A coordinated optimization control method for dual full-bridge DC-DC converters in single-phase power electronic conversion systems

Abstract

The present invention belongs to the field of power electronics technology, and specifically relates to a coordinated optimization control method for a dual full-bridge DC-DC converter in a single-phase power electronic conversion system, comprising: obtaining operation data of the single-phase power electronic conversion system at the beginning of a control cycle; setting a maximum limit value of a maximum double frequency ripple amplitude; calculating an upper limit and a lower limit of a maximum double frequency ripple amplitude of direct current on both sides; comparing the upper and lower limits with the maximum limit value, and calculating an optimized value of the double frequency power amplitude of a dual full-bridge DCDC converter; calculating a feedforward compensation value of the double frequency power; converting the feedforward compensation value into a phase shift angle, and using the phase shift angle as a control instruction, and optimizing and controlling the dual full-bridge DCDC converter through the control instruction; a novel control technology proposed by the present invention realizes coordinated control between two goals of suppressing a double frequency ripple of a DC voltage and suppressing a low-frequency fluctuation of a DC / DC converter current in a single-phase AC / DC conversion system.

Description

Technical Field

[0001] The invention belongs to the technical field of power electronics, and in particular relates to a coordinated optimization control method for a dual full-bridge DC-DC converter in a single-phase power electronic conversion system. Background Art

[0002] In the field of power electronics technology, single-phase AC / DC ( / AC) power electronic conversion systems are widely used in many practical fields, such as power electronic transformers, electric vehicle charging, battery energy storage, renewable energy generation, etc.; and the dual full-bridge DC / DC converter + H-bridge converter is one of the typical topological structures in the single-phase AC / DC ( / AC) power electronic conversion system. In the single-phase AC / DC power electronic conversion system, there is an inherent instantaneous power flow with double frequency, which will not only cause a large double frequency ripple in the DC bus voltage, affecting the safe and stable operation of the converter and the power quality, but also cause the DC / DC converter current fluctuation to cause a significant increase in current stress and reduce work efficiency.

[0003] In the prior art, there are still many problems in the single-phase AC / DC power electronic conversion system. For example, when suppressing the double frequency fluctuation of the DC bus voltage, a larger inductor and capacitor series resonant branch is connected in parallel on the DC bus to absorb the double frequency power in the system with passive devices; additional active switching devices and smaller capacitors and inductors are added to construct auxiliary power electronic converters to actively absorb the double frequency power on the DC side; however, both of the above methods require additional hardware, which increases economic costs, control complexity and power loss. Therefore, how to suppress DC voltage ripple by only using specific control technology without adding additional devices is an urgent problem to be solved; in the prior art, a DC / DC converter is used to absorb and transmit all the double frequency power on the primary DC side to the secondary DC side, or a DC / DC converter is used to absorb and transmit all the double frequency power on the secondary DC side to the primary DC side, or a DC / DC converter is used to transmit all the double frequency power on the primary DC side to the secondary DC side and achieve complete cancellation based on a three-phase symmetrical structure or phase compensation principle, or a virtual impedance control technology is introduced to suppress the input or output current of the DC / DC converter. However, the above method, while suppressing the low-frequency ripple of DC voltage, leads to larger low-frequency fluctuation of DC / DC converter current; while suppressing the low-frequency fluctuation of DC / DC converter current, leads to larger low-frequency ripple of DC voltage; in practical applications, some loads have high requirements on the power quality of DC voltage, in which case the voltage ripple should be reduced as much as possible; other loads are not sensitive to voltage ripple, in which case the current fluctuation of DC / DC converter should be reduced as much as possible to improve working efficiency. Summary of the invention

[0004] In order to solve the problem that the existing control technology cannot simultaneously take into account and flexibly regulate the two goals of suppressing DC voltage ripple and suppressing DC / DC current fluctuation, the coordinated optimization control of DC voltage double frequency ripple and DC / DC current low-frequency fluctuation is realized. The present invention proposes a coordinated optimization control method for a dual full-bridge DC-DC converter in a single-phase power electronic conversion system, which includes:

