A three-phase grid-connected inverter system harmonic suppression predictive control method and module

Abstract

The present invention discloses a harmonic suppression predictive control method and module for a three-phase grid-connected inverter system, belonging to the field of power electronic control. First, a continuous domain state space model of the three-phase grid-connected inverter system is established in a dq coordinate system, and the state space model is discretized at time k to obtain a prediction model for the grid current sampled at k+1; the grid current prediction model is made to reach the grid current reference value at the k+1 sampling time, and a reference inverter voltage control reference value is calculated; the reference inverter voltage control reference value and a discretized quasi-resonant controller are combined to calculate an inverter voltage control reference value for integrated harmonic suppression; the optimal voltage vector and action time for synthesizing the inverter voltage control reference value for integrated harmonic suppression are determined; a control pulse signal is generated and applied to the switch tube of the three-phase grid-connected inverter to realize harmonic suppression predictive control of the three-phase grid-connected inverter system. The steps are simple and the prediction and suppression control effects of harmonics are good.

Description

Technical Field

[0001] The present invention relates to the field of electric drive technology, and in particular to a harmonic suppression predictive control method and module for a three-phase grid-connected inverter system. Background Art

[0002] Photovoltaic energy, with its numerous advantages such as cleanliness, renewable energy, flexibility, and reliability, is a crucial component of distributed energy systems. As the key interface device between distributed photovoltaic power sources and the power grid, the performance of three-phase grid-tied inverters directly impacts the quality of grid connection and grid stability. While this has increased the proportion of clean energy, it has also led to increasingly prominent power quality issues within three-phase grid-tied inverter systems. Three-phase grid-tied inverters suffer from harmonic issues caused by component aging and imbalance, resulting in severe output current distortion in photovoltaic power generation systems. Consequently, large-scale deployment of three-phase grid-tied inverter systems can generate significant harmonic pollution and disturbances on the power grid. These severe harmonic issues significantly reduce the power quality of three-phase grid-tied inverter systems, severely limiting the further expansion of photovoltaic power generation system penetration.

[0003] In existing technology, the primary approach to addressing harmonic pollution in three-phase grid-connected inverter systems is to absorb the harmonic currents generated by the harmonic source using power electronic devices. This approach primarily employs passive and active filters. However, passive filters can resonate with the system impedance and can only filter specific harmonics, relying heavily on component parameters. This makes them less effective for loads whose harmonic order varies over time. Active filter equipment is prohibitively expensive and lacks the ability to achieve differentiated, targeted treatment. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, a harmonic suppression predictive control method and module for a three-phase grid-connected inverter system are provided. The method can reduce the background harmonics of the three-phase grid-connected inverter system through control strategy without changing the hardware circuit, thereby improving the quality of the grid.

[0005] To achieve the above technical objectives, the present invention provides a three-phase grid-connected inverter system harmonic suppression predictive control method, the steps are as follows:

[0006] The grid current and voltage state variables of the three-phase grid-connected inverter system are sampled, and the grid voltage phase is then obtained through a phase-locked loop. The state variables in the abc coordinate system are transformed using Park transform to obtain the state variables in the dq coordinate system. The grid current and voltage are used to establish a continuous domain state space model of the three-phase grid-connected inverter system in the dq coordinate system.

[0007] At time k, the continuous domain state space model of the three-phase grid-connected inverter system in the dq coordinate system is accurately discretized, and the grid current prediction model i at time k+1 is obtained by recursion. g,k+1 ;

[0008] Let the grid current prediction model i g,k+1 At the next k+1 sampling time, the grid current reference value can be reached, and the reference inverter voltage control reference value v* k is calculated;

[0009] Combining the reference inverter voltage control value v*k with the discrete quasi-resonant controller, the inverter voltage control reference value v*h,k with integrated harmonic suppression h in the dq coordinate system is calculated, and then the inverse Park transform is performed to obtain the inverter voltage control reference value v*hαβ,k with integrated harmonic suppression in the stationary αβ coordinate system.

[0010] The volt-second balance principle is used to determine the optimal voltage vectors v0, v1, v2 and action times t0, t1, t2 of the inverter voltage control reference value that can synthesize integrated harmonic suppression, generate corresponding control pulse signals, and apply the control pulse signals to the switching tubes of the three-phase grid-connected inverter to realize harmonic suppression predictive control of the three-phase grid-connected inverter system.

