A full-condition ZVS bidirectional resonant DAB control method

Abstract

The application discloses a bidirectional resonant DAB control method of full working condition ZVS. According to a power interval of a given power, the working mode of the bidirectional resonant DAB is divided into an extremely light load mode, a medium-low load mode and a medium-high load mode, and then the three degrees of freedom of three-phase shift and frequency modulation are controlled. The application can switch among the three modes according to different given power conditions, can realize ZVS in a full working condition range (including a forward full working condition and a reverse full working condition), and can improve the circuit operation efficiency under heavy load and medium load working conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to a control method of a resonant dual active bridge circuit (DAB) in the field of new energy converters, and in particular to a control method and system capable of achieving wide gain range, full operating condition ZVS and efficiency optimization for a bidirectional resonant dual active bridge DC-DC circuit. BACKGROUND

[0002] Wide-range bidirectional DC-DC converters are in increasing demand in the fields of electric vehicle charging piles, energy storage converters, communication power supplies, etc. For example, in the field of electric vehicle charging piles, high efficiency, miniaturization and low cost are the development trends in the current market. In addition, the construction of smart energy networks accelerates, making the demand for bidirectional energy transmission (V2G) of charging piles increasing, and requiring charging pile circuits to have bidirectional working capability.

[0003] Early direct-current charging piles use a two-stage topology, with the front stage being an AC-DC rectifier circuit and the rear stage being an LLC as a DC-DC converter. However, the traditional LLC circuit lacks bidirectional capability and cannot realize V2G function. Although the CLLC circuit has bidirectional buck-boost capability, its gain range is limited and cannot adapt to the needs of battery capacity and grid voltage fluctuations. A too wide gain range will make the design of the CLLC resonant cavity difficult, and in some scenarios, the resonant cavity parameters that meet a specific gain can only exist in theory and are difficult to be productized. Some products (including charging piles, user energy storage systems and similar products) expand the gain range of the converter by adding a stage of step-down or step-up circuit after the CLLC, but the three-stage circuit increases the cost and product size.

[0004] Dual active bridge circuits (DAB) can meet the bidirectional wide-range requirement, but the traditional dual active bridge circuit has defects such as large reactive current circulation and large off-current, and has not been widely used in commercial applications. In recent years, there have been researches on resonant DAB circuits and methods of using multiple phase-shifting techniques to improve efficiency, but it is difficult to simultaneously consider efficiency, wide range and zero-voltage switching (ZVS).

[0005] Once ZVS is lost, on the one hand, switching loss is increased, and on the other hand, at a high voltage platform (for example, 400V), power electronic switching devices can only be selected from IGBT, SiC, etc. IGBT devices have slow operating speed and low operating frequency, which is not conducive to circuit miniaturization design. SiC devices are expensive and not conducive to cost control, and in the case of hard switching, the switching stress of power electronic devices is large, and the corresponding driving signal, voltage and current spikes are difficult to suppress, which can cause serious electromagnetic interference and reduce the stability and reliability of the circuit operation. SUMMARY

[0006] In order to solve the problems in the background art, the application provides a wide-range and full-condition ZVS bidirectional resonant DAB control method.

[0007] The technical solutions of the application are as follows:

[0008] One kind of wide-range and full-condition ZVS bidirectional resonant DAB control method

[0009] The input voltage U of the bidirectional resonant DAB is obtained in , the output voltage U is obtained out , the boost / buck condition of the bidirectional resonant DAB is determined according to the input voltage U in and the output voltage U out .

[0010] The given power P of the bidirectional resonant DAB is obtained ref , the working mode of the bidirectional resonant DAB is determined according to the given power P of the bidirectional resonant DAB ref .

[0011] The input voltage U of the bidirectional resonant DAB is obtained in , the output voltage U is obtained out , the boost / buck condition and the working mode, the primary side inner phase shift angle α, the secondary side inner phase shift angle β, the outer phase shift angle and the switching frequency f w of the bidirectional resonant DAB are controlled, so that the bidirectional resonant DAB does not lose ZVS in full condition, and the primary side inner phase shift angle α, the secondary side inner phase shift angle β, the outer phase shift angle and the switching frequency f w smoothly switch between different working modes.

