A Line Sequence Adaptive Control Method for PWM Rectifier

Abstract

The present invention discloses a PWM rectifier line sequence adaptive control method, which detects U RS and U RT , and calculate U ST And convert the three-phase voltage value from the ABC coordinate system to the synchronous rotating coordinate system; q Input closed-loop control system; determine the line sequence correspondence between the grid voltage detection line and the power input power line; determine whether the actual phase sequence needs to be updated; RS , U RT , U ST Reconstruct; use the updated actual phase sequence as the initial detection phase sequence, use the reconstructed three-phase voltage value as the three-phase line voltage value of the PWM rectifier grid voltage detection line, repeat the judgment; output the updated phase angle θ" 0 , completing the line sequence control of the PWM rectifier in any state. The adaptive control method of the present invention can adaptively control under any wiring line sequence of the PWM rectifier, solving the problems of strict requirements on phase sequence in the application technology of PWM rectifier and difficulty in troubleshooting.

Description

Technical Field

[0001] The invention relates to the field of power electronic control, and in particular to a PWM rectifier line sequence adaptive control method. Background Art

[0002] In a three-phase PWM rectifier, the commonly used technical solution requires an independent three-phase line for detecting the grid status. This three-phase line must be the same source as the three-phase power input line on the grid side, and the line sequence must correspond one to one. Otherwise, the controlled voltage vector will not match the actual grid vector, resulting in failure of the control model, inability of the equipment to work, and the risk of damage to the equipment.

[0003] Moreover, in actual applications, if a line sequence error occurs, the fault of the PWM rectifier requires comprehensive manual confirmation, which is not conducive to improving work efficiency. There is also a risk of line sequence error in the subsequent maintenance process, which greatly increases the risk of equipment damage. Summary of the invention

[0004] The present invention provides a PWM rectifier line sequence adaptive control method to overcome the above technical problems.

[0005] A PWM rectifier line sequence adaptive control method comprises the following steps:

[0006] S1: Assume that the initial detection phase sequence of the power grid is Sequence_0;

[0007] S2: Assume that the PWM rectifier grid voltage detection lines are R phase line, S phase line, and T phase line respectively.

[0008] S3: Detect the grid voltage value U between the R phase line and the S phase line RS The grid voltage value U between the R phase line and the T phase line RT , and calculate the grid voltage value U between the S phase line and the T phase line ST ;

[0009] S4: The U RS , U RT and U ST Convert from the ABC coordinate system to the synchronous rotating coordinate system and obtain the corresponding voltage value u on the d-axis in the rotating coordinate system d and the corresponding voltage value u on the q axis q ;

[0010] S5: will u q The input contains the updated voltage value u' on the q-axis q and the initial phase angle θ of the R phase 0 A closed-loop control system is provided to perform closed-loop control on it;

[0011] If the updated voltage value u' on the q-axis q ≥ the first threshold, it is determined that the actual phase sequence of the PWM rectifier grid voltage is opposite to the initial detection phase sequence Sequence_0, and the actual phase sequence needs to be updated; then S6 is started;

[0012] If the updated voltage value u' on the q-axis q < the first threshold, it is determined that the actual phase sequence of the PWM rectifier grid voltage is the same as the initial detection phase sequence Sequence_0; then S10 is started;

[0013] S6: Determine the line sequence correspondence between the grid voltage detection R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line; to determine whether the line sequence of the grid voltage detection R phase line, S phase line, T phase line is consistent with the actual line sequence of the grid voltage;

[0014] If the line sequence of the R phase line, S phase line, and T phase line detected by the grid voltage is consistent with the actual line sequence of the grid voltage, execute S10;

[0015] If the line sequence of the R phase line, S phase line, and T phase line detected by the grid voltage is inconsistent with the actual line sequence of the grid voltage, S7 is started;

[0016] S7: judging whether it is necessary to update the actual phase sequence according to the corresponding relationship between the R phase line, the S phase line, the T phase line and the power input power line U phase line, the V phase line and the W phase line of the grid voltage detection; and obtaining the updated actual phase sequence;

[0017] If the actual phase sequence needs to be updated, start S8 and S9;

[0018] If the actual phase sequence does not need to be updated, S10 is started;

[0019] S8: The grid voltage value U between the R phase line and the S phase line RS , the grid voltage value U between the R phase line and the T phase line RT , the grid voltage value U between the S phase line and the T phase line ST Reconstruct; obtain the reconstructed grid voltage value U′ between the R phase line and the S phase line RS , the reconstructed grid voltage value U′ between the R phase line and the T phase line RT , the grid voltage value U′ between the S phase line and the T phase line ST ;

[0020] S9: Use the updated actual phase sequence as the initial detection phase sequence in S1, and use the reconstructed grid voltage value U′ between the reconstructed R phase line and the S phase line RS , the reconstructed grid voltage value U′ between the R phase line and the T phase line RT , the grid voltage value U′ between the S phase line and the T phase lineST As the three-phase line voltage value of the PWM rectifier grid voltage detection line in S2, repeat S3 to S5;

[0021] S10: Output the updated phase angle θ of the R phase" 0 , completing the line sequence control of any state of the PWM rectifier.

[0022] Furthermore, the calculation of U in S3 ST The formula for the line voltage value is as follows:

[0023] U ST =-(U RS +U RT ).