[0011] Furthermore, the continuous domain state space model of the three-phase grid-connected inverter system in the dq coordinate system is as follows:

[0012] ;

[0013] Where: is the state variable, is the control input, and the coefficient matrices A and B are: , , where i gd 、i gq 、v d 、v q 、u gd 、u gq are the grid current, inverter voltage and grid voltage of the three-phase grid-connected inverter system in the dq coordinate system, L and R represent the filter inductance and filter inductance parasitic resistance respectively, ω g is the fundamental angular frequency of the grid voltage.

[0014] Furthermore, the grid current prediction model i of the grid current at time k+1 is obtained g,k+1 The specific process is as follows:

[0015] Assume that the sampling period of the three-phase grid-connected inverter system is T s At time k, the precise discretization method is used to discretize the state space model in the continuous domain, and the prediction model of the three-phase grid-connected inverter system is obtained as follows:

[0016] ;

[0017] Where i g,k = [i gd,k i gq,k ] T , represents the grid current collected at time k, i g,k+1 = [i gd,k+1 i gq,k+1 ] T , represents the prediction model of the grid current at time k+1, u k = [v d,k v q,k u gd,k u gq,k ] T , represents the inverter voltage and grid voltage collected at time k, A d 、B d They represent the system discretization model coefficient matrices calculated using the exact discretization method: , where e is the base of the natural logarithm and I2 is the second-order identity matrix.

[0018] Furthermore, based on the grid current prediction model i g,k+1 At the k+1 sampling time, the grid current reference value is reached and the reference inverter voltage control reference value is calculated. The process is as follows:

[0019] According to the system grid current reference value and its prediction model, let i g,k+1 = i* g,k, the reference value v* k of the three-phase grid-connected inverter system can be calculated:

[0020] ;

[0021] where v* k = [v* d,kv* q,k] T is the reference value for the base inverter voltage control, i* g,k = [i*gd,ki* gq,k] T is the grid current reference value, u g,k = [u gd,k u gq,k ] T is the grid voltage at time k, , , C1 and C2 are coefficient matrices.

[0022] Furthermore, in order to resist the interference of harmonic disturbance on the three-phase grid-connected inverter system, a discrete quasi-resonant controller is used to suppress the harmonics of a specific order of the three-phase grid-connected inverter system. The discrete quasi-resonant controller is as follows:

[0023] ;

[0024] in, , , , ;K r represents the proportional coefficient; ω c represents the cutoff frequency; T s Indicates the sampling period of the three-phase grid-connected inverter system; l takes the values ​​of 1, 2, 3, etc. By adjusting the value of l, harmonics of different orders can be suppressed.

[0025] Furthermore, based on the benchmark inverter voltage control reference value v*k of the three-phase grid-connected inverter system and the discrete quasi-resonant controller, the inverter voltage control reference value v*h,k of the three-phase grid-connected inverter system with integrated harmonic suppression is calculated:

[0026] ;

[0027] After finishing, we can get:

[0028] ;

[0029] where v* k = [v* d,kv* q,k] T , v* k-2 = [v* d,k-2 v* q,k-2] T denotes the reference inverter voltage control reference values ​​at time k and time k-2, respectively, v* h,k = [v* hd,kv* hq,k] T , v* h,k-1 =[v* hd,k-1 v* hq,k-1] T , v* h,k-2 = [v* hd,k-2 v* hq,k-2] T are the inverter voltage control reference values ​​for integrated harmonic suppression at time k, k-1 and k-2 respectively.

[0030] Furthermore, by performing Park inverse transformation on the dq axis representing the inverter voltage control reference value with integrated harmonic suppression, the inverter voltage control reference value with integrated harmonic suppression in the stationary αβ coordinate system is obtained:

[0031] ;

[0032] Where θ is the grid voltage phase, v* hαβ,k = [v* hα,kv* hβ,k] T It represents the inverter voltage control reference value with integrated harmonic suppression in the stationary αβ coordinate system.