[0012] The boost / buck condition of the bidirectional resonant DAB is determined according to the input voltage U in and the output voltage U out , specifically:

[0013] When the input voltage U is the primary side terminal voltage in , and the output voltage U is the secondary side terminal voltage out , the bidirectional resonant DAB in the boost condition satisfies n·U in >U out , and the bidirectional resonant DAB in the buck condition satisfies n·U in ≤U out , wherein n is the ratio of the number of turns of the secondary side to the number of turns of the primary side.

[0014] the given power P of the bidirectional resonant type DAB ref determining the working mode of the bidirectional resonant type DAB, specifically:

[0015] when the given power P of the bidirectional resonant type DAB ref is greater than the medium-high load power lower limit P1, then the working mode of the bidirectional resonant type DAB is the medium-high load mode;

[0016] when the given power P of the bidirectional resonant type DAB ref is greater than the medium-low load power lower limit P2 and less than or equal to the medium-high load power lower limit P1, then the working mode of the bidirectional resonant type DAB is the medium-low load mode;

[0017] when the given power P of the bidirectional resonant type DAB ref is less than or equal to the medium-low load power lower limit P2, then the working mode of the bidirectional resonant type DAB is the extremely light load mode.

[0018] In the case of step-up, when the working mode of the bidirectional resonant type DAB is the medium-high load mode, the values of the medium-high load mode primary side inner phase angle α, secondary side inner phase angle β, outer phase angle and switching frequency f w are specifically:

[0019] α = 0,

[0020]

[0021]

[0022] a = L r · C r · P ref ,

[0023] c = -P ref ,

[0024] wherein L r is the resonant inductance value, C r is the resonant capacitance value, a, b, c are respectively the first-third intermediate parameters, θ is the preset deviation phase angle, and n is the ratio of the secondary side turn number to the primary side turn number.

[0025] In the case of step-up, when the working mode of the bidirectional resonant type DAB is the medium-low load mode, the values of the medium-low load mode primary side inner phase angle α, secondary side inner phase angle β, outer phase angle and switching frequency f w are specifically:

[0026]

[0027] a = L r · C r · P ref ,

[0028] c = -P ref ,

[0029] wherein, L r is a resonance inductance value, C r is a resonance capacitance value, a, b, c are respectively the first-third intermediate parameters, θ is a preset deviation phase angle, n is a ratio of the number of turns of the secondary side to the number of turns of the primary side, P2 is a lower limit of medium-low load power, and P1 is an upper limit of medium-high load power.

[0030] In the case of step-up, when the working mode of the bidirectional resonant DAB is the extremely light load mode, the primary side inner phase shift angle α, the secondary side inner phase shift angle β, the outer phase shift angle and the switching frequency f w are specifically as follows:

[0031]

[0032] β = π - α - 2θ

[0033] a = L r · C r · P2,

[0034] c = -P2

[0035]

[0036] wherein, L r is a resonance inductance value, C r is a resonance capacitance value, a, b, c are respectively the first-third intermediate parameters, θ is a preset deviation phase angle, n is a ratio of the number of turns of the secondary side to the number of turns of the primary side, P2 is a lower limit of medium-low load power, and P1 is an upper limit of medium-high load power.

[0037] II. A bidirectional resonant DAB control system with wide range and full working condition ZVS

[0038] a circuit boost / buck condition determination module, configured to determine the boost / buck condition of the bidirectional resonant DAB according to the input voltage U in and the output voltage U out ;

[0039] a circuit working mode determination module, configured to determine the working mode of the bidirectional resonant DAB according to the given power P ref of the bidirectional resonant DAB;

[0040] A controller for controlling, according to the input terminal voltage U in and output terminal voltage U out of a bidirectional resonant DAB, as well as the step-up / step-down condition and working mode, the primary internal phase-shift angle α, secondary internal phase-shift angle β, external phase-shift angle and switching frequency f w of the bidirectional resonant DAB, so that the bidirectional resonant DAB does not lose ZVS under all working conditions, and the primary internal phase-shift angle α, secondary internal phase-shift angle β, external phase-shift angle and switching frequency f<00,00048>smoothly switch between different working modes.