[0005] S1: acquiring the operating data of the single-phase power electronic conversion system in real time at the beginning of the control cycle;

[0006] S2: Set the maximum limit value V of the maximum double frequency ripple amplitude of the DC voltage v2 and v1 on both sides of the primary and secondary sides in the single-phase power electronic conversion system f,lim ;

[0007] S3: Calculate the maximum double frequency ripple amplitude upper limit V of the DC voltages v2 and v1 on both sides based on the operating data f,max | AGCSM and the lower limit V f,max | GVRM ;

[0008] S4: Set the maximum double frequency ripple amplitude upper limit V f,max | AGCSM and the lower limit V f,max | GVRM With the maximum limit value V f,lim Compare and calculate the optimal value P of the double frequency power amplitude of the dual full-bridge DCDC converter according to the comparison results DABf,aopt ;

[0009] S5: Optimize the value P according to the double frequency power amplitude DABf,aopt Calculation of the optimal power phase value γ of the double frequency dual full-bridge DCDC converter aopt ;

[0010] S6: Calculate the feedforward compensation value p of the double frequency power according to the double frequency power phase optimization value of the dual full-bridge DCDC converter f ;

[0011] S7: The feedforward compensation value p of the double frequency power f The phase shift angle δ is converted into the phase shift angle δ of the dual full-bridge DCDC converter, and the phase shift angle δ is used as a control instruction to optimize the dual full-bridge DCDC converter through the control instruction.

[0012] Preferably, the operating data includes the AC output voltage v of the single-phase H-bridge inverter s1 The amplitude U s1 , AC output current i of single-phase H-bridge inverter s1 The amplitude I s1 , AC output voltage v of single-phase H-bridge rectifiers2 The amplitude U s2 , grid-connected current i of single-phase H-bridge rectifier s2 The amplitude I s2 , single-phase H-bridge inverter AC side power factor angle And the AC side power factor angle of the single-phase H-bridge rectifier

[0013] Preferably, the maximum double frequency ripple amplitude upper limit V of the DC voltages v2 and v1 on both sides is calculated. f,max | AGCSM and the lower limit V f,max | GVRM The formula is:

[0014]

[0015]

[0016] Among them, U s1 is the AC output voltage v of the single-phase H-bridge inverter s1 The amplitude, I s1 is the AC output current i of the single-phase H-bridge inverter s1 The amplitude, U s2 is the AC output voltage v of the single-phase H-bridge rectifier s2 The amplitude, I s2 is the grid-connected current i of the single-phase H-bridge rectifier s2 The amplitude of is the AC side power factor angle of the single-phase H-bridge inverter, is the AC side power factor angle of the single-phase H-bridge rectifier, is the voltage v s1 and v s2 Phase difference, V 2,ref and V 1,ref are the reference values ​​of DC voltages v2 and v1, ω g is the grid voltage v g angular frequency, C2 and C1 are the DC side capacitance values ​​of the primary and secondary sides of the dual full-bridge DC / DC converter respectively.

[0017] Preferably, the double frequency power amplitude optimization value P of the dual full-bridge DCDC converter is calculated according to the comparison result. DABf,aopt The process includes: when V f,max | GVRM ≤V f,lim ≤V f,max | AGCSM When the double-bridge DCDC converter double frequency power amplitude optimization value P is calculated DABf,aopt1 ; When V f,lim <V f,max | GVRMWhen the double-bridge DCDC converter double frequency power amplitude optimization value P is calculated DABf,aopt2 ; When V f,lim >V f,max | AGCSM When the double-bridge DCDC converter double frequency power amplitude optimization value P is calculated DABf,aopt3 .