[0033] Furthermore, the volt-second balance principle is used to determine the optimal voltage vectors v0, v1, v2 and action times t0, t1, t2 of the inverter voltage control reference value that can synthesize integrated harmonic suppression, and generate corresponding control pulse signals. The control pulse signals are applied to the switching tubes of the three-phase grid-connected inverter to achieve harmonic suppression predictive control of the three-phase grid-connected inverter system. The process is as follows:

[0034] According to the predictive control reference value v* hαβ,k of the three-phase grid-connected inverter with integrated resonance suppression, three intermediate variables A, B, and C are set to be expressed as:

[0035] ;

[0036] When A>0, B>0, C<0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,1 and v2=v αβ,2 ; When A>0, B<0, C<0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,2 and v2=v αβ,3 ; When A>0, B<0, C>0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,3 and v2=v αβ,4 ; When A<0, B<0, C>0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,4 and v2=v αβ,5 ; When A<0, B>0, C>0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,5 and v2=v αβ,6 ; When A<0, B>0, C<0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,6 and v2=v αβ,1 ;

[0037] Assume that the action time of the optimal voltage vectors v0, v1, and v2 are t0, t1, and t2 respectively; in a sampling period T s Based on the volt-second balance principle, we can get:

[0038] ;

[0039] From the above formula, the action time of each vector can be solved as:

[0040] ;

[0041] Among them, V dcis the DC bus voltage; v* hα,k and v* hβ,k are the inverter voltage control reference values ​​for integrated harmonic suppression in the αβ coordinate system;

[0042] The switch states corresponding to the optimal voltage vectors v0, v1, and v2 are respectively acted on according to the 7-segment symmetrical model at the action times t0, t1, and t2 to generate the control pulse signals as follows:

[0043] ;

[0044] Finally, predictive control can be achieved by directly applying the control pulse signal to the switch tube of the three-phase grid-connected inverter system.

[0045] A computer device includes a processor and a memory, wherein the processor is electrically connected to the memory, the memory is used to store instructions and data, and the processor is used to execute the harmonic suppression predictive control method and module for a three-phase grid-connected inverter system.

[0046] A three-phase grid-connected inverter system harmonic suppression prediction control module, including a sequentially connected prediction model construction module, a reference inverter voltage control reference value calculation module, a harmonic suppression module and a pulse generation module

[0047] The prediction model building module samples the grid current and grid voltage of the three-phase grid-connected inverter system, establishes a continuous domain state space model of the three-phase grid-connected inverter system in the dq coordinate system, and performs precise discretization to obtain the grid current prediction model of the three-phase grid-connected inverter system at time k+1;

[0048] The reference inverter voltage control reference value calculation module calculates the reference inverter voltage control reference value based on the idea of ​​making the grid current prediction model reach the grid current reference value at the k+1 sampling time;

[0049] The harmonic suppression module combines the reference inverter voltage control value with the discrete quasi-resonant controller to calculate the inverter voltage control reference value with integrated harmonic suppression in the dq coordinate system, and performs an inverse Park transform to obtain the inverter voltage control reference value with integrated harmonic suppression in the stationary αβ coordinate system.

[0050] The pulse generation module uses the volt-second balance principle to determine the optimal voltage vectors v0, v1, v2 and action times t0, t1, t2 that can synthesize the inverter voltage control reference value with integrated harmonic suppression, and generates the corresponding three-phase grid-connected inverter system control pulse signal.

[0051] Compared with existing technologies, the present invention offers the following advantages: It provides a predictive control strategy for three-phase grid-connected inverter systems to reduce grid background harmonics and improve grid quality. Compared with existing solutions, the method provided by the present invention requires no changes to external hardware circuits, resulting in low operation and use costs and greater ease of engineering deployment. The present invention employs a quasi-resonant controller embedded in a predictive control strategy to suppress grid background harmonics, resulting in enhanced anti-disturbance capabilities compared to existing technologies and applicable to a variety of operating scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 1 is a flowchart of a harmonic suppression prediction control method for a three-phase grid-connected inverter system according to an embodiment of the present invention;

[0053] Figure 2 Schematic diagram of the grid-connected current steady-state waveform and harmonic spectrum when no harmonic suppression item is added to the three-phase grid-connected inverter system according to an embodiment of the present invention;

[0054] Figure 3 Schematic diagram of the grid-connected current steady-state waveform and harmonic spectrum when a harmonic suppression item is added to the phase-connected grid-connected inverter system in an embodiment of the present invention. DETAILED DESCRIPTION

[0055] The embodiments of the present invention are further described below with reference to the accompanying drawings:

[0056] like Figure 1 As shown, the three-phase grid-connected inverter system applicable to the present invention includes: a DC bus voltage source is converted into an AC voltage square wave signal through a three-phase voltage source inverter, and then connected to the grid through an output L filter. The three-phase grid current and three-phase grid voltage are sampled in sequence.