[0024] Further, in S4, the U RS , U RT and U ST Convert from the ABC coordinate system to the synchronously rotating coordinate system.

[0025] Furthermore, the closed-loop control system in S5 includes a PI regulator, an integrator and a mod module:

[0026] S51: u q Input the PI regulator to obtain the output PI_out of the PI regulator;

[0027] S52: The integrator calculates as follows:

[0028] ω 0 =ω * +PI_out

[0029] θ' 0 =θ 0 +ω 0

[0030] Among them, ω 0 is the output angular frequency; ω * is the rated angular frequency of the grid voltage; θ' 0 is the intermediate parameter for calculating the updated phase angle of the R phase; θ 0 is the initial phase angle of R phase;

[0031] S53: The mod module calculates θ' 0 as follows;

[0032] When θ' 0 >2π,

[0033] θ” 0 =θ' 0 -2π;

[0034] When 0≤θ' 0 When ≤2π,

[0035] θ″ 0 =θ′ 0 ;

[0036] In the formula, θ″ 0 is the updated phase angle of phase R.

[0037] Furthermore, in S6, the line sequence relationship judgment module is used to judge the line sequence correspondence between the grid voltage detection R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line;

[0038] The line sequence relationship judgment module includes a U-phase upper bridge arm T1, a U-phase lower bridge arm T4, a V-phase upper bridge arm T2, a V-phase lower bridge arm T5, a W-phase upper bridge arm T3, a W-phase lower bridge arm T6, a first inductor L1, a second inductor L2, a third inductor L3, and a capacitor C;

[0039] The U-phase upper bridge arm T1 and the U-phase lower bridge arm T4 are connected in series; the V-phase upper bridge arm T2 and the V-phase lower bridge arm T5 are connected in series; the W-phase upper bridge arm T3 and the W-phase lower bridge arm T6 are connected in series; the U-phase upper bridge arm T1, the V-phase upper bridge arm T2 and the W-phase upper bridge arm T3 are connected at one point; the U-phase lower bridge arm T4, the V-phase lower bridge arm T5 and the W-phase lower bridge arm T6 are connected at one point;

[0040] One side of the first inductor L1 is connected to the connection between the U-phase upper bridge arm T1 and the U-phase lower bridge arm T4, and the other side is connected to the a-phase input ua of the power grid; one side of the second inductor L2 is connected to the connection between the V-phase upper bridge arm T2 and the V-phase lower bridge arm T5, and the other side is connected to the b-phase input ub of the power grid; one side of the third inductor L3 is connected to the connection between the W-phase upper bridge arm T3 and the W-phase lower bridge arm T6, and the other side is connected to the c-phase input uc of the power grid; one side of the capacitor C is connected to the connection between the V-phase upper bridge arm T2 and the W-phase upper bridge arm T3, and the other side of the capacitor C is connected to the connection between the V-phase lower bridge arm T5 and the W-phase lower bridge arm T6.

[0041] Further, in S6, the method for determining the line sequence correspondence between the grid voltage detection R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line by the line sequence relationship judgment module is:

[0042] S61: When U RT When the line voltage phase angle is 90 degrees, the U-phase lower bridge arm T4 and the W-phase lower bridge arm T6 are opened, and the other bridge arms are closed, and t 1 Time measurement I U1 ,I W1 ;

[0043] Among them, t1 For U RT The pulse test time when the line voltage phase angle is 90 degrees, I U1 t 1 U phase current at the moment; I W1 t 1 W phase current at the moment;

[0044] S62: When U RT When the line voltage phase angle is 270 degrees, the U-phase lower bridge arm T4 and the W-phase lower bridge arm T6 are opened, and the other bridge arms are closed. t 2 I measured at all times U2 ,I W2 ;

[0045] Among them, t 2 For U RT The pulse test time when the line voltage phase angle is 270 degrees, I U2 t 2 U phase current at the moment; I W2 t 2 W phase current at the moment;

[0046] S63: Determine the I U1 ,I W1 ,I U2 ,I W2 The corresponding relationship between the current data characteristics and the grid voltage detection line and the power input power line can determine whether the line sequence of the grid voltage detection R phase line, S phase line, and T phase line is consistent with the actual line sequence of the grid voltage.

[0047] Further, in S63, the I U1 ,I W1 ,I U2 ,I W2 The corresponding relationship between the current data characteristics and the grid voltage detection line and the power input power line includes:

[0048] S631: When I U1 >80%I max , I W1 <-80%I max , I U2 <-80%I max , I W2 >80%I max When the grid voltage detection line R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line have the same line sequence;

[0049] S632: When I U1 <-80%I max , I W1>80%I max , I U2 >80%I max , I W2 <-80%I max When the grid voltage detection line T phase line, S phase line, R phase line and the power input power line W phase line, V phase line and U phase line have the same line sequence;

[0050] S633: When 20% I max U1 <80% I max , -20%I max >I W1 >-80%I max , I U2 <-80%I max , I W2 <20% I max When the grid voltage detection line T phase line, R phase line, S phase line and the power input power line V phase line, W phase line, U phase line have the same line sequence;

[0051] S634: When -20% I max >I U1 >-80%I max , 20%I max W1 <80% I max , I U2 <20% I max , I W2 >-80%I max When the grid voltage detection line R phase line, T phase line, S phase line and the power input power line U phase line, W phase line, V phase line line sequence are consistent;

[0052] S635: When 20% I max >I U1 , I W1 <-80%I max , -20%I max >I U2 >-80%I max , 80%I max >I W2 >20%I max When the power grid voltage detection line S phase line, R phase line, T phase line and the power input power line V phase line, U phase line, W phase line line sequence are consistent;

[0053] S636: When 20% I max U1 <80% I max , 20%I max W1 <80% I​​​​max , I U2 <20% I max , I W2 >-80%I max When the power grid voltage detection line S phase line, T phase line, R phase line and the power input power line W phase line, U phase line, V phase line line are consistent in line sequence;

[0054] Among them, I max It is the current threshold of the pulse test process.