[0018] Preferably, the formula for calculating the double frequency power phase optimization value of the dual full-bridge DCDC converter is:

[0019]

[0020] in, is the AC side power factor angle of the single-phase H-bridge inverter, is the AC side power factor angle of the single-phase H-bridge rectifier, is the voltage v s1 and v s2 The phase difference between them.

[0021] Preferably, the optimized feedforward compensation value p of the double frequency power of the dual full-bridge DCDC converter is f The calculation formula is:

[0022] p f =P DABf,aopt1(2)(3) sin(2ω g t+γ aopt )+k p V 1f,aopt sin(2ω g t+θ 1,aopt )

[0023] Among them, ω g is the grid voltage v g angular frequency, t is time, γ aopt is the optimal value of the double frequency power phase of the dual full-bridge DCDC converter, k p is the proportional coefficient in the voltage closed-loop PI controller, V 1f,aopt is the optimized amplitude of the double frequency component in the DC voltage v1, θ 1,aopt is the optimized phase of the double frequency component in the DC voltage v1.

[0024] Preferably, the feedforward compensation value p of the double frequency power is f The process of converting into the phase shift angle of the dual full-bridge DCDC converter includes: converting the optimized feedforward compensation value p of the double frequency power of the dual full-bridge DCDC converter f Converted into the output power reference value p of the dual full-bridge DCDC converter ref , the output power reference value p ref Converted into the phase shift angle δ of the dual full-bridge DCDC converter; its calculation formula is:

[0025] p ref =p f +k p (V 1,ref -v1)+k i ∫(V 1,ref -v1)dt

[0026]

[0027] ω s =2πf s

[0028] Among them, k p is the proportional coefficient in the voltage closed-loop PI controller, k i is the integral coefficient in the voltage closed-loop PI controller, V 1,ref represents the reference value of DC voltage v1, L is the auxiliary inductance of high-frequency transformer T, f s is the switching frequency of the dual full-bridge DCDC converter.

[0029] Beneficial effects of the present invention:

[0030] A new control technology proposed in the present invention realizes the coordinated control between the two goals of suppressing the double frequency ripple of the DC voltage and suppressing the low-frequency fluctuation of the DC / DC converter current in a single-phase AC / DC ( / AC) conversion system, and can be flexibly adjusted according to actual working conditions; A new control technology proposed in the present invention can always control the low-frequency fluctuation amplitude of the DC / DC converter current to the minimum value under the current DC voltage ripple amplitude, that is, realizes the optimal trajectory control of voltage ripple-current fluctuation, and effectively improves the working efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of a coordinated optimization control method for a dual full-bridge DC / DC converter of the present invention;

[0032] Figure 2 A topological structure diagram of a single-phase AC / DC / AC power electronic conversion system of the present invention;

[0033] Figure 3 It is a coordinated optimization control principle diagram of the dual full-bridge DC-DC converter of the present invention;

[0034] Figure 4 is the optimal control trajectory diagram of the present invention;

[0035] Figure 5 This is the key working waveform diagram of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] A coordinated optimization control method for dual full-bridge DC-DC converters in a single-phase power electronic conversion system. Figure 1 As shown, the method includes:

[0038] S1: acquiring the operating data of the single-phase power electronic conversion system in real time at the beginning of the control cycle;

[0039] S2: Set the maximum limit value V of the maximum double frequency ripple amplitude of the DC voltage v2 and v1 on both sides of the primary and secondary sides in the single-phase power electronic conversion system f,lim ;

[0040] S3: Calculate the maximum double frequency ripple amplitude upper limit V of the DC voltages v2 and v1 on both sides based on the operating data f,max | AGCSM and the lower limit V f,max | GVRM ;

[0041] S4: Set the maximum double frequency ripple amplitude upper limit V f,max | AGCSM and the lower limit V f,max | GVRM With the maximum limit value V f,lim Compare and calculate the optimal value P of the double frequency power amplitude of the dual full-bridge DCDC converter according to the comparison results DABf,aopt ;