[0057] In the figure, V dc Represents the DC bus voltage; L and R represent the filter inductance and parasitic resistance respectively. g,abc Indicates the grid current; u g,abc Indicates the grid voltage; i g * is the grid reference current; i g,k and v g,k They represent the grid current, grid voltage, filter capacitor voltage, and filter inductor current in the α-β stationary coordinate system at time k respectively; the sampled grid voltage is sent to the phase-locked loop to obtain the grid voltage phase θ; v* hαβ,k represents the inverter voltage control reference value of the three-phase grid-connected inverter system with integrated harmonic suppression in the stationary αβ coordinate system at time k; S represents the switching state of the inverter upper arm switch tube.

[0058] The present invention discloses a three-phase grid-connected inverter system harmonic suppression predictive control method, the steps of which are as follows:

[0059] Step 1: Construct the state space model of the three-phase grid-connected inverter system in the continuous domain in the dq coordinate system:

[0060] ;

[0061] Where: is the state variable, is the control input, and the coefficient matrices A and B are: , Among them, i gd 、i gq 、v d 、v q 、u gd 、u gq are the grid current, inverter voltage and grid voltage in the dq coordinate system, L and R filter inductors and filter inductor parasitic resistance, ω g is the fundamental angular frequency of the grid voltage.

[0062] Step 2: Assume that the sampling period of the three-phase grid-connected inverter system is T s At time k, the precise discretization method is used to discretize the state space model in the continuous domain, and the prediction model of the three-phase grid-connected inverter system is obtained as follows:

[0063] ;

[0064] Where i g,k = [i gd,k i gq,k ] T represents the grid current collected at time k, i g,k+1 = [i gd,k+1 i gq,k+1 ] T is the prediction model of the grid current at time k+1, u k = [v d,k v q,k u gd,k u gq,k ] T represents the inverter voltage and grid voltage collected at time k, A d 、B d The discretization model coefficient matrix of the system calculated using the exact discretization method is: , where e is the base of the natural logarithm and I2 is the second-order identity matrix.

[0065] Step 3: According to the system grid current reference value and its prediction model, let i g,k+1 = i* g,k, the benchmark inverter voltage control reference value v* k of the three-phase grid-connected inverter system can be calculated:

[0066] ;

[0067] where v* k = [v* d,kv* q,k] T is the reference value for the base inverter voltage control, i* g,k = [i*gd,ki* gq,k] T is the grid current reference value, u g,k = [u gd,k u gq,k ] T is the grid voltage at time k. , , C1 and C2 are coefficient matrices.

[0068] Step 4: To prevent harmonic disturbances from affecting the three-phase grid-connected inverter system, a model similar to the input signal needs to be added to the control loop of the three-phase grid-connected inverter system. The input quantity of the three-phase grid-connected inverter system is a sinusoidal current, so a discrete quasi-resonant controller is used to suppress the harmonics of a specific order in the three-phase grid-connected inverter system. The discrete quasi-resonant controller is:

[0069] ;

[0070] in, , , , . K r is the proportionality coefficient, ω c is the cutoff frequency, and l can be 1, 2, 3, etc. By adjusting the value of l, harmonics of different orders can be suppressed.

[0071] Based on the benchmark inverter voltage control reference value v*k of the three-phase grid-connected inverter system and the discrete quasi-resonant controller, the inverter voltage control reference value v*h,k of the three-phase grid-connected inverter system with integrated harmonic suppression is calculated:

[0072] ;

[0073] After finishing, we can get:

[0074] ;

[0075] where v* k = [v* d,kv* q,k] T , v* k-2 = [v* d,k-2 v* q,k-2] T denotes the reference inverter voltage control reference values ​​at time k and time k-2, respectively, v* h,k = [v* hd,kv* hq,k] T, v* h,k-1 =[v* hd,k-1 v* hq,k-1] T , v* h,k-2 = [v* hd,k-2 v* hq,k-2] T are the inverter voltage control reference values ​​for integrated harmonic suppression at time k, k-1 and k-2 respectively.