[0055] Furthermore, in S7, the method for determining whether the actual phase sequence needs to be updated is:

[0056] When the line sequence of the grid voltage detection line R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line is consistent, it is judged that the actual phase sequence is the same as the initial detection phase sequence, and there is no need to update the actual phase sequence;

[0057] When the line sequence of the grid voltage detection line T phase line, S phase line, R phase line and the power input power line W phase line, V phase line and U phase line is consistent, it is judged that the actual phase sequence is opposite to the initial detection phase sequence, and the actual phase sequence needs to be updated;

[0058] When the line sequence of the grid voltage detection line T phase line, R phase line, S phase line and the power input power line V phase line, W phase line, U phase line is consistent, it is judged that the actual phase sequence is the same as the initial detection phase sequence, and there is no need to update the actual phase sequence;

[0059] When the line sequence of the grid voltage detection line R phase line, T phase line, S phase line and the power input power line U phase line, W phase line, V phase line is consistent, it is judged that the actual phase sequence is opposite to the initial detection phase sequence, and the actual phase sequence needs to be updated;

[0060] When the line sequence of the grid voltage detection line S phase line, R phase line, T phase line and the power input power line V phase line, U phase line, W phase line is consistent, it is judged that the actual phase sequence is opposite to the initial detection phase sequence, and the actual phase sequence needs to be updated;

[0061] When the line sequence of the grid voltage detection lines S phase line, T phase line, R phase line and the power input power lines W phase line, U phase line, V phase line are consistent, it is judged that the actual phase sequence is the same as the initial detection phase sequence, and the actual phase sequence does not need to be updated.

[0062] Furthermore, in S8, the grid voltage value U between the R phase line and the S phase line is RS , the grid voltage value U between the R phase line and the T phase line RT , the grid voltage value U between the S phase line and the T phase line ST The reconstruction method is:

[0063] When the line sequence of the grid voltage detection lines R, S, and T in S631 is consistent with the line sequence of the power input power lines U, V, and W, U' RS =U RS , U' RT =U RT , U' ST =U ST ;

[0064] When the line sequence of the grid voltage detection lines T, S, and R in S632 is consistent with the line sequence of the power input power lines W, V, and U, U' RS =U ST , U' RT =U RT , U' ST =U RS ;

[0065] When the line sequence of the grid voltage detection line T phase line, R phase line, S phase line and the power input power line V phase line, W phase line, U phase line in S633 is consistent, U' RS =U ST , U' RT =U RS , U' ST =U ST ;

[0066] When the line sequence of the grid voltage detection line R phase line, T phase line, S phase line and the power input power line U phase line, W phase line, V phase line in S634 is consistent, U' RS =U ST , U' RT =U ST , U' ST =U RT ;

[0067] When the line sequence of the grid voltage detection line S phase line, R phase line, T phase line and the power input power line V phase line, U phase line, W phase line in S635 is consistent, U' RS =U RT , U' RT =U ST , U' ST =U RS ;

[0068] When the line sequence of the grid voltage detection line S phase line, T phase line, R phase line and the power input power line W phase line, U phase line, V phase line in S636 is consistent, U' RS =-U ST , U' RT =-U RT , U' ST =-U RS .

[0069] The present invention discloses a PWM rectifier line sequence adaptive control method, which can adaptively control under any wiring line sequence of the PWM rectifier, and solves the problems of strict requirements on phase sequence and difficulty in troubleshooting in PWM rectifier application technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0071] Figure 1 It is a synchronous coordinate system phase-locked loop vector diagram of the present invention;

[0072] Figure 2 This is the principle diagram of the SSRF-SPLL control structure of the present invention;

[0073] Figure 3 The basic hardware structure of the PWM rectifier of the present invention;

[0074] Figure 4 It is a basic block diagram of the self-use control method of the present invention. DETAILED DESCRIPTION

[0075] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0076] In order to overcome the problems of strict phase sequence requirements in PWM rectifier application technology and difficulty in troubleshooting, this invention provides a method for adaptive control under arbitrary wiring sequence of PWM rectifier.

