Three-phase inverter based on voltage amplitude phase joint control delay compensation method

Abstract

The application relates to a time delay compensation method of a three-phase converter based on joint control of voltage amplitude and phase, which comprises the following steps: calculating the phase and amplitude of a predicted voltage; calculating the phase and amplitude of a current instruction voltage; calculating a phase difference and a linear amplitude ratio; calculating a phase difference change rate of a kth period; calculating a new advance compensation phase angle; obtaining a final compensation phase angle; and performing phase compensation on a voltage instruction output by a current regulator. The application predicts the change trend of time delay by predicting the phase difference and the change rate of the phase difference between a bridge arm output voltage and an instruction voltage, significantly increases the compensation phase response speed in a dynamic process, and suppresses current overshoot; by calculating the linear amplitude ratio and adopting nonlinear processing of the linear amplitude ratio to dynamically adjust a differential gain, the overcompensation risk caused by model errors, working condition changes and other factors can be effectively reduced, so that the system remains stable.

Description

Technical Field

[0001] This invention relates to the field of digital control technology, and in particular to a delay compensation method for a three-phase converter based on the joint control of voltage amplitude and phase. Background Technology

[0002] Three-phase converters under digital control, such as rectifiers, commonly suffer from sampling calculation delays and pulse width modulation (PWM) delays. The sampling calculation delay is approximately one sampling cycle, and the PWM delay is approximately 0.5 sampling cycles. In a rotating coordinate system, these delays can lead to coupling between active and reactive currents, impacting control performance. Existing technologies have several shortcomings:

[0003] First, traditional fixed-angle compensation methods have poor accuracy in dynamic processes: traditional methods directly use a fixed compensation phase angle. Compensation can be performed, but this method only applies to steady state. When the converter is in startup, or when the current reference changes abruptly, the pulse width modulation delay no longer maintains 0.5 sampling periods, causing the equivalent delay to change, and the decoupling effect of the traditional method will deteriorate.

[0004] Second, the existing predictive phase method cannot predict the future trend of system delay when the system delay changes rapidly. Therefore, it can only passively lag or follow, and the compensation effect under such conditions is not good. It cannot adapt to changes in operating conditions and model errors, and its robustness is poor. Summary of the Invention

[0005] To address the issues of poor accuracy and the inability to calculate the ideal delay function in the s-domain during dynamic processes using traditional compensation methods, this invention aims to provide a delay compensation method for three-phase converters based on joint voltage amplitude and phase control that significantly increases the compensation phase response speed during dynamic processes, achieves high accuracy, and exhibits strong robustness.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a delay compensation method for a three-phase converter based on joint control of voltage amplitude and phase, the method comprising the following sequential steps:

[0007] (1) Based on the α-axis component of the inverter bridge arm output voltage in the LCL filter Grid voltage Reference current under the αβ axis And the s-domain voltage equation, using a discretization method, is transformed into a difference recursive formula to obtain the predicted voltage u in the k-th period. α_k and u β_k And calculate the predicted voltage u α_k and u β_k phase θ k And amplitude | |;

[0008] (2) Calculate the phase θ of the current command voltage. k1 And amplitude | |;(3)Based on the predicted voltage u α_k and u β_k phase θ k And amplitude | | and the phase θ of the current command voltage k1 And amplitude | | Calculate the phase difference ∆ (k) and linear magnitude ratio (4) Based on the predicted voltage u α_k and u β_k and phase difference ∆ (k), calculate the phase difference change rate in the kth period. (k) and advance compensation phase angle (t); (5) For linear amplitude ratio Perform nonlinear processing and adjust the differential gain. According to the phase difference change rate of the kth period (k) Calculate the new advance compensation phase angle (k);

[0009] (6) For the new advance compensation phase angle (k) Perform clipping processing to obtain the clipped advance compensation phase angle. ;

[0010] (7) Then With sampling delay • The final compensated phase angle is obtained by superposition. (k);

[0011] (8) By finally compensating the phase angle (k) Perform phase compensation on the voltage command output by the current regulator.