[0042] S5: Optimize the value P according to the double frequency power amplitude DABf,aopt Calculation of the optimal power phase value γ of the double frequency dual full-bridge DCDC converter aopt ;

[0043] S6: Calculate the feedforward compensation value p of the double frequency power according to the double frequency power phase optimization value of the dual full-bridge DCDC converter f ;

[0044] S7: The feedforward compensation value p of the double frequency power f The phase shift angle δ is converted into the phase shift angle δ of the dual full-bridge DCDC converter, and the phase shift angle δ is used as a control instruction to optimize the dual full-bridge DCDC converter through the control instruction.

[0045] A specific implementation of a single-phase AC / DC / AC system topology. Figure 2As shown in the figure, the system consists of a single-phase H-bridge rectifier, a dual full-bridge DC / DC converter (Dual Active Bridge, DAB) and a single-phase H-bridge inverter. The AC side of the single-phase H-bridge rectifier is connected to a single-phase AC grid, and the voltage of the single-phase AC grid is v g The single-phase H-bridge rectifier consists of four power electronic fully controlled switching devices (MOSFET or IGBT) from S1 to S4. s2 It is the grid-connected filter inductor of the single-phase H-bridge rectifier. s2 and i s2 They are the AC output voltage and grid-connected current of the single-phase H-bridge rectifier respectively. The dual full-bridge DC / DC converter consists of the primary H-bridge (Q1~Q4), the secondary H-bridge (Q5~Q8), the high-frequency transformer T and the auxiliary inductor L. Q1~Q4 and Q5~Q8 are all power electronic fully controlled switching devices (MOSFET or IGBT). L is the current of the high frequency transformer T. L,peak is the current i L The maximum value is the current stress of the dual full-bridge DC / DC converter. C2 is the primary DC side capacitor of the dual full-bridge DC / DC converter, and C1 is the secondary DC side capacitor of the dual full-bridge DC / DC converter. v2 and v1 are the voltages of DC capacitors C2 and C1 respectively (i.e. the primary and secondary DC side voltages of the dual full-bridge DCDC converter). The single-phase H-bridge inverter is also composed of four switching devices, v s1 and i s1 are the AC output voltage and AC output current of the single-phase H-bridge inverter respectively. s1 It is the AC output filter inductor of the single-phase H-bridge inverter.

[0046] A coordinated optimization control method for a dual full-bridge DC / DC converter in a single-phase AC / DC / AC system can be applied to a digital signal processor or controller such as a DSP / FPGA / ARM, in which the following ten steps S1 to S10 are periodically and repeatedly executed. The method includes:

[0047] S1: The kth control cycle starts, collecting and acquiring real-time operation data, including the AC output voltage v of the single-phase H-bridge inverter s1 and current i s1 The amplitude U s1 and I s1 , the AC output voltage v of the single-phase H-bridge rectifier s2 and grid current i s2 The amplitude U s2 and I s2 , single-phase H-bridge inverter AC side power factor angle Single-phase H-bridge rectifier AC side power factor angle Voltages1 and v s2 Phase difference v2 and v1 are the DC side voltages of the primary and secondary sides of the dual full-bridge DCDC converter respectively;

[0048] S2: Set the maximum limit value V of the maximum double frequency ripple amplitude of the DC voltage v2 and v1 on both sides of the primary and secondary sides f,lim ;

[0049] S3: Calculate the maximum double frequency ripple amplitude upper limit V of the DC voltages v2 and v1 on both sides f,max | AGCSM and the lower limit V f,max | GVRM , the calculation formula is as follows:

[0050]

[0051]