[0041] The controller includes a medium-high load mode control unit, a medium-low load mode control unit, and an extremely light load mode control unit. <00002,69><0,000270>III. A computer device

[0043] The device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the steps of the method for controlling a bidirectional resonant DAB with wide-range and full-condition ZVS are implemented.

[0044] IV. A computer-readable storage medium

[0045] The medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for controlling a bidirectional resonant DAB with wide-range and full-condition ZVS are implemented.

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0047] (1) The present invention can achieve full-range ZVS, ensuring that the circuit does not lose soft switching under medium-high load, medium-low load, especially extremely light load;

[0048] (2) When the resonant DAB circuit of the present invention operates in the medium-high load section, the working frequency is the lowest, close to the resonant frequency, and the degree of resonance is very high, which is beneficial to improving the working efficiency of the circuit;

[0049] (3) When the resonant DAB circuit of the present invention operates in the medium-high load and medium-low load sections, it always operates near the critical full-ZVS point (one arm of each of the primary and secondary sides is near ZVS, hereinafter referred to as critical full-ZVS), making the turn-off current of the switching devices of the two groups of arms close to 0, which is beneficial to improving the working efficiency of the circuit;

[0050] (4) When the resonant DAB circuit of the present invention operates in the medium-high load section, it greatly reduces i under the condition of the same power rThe effective value (RMS) improves the overall working efficiency of the circuit;

[0051] (5) The resonant DAB circuit of the application can be smoothly connected through mode switching between very light load mode, medium-low load mode, medium-high load mode and forward and reverse operation, and the phase shift angle and frequency do not jump. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 It is a schematic diagram of a bidirectional resonant DAB circuit and a control system thereof.

[0053] Figure 2 It is a flowchart of the optimization control method proposed by the application. DETAILED DESCRIPTION

[0054] The application will be described in detail below in combination with the drawings and examples.

[0055] The bidirectional resonant DAB control method proposed by the application can realize ZVS in a wide range and full working condition according to the given power P ref The power range of the bidirectional resonant DAB circuit is divided into very light load mode, medium-low load mode and medium-high load mode, and through the control of three phase shifts and frequency modulation, the four degrees of freedom can be switched among the three modes according to different given power conditions, ZVS can be realized in the full working condition range (including forward full working condition and reverse full working condition), and the circuit running efficiency under heavy load and medium load working conditions can be improved.

[0056] The resonant DAB circuit and the control system thereof are as follows Figure 1As shown, the resonant DAB circuit includes eight switches S1 to S8. The input of the resonant DAB circuit is defined as the primary side, and the output as the secondary side, with power transferred from the input to the output. The first and second switches S1 and S2 on the primary side form one bridge arm, and the third and fourth switches S3 and S4 form another bridge arm. On the secondary side, the fifth and sixth switches S5 and S6 form one bridge arm, and the seventh and eighth switches S7 and S8 form another bridge arm, resulting in two full-bridge circuits. The transformer T, the resonant capacitor (capacitance value Cr), and the secondary resonant inductor (inductance value Lr) are connected in series. In the control signals of the resonant DAB circuit, the control signals for all eight switches S1 to S8 are square waves with a dead time and a 50% duty cycle. The control signals for the first and second switches S1 and S2 are complementary, as are the control signals for the third and fourth switches S3 and S4, the control signals for the fifth and sixth switches S5 and S6, and the control signals for the seventh and eighth switches S7 and S8. The phase difference between the control signals of the two half-bridge circuits on the primary side (i.e., the phase difference between the control signals of S1 and S3) is denoted as the primary side internal phase shift angle α, the phase difference between the control signals of the two half-bridge circuits on the secondary side (i.e., the phase difference between the control signals of S5 and S7) is denoted as the secondary side internal phase shift angle β, and the phase difference between the voltage difference at the midpoint of the primary side bridge arm and the voltage difference at the midpoint of the secondary side bridge arm is denoted as the external phase shift angle.