[0077] A PWM rectifier line sequence adaptive control method comprises the following steps, as shown in the attached Figure 4 As shown:

[0078] S1: Assume that the initial detection phase sequence of the power grid is Sequence_0;

[0079] S2: Assume that the PWM rectifier grid voltage detection lines are R phase line, S phase line, and T phase line, to obtain the three-phase line voltage value of the PWM rectifier grid voltage detection line; that is, the grid voltage value between the R phase line and the S phase line is U RS The grid voltage between the R phase line and the T phase line is U RT The grid voltage between the S phase line and the T phase line is U ST ;

[0080] S3: Detection U RS and U RT , and calculate U ST Specifically, calculate U ST The formula for the line voltage value is as follows:

[0081] U ST =-(U RS +U RT )

[0082] Specifically, in this embodiment, the line voltage detection module in the PWM rectifier is used to detect the U RS , U RT The two sets of line voltage values ​​are detected, and U is calculated based on the characteristic that the vector sum of the three-phase power grid line voltage is zero. ST The line voltage value;

[0083] S4: The U RS , U RT and U ST Convert from the ABC coordinate system to the synchronous rotating coordinate system and obtain the corresponding voltage value u on the d-axis in the rotating coordinate system d and the corresponding voltage value u on the q axis d and u q ; as attached Figure 1 and attached Figure 2 As shown;

[0084] Specifically, in this embodiment, the U RS , U RT and U ST Convert from the ABC coordinate system to the synchronously rotating coordinate system.

[0085] Specifically, this embodiment uses a synchronous coordinate system to calculate the grid voltage phase angle and determine the phase sequence; because in the synchronous rotating coordinate system, according to the basic performance requirements of the phase-locked loop, the vector U sPLL and U s Phase locking can only be achieved by complete overlap, so through closed-loop control, u q < the first threshold, phase locking can be achieved.

[0086] S5: will u qInput contains u q and the initial phase angle θ of the R phase 0 A closed-loop control system is provided to perform closed-loop control on it;

[0087] Specifically, the closed-loop control process in this embodiment includes a PI regulator, an integral link and a mod module:

[0088] S51: u q Input PI regulator to obtain the output PI_out of PI regulator; when the grid voltage rated angular frequency ω of PWM rectifier * When locked, since the PI regulator has the DC zero-static-error regulation characteristic, by adjusting u q PI regulation can make u' q <The first threshold is used to achieve phase locking. In the present invention, the first threshold is 30%*PI_out;

[0089] S52: The integral step is calculated as follows:

[0090] ω 0 =ω * +PI_out

[0091] θ' 0 =θ 0 +ω 0

[0092] Among them, ω 0 is the output angular frequency; ω * is the rated angular frequency of the grid voltage; θ' 0 is the intermediate parameter for calculating the updated phase angle of the R phase; θ 0 is the initial phase angle of R phase;

[0093] S53: The mod module is calculated as follows;

[0094] When θ' 0 >2π,

[0095] θ” 0 =θ' 0 -2π;

[0096] When 0≤θ' 0 When ≤2π,

[0097] θ″ 0 =θ′ 0 ;

[0098] In the formula, θ″ 0 is the updated phase angle of phase R;

[0099] Specifically, the mod module of the present invention takes 2π as the limiting parameter and sets θ 0Output is limited to [0,2π]

[0100] If the updated voltage value u' on the q-axis q ≥ the first threshold, the actual phase sequence of the PWM rectifier grid voltage is opposite to the initial detection phase sequence Sequence_0, and the actual phase sequence needs to be updated; then S6 is started;

[0101] If the updated voltage value u' on the q-axis q < the first threshold value, at this time, the actual phase sequence of the PWM rectifier grid voltage is the same as the initial detection phase sequence Sequence_0; then start S10;

[0102] Specifically, the method for adjusting the actual phase sequence is: if the initial detected phase sequence Sequence_0 is a positive phase sequence, the actual phase sequence is a negative phase sequence; if the initial detected phase sequence Sequence_0 is a negative phase sequence, the actual phase sequence is a positive phase sequence;

[0103] S6: Determine the line sequence correspondence between the grid voltage detection R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line; to determine whether the line sequence of the grid voltage detection R phase line, S phase line, T phase line is consistent with the actual line sequence of the grid voltage;

[0104] If the line sequence of the R phase line, the S phase line, and the T phase line detected by the grid voltage is consistent with the actual line sequence of the grid voltage, execute S10;

[0105] If the line sequence of the R phase line, S phase line and T phase line detected by the grid voltage is inconsistent with the actual line sequence of the grid voltage, S7 is started;

[0106] Specifically, in this embodiment, the pulse method is used to measure the corresponding relationship of the current at different phase angles, and the line sequence relationship judgment module is used to judge the line sequence correspondence between the grid voltage detection R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line;

[0107] As attached Figure 3 As shown, the line sequence relationship judgment module includes a U-phase upper bridge arm T1, a U-phase lower bridge arm T4, a V-phase upper bridge arm T2, a V-phase lower bridge arm T5, a W-phase upper bridge arm T3, a W-phase lower bridge arm T6, a first inductor L1, a second inductor L2, a third inductor L3, and a capacitor C;

[0108] The U-phase upper bridge arm T1 and the U-phase lower bridge arm T4 are connected in series; the V-phase upper bridge arm T2 and the V-phase lower bridge arm T5 are connected in series; the W-phase upper bridge arm T3 and the W-phase lower bridge arm T6 are connected in series; the U-phase upper bridge arm T1, the V-phase upper bridge arm T2 and the W-phase upper bridge arm T3 are connected at one point; the U-phase lower bridge arm T4, the V-phase lower bridge arm T5 and the W-phase lower bridge arm T6 are connected at one point;