[0012] In step (1), the α-axis component of the inverter bridge arm output voltage in the LCL filter Grid voltage Reference current under the αβ axis The frequency domain relationships of the s-domain voltage equation are as follows:

[0013] (1);

[0014] In the formula, s is the Laplace operator; For the inverter bridge arm output voltage Phase voltage; for ; For grid-side inductance; Inductance on the inverter side; For filtering capacitors;

[0015] Equation (1) is discretized to obtain:

[0016] ;

[0017] In the formula, The α-axis component of the reference current under the αβ axis in the k-th cycle; The α-axis component of the current reference under the αβ axis in the (k-1)th cycle; The α-axis component of the reference current under the αβ axis in the (k-2)th cycle; The α-axis component of the reference current under the αβ axis in the (k-3)th cycle; For the k-th period ; For the (k-1)th period ; For the (k-2)th period ;

[0018] Calculate the reference current along the αβ axis:

[0019] ;

[0020] In the formula, , θ is the reference current along the dq axis; θ1 is the phase angle of the grid voltage;

[0021] Both the αβ and abc coordinate systems are stationary coordinate systems, therefore the a-axis coincides with the α-axis. = , = The parameters of phase a filter are obtained as follows:

[0022] ;

[0023] For a digital controller, let the instantaneous value in each calculation cycle be the variable plus the index k. The term is discretized under digital control as follows:

[0024] ;

[0025] in, For the calculation period;

[0026] The term is discretized under digital control as follows:

[0027] ;

[0028] The term is discretized under digital control as follows:

[0029] ;

[0030] Therefore, the overall discretization formula is expressed as:

[0031] In the αβ coordinate system, since the β axis lags behind the α axis by 90 degrees, a phase-shifting filter is used to... A 90-degree phase shift yields the result. The phase shift formula is:

[0032] ;

[0033] in, The angular frequency of the power grid; The system damping coefficient of the phase-shifting filter is 0.707.

[0034] Multiply ,have to:

[0035] ;

[0036] Calculate the predicted voltage u α_k and u β_k phase angle θ k :

[0037] ;

[0038] Calculate the predicted voltage u α_k and u β_k Amplitude:

[0039] | |= .

[0040] Step (2) specifically refers to: calculating the phase and amplitude of the current command voltage, in order to obtain the phase θ of the current command voltage. k1 First, the command voltage before compensation needs to be generated in the dq coordinate system. and Transform to the αβ coordinate system, and let the transformed voltage be... and The conversion formula is:

[0041] ;

[0042] In the formula, θ1 is the phase angle of the grid voltage;

[0043] θk1 Depend on and Find:

[0044] ;

[0045] Current command voltage amplitude | |for:

[0046] | |= .

[0047] Step (3) specifically refers to:

[0048] Calculate the phase difference ∆ (k):

[0049] ∆ (k)= - ;

[0050] Calculate the linear amplitude ratio :

[0051] = .

[0052] Step (4) specifically refers to: based on the phase difference ∆ (k) Calculate σ(k):

[0053] σ(k) = ∆ (k);

[0054] In the formula, σ(k) is the phase difference of the kth period;

[0055] Calculate the phase difference change rate of the kth period based on σ(k). (k):

[0056] (k) = ;

[0057] In the formula, This represents the phase difference during the (k-1)th period; The sampling period;

[0058] The system's delay changes continuously, and in the time domain:

[0059] ∆ (t) = .τ(t);

[0060] In the formula, ∆ (t) represents the phase difference between the predicted bridge arm output voltage and the current voltage at time t. Let ω be the grid angular frequency; τ(t) be the equivalent delay at time t.

[0061] Phase difference ∆ after one period (t+ The formula for calculating ) is:

[0062] ∆ (t+ )=∆ (t)+ • +O( (2);

[0063] In the formula, O(t) represents the rate of change of phase difference at time t. ) represents second-order or higher-order infinitesimal terms;

[0064] Based on equation (2), the predicted phase difference value for the next cycle is obtained, and the advance compensation phase angle is calculated. (t):

[0065] (t)=∆ (t)+ (3);

[0066] Equation (3) is discretized and an adjustable proportional gain is introduced. and differential gain The following formula is obtained:

[0067] (k) = ∙σ(k)+ • (k);

[0068] In the formula, (k) is the advance compensation phase angle for the kth cycle; The value range is from 0.9 to 1.2; The value range is 0.6 Up to 0.8 .

[0069] In step (5), the linear amplitude ratio is first... Nonlinear processing is performed to determine the deviation of the linear amplitude ratio. for:

[0070] g=| |;

[0071] Deviation from linear magnitude ratio Perform nonlinear processing to obtain the deviation after nonlinear transformation. :

[0072] = ;

[0073] in:

[0074] = ;

[0075] In the formula, It is a power exponent; The power exponent is the one whose linear magnitude deviates relatively little. The power exponent is the one whose linear magnitude deviates significantly from the linear ratio. The set deviation threshold; The deviation after nonlinear transformation;

[0076] Deviation after nonlinear transformation Adjusting the differential gain The adjusted differential gain is obtained. :

[0077] = ;

[0078] In the formula, This is the proportionality coefficient. The range of values ​​is ;

[0079] Calculate the new advance compensation phase angle (k):

[0080] (k)= ∙σ(k)+ • (k);

[0081] In the formula, σ(k) is the phase difference of the kth period; (k) represents the rate of change of phase difference in the kth period.