[0057] Input voltage U in Output voltage U out For detection and acquisition; transformer turns ratio n is an inherent parameter of the circuit; P ref For system given values: primary side inward phase shift angle α, secondary side inward phase shift angle β, and external phase shift angle. and switching frequency f w All of these are controllable variables that can be set by the control system. In this invention, the primary side inward phase shift angle α, the secondary side inward phase shift angle β, and the outer phase shift angle are all controllable variables that can be set by the control system. and switching frequency f w The specific value can be calculated using an optimization control method proposed in this invention.

[0058] like Figure 2 As shown, the bidirectional resonant DAB control method with wide-range and full-condition ZVS proposed in this invention includes:

[0059] Obtain the input voltage U of the bidirectional resonant DAB in Output voltage U out According to the input voltage U in and output voltage U out Determine the boost / buck characteristics of the bidirectional resonant DAB;

[0060] Obtain the given power P of the bidirectional resonant DAB ref According to the given power P of the bidirectional resonant DABref determining the working mode of the bidirectional resonant DAB;

[0061] determining the working mode of the bidirectional resonant DAB according to the input voltage U in , the output voltage U out and the boost / buck condition, the working mode, the primary side inner phase shift angle α, the secondary side inner phase shift angle β, the outer phase shift angle and the switching frequency f w of the bidirectional resonant DAB are controlled so that the bidirectional resonant DAB operates with high efficiency and does not lose ZVS in all working conditions, and the four control quantities α, β, f and the switching frequency f w are smoothly switched between different working modes, and the transitions of the three modes are α, β, f w The four control quantities are continuous (without abrupt change).

[0062] determining the boost / buck condition of the bidirectional resonant DAB according to the input voltage U in and the output voltage U out , specifically:

[0063] When the input voltage U in is the primary side terminal voltage and the output voltage U out is the secondary side terminal voltage, the bidirectional resonant DAB in the boost condition satisfies n·U in >U out , and the bidirectional resonant DAB in the buck condition satisfies n·U in ≤U out , where n is the ratio of the number of turns of the secondary side to the number of turns of the primary side.

[0064] determining the working mode of the bidirectional resonant DAB according to the given power P ref of the bidirectional resonant DAB, specifically:

[0065] When the given power P ref of the bidirectional resonant DAB is greater than the lower limit of the medium-high load power P1, the working mode of the bidirectional resonant DAB is the medium-high load mode, i.e. mode one, and P1 is 50% of the rated power of the resonant DAB;

[0066] When the given power P ref of the bidirectional resonant DAB is greater than the lower limit of the medium-low load power P2 and less than or equal to the lower limit of the medium-high load power P1, the working mode of the bidirectional resonant DAB is the medium-low load mode, i.e. mode two, and P2 is 20% of the rated power;

[0067] When the given power P refWhen the input power is less than or equal to the low-middle load power lower limit P2, the working mode of the bidirectional resonant DAB is the extremely light load mode, i.e., mode three.

[0068] In the boost case, when the working mode of the bidirectional resonant DAB is the middle-high load mode, the middle-high load mode primary side inner phase shift angle a, secondary side inner phase shift angle b, outer phase shift angle and switching frequency f w have the following values:

[0069] In the ideal case without considering the dead zone, the middle-high load mode primary side inner phase shift angle a, secondary side inner phase shift angle b, outer phase shift angle and switching frequency f w respectively satisfy the following formulas:

[0070]

[0071] a = L r · C r · P ref , c = -P ref

[0072] The outer phase shift angle is uniquely determined according to the input end voltage U in , output end voltage U out , and the ratio of the secondary side turn number to the primary side turn number n. Therefore, the calculation expression of the primary side inner phase shift angle a and the secondary side inner phase shift angle b can be simplified as:

[0073] a = 0, i.e., the primary side has no inner phase shift angle;

[0074] In the case of considering the dead zone, the outer phase shift angle is greater than the value of the outer phase shift angle in the ideal state, which can widen the soft switching range considering the dead zone (easier to achieve soft switching). The specific formula is as follows:

[0075] a = 0,

[0076]

[0077] a = L r · C r · P ref ,

[0078] c = -P ref ,

[0079] wherein, L r is the resonant inductance value, C rFor resonance capacitance value, a, b, c are the first-third intermediate parameters respectively, θ is a preset deviation phase angle, the specific value of θ can be defined according to the ZVS condition, the greater θ is, the wider the ZVS range is, but at the same time, the circuit operation efficiency will be reduced to a certain extent, and n is the ratio of the secondary winding number to the primary winding number.

[0080] This mode has three characteristics:

[0081] ①The same power resonant cavity current i r The effective value is minimum, which can greatly improve the circuit operation efficiency under medium and high load;

[0082] ②The primary and secondary sides are in the critical full ZVS (i.e. the primary and secondary sides each have a group of bridge arms in critical ZVS - open near zero current, and the remaining bridge arms all achieve ZVS) condition.

[0083] ③The resonant inductance and resonant capacitance can be configured to make the switching frequency close to the resonant frequency under this mode, which is beneficial to improve the circuit operation efficiency.

[0084] In the boost case, when the working mode of the bidirectional resonant type DAB is the medium and low load mode, the primary side inner shift phase angle α, the secondary side inner shift phase angle β, the outer shift phase angle and the switching frequency f w The values of the above are as follows:

[0085] In the ideal state without considering the dead zone, the formula of the primary side inner shift phase angle α, the secondary side inner shift phase angle β, and the switching frequency f w is the same as that of the medium and high load mode without considering the dead zone, so α, β and f w will not change suddenly when the mode is switched, and the specific values are as follows:

[0086]

[0087] a = L r · C r · P ref ,

[0088] c = - P ref

[0089] The outer shift phase angle changes with the given transmission power P ref , and the specific calculation formula is as follows:

[0090]

[0091] If P ref takes the lower limit of the medium and high load power P1, and the same as in mode one By taking consistent values, an outward phase shift can be achieved. Smooth transition when switching between Mode 1 and Mode 2.

[0092] Considering dead time, the primary side inward phase shift angle α, the secondary side inward phase shift angle β, and the outer phase shift angle in low-to-medium load mode are... and switching frequency f w The formula is as follows:

[0093]

[0094] a = L r ·C r -P ref ,

[0095] c = -P ref ,

[0096] Among them, L r C is the resonant inductance value. r P1 is the resonant capacitor value, a, b, and c are the first to third intermediate parameters respectively, θ is the preset deviation phase angle, and the specific value of θ can be customized according to the ZVS situation. The larger θ is, the wider the ZVS range, but at the same time, it will reduce the circuit operating efficiency to a certain extent. n is the ratio of the number of turns on the secondary side to the number of turns on the primary side, P2 is the lower limit of power for medium and low loads, and P1 is the lower limit of power for medium and high loads.

[0097] This model has two characteristics:

[0098] ①Critical full ZVS of primary and secondary side switching transistors.

[0099] ②f w , At a given time, under the condition of achieving critical full ZVS, the transmission power is minimized. This can reduce the peak switching frequency of Mode 2 to a certain extent, improve circuit operating efficiency, and avoid electromagnetic compatibility problems caused by excessively high switching frequencies.