[0052] Among them, U s1 is the AC output voltage v of the single-phase H-bridge inverter s1 The amplitude, I s1 is the AC output current i of the single-phase H-bridge inverter s1 The amplitude, U s2 is the AC output voltage v of the single-phase H-bridge rectifier s2 The amplitude, I s2 is the grid-connected current i of the single-phase H-bridge rectifier s2 The amplitude of is the AC side power factor angle of the single-phase H-bridge inverter, is the AC side power factor angle of the single-phase H-bridge rectifier, is the voltage v s1 and v s2 Phase difference, V 2,ref and V 1,ref are the reference values ​​of DC voltages v2 and v1, ω g is the grid voltage v g angular frequency, C2 and C1 are the DC side capacitance values ​​of the primary and secondary sides of the dual full-bridge DC / DC converter respectively.

[0053] S4: Determine and compare the set value V f,lim With upper limit V f,max | AGCSM and the lower limit V f,max | GVRM The size relationship between them is, if V f,lim Less than or equal to V f,max | AGCSM And V f,lim Greater than or equal to V f,max | GVRM, then execute S5. If V f,lim Less than V f,max | GVRM , then execute S6, if V f,lim Greater than V f,max | AGCSM , then execute S7;

[0054] S5: Calculate the optimal value P of the double frequency power amplitude of the dual full-bridge DCDC converter DABf,aopt1 , execute S8;

[0055] S6: Calculate the optimal value P of the double frequency power amplitude of the dual full-bridge DCDC converter DABf,aopt2 , execute S8;

[0056] S7: Calculate the optimal value P of the double frequency power amplitude of the dual full-bridge DCDC converter DABf,aopt3 , execute S8; P DABf,aopt1 , P DABf,aopt2 and P DABf,aopt3 The calculation formula is:

[0057]

[0058]

[0059] P DABf,aopt3 =0

[0060] in, is the AC side power factor angle of the single-phase H-bridge inverter, is the AC side power factor angle of the single-phase H-bridge rectifier, is the voltage v s1 and v s2 The phase difference between them.

[0061] S8: Calculate the optimal value γ of the double frequency power phase of the dual full-bridge DCDC converter aopt , the calculation formula is as follows:

[0062]

[0063] S9: Calculate the feedforward compensation value p of the double frequency power f , the calculation formula is as follows:

[0064] p f =P DABf,aopt1(2)(3) sin(2ω g t+γ aopt )+k p V 1f,aopt sin(2ω g t+θ 1,aopt )

[0065] Where V1f,aopt and θ 1,aopt The calculation formula is:

[0066]

[0067]

[0068] S10: Real-time calculation of the output power reference value p of the dual full-bridge DCDC converter ref And the phase shift angle δ of the dual full-bridge DCDC converter is used as the control instruction, and the calculation formula is as follows:

[0069] p ref =p f +k p (V 1,ref -v1)+k i ∫(V 1,ref -v1)dt

[0070]

[0071] After the above calculation is completed, the kth control cycle ends, and after waiting for the next control cycle (i.e., the k+1th control cycle) to start, the ten steps S1 to S10 are repeated, and this process is repeated repeatedly to achieve real-time optimization control of the power electronic system. Figure 3 shown.

[0072] In this embodiment, the parameters of the single-phase AC / DC / AC system include: grid-connected filter inductance L s2 =4mH, auxiliary inductor L = 63uH, double-side DC capacitor C1 = C2 = 420uF, output filter inductor L s1 =3mH, grid voltage v g The amplitude is 84.85V, and the AC output voltage v of the single-phase H-bridge inverter is s1 and current i s1 The amplitude U s1 and I s1 They are 84.85V and 11.78A respectively. The AC side power factor of the single-phase H-bridge inverter is Single-phase H-bridge rectifier AC side power factor angle Voltage s1 and v s2 Phase difference Reference value V of the DC voltage v2 and v1 on both sides 2,ref and V 1,ref Both are 100V.