[0076] By performing Park inverse transformation on the inverter voltage control reference value with integrated harmonic suppression represented by the dq axis, the inverter voltage control reference value with integrated harmonic suppression in the stationary αβ coordinate system is obtained:

[0077] ;

[0078] Where θ is the grid voltage phase, v* hαβ,k = [v* hα,kv* hβ,k] T It represents the inverter voltage control reference value with integrated harmonic suppression in the stationary αβ coordinate system.

[0079] Step 5: According to the predictive control reference value v* hαβ,k of the three-phase grid-connected inverter with integrated resonance suppression, set the three intermediate variables A, B, and C to be expressed as:

[0080] ;

[0081] When A>0, B>0, C<0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,1 and v2=v αβ,2 ; When A>0, B<0, C<0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,2 and v2=v αβ,3 ; When A>0, B<0, C>0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,3 and v2=v αβ,4 ; When A<0, B<0, C>0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,4 and v2=v αβ,5 ; When A<0, B>0, C>0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,5 and v2=v αβ,6 ; When A<0, B>0, C<0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,6 and v2=v αβ,1 .

[0082] Assume that the optimal voltage vectors v0, v1, and v2 that can synthesize the inverter voltage control reference value v* hαβ,k with integrated harmonic suppression have action times of t0, t1, and t2 respectively. s Based on the volt-second balance principle, we can get:

[0083] ;

[0084] From the above formula, the action time of each vector can be solved as:

[0085] ;

[0086] Among them, V dc is the DC bus voltage. v* hα,k and v* hβ,k are the inverter voltage control reference values ​​for integrated harmonic suppression in the αβ coordinate system.

[0087] The switching states corresponding to the optimal voltage vectors v0, v1, and v2 of the inverter voltage control reference value that can synthesize integrated harmonic suppression are symmetrically acted in 7 stages according to the action times t0, t1, and t2, and the control pulse signals are generated as follows:

[0088] ;

[0089] Finally, the control pulse signal is directly applied to the switch tube of the three-phase grid-connected inverter.

[0090] In order to test the harmonic suppression prediction control method and module of the three-phase grid-connected inverter system provided by the present invention, the method provided by the present invention is applied to the three-phase grid-connected inverter system. The specific parameters are given in Table 1:

[0091] Table 1

[0092] ;

[0093] Figure 2 Schematic diagram of the steady-state waveform of the grid current and the harmonic spectrum when the harmonic suppression predictive control method of the three-phase grid-connected inverter system of the present invention does not add the harmonic suppression term. Figure 3 The diagram of the steady-state waveform of the grid current and the harmonic spectrum when the harmonic suppression term is added to the harmonic suppression prediction control method of the three-phase grid-connected inverter system of the present invention. Figure 2 and Figure 3 By comparison, the method provided by the present invention can effectively reduce grid current harmonics in steady-state conditions, ensuring the power generation quality of the three-phase grid-connected inverter system. Comparison with the harmonic spectrum diagram shows that the method provided by the present invention can achieve lower grid current harmonic distortion.

Claims

1. A three-phase grid-connected inverter system harmonic suppression predictive control method, characterized in that: Here are the steps: The grid current and grid voltage, the state variables of the three-phase grid-connected inverter system, are sampled, and the grid voltage phase is obtained through a phase-locked loop. The state variables in the abc coordinate system are transformed by Park to obtain the state variables in the dq coordinate system. The grid current and grid voltage are used to establish a continuous domain state space model of the three-phase grid-connected inverter system in the dq coordinate system. At time k, the continuous domain state space model of the three-phase grid-connected inverter system in the dq coordinate system is accurately discretized, and the grid current prediction model i at time k+1 is obtained by recursion. g,k+1 ; Let the grid current prediction model i g,k+1 At the next k+1 sampling time, the grid current reference value can be reached, and the reference inverter voltage control reference value v* k is calculated; Combining the reference inverter voltage control value v*k with the discrete quasi-resonant controller, the inverter voltage control reference value v*h,k with integrated harmonic suppression h in the dq coordinate system is calculated, and then the inverse Park transform is performed to obtain the inverter voltage control reference value v*hαβ,k with integrated harmonic suppression in the stationary αβ coordinate system. The volt-second balance principle is used to determine the optimal voltage vectors v0, v1, v2 and action times t0, t1, t2 that can synthesize the inverter voltage control reference value for integrated harmonic suppression. The corresponding control pulse signal is generated and applied to the switching tubes of the three-phase grid-connected inverter to achieve harmonic suppression predictive control of the three-phase grid-connected inverter system. In order to resist the interference of harmonic disturbance on the three-phase grid-connected inverter system, a discrete quasi-resonant controller is used to suppress the harmonics of specific orders of the three-phase grid-connected inverter system. The discrete quasi-resonant controller is as follows: ； in, , , , ;K r represents the proportional coefficient; ω c represents the cutoff frequency; T s Indicates the sampling period of the three-phase grid-connected inverter system; l takes the values ​​of 1, 2, 3, etc. By adjusting the value of l, harmonics of different orders can be suppressed.