[0100] In boost mode, when the bidirectional resonant DAB operates in ultra-light load mode, the primary side inward phase shift angle α, the secondary side inward phase shift angle β, and the outer phase shift angle are... and switching frequency f w The specific values ​​are as follows:

[0101] In an ideal state without considering dead time, the primary side phase shift angle α, the secondary side phase shift angle β, and the switching frequency f are... w P in Mode 2 ref =P2、 The corresponding α, β, f w The values ​​of α, β, and f are consistent and remain unchanged, thus ensuring that α, β, and f are constant during mode switching.w It will not mutate, that is:

[0102]

[0103] a = L r ·C r P2,

[0104] c = -P2.

[0105] α, β, f w All three remain unchanged. With P ref Change, The specific calculation method is as follows:

[0106] in

[0107] The calculation formula shows that if P ref Obtain the upper limit of power P2 in mode 3. P in Mode 2 ref When obtaining the lower limit power of mode two By taking consistent values, an outward phase shift can be achieved. A smooth transition from Mode 2 to Mode 3.

[0108] Considering the dead zone, the primary side inward phase shift angle α, the secondary side inward phase shift angle β, and the outer phase shift angle in the extremely light load mode are... and switching frequency f w The formula is as follows:

[0109]

[0110] a = L r ·C r P2,

[0111] c = -P2

[0112]

[0113] Among them, L r C is the resonant inductance value. r P1 is the resonant capacitor value, a, b, and c are the first to third intermediate parameters respectively, θ is the preset deviation phase angle, and the specific value of θ can be customized according to the ZVS situation. The larger θ is, the wider the ZVS range, but at the same time, it will reduce the circuit operating efficiency to a certain extent. n is the ratio of the number of turns on the secondary side to the number of turns on the primary side, and P2 is the lower limit of medium and low load power.

[0114] The buck case is symmetrical to the boost case, i.e. the input voltage U in in the formula is exchanged with the output voltage U out , and the primary side internal phase shift angle a and the secondary side internal phase shift angle b are exchanged. Specifically as follows:

[0115] Mode one, i.e. the medium-high load section:

[0116] 1) In the ideal case without considering the dead zone, the a, b, f w of mode one and mode two all satisfy:

[0117]

[0118]

[0119] a = L r · C r · P ref ,

[0120] c = -P ref

[0121] In mode one , according to the detection values U in , U out and n, it is uniquely determined, Therefore, the above condition about the calculation expression of the internal phase shift angles a and b can be simplified as:

[0122] The secondary side internal phase shift angle b = 0, i.e. the secondary side has no internal phase shift angle;

[0123] The primary side internal phase shift angle

[0124] 2) Considering the dead zone case:

[0125] The primary side internal phase shift angle is consistent with the ideal state;

[0126] The secondary side internal phase shift angle b = 0 is consistent with the ideal state;

[0127] Considering the dead zone case, the external phase shift angle is greater than the value of the external phase shift angle in the ideal state (the same for mode two), which can widen the soft switching range considering the dead zone case (easier to achieve soft switching) Wherein The specific value of theta can be defined according to the ZVS condition. The greater the theta, the wider the ZVS range, but at the same time, the circuit operating efficiency will be reduced to some extent;

[0128] The switching frequency expression is unchanged, Wherein, a = L r · Cr • P ref , c = -P ref . But the value of the switching frequency is also different from the ideal case. Unlike the ideal case, the value of the switching frequency is also different from the ideal case.

[0129] Mode two, i.e. the transition state of the medium-low load section:

[0130] 1) In the ideal state without considering the dead zone, α, β, f w still satisfy the formula in mode one, so α, β, f w will not change abruptly when the mode is switched:

[0131]

[0132] a = L r • C r • P ref ,

[0133] c = -P ref

[0134] With the given transmission power P ref change, The specific calculation method is:

[0135]

[0136] 2) Considering the case of the dead zone:

[0137]

[0138] a = L r • C r • P ref ,

[0139] c = -P ref ;

[0140] With the given transmission power P ref change, The specific calculation method is:

[0141]

[0142] Mode three, i.e. the extremely light load section:

[0143] 1) In the ideal case without considering the dead zone, α, β, f w satisfy:

[0144] α = π - β,

[0145] a = L r ·C r P2, c = -P² and α, β, f w All three remain unchanged. With P ref Change, The specific calculation method is as follows:

[0146]

[0147] 2) Considering the dead zone, the phase angle shifts inward on the primary side by α, inward on the secondary side by β, and outward by β. and switching frequency f w The formula is as follows:

[0148]

[0149] a = L r ·C r P2,

[0150] c = -P2

[0151]

[0152] This invention also proposes a wide-range, full-condition ZVS bidirectional resonant DAB control system, the system comprising:

[0153] The circuit boost / buck voltage determination module is used to determine the input voltage U. in and output voltage U out Determine the boost / buck characteristics of the bidirectional resonant DAB;

[0154] The circuit operating mode determination module is used to determine the given power P of the bidirectional resonant DAB. ref Determine the operating mode of the bidirectional resonant DAB;

[0155] The controller is used to determine the input voltage U of the bidirectional resonant DAB. in Output voltage U out Including boost / buck conditions, operating modes, and the primary side inward phase shift angle α, secondary side inward phase shift angle β, and external phase shift angle of the bidirectional resonant DAB. and switching frequency f w Control is implemented to ensure that the bidirectional resonant DAB does not lose ZVS under all operating conditions, and that the primary side inward phase shift angle α, the secondary side inward phase shift angle β, and the outward phase shift angle are all controlled. And the switching frequency f w Smooth switching between different operating modes.

[0156] The controller comprises a medium-high load mode control unit, a medium-low load mode control unit and an extremely light load mode control unit.

[0157] The application further provides a computer device, comprising a memory and a processor, the memory stores a computer program, and the processor implements the steps of the wide-range and full-condition ZVS bidirectional resonant DAB control method when executing the computer program.

[0158] The application further provides a computer readable storage medium, which stores a computer program, and the computer program implements the steps of the wide-range and full-condition ZVS bidirectional resonant DAB control method when executed by a processor.

[0159] Finally, it should be noted that the above examples and descriptions are only used to illustrate the technical solutions of the present application and not to limit the present application. Those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solution disclosed by the present application, and all of them should be covered in the protection scope of the claims of the present application.

Claims

1. A full-load ZVS bidirectional resonant DAB control method, characterized in that, Comprising: Obtaining input voltage U of bidirectional resonant type DAB in , output voltage U out , determining boost / buck condition of bidirectional resonant type DAB according to input voltage U in and output voltage U out ​ Obtaining a given power P of bidirectional resonant type DAB ref , determining the operating mode of bidirectional resonant type DAB according to the given power P of bidirectional resonant type DAB ref ​ According to the input voltage U of the bidirectional resonant type DAB in , the output voltage U out , the boost / buck case, the working mode, the primary side inner phase angle α of the bidirectional resonant type DAB, the secondary side inner phase angle β, the outer phase angle and the switching frequency f w are controlled, so that the bidirectional resonant type DAB does not lose ZVS under all working conditions, and the primary side inner phase angle α, the secondary side inner phase angle β, the outer phase angle and the switching frequency f w smoothly switch between different working modes; The given power P according to bidirectional resonant type DAB ref Determine the working mode of bidirectional resonant type DAB, specifically: When the given power P of the bidirectional resonant type DAB is greater than the low load power upper limit P2, the working mode of the bidirectional resonant type DAB is the low load mode. ref When the given power P of the bidirectional resonant type DAB is greater than the low load power upper limit P2, the working mode of the bidirectional resonant type DAB is the low load mode. When the given power P of the bidirectional resonant DAB ref When the power limit P2 is greater than the lower limit of medium-low load power and less than or equal to the lower limit of medium-high load power P1, the operating mode of the bidirectional resonant DAB is the medium-low load mode. When the given power P of the bidirectional resonant type DAB is less than or equal to the low load power upper limit P1, the working mode of the bidirectional resonant type DAB is the light load mode. ref When the given power P of the bidirectional resonant type DAB is less than or equal to the low load power upper limit P1, the working mode of the bidirectional resonant type DAB is the light load mode. In the case of step-up, when the working mode of the bidirectional resonant DAB is the medium-high load mode, the values of the medium-high load mode primary side inner phase shift angle α, secondary side inner phase shift angle β, outer phase shift angle and switching frequency f w are specifically as follows: α＝0， Wherein, L r is a resonance inductance value, C r is a resonance capacitance value, a, b, c are respectively first-third intermediate parameters, θ is a preset deviation phase angle, and n is a ratio of a secondary winding number to a primary winding number.