[0073] The optimal control trajectory of the control method proposed by the present invention is always Figure 4 As shown. Figure 4The optimal control trajectory can control the low-frequency current fluctuation amplitude of the DC / DC converter to the minimum value under the current DC voltage ripple amplitude based on this trajectory, that is, the voltage ripple-current fluctuation optimal trajectory control is realized, which effectively improves the working efficiency of the system.

[0074] Under the control method proposed by the present invention, the key working waveforms of the system are as follows: Figure 5 As shown. At t = 0s, t = 0.05s and t = 0.1s, V is actively set. f,lim 3V, 6V and 16V, it can be seen that the double frequency ripple amplitudes of DC voltages v1 and v2 also change to 3V, 6V and 16V respectively. Moreover, it can be seen that as V f,lim The increase of current stress i L,peak The maximum current stress is about twice the minimum value, and the maximum voltage ripple is about 10 times the minimum voltage ripple. The values ​​of current stress and voltage ripple are consistent with Figure 4 The optimal control trajectory shown has a wide adjustable range of voltage ripple and current stress, which can meet the diverse needs under different working conditions. The working waveform shows that the control method proposed in the present invention can achieve flexible control of the two objectives of voltage ripple and current stress, and can optimize the current stress.

[0075] The above embodiments further illustrate the purpose, technical solutions and advantages of the present invention in detail. It should be understood that the above embodiments are only preferred implementation modes of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made to the present invention within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A coordinated optimization control method for a dual full-bridge DC-DC converter in a single-phase power electronic conversion system, characterized in that: include: S1: Acquire the operating data of the single-phase power electronic conversion system in real time at the beginning of the control cycle; the operating data includes the AC output voltage v of the single-phase H-bridge inverter s1 The amplitude U s1 , AC output current i of single-phase H-bridge inverter s1 The amplitude I s1 , AC output voltage v of single-phase H-bridge rectifier s2 The amplitude U s2 , grid-connected current i of single-phase H-bridge rectifier s2 The amplitude I s2 , single-phase H-bridge inverter AC side power factor angle And the AC side power factor angle of the single-phase H-bridge rectifier S2: Set the maximum limit value V of the maximum double frequency ripple amplitude of the DC voltage v2 and v1 on both sides of the primary and secondary sides in the single-phase power electronic conversion system f,lim ; S3: Calculate the maximum double frequency ripple amplitude upper limit V of the DC voltages v2 and v1 on both sides based on the operating data f,max | AGCSM and the lower limit V f,max | GVRM ; S4: Set the maximum double frequency ripple amplitude upper limit V f,max | AGCSM and the lower limit V f,max | GVRM With the maximum limit value V f,lim Compare and calculate the optimal value P of the double frequency power amplitude of the dual full-bridge DCDC converter according to the comparison results DABf,aopt ; S5: Optimize the value P according to the double frequency power amplitude DABf,aopt Calculation of the optimal power phase value γ of the double frequency dual full-bridge DCDC converter aopt ; S6: Calculate the feedforward compensation value p of the double frequency power according to the double frequency power phase optimization value of the dual full-bridge DCDC converter f ; S7: The feedforward compensation value p of the double frequency power f The phase shift angle δ is converted into the phase shift angle δ of the dual full-bridge DCDC converter, and the phase shift angle δ is used as a control instruction to optimize the dual full-bridge DCDC converter through the control instruction.

2. The coordinated optimization control method of a dual full-bridge DC-DC converter in a single-phase power electronic conversion system according to claim 1, characterized in that: Calculate the maximum double frequency ripple amplitude upper limit V of the DC voltage v2 and v1 on both sides f,max | AGCSM and the lower limit V f,max | GVRM The formula is: Among them, U s1 is the AC output voltage v of the single-phase H-bridge inverter s1 The amplitude, I s1 is the AC output current i of the single-phase H-bridge inverter s1 The amplitude, U s2 is the AC output voltage v of the single-phase H-bridge rectifier s2 The amplitude, I s2 is the grid-connected current i of the single-phase H-bridge rectifier s2 The amplitude of is the AC side power factor angle of the single-phase H-bridge inverter, is the AC side power factor angle of the single-phase H-bridge rectifier, is the voltage v s1 and v s2 Phase difference, V 2,ref and V 1,ref are the reference values ​​of DC voltages v2 and v1, ω g is the grid voltage v g angular frequency, C2 and C1 are the DC side capacitance values ​​of the primary and secondary sides of the dual full-bridge DC / DC converter respectively.