[0082] In step (6), the advance compensation phase angle after clipping is... The formula is:

[0083] =max ;

[0084] In the formula, For the maximum allowable compensation phase, = ∙2.5 , The angular frequency of the power grid. The sampling period.

[0085] In step (7), the final compensated phase angle The formula for calculating (k) is as follows:

[0086] = • + ;

[0087] In the formula, The angular frequency of the power grid. The sampling period.

[0088] Step (8) specifically refers to: adjusting the final compensated phase angle (k) Substitute this into the phase compensation stage of the converter to perform phase compensation on the command voltage output by the current regulator, and obtain the compensated command voltage. , :

[0089] ;

[0090] In the formula, , The command voltage before compensation.

[0091] As can be seen from the above technical solution, the beneficial effects of the present invention are as follows: First, fast dynamic response and small overshoot: The present invention predicts the trend of delay by predicting the phase difference and rate of change between the bridge arm output voltage and the command voltage, which significantly increases the compensation phase response speed in the dynamic process and suppresses current overshoot; Second, high accuracy and strong robustness: By calculating the linear amplitude ratio and using nonlinear processing of the linear amplitude ratio to dynamically adjust the differential gain, the risk of overcompensation caused by model error, operating condition changes and other factors can be effectively reduced, so that the system remains stable; Third, clear physical logic: The present invention combines the phase lag and amplitude change of the voltage vector in digital control delay for joint analysis, reflecting the trend of system delay change from the rate of change of phase difference, while the amplitude ratio reflects the degree of model matching, and the principle is clear. Attached Figure Description

[0092] Figure 1 This is a flowchart of the method of the present invention;

[0093] Figure 2 This is a converter control block diagram. Detailed Implementation

[0094] like Figure 1 , Figure 2 As shown, a delay compensation method for a three-phase converter based on joint voltage amplitude and phase control is disclosed. The method includes the following sequential steps:

[0095] (1) Based on the α-axis component of the inverter bridge arm output voltage in the LCL filter Grid voltage Reference current under the αβ axis And the s-domain voltage equation, using a discretization method, is transformed into a difference recursive formula to obtain the predicted voltage u in the k-th period. α_k and u β_k And calculate the predicted voltage u α_k and u β_k phase θ k And amplitude | |;

[0096] (2) Calculate the phase θ of the current command voltage. k1 And amplitude | |;(3)Based on the predicted voltage u α_k and u β_k phase θ k And amplitude | | and the phase θ of the current command voltage k1 And amplitude | | Calculate the phase difference ∆ (k) and linear magnitude ratio (4) Based on the predicted voltage u α_k and u β_k and phase difference ∆ (k), calculate the phase difference change rate in the kth period. (k) and advance compensation phase angle (t); (5) For linear amplitude ratio Perform nonlinear processing and adjust the differential gain. According to the phase difference change rate of the kth period (k) Calculate the new advance compensation phase angle (k);

[0097] (6) For the new advance compensation phase angle (k) Perform clipping processing to obtain the clipped advance compensation phase angle. ;

[0098] (7) Then With sampling delay • The final compensated phase angle is obtained by superposition. (k);

[0099] (8) By finally compensating the phase angle (k) Perform phase compensation on the voltage command output by the current regulator.

[0100] In step (1), the α-axis component of the inverter bridge arm output voltage in the LCL filter Grid voltage Reference current under the αβ axis The frequency domain relationships of the s-domain voltage equation are as follows:

[0101] (1);

[0102] In the formula, s is the Laplace operator; For the inverter bridge arm output voltage Phase voltage; for ; For grid-side inductance; Inductance on the inverter side; For filtering capacitors;

[0103] Equation (1) is discretized to obtain:

[0104] ;

[0105] In the formula, The α-axis component of the reference current under the αβ axis in the k-th cycle; The α-axis component of the current reference under the αβ axis in the (k-1)th cycle; The α-axis component of the reference current under the αβ axis in the (k-2)th cycle; The α-axis component of the reference current under the αβ axis in the (k-3)th cycle; For the k-th period ; For the (k-1)th period ; For the (k-2)th period ;