2. The harmonic suppression predictive control method for a three-phase grid-connected inverter system according to claim 1, characterized in that: The continuous domain state space model of the three-phase grid-connected inverter system in the dq coordinate system is as follows: ; in: is the state variable, is the control input, and the coefficient matrices A and B are: , , where i gd 、i gq 、v d 、v q 、u gd 、u gq are the grid current, inverter voltage and grid voltage of the three-phase grid-connected inverter system in the dq coordinate system, L and R represent the filter inductance and filter inductance parasitic resistance respectively, ω g is the fundamental angular frequency of the grid voltage.

3. The harmonic suppression predictive control method for a three-phase grid-connected inverter system according to claim 2, characterized in that: Get the grid current prediction model i at time k+1 g,k+1 The specific process is as follows: Assume that the sampling period of the three-phase grid-connected inverter system is T s At time k, the precise discretization method is used to discretize the state space model in the continuous domain, and the prediction model of the three-phase grid-connected inverter system is obtained as follows: ； Where i g,k = [i gd,k i gq,k ] T , represents the grid current collected at time k, i g,k+1 = [i gd,k+1 i gq,k+1 ] T , represents the prediction model of the grid current at time k+1, u k = [v d,k v q,k u gd,k u gq,k ] T , represents the inverter voltage and grid voltage collected at time k, A d 、B d They represent the system discretization model coefficient matrices calculated using the exact discretization method: , where e is the base of the natural logarithm and I2 is the second-order identity matrix.

4. The harmonic suppression predictive control method for a three-phase grid-connected inverter system according to claim 3, characterized in that: Based on the grid current prediction model i g,k+1 At the k+1 sampling time, the grid current reference value is reached and the reference inverter voltage control reference value is calculated. The process is as follows: According to the system grid current reference value and its prediction model, let i g,k+1 = i* g,k, the reference value v* k of the three-phase grid-connected inverter system can be calculated: ； where v* k = [v* d,kv* q,k] T is the reference value for the base inverter voltage control, i* g,k = [i* gd,ki*gq,k] T is the grid current reference value, u g,k = [u gd,k u gq,k ] T is the grid voltage at time k, , , C1 and C2 are coefficient matrices.

5. The harmonic suppression predictive control method for a three-phase grid-connected inverter system according to claim 4, characterized in that: Based on the benchmark inverter voltage control reference value v*k of the three-phase grid-connected inverter system and the discrete quasi-resonant controller, the inverter voltage control reference value v*h,k of the three-phase grid-connected inverter system with integrated harmonic suppression is calculated: ； After finishing, we can get: ； where v* k = [v* d,kv* q,k] T , v* k-2 = [v* d,k-2 v* q,k-2] T denotes the reference inverter voltage control reference values ​​at time k and time k-2, respectively, v* h,k = [v* hd,kv* hq,k] T , v* h,k-1 = [v*hd,k-1 v* hq,k-1] T , v* h,k-2 = [v* hd,k-2 v* hq,k-2] T are the inverter voltage control reference values ​​for integrated harmonic suppression at time k, k-1 and k-2 respectively.