[0109] One side of the first inductor L1 is connected to the connection between the U-phase upper bridge arm T1 and the U-phase lower bridge arm T4, and the other side is connected to the a-phase input ua of the power grid; one side of the second inductor L2 is connected to the connection between the V-phase upper bridge arm T2 and the V-phase lower bridge arm T5, and the other side is connected to the b-phase input ub of the power grid; one side of the third inductor L3 is connected to the connection between the W-phase upper bridge arm T3 and the W-phase lower bridge arm T6, and the other side is connected to the c-phase input uc of the power grid; one side of the capacitor C is connected to the connection between the V-phase upper bridge arm T2 and the W-phase upper bridge arm T3, and the other side of the capacitor C is connected to the connection between the V-phase lower bridge arm T5 and the W-phase lower bridge arm T6;

[0110] The method for determining the line sequence correspondence between the grid voltage detection R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line through the line sequence relationship judgment module is as follows:

[0111] When the R phase is updated after the phase angle θ" 0 When it is equal to 90° or 270°, the amplitude of URT is maximum in the positive direction or maximum in the negative direction.

[0112] S61: When U RT When the line voltage phase angle is 90 degrees, the U-phase lower bridge arm T4 and the W-phase lower bridge arm T6 are opened, and the other bridge arms are closed, and t 1 Time measurement I U1 ,I W1 ;

[0113] Among them, t 1 For U RT The pulse test time when the line voltage phase angle is 90 degrees, I U1 t 1 U phase current at the moment; I W1 t 1 W phase current at the moment;

[0114] S62: When U RT When the line voltage phase angle is 270 degrees, the U-phase lower bridge arm T4 and the W-phase lower bridge arm T6 are opened, and the other bridge arms are closed. t 2 I measured at all times U2 ,I W2 ;

[0115] Among them, t 2 For U RT The pulse test time when the line voltage phase angle is 270 degrees, I U2 t 2 U phase current at the moment; I W2 t 2 W phase current at the moment;

[0116] S63: Determine the I U1 ,I W1 ,I U2 ,I W2 The corresponding relationship between the current data characteristics and the grid voltage detection line and the power input power line, that is, whether the line sequence of the grid voltage detection R phase line, S phase line, and T phase line is consistent with the actual line sequence of the grid voltage;

[0117] Specifically, the I U1 ,I W1 ,I U2 ,I W2 The corresponding relationship between the current data characteristics and the grid voltage detection line and the power input power line includes:

[0118] S631: When I U1 >80%I max , I W1 <-80%I max , I U2 <-80%I max , I W2 >80%I max When the grid voltage detection line R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line have the same line sequence;

[0119] S632: When I U1 <-80%I max , I W1 >80%I max , I U2 >80%I max , I W2 <-80%I max When the grid voltage detection line T phase line, S phase line, R phase line and the power input power line W phase line, V phase line and U phase line have the same line sequence;

[0120] S633: When 20% I max U1 <80% I max , -20%I max >I W1 >-80%I max , I U2 <-80%I max , I W2 <20% I max When the grid voltage detection line T phase line, R phase line, S phase line and the power input power line V phase line, W phase line, U phase line have the same line sequence;

[0121] S634: When -20% I max >I U1 ​>-80%I max , 20%I max W1 <80% I max , I U2 <20% I max , I W2 >-80%I max When the grid voltage detection line R phase line, T phase line, S phase line and the power input power line U phase line, W phase line, V phase line line sequence are consistent;

[0122] S635: When 20% I max >I U1 , I W1 <-80%I max , -20%I max >I U2 >-80%I max , 80%I max >I W2 >20%I max When the power grid voltage detection line S phase line, R phase line, T phase line and the power input power line V phase line, U phase line, W phase line line sequence are consistent;

[0123] S636: When 20% I max U1 <80% I max , 20%I max W1 <80% I max , I U2 <20% I max , I W2 >-80%I max When the power grid voltage detection line S phase line, T phase line, R phase line and the power input power line W phase line, U phase line, V phase line line are consistent in line sequence;

[0124] Among them, I max Current threshold for pulse test process.

[0125] S7: judging whether it is necessary to update the actual phase sequence according to the corresponding relationship between the R phase line, the S phase line, the T phase line and the power input power line U phase line, the V phase line and the W phase line of the grid voltage detection; and obtaining the updated actual phase sequence;

[0126] If the actual phase sequence needs to be updated, start S8 and S9;

[0127] If the actual phase sequence does not need to be updated, S10 is started;

[0128] Specifically, the method in this embodiment using the phase sequence update module to determine whether the actual phase sequence needs to be updated is: ​​​

[0129] When the line sequence of the grid voltage detection line R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line is consistent, the actual phase sequence is the same as the initial detection phase sequence, and the actual phase sequence does not need to be updated;

[0130] When the line sequence of the grid voltage detection line T phase line, S phase line, R phase line and the power input power line W phase line, V phase line and U phase line is consistent, the actual phase sequence is opposite to the initial detection phase sequence, and the actual phase sequence needs to be updated;

[0131] When the line sequence of the grid voltage detection line T phase line, R phase line, S phase line and the power input power line V phase line, W phase line, U phase line is consistent, the actual phase sequence is the same as the initial detection phase sequence, and the actual phase sequence does not need to be updated;