[0106] Calculate the reference current along the αβ axis:

[0107] ;

[0108] In the formula, , θ is the reference current along the dq axis; θ1 is the phase angle of the grid voltage;

[0109] Both the αβ and abc coordinate systems are stationary coordinate systems, therefore the a-axis coincides with the α-axis. = , = The parameters of phase a filter are obtained as follows:

[0110] ;

[0111] For a digital controller, let the instantaneous value in each calculation cycle be the variable plus the index k. The term is discretized under digital control as follows:

[0112] ;

[0113] in, For the calculation period;

[0114] The term is discretized under digital control as follows:

[0115] ;

[0116] The term is discretized under digital control as follows:

[0117] ;

[0118] Therefore, the overall discretization formula is expressed as:

[0119] In the αβ coordinate system, since the β axis lags behind the α axis by 90 degrees, a phase-shifting filter is used to... A 90-degree phase shift yields the result. The phase shift formula is:

[0120] ;

[0121] in, The angular frequency of the power grid; The system damping coefficient of the phase-shifting filter is 0.707.

[0122] Multiply ,have to:

[0123] ;

[0124] Calculate the predicted voltage u α_k and u β_k phase angle θ k :

[0125] ;

[0126] Calculate the predicted voltage u α_k and u β_k Amplitude:

[0127] | |= .

[0128] Step (2) specifically refers to: calculating the phase and amplitude of the current command voltage, in order to obtain the phase θ of the current command voltage. k1 First, the command voltage before compensation needs to be generated in the dq coordinate system. and Transform to the αβ coordinate system, and let the transformed voltage be... and The conversion formula is:

[0129] ;

[0130] In the formula, θ1 is the phase angle of the grid voltage;

[0131] θ k1 Depend on and Find:

[0132] ;

[0133] Current command voltage amplitude | |for:

[0134] | |= .

[0135] Step (3) specifically refers to:

[0136] Calculate the phase difference ∆ (k):

[0137] ∆ (k)= - ;

[0138] Calculate the linear amplitude ratio :

[0139] = .

[0140] Step (4) specifically refers to: based on the phase difference ∆ (k) Calculate σ(k):

[0141] σ(k) = ∆ (k);

[0142] In the formula, σ(k) is the phase difference of the kth period;

[0143] Calculate the phase difference change rate of the kth period based on σ(k). (k):

[0144] (k) = ;

[0145] In the formula, This represents the phase difference during the (k-1)th period; The sampling period;

[0146] The system's delay changes continuously, and in the time domain:

[0147] ∆ (t) = .τ(t);

[0148] In the formula, ∆ (t) represents the phase difference between the predicted bridge arm output voltage and the current voltage at time t. Let ω be the grid angular frequency; τ(t) be the equivalent delay at time t.

[0149] Phase difference ∆ after one period (t+ The formula for calculating ) is:

[0150] ∆ (t+ )=∆ (t)+ • +O( (2);

[0151] In the formula, O(t) represents the rate of change of phase difference at time t. ) represents second-order or higher-order infinitesimal terms;

[0152] Based on equation (2), the predicted phase difference value for the next cycle is obtained, and the advance compensation phase angle is calculated. (t):

[0153] (t)=∆ (t)+ (3);

[0154] Equation (3) is discretized and an adjustable proportional gain is introduced. and differential gain The following formula is obtained:

[0155] (k) = ∙σ(k)+ • (k);

[0156] In the formula, (k) is the advance compensation phase angle for the kth cycle; The value range is from 0.9 to 1.2; The value range is 0.6 Up to 0.8 .

[0157] In step (5), the linear amplitude ratio is first... Nonlinear processing is performed to determine the deviation of the linear amplitude ratio. for:

[0158] g=| |;

[0159] Deviation from linear magnitude ratio Perform nonlinear processing to obtain the deviation after nonlinear transformation. :

[0160] = ;

[0161] in:

[0162] = ;

[0163] In the formula, It is a power exponent; The power exponent is the one whose linear magnitude deviates relatively little. The power exponent is the one whose linear magnitude deviates significantly from the linear ratio. The set deviation threshold; The deviation after nonlinear transformation;

[0164] Deviation after nonlinear transformation Adjusting the differential gain The adjusted differential gain is obtained. :

[0165] = ;

[0166] In the formula, This is the proportionality coefficient. The range of values ​​is ;

[0167] Calculate the new advance compensation phase angle (k):

[0168] (k)= ∙σ(k)+ • (k);

[0169] In the formula, σ(k) is the phase difference of the kth period; (k) represents the rate of change of phase difference in the kth period.