2. The full-load ZVS bidirectional resonant DAB control method according to claim 1, characterized in that, The input voltage U in and the output voltage U out determine the boost / buck condition of the bidirectional resonant DAB, specifically: When input voltage U in is primary side terminal voltage, output voltage U out is secondary side terminal voltage, n·U in >U out , the bidirectional resonant type DAB is in boost case, and n·U in ≤U out , the bidirectional resonant type DAB is in buck case, wherein n is the ratio of secondary side turns to primary side turns.

3. The full-load ZVS bidirectional resonant DAB control method according to claim 1, characterized in that, In the case of voltage boosting, when the working mode of the bidirectional resonant type DAB is the medium-low load mode, the values of the primary side inner phase shift angle α, the secondary side inner phase shift angle β, the outer phase shift angle and the switching frequency f w of the medium-low load mode are specifically as follows: Wherein, L r is a resonance inductance value, C r is a resonance capacitance value, a, b, c are respectively the first-third intermediate parameters, θ is a preset deviation phase angle, n is a ratio of the secondary winding number to the primary winding number, P2 is a lower limit of the medium-low load power, and P1 is an upper limit of the medium-high load power.

4. The full-load ZVS bidirectional resonant DAB control method according to claim 1, characterized in that, In the case of step-up, when the working mode of the bidirectional resonant type DAB is the extremely light load mode, the values of the primary side inner phase shift angle α, the secondary side inner phase shift angle β, the outer phase shift angle and the switching frequency f w of the extremely light load mode are specifically as follows: β = π - a - 2θ Wherein, L r is the resonance inductance value, C r is the resonance capacitance value, a, b, c are the first-third intermediate parameters, θ is the preset deviation phase angle, n is the ratio of the secondary winding number to the primary winding number, and P2 is the lower limit of the medium-low load power.

5. A full-range ZVS bidirectional resonant DAB control system for implementing the DAB control method of claim 1, characterized in that, The controller comprises a medium-high load mode control unit, a medium-low load mode control unit and an extremely light load mode control unit. The circuit step-up / step-down condition judging module is used for judging the step-up / step-down condition of the bidirectional resonant type DAB according to the input terminal voltage U in and the output terminal voltage U out determining the step-up / step-down condition of the bidirectional resonant type DAB. The circuit operation mode judging module is configured to determine the operation mode of the bidirectional resonant DAB according to a given power P ref determine the operation mode of the bidirectional resonant DAB; A controller is configured to control the primary side inner phase shift angle α, the secondary side inner phase shift angle β, the outer phase shift angle and the switching frequency f w of a bidirectional resonant DAB according to the input voltage U in , the output voltage U out and the boost / buck condition, the operation mode, so that the bidirectional resonant DAB does not lose ZVS under all operating conditions, and the primary side inner phase shift angle α, the secondary side inner phase shift angle β, the outer phase shift angle and the switching frequency f w smoothly switch between different operation modes.

6. The full-load ZVS bidirectional resonant DAB control system according to claim 5, wherein, The processor, when executing the computer program, implements the steps of the full-mode ZVS bidirectional resonant type DAB control method in any one of claims 1 to 4. 7.A computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer device is configured to perform the method according to any one of claims 1-6 when the computer program is executed by the processor. The computer program, when executed by the processor, implements the steps of the full-mode ZVS bidirectional resonant type DAB control method in any one of claims 1 to 4.

8. A computer-readable storage medium having stored thereon a computer program, characterized in that, ​

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