3. The coordinated optimization control method of a dual full-bridge DC-DC converter in a single-phase power electronic conversion system according to claim 1, characterized in that: According to the comparison results, the optimal value P of the double frequency power amplitude of the dual full-bridge DCDC converter is calculated. DABf,aopt The process includes: when V f,max | GVRM ≤V f,lim ≤V f,max | AGCSM When the double-bridge DCDC converter double frequency power amplitude optimization value P is calculated DABf,aopt1 ; When V f,lim <V f,max | GVRM When the double-bridge DCDC converter double frequency power amplitude optimization value P is calculated DABf,aopt2 ; When V f,lim >V f,max | AGCSM When the double-bridge DCDC converter double frequency power amplitude optimization value P is calculated DABf,aopt3 .

4. The coordinated optimization control method of a dual full-bridge DC-DC converter in a single-phase power electronic conversion system according to claim 3, characterized in that: The calculation formula for the optimal value of the double frequency power amplitude of the dual full-bridge DCDC converter is: P DABf,aopt3 ＝0 in, is the AC side power factor angle of the single-phase H-bridge inverter, is the AC side power factor angle of the single-phase H-bridge rectifier, is the voltage v s1 and v s2 The phase difference between them.

5. The coordinated optimization control method of a dual full-bridge DC-DC converter in a single-phase power electronic conversion system according to claim 1, characterized in that: The formula for calculating the optimal value of the double frequency power phase of the dual full-bridge DCDC converter is: in, is the AC side power factor angle of the single-phase H-bridge inverter, is the AC side power factor angle of the single-phase H-bridge rectifier, is the voltage v s1 and v s2 The phase difference between them.

6. The coordinated optimization control method of a dual full-bridge DC-DC converter in a single-phase power electronic conversion system according to claim 1, characterized in that: The calculation formula of the optimized feedforward compensation value pf of the double frequency power of the dual full-bridge DCDC converter is: p f =P DABf,aopt1(2)(3) sin(2ω g t+c aopt )+k p V 1f,aopt sin(2ω g t+θ 1,aopt ) Among them, ω g is the grid voltage v g angular frequency, t is time, γ aopt is the optimal value of the double frequency power phase of the dual full-bridge DCDC converter, k p is the proportional coefficient in the voltage closed-loop PI controller, V 1f,aopt is the optimized amplitude of the double frequency component in the DC voltage v1, θ 1,aopt is the optimized phase of the double frequency component in the DC voltage v1.

7. The coordinated optimization control method of a dual full-bridge DC-DC converter in a single-phase power electronic conversion system according to claim 1, characterized in that: The process of converting the feedforward compensation value pf of the double frequency power into the phase shift angle of the dual full-bridge DCDC converter includes: converting the optimized feedforward compensation value pf of the double frequency power of the dual full-bridge DCDC converter into the output power reference value pref of the dual full-bridge DCDC converter, and converting the output power reference value pref into the phase shift angle δ of the dual full-bridge DCDC converter; the calculation formula is: p ref =p f +k p (V 1,ref -v1)+k i ∫(V 1,ref -v1)dt Among them, k p is the proportional coefficient in the voltage closed-loop PI controller, k i is the integral coefficient in the voltage closed-loop PI controller, V 1,ref represents the reference value of DC voltage v1, L is the auxiliary inductance of high-frequency transformer T, f s is the switching frequency of the dual full-bridge DCDC converter.

Images