[0170] In step (6), the advance compensation phase angle after clipping is... The formula is:

[0171] =max ;

[0172] In the formula, For the maximum allowable compensation phase, = ∙2.5 , The angular frequency of the power grid. The sampling period.

[0173] In step (7), the final compensated phase angle The formula for calculating (k) is as follows:

[0174] = • + ;

[0175] In the formula, The angular frequency of the power grid. The sampling period.

[0176] Step (8) specifically refers to: adjusting the final compensated phase angle (k) Substitute this into the phase compensation stage of the converter to perform phase compensation on the command voltage output by the current regulator, and obtain the compensated command voltage. , :

[0177] ;

[0178] In the formula, , The command voltage before compensation.

[0179] The innovation of this invention lies in its non-reliance on the phase difference at the current moment. By introducing the phase difference change rate to calculate the advance compensation phase angle, it is more suitable for operating conditions with large system delay variations, improving the system's dynamic response speed and suppressing overshoot. When the amplitude ratio deviates significantly, the method rapidly reduces the differential gain to decrease the impact of non-delay components (such as model errors) on phase compensation, preventing overcompensation and making phase compensation smoother and more stable.

[0180] In summary, this invention features fast dynamic response and low overshoot. By introducing the concept of phase difference change rate to predict the delay of the next cycle, and calculating the pre-compensation phase angle using a proportional-integral form, the final compensation amount can sense changes in system delay, significantly improving the system's dynamic response speed and suppressing current overshoot. Furthermore, it utilizes the amplitude ratio to improve model reliability. When the amplitude ratio deviation is not severe, it maintains a fast response; when the amplitude ratio deviation is severe, it reduces the influence of the differential term to resist interference and prevent overcompensation.

[0181] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A delay compensation method for a three-phase converter based on joint control of voltage amplitude and phase, characterized in that: The method includes the following steps in sequence: (1) Based on the α-axis component of the inverter bridge arm output voltage in the LCL filter Grid voltage Reference current under the αβ axis And the s-domain voltage equation, using a discretization method, is transformed into a difference recursive formula to obtain the predicted voltage u in the k-th period. α_k and u β_k And calculate the predicted voltage u α_k and u β_k phase θ k And amplitude | |; (2) Calculate the phase θ of the current command voltage. k1 And amplitude | |;(3)Based on the predicted voltage u α_k and u β_k phase θ k And amplitude | | and the phase θ of the current command voltage k1 And amplitude | | Calculate the phase difference ∆ (k) and linear magnitude ratio linear amplitude ratio The calculation formula is: = (4) Based on the predicted voltage u α_k and u β_k and phase difference ∆ (k), calculate the phase difference change rate in the kth period. (k) and advance compensation phase angle (t); Based on the phase difference ∆ (k) Calculate σ(k): σ(k)=∆ (k); In the formula, σ(k) is the phase difference of the kth period; Calculate the phase difference change rate of the kth period based on σ(k). (k): （k）= ； In the formula, This represents the phase difference during the (k-1)th period; The sampling period; After discretization and the introduction of an adjustable proportional gain and differential gain The following formula is obtained: (k)= ∙σ(k)+ ∙ (k); In the formula, (k) is the advance compensation phase angle for the kth cycle; The value range is from 0.9 to 1.2; The value range is 0.6 Up to 0.8 (5) For linear amplitude ratio Perform nonlinear processing and adjust the differential gain. According to the phase difference change rate of the kth period (k) Calculate the new advance compensation phase angle (k); Deviation from linear magnitude ratio Perform nonlinear processing to obtain the deviation after nonlinear transformation. : = ； in: = ； In the formula, It is a power exponent; The power exponent is the one whose linear magnitude deviates relatively little. The power exponent is the one whose linear magnitude deviates significantly from the linear ratio. The set deviation threshold; Deviation after nonlinear transformation Adjusting the differential gain The adjusted differential gain is obtained. : = ； In the formula, This is the proportionality coefficient. The range of values ​​is ; Calculate the new advance compensation phase angle (k): (k)= ∙σ(k)+ ∙ (k); (6) For the new advance compensation phase angle (k) Perform clipping processing to obtain the clipped advance compensation phase angle. Advance compensation phase angle after amplitude limiting The formula is: =max ; In the formula, For the maximum allowable compensation phase, = ∙2.5 , The angular frequency of the power grid; (7) Then With sampling delay • The final compensated phase angle is obtained by superposition. (k); (8) By finally compensating the phase angle (k) Perform phase compensation on the voltage command output by the current regulator.