[0132] When the line sequence of the grid voltage detection line R phase line, T phase line, S phase line and the power input power line U phase line, W phase line, V phase line is consistent, the actual phase sequence is opposite to the initial detection phase sequence, and the actual phase sequence needs to be updated;

[0133] When the line sequence of the grid voltage detection line S phase line, R phase line, T phase line and the power input power line V phase line, U phase line, W phase line is consistent, the actual phase sequence is opposite to the initial detection phase sequence, and the actual phase sequence needs to be updated;

[0134] When the line sequence of the grid voltage detection line S phase line, T phase line, R phase line and the power input power line W phase line, U phase line, V phase line is consistent, the actual phase sequence is the same as the initial detection phase sequence, and the actual phase sequence does not need to be updated;

[0135] S8: The grid voltage value U between the R phase line and the S phase line RS , the grid voltage value U between the R phase line and the T phase line RT , the grid voltage value U between the S phase line and the T phase line ST Reconstruct; obtain the reconstructed grid voltage value U′ between the R phase line and the S phase line RS , the reconstructed grid voltage value U′ between the R phase line and the T phase line RT , the grid voltage value U′ between the S phase line and the T phase line ST ;

[0136] Specifically, when the actual phase sequence is different from the initial detected phase sequence, if the phase sequence and phase angle calculated by the detected line voltage are used for control, the controlled device will be out of control. Therefore, the voltage value needs to be reconstructed. Specifically, the voltage reconstruction module in this embodiment reconstructs the grid voltage value U between the R phase line and the S phase line. RS , the grid voltage value U between the R phase line and the T phase line RT , the grid voltage value U between the S phase line and the T phase line ST The reconstruction method is:

[0137] When the line sequence of the grid voltage detection lines R, S, and T in S631 is consistent with the line sequence of the power input power lines U, V, and W, U' RS =U RS , U' RT =U RT , U' ST =U ST ;

[0138] When the line sequence of the grid voltage detection lines T, S, and R in S632 is consistent with the line sequence of the power input power lines W, V, and U, U' RS =U ST , U' RT =U RT , U' ST =U RS ;

[0139] When the line sequence of the grid voltage detection line T phase line, R phase line, S phase line and the power input power line V phase line, W phase line, U phase line in S633 is consistent, U' RS =U ST , U' RT =U RS , U' ST =U ST ;

[0140] When the line sequence of the grid voltage detection line R phase line, T phase line, S phase line and the power input power line U phase line, W phase line, V phase line in S634 is consistent, U' RS =U ST , U' RT =U ST , U' ST =U RT ;

[0141] When the line sequence of the grid voltage detection line S phase line, R phase line, T phase line and the power input power line V phase line, U phase line, W phase line in S635 is consistent, U' RS =U RT , U' RT =U ST , U' ST =U RS ;

[0142] When the line sequence of the grid voltage detection line S phase line, T phase line, R phase line and the power input power line W phase line, U phase line, V phase line in S636 is consistent, U' RS =-U ST , U' RT =-U RT , U' ST =-U RS.

[0143] S9: Use the updated actual phase sequence as the initial detection phase sequence in S1, and reconstruct U′ RS , U′ RT , U′ ST As the three-phase line voltage value of the PWM rectifier grid voltage detection line in S2, repeat S1 to S5;

[0144] S10: Get the updated phase angle θ of the R phase" 0 , completing the line sequence control of any state of the PWM rectifier.

[0145] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A PWM rectifier line sequence adaptive control method, characterized in that: The method comprises the following steps: S1: Assume that the initial detection phase sequence of the power grid is Sequence_0; S2: Assume that the grid voltage detection lines of the PWM rectifier are R phase line, S phase line, and T phase line respectively; S3: Detect the grid voltage value U between the R phase line and the S phase line RS The grid voltage value U between the R phase line and the T phase line RT , and calculate the grid voltage value U between the S phase line and the T phase line ST ; S4: The U RS , U RT and U ST Convert from the ABC coordinate system to the synchronous rotating coordinate system and obtain the corresponding voltage value u on the d-axis in the rotating coordinate system d and the corresponding voltage value u on the q axis q ; S5: will u q The input contains the updated voltage value u' on the q-axis q and a closed-loop control system of the initial phase angle θ0 of the R phase to perform closed-loop control thereof; If the updated voltage value u' on the q-axis q ≥ the first threshold, it is determined that the actual phase sequence of the PWM rectifier grid voltage is opposite to the initial detection phase sequence Sequence_0, and the actual phase sequence needs to be updated; then S6 is started; If the updated voltage value u' on the q-axis q < the first threshold, it is determined that the actual phase sequence of the PWM rectifier grid voltage is the same as the initial detection phase sequence Sequence_0; then S10 is started; S6: Determine the line sequence correspondence between the grid voltage detection R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line; To determine whether the line sequence of the R phase line, S phase line, and T phase line detected by the grid voltage is consistent with the actual line sequence of the grid voltage; If the line sequence of the R phase line, S phase line, and T phase line detected by the grid voltage is consistent with the actual line sequence of the grid voltage, execute S10; If the line sequence of the R phase line, S phase line, and T phase line detected by the grid voltage is inconsistent with the actual line sequence of the grid voltage, S7 is started; S7: judging whether it is necessary to update the actual phase sequence according to the corresponding relationship between the R phase line, the S phase line, the T phase line and the power input power line U phase line, the V phase line and the W phase line of the grid voltage detection; and obtaining the updated actual phase sequence; If the actual phase sequence needs to be updated, start S8 and S9; If the actual phase sequence does not need to be updated, S10 is started; S8: The grid voltage value U between the R phase line and the S phase line RS , the grid voltage value U between the R phase line and the T phase line RT , the grid voltage value U between the S phase line and the T phase line ST Reconstruct; obtain the reconstructed grid voltage value U′ between the R phase line and the S phase line RS , the reconstructed grid voltage value U′ between the R phase line and the T phase line RT , the reconstructed grid voltage value U′ between the S phase line and the T phase line ST ; S9: Use the updated actual phase sequence as the initial detection phase sequence in S1, and use the reconstructed grid voltage value U′ between the reconstructed R phase line and the S phase line RS , the reconstructed grid voltage value U′ between the R phase line and the T phase line RT , the reconstructed grid voltage value U′ between the S phase line and the T phase line ST As the three-phase line voltage value of the PWM rectifier grid voltage detection line in S2, repeat S3 to S5; S10: Output the updated phase angle θ"0 of the R phase, completing the line sequence control of any state of the PWM rectifier.