6. The harmonic suppression predictive control method for a three-phase grid-connected inverter system according to claim 5, characterized in that: By performing Park inverse transformation on the inverter voltage control reference value with integrated harmonic suppression represented by the dq axis, the inverter voltage control reference value with integrated harmonic suppression in the stationary αβ coordinate system is obtained: ； Where θ is the grid voltage phase, v* hαβ,k = [v* hα,kv* hβ,k] T It represents the inverter voltage control reference value with integrated harmonic suppression in the stationary αβ coordinate system.

7. A three-phase grid-connected inverter system harmonic suppression predictive control method according to claim 6, characterized in that: The volt-second balance principle is used to determine the optimal voltage vectors v0, v1, v2 and action times t0, t1, t2 of the inverter voltage control reference value that can synthesize integrated harmonic suppression, and generate corresponding control pulse signals. The control pulse signals are applied to the switching tubes of the three-phase grid-connected inverter to achieve harmonic suppression predictive control of the three-phase grid-connected inverter system. The process is as follows: According to the predictive control reference value v* hαβ,k of the three-phase grid-connected inverter with integrated resonance suppression, three intermediate variables A, B, and C are set to be expressed as: ； When A>0, B>0, C<0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,1 and v2=v αβ,2 ; When A>0, B<0, C<0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,2 and v2=v αβ,3 ; When A>0, B<0, C>0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,3 and v2=v αβ,4 ; When A<0, B<0, C>0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,4 and v2=v αβ,5 ; When A<0, B>0, C>0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,5 and v2=v αβ,6 ; When A<0, B>0, C<0, the corresponding optimal voltage vector is v0=v αβ,0 、v1=v αβ,6 and v2=v αβ,1 ; Assume that the action time of the optimal voltage vectors v0, v1, and v2 are t0, t1, and t2 respectively; in a sampling period T s Based on the volt-second balance principle, we can get: ； From the above formula, the action time of each vector can be solved as: ； Among them, V dc is the DC bus voltage; v* hα,k and v* hβ,k are the inverter voltage control reference values ​​for integrated harmonic suppression in the αβ coordinate system; The switch states corresponding to the optimal voltage vectors v0, v1, and v2 are respectively acted on according to the 7-segment symmetrical model at the action times t0, t1, and t2 to generate the control pulse signals as follows: ； Finally, predictive control can be achieved by directly applying the control pulse signal to the switch tube of the three-phase grid-connected inverter system.

8. A computer device, characterized in that: It includes a processor and a memory, the processor is electrically connected to the memory, the memory is used to store instructions and data, and the processor is used to execute the harmonic suppression prediction control method for a three-phase grid-connected inverter system according to any one of claims 1-7.

9. A three-phase grid-connected inverter system harmonic suppression prediction control module, characterized in that: Includes sequentially connected prediction model building module, reference inverter voltage control reference value calculation module, harmonic suppression module and pulse generation module The prediction model building module samples the grid current and grid voltage of the three-phase grid-connected inverter system, establishes a continuous domain state space model of the three-phase grid-connected inverter system in the dq coordinate system, and performs precise discretization to obtain the grid current prediction model of the three-phase grid-connected inverter system at time k+1; The reference inverter voltage control reference value calculation module calculates the reference inverter voltage control reference value based on the idea of ​​making the grid current prediction model reach the grid current reference value at the k+1 sampling time; The harmonic suppression module combines the reference inverter voltage control value with the discrete quasi-resonant controller to calculate the inverter voltage control reference value with integrated harmonic suppression in the dq coordinate system, and performs an inverse Park transform to obtain the inverter voltage control reference value with integrated harmonic suppression in the stationary αβ coordinate system. The pulse generation module uses the volt-second balance principle to determine the optimal voltage vectors v0, v1, v2 and action times t0, t1, t2 that can synthesize the inverter voltage control reference value with integrated harmonic suppression, and generates the corresponding three-phase grid-connected inverter system control pulse signal; In order to resist the interference of harmonic disturbance on the three-phase grid-connected inverter system, a discrete quasi-resonant controller is used to suppress the harmonics of specific orders of the three-phase grid-connected inverter system. The discrete quasi-resonant controller is as follows: ； in, , , , ;K r represents the proportional coefficient; ω c represents the cutoff frequency; T s Indicates the sampling period of the three-phase grid-connected inverter system; l takes the values ​​of 1, 2, 3, etc. By adjusting the value of l, harmonics of different orders can be suppressed.

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