2. The delay compensation method for a three-phase converter based on joint control of voltage amplitude and phase according to claim 1, characterized in that: In step (1), the α-axis component of the inverter bridge arm output voltage in the LCL filter Grid voltage Reference current under the αβ axis The frequency domain relationships of the s-domain voltage equation are as follows: （1）； In the formula, s is the Laplace operator; For the inverter bridge arm output voltage Phase voltage; for ; For grid-side inductance; Inductance on the inverter side; For filtering capacitors; Equation (1) is discretized to obtain: ； In the formula, The α-axis component of the reference current under the αβ axis in the k-th cycle; The α-axis component of the current reference under the αβ axis in the (k-1)th cycle; The α-axis component of the reference current under the αβ axis in the (k-2)th cycle; The α-axis component of the reference current under the αβ axis in the (k-3)th cycle; For the k-th period ; For the (k-1)th period ; For the (k-2)th period ; Calculate the reference current along the αβ axis: ； In the formula, , θ is the reference current along the dq axis; θ1 is the phase angle of the grid voltage; Both the αβ and abc coordinate systems are stationary coordinate systems, therefore the a-axis coincides with the α-axis. = , = The parameters of phase a filter are obtained as follows: ； For a digital controller, let the instantaneous value in each calculation cycle be the variable plus the index k. The term is discretized under digital control as follows: ； in, For the calculation period; The term is discretized under digital control as follows: ； The term is discretized under digital control as follows: ； Therefore, the overall discretization formula is expressed as: In the αβ coordinate system, since the β axis lags behind the α axis by 90 degrees, a phase-shifting filter is used to... A 90-degree phase shift yields the result. The phase shift formula is: ； in, The angular frequency of the power grid; The system damping coefficient of the phase-shifting filter is 0.

707. Multiply ,have to: ； Calculate the predicted voltage u α_k and u β_k phase angle θ k : ； Calculate the predicted voltage u α_k and u β_k Amplitude: | |= 。 3. The delay compensation method for a three-phase converter based on joint voltage amplitude and phase control according to claim 1, characterized in that: Step (2) specifically refers to: calculating the phase and amplitude of the current command voltage, in order to obtain the phase θ of the current command voltage. k1 First, the command voltage before compensation needs to be generated in the dq coordinate system. and Transform to the αβ coordinate system, and let the transformed voltage be... and The conversion formula is: ； In the formula, θ1 is the phase angle of the grid voltage; θ k1 Depend on and Find: ； Current command voltage amplitude | |for: | |= 。 4. The delay compensation method for a three-phase converter based on joint voltage amplitude and phase control according to claim 1, characterized in that: Step (3) specifically refers to: Calculate the phase difference ∆ (k): ∆ (k)= - 。 5. The delay compensation method for a three-phase converter based on joint voltage amplitude and phase control according to claim 1, characterized in that: Step (4) specifically refers to: The system's delay changes continuously, and in the time domain: ∆ (t)= .τ(t); In the formula, ∆ (t) represents the phase difference between the predicted bridge arm output voltage and the current voltage at time t, and τ(t) represents the equivalent delay at time t; Phase difference ∆ after one period (t+ The formula for calculating ) is: ∆ (t+ )=∆ (t)+ ∙ +O( )(2); In the formula, O(t) represents the rate of change of phase difference at time t. ) represents second-order or higher-order infinitesimal terms; Based on equation (2), the predicted phase difference value for the next cycle is obtained, and the advance compensation phase angle is calculated. (t): (t)=∆ (t)+ (3)。 6. The delay compensation method for a three-phase converter based on joint voltage amplitude and phase control according to claim 1, characterized in that: In step (5), the linear amplitude ratio is first... Nonlinear processing is performed to determine the deviation of the linear amplitude ratio. for: ɡ=| |。 7. The delay compensation method for a three-phase converter based on joint voltage amplitude and phase control according to claim 1, characterized in that: In step (7), the final compensated phase angle The formula for calculating (k) is as follows: = ∙ + 。 8. The delay compensation method for a three-phase converter based on joint voltage amplitude and phase control according to claim 1, characterized in that: Step (8) specifically refers to: adjusting the final compensated phase angle (k) Substitute this into the phase compensation stage of the converter to perform phase compensation on the command voltage output by the current regulator, and obtain the compensated command voltage. , : ； In the formula, , The command voltage before compensation.

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