2. A PWM rectifier line sequence adaptive control method according to claim 1, characterized in that: The S3 calculates U ST The formula for the line voltage value is as follows: IN ST =-(U RS +U RT )。 3. A PWM rectifier line sequence adaptive control method according to claim 1, characterized in that: In S4, the U is transformed by Clark transformation and Park transformation. RS , U RT and U ST Convert from the ABC coordinate system to the synchronously rotating coordinate system.

4. A PWM rectifier line sequence adaptive control method according to claim 1, characterized in that: The closed-loop control system in S5 includes a PI regulator, an integrator and a mod module: S51: Put u q Input the PI regulator to obtain the output PI_out of the PI regulator; S52: The integrator calculates as follows: ω0=ω * +PI_out θ'0=θ0+ω0 Where, ω0 is the output angular frequency; ω * is the rated angular frequency of the grid voltage; θ'0 is the intermediate parameter for calculating the updated phase angle of the R phase; θ0 is the initial phase angle of the R phase; S53: The mod module calculates θ0″ as follows; When θ'0>2π, θ”0=θ'0-2π; When 0≤θ'0≤2π, θ″0=θ′0; Where θ″0 is the phase angle after the R phase is updated.

5. A PWM rectifier line sequence adaptive control method according to claim 1, characterized in that: In S6, the line sequence relationship judgment module is used to judge the line sequence correspondence between the grid voltage detection R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line; The line sequence relationship judgment module includes a U-phase upper bridge arm T1, a U-phase lower bridge arm T4, a V-phase upper bridge arm T2, a V-phase lower bridge arm T5, a W-phase upper bridge arm T3, a W-phase lower bridge arm T6, a first inductor L1, a second inductor L2, a third inductor L3, and a capacitor C; The U-phase upper bridge arm T1 and the U-phase lower bridge arm T4 are connected in series; the V-phase upper bridge arm T2 and the V-phase lower bridge arm T5 are connected in series; the W-phase upper bridge arm T3 and the W-phase lower bridge arm T6 are connected in series; the U-phase upper bridge arm T1, the V-phase upper bridge arm T2 and the W-phase upper bridge arm T3 are connected at one point; The U-phase lower bridge arm T4, the V-phase lower bridge arm T5 and the W-phase lower bridge arm T6 are connected at one point; One side of the first inductor L1 is connected to the connection between the U-phase upper bridge arm T1 and the U-phase lower bridge arm T4, and the other side is connected to the a-phase input ua of the power grid; one side of the second inductor L2 is connected to the connection between the V-phase upper bridge arm T2 and the V-phase lower bridge arm T5, and the other side is connected to the b-phase input ub of the power grid; one side of the third inductor L3 is connected to the connection between the W-phase upper bridge arm T3 and the W-phase lower bridge arm T6, and the other side is connected to the c-phase input uc of the power grid; One side of the capacitor C is connected to the connection point of the V-phase upper bridge arm T2 and the W-phase upper bridge arm T3, and the other side of the capacitor C is connected to the connection point of the V-phase lower bridge arm T5 and the W-phase lower bridge arm T6.

6. A PWM rectifier line sequence adaptive control method according to claim 5, characterized in that: In S6, the method for determining the line sequence correspondence between the grid voltage detection R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line by the line sequence relationship determination module is: S61: When U RT When the line voltage phase angle is 90 degrees, the U-phase lower bridge arm T4 and the W-phase lower bridge arm T6 are opened, and the other bridge arms are closed. The I is measured at time t1. U1 ,I W1 ; Where t1 is U RT The pulse test time when the line voltage phase angle is 90 degrees, I U1 is the U phase current at time t1; I W1 is the W phase current at time t1; S62: When U RT When the line voltage phase angle is 270 degrees, the U-phase lower bridge arm T4 and the W-phase lower bridge arm T6 are opened, and the other bridge arms are closed. The I measured at time t2 is measured. U2 ,I W2 ; Where t2 is U RT The pulse test time when the line voltage phase angle is 270 degrees, I U2 is the U phase current at time t2; I W2 is the W phase current at time t2; S63: Determine the I U1 ,I W1 ,I U2 ,I W2 The corresponding relationship between the current data characteristics and the grid voltage detection line and the power input power line can determine whether the line sequence of the grid voltage detection R phase line, S phase line, and T phase line is consistent with the actual line sequence of the grid voltage.

