the double-fed asynchronous motor.

10. A computer-readable storage medium, characterized in that: Used to store computer programs; when the computer programs are executed by a processor, the steps of the three-vector model predictive direct power control method for a doubly-fed asynchronous motor as described in any one of claims 1-8 are implemented.

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