7. A PWM rectifier line sequence adaptive control method according to claim 6, characterized in that: In the S63, the I U1 ,I W1 ,I U2 ,I W2 The corresponding relationship between the current data characteristics and the grid voltage detection line and the power input power line includes: S631: When I U1 >80%I max , I W1 <-80%I max , I U2 <-80%I max , I W2 >80%I max When the grid voltage detection line R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line have the same line sequence; S632: When I U1 <-80%I max , I W1 >80%I max , I U2 >80%I max , I W2 <-80%I max When the grid voltage detection line T phase line, S phase line, R phase line and the power input power line W phase line, V phase line and U phase line have the same line sequence; S633: When 20% I max U1 <80% I max , -20%I max >I W1 >-80%I max , I U2 <-80%I max , I W2 <20% I max When the grid voltage detection line T phase line, R phase line, S phase line and the power input power line V phase line, W phase line, U phase line line are consistent in line sequence;​ S634: When -20% I max >I U1 >-80%I max , 20%I max W1 <80% I max , I U2 <20% I max , I W2 >-80%I max When the grid voltage detection line R phase line, T phase line, S phase line and the power input power line U phase line, W phase line, V phase line line sequence are consistent;​ S635: When 20% I max >I U1 , I W1 <-80%I max , -20%I max >I U2 >-80%I max , 80%I max >I W2 >20%I max When the power grid voltage detection line S phase line, R phase line, T phase line and the power input power line V phase line, U phase line, W phase line line sequence are consistent; S636: When 20% I max U1 <80% I max , 20%I max W1 <80% I max , I U2 <20% I max , I W2 >-80%I max When the power grid voltage detection line S phase line, T phase line, R phase line and the power input power line W phase line, U phase line, V phase line line are consistent in line sequence;​​ Among them, I max It is the current threshold of the pulse test process.

8. A PWM rectifier line sequence adaptive control method according to claim 7, characterized in that: In S7, the method for determining whether the actual phase sequence needs to be updated is: When the line sequence of the grid voltage detection line R phase line, S phase line, T phase line and the power input power line U phase line, V phase line and W phase line is consistent, it is judged that the actual phase sequence is the same as the initial detection phase sequence, and there is no need to update the actual phase sequence; When the line sequence of the grid voltage detection line T phase line, S phase line, R phase line and the power input power line W phase line, V phase line and U phase line is consistent, it is judged that the actual phase sequence is opposite to the initial detection phase sequence, and the actual phase sequence needs to be updated; When the line sequence of the grid voltage detection line T phase line, R phase line, S phase line and the power input power line V phase line, W phase line, U phase line is consistent, it is judged that the actual phase sequence is the same as the initial detection phase sequence, and there is no need to update the actual phase sequence; When the line sequence of the grid voltage detection line R phase line, T phase line, S phase line and the power input power line U phase line, W phase line, V phase line is consistent, it is judged that the actual phase sequence is opposite to the initial detection phase sequence, and the actual phase sequence needs to be updated; When the line sequence of the grid voltage detection line S phase line, R phase line, T phase line and the power input power line V phase line, U phase line, W phase line is consistent, it is judged that the actual phase sequence is opposite to the initial detection phase sequence, and the actual phase sequence needs to be updated; When the line sequence of the grid voltage detection lines S phase line, T phase line, R phase line and the power input power lines W phase line, U phase line, V phase line are consistent, it is judged that the actual phase sequence is the same as the initial detection phase sequence, and the actual phase sequence does not need to be updated.

9. A PWM rectifier line sequence adaptive control method according to claim 8, characterized in that: In S8, the grid voltage value U between the R phase line and the S phase line is RS , the grid voltage value U between the R phase line and the T phase line RT , the grid voltage value U between the S phase line and the T phase line ST The reconstruction method is: When the line sequence of the grid voltage detection lines R, S, and T in S631 is consistent with the line sequence of the power input power lines U, V, and W, U' RS =U RS , U' RT =U RT , U' ST =U ST ; When the line sequence of the grid voltage detection lines T, S, and R in S632 is consistent with the line sequence of the power input power lines W, V, and U, U' RS =U ST , U' RT =U RT , U' ST =U RS ; When the line sequence of the grid voltage detection line T phase line, R phase line, S phase line and the power input power line V phase line, W phase line, U phase line in S633 is consistent, U' RS =U ST , U' RT =U RS , U' ST =U ST ; When the line sequence of the grid voltage detection line R phase line, T phase line, S phase line and the power input power line U phase line, W phase line, V phase line in S634 is consistent, U' RS =U ST , U' RT =U ST , U' ST =U RT ; When the line sequence of the grid voltage detection line S phase line, R phase line, T phase line and the power input power line V phase line, U phase line, W phase line in S635 is consistent, U' RS =U RT , U' RT =U ST , U' ST =U RS ; When the line sequence of the grid voltage detection line S phase line, T phase line, R phase line and the power input power line W phase line, U phase line, V phase line in S636 is consistent, U' RS =-U ST , U' RT =-U RT , U' ST =-U RS .

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