Power supply device and output voltage-sharing control method thereof

Abstract

The invention discloses a power supply device and an output voltage-sharing control method thereof, and the output voltage-sharing control method comprises the steps: an obtaining step: obtaining the output voltage of two DC / DC units, and calculating the output voltage deviation value of the two DC / DC units; a judgment step: judging whether the output voltage deviation value is greater than a preset first voltage value or not; and a control step: when the output voltage deviation value is greater than the first voltage value, adjusting the output voltage of the corresponding DC / DC unit by adjusting the control parameter of at least one DC / DC unit, and / or adjusting the input voltage of the two DC / DC units by adjusting the control parameter of the AC / DC module. By implementing the technical scheme of the invention, the software-based voltage-sharing control mode not only reduces the cost of the power supply device and reduces the volume of the power supply device, but also improves the reliability of voltage-sharing control.

Description

Technical Field

[0001] The present application relates to the field of power supply technology, and in particular to a power supply device and an output voltage equalization control method thereof. Background Art

[0002] In the power supply circuit, facing the requirements of high voltage, high current and cost, three-level AC / DC modules are usually used in the front stage and two sets of DC / DC modules are used in the back stage. Figure 1 As shown, the output voltage of the AC / DC module is V i , where V i =V i1 +V i2 , V i1 =V i2 The input voltages of the two DC / DC modules are V i1 、V i2 , the output voltage is V o1 、V o2 When low voltage and high current are required, output capacitors Co1 and Co2 are connected in parallel. o =V o1 =V o2 ; When high voltage and low current are required, output capacitors Co1 and Co2 are connected in series. At this time, V o =V o1 +V o2 .

[0003] The mainstream DC / DC unit is the LLC converter, such as Figure 2 As shown in Figure 1, the LLC converter includes a switch network, a resonant cavity, a transformer, and a rectifier network connected in sequence. In engineering applications, the resonance parameters of the resonant cavity will have a certain engineering tolerance, and at the same time, due to the influence of layout and wiring, there will be a certain impedance deviation. These deviations will cause the output voltages of the two groups of DC / DC modules to be unequal, that is, V o1 ≠V o2 When this deviation is large, it may affect the life of the output capacitors Co1 and Co2 in the two groups of DC / DC modules, and in serious cases, it may cause product damage.

[0004] At present, the industry usually adopts the method of adding a voltage equalization circuit to reduce the deviation of the output voltage, but this method has the following problems:

[0005] 1. The cost is high and some additional devices are needed, which will bring cost pressure;

[0006] 2. Adding more devices will take up some space or plane area, affecting the power density;

[0007] 3. Poor reliability. When one of the components fails, the entire function will fail. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a power supply device and an output voltage equalization control method thereof in view of the above-mentioned technical defects in the prior art.

[0009] The technical solution adopted by the present invention to solve the technical problem is: constructing an output voltage equalization control method for a power supply device, the power supply device includes an AC / DC module and a DC / DC module connected to each other, the DC / DC module includes two DC / DC units, including:

[0010] Acquisition step: acquiring the output voltages of the two DC / DC units, and calculating the output voltage deviation of the two DC / DC units;

[0011] Determining step: determining whether the output voltage deviation is greater than a preset first voltage value;

[0012] Control step: when the output voltage deviation is greater than the first voltage value, the output voltage of the corresponding DC / DC unit is adjusted by adjusting the control parameters of at least one DC / DC unit, and / or the input voltage of the two DC / DC units is adjusted by adjusting the control parameters of the AC / DC module.

[0013] Preferably, the DC / DC unit is an LLC converter;

[0014] The method adjusts the output voltage of the corresponding DC / DC unit by adjusting the control parameter of at least one DC / DC unit, comprising:

[0015] adjusting the output voltage of the corresponding DC / DC unit by adjusting the conduction angle of the inverter circuit in at least one DC / DC unit; and / or,

[0016] The output voltage of the corresponding DC / DC unit is adjusted by adjusting the driving density of the inverter circuit in at least one DC / DC unit.

[0017] Preferably, the DC / DC unit with a larger output voltage among the two DC / DC units is used as the first DC / DC unit, and the DC / DC unit with a smaller output voltage among the two DC / DC units is used as the second DC / DC unit;

[0018] The control step comprises:

[0019] Step S311, determining whether the first DC / DC unit meets the phase shift condition, if yes, executing step S312; if no, executing step S313;

[0020] Step S312, reducing the conduction angle of the inverter circuit of the first DC / DC unit, and then executing step S316;

[0021] Step S313, obtaining the current input voltages of the two DC / DC units, and determining whether the input voltage adjustment condition is met according to the current input voltages, if so, executing step S314; if not, executing step S315;

[0022] Step S314, adjusting the control parameters of the AC / DC module to reduce the input voltage of the first DC / DC unit and / or increase the input voltage of the second DC / DC unit, and then executing step S316;

[0023] Step S315, reducing the driving density of the inverter circuit of the first DC / DC unit;

[0024] Step S316, obtaining the current output voltages of the two DC / DC units, calculating the current output voltage deviation of the two DC / DC units, and determining whether the current output voltage deviation is less than a preset second voltage value, the second voltage value is less than or equal to the first voltage value, if so, executing step S317; if not, executing step S311;

[0025] Step S317, maintaining control parameters of the two DC / DC units and the AC / DC module.

[0026] Preferably, the controlling step comprises:

[0027] Obtaining the required power of the power supply device, and determining whether the current load is light, heavy, or no load according to the required power;

[0028] When the load is light, the output voltage of the corresponding DC / DC unit is adjusted by adjusting the conduction angle of the inverter circuit in at least one DC / DC unit and / or adjusting the driving density of the inverter circuit in at least one DC / DC unit;

[0029] When the load is heavy, the output voltage of the corresponding DC / DC unit is adjusted by adjusting the conduction angle of the inverter circuit in at least one DC / DC unit, and / or the input voltage of the two DC / DC units is adjusted by adjusting the control parameters of the AC / DC module;

[0030] When the system is unloaded, the output voltage of the corresponding DC / DC unit is adjusted by adjusting the driving density of the inverter circuit in at least one DC / DC unit.

[0031] Preferably, the controlling step comprises:

[0032] When the output voltage deviation is greater than the maximum withstand bias voltage of the DC / DC module, a first component and a second component are determined according to the output voltage deviation, and the DC / DC module withstands the first component, and according to the second component, the input voltages of the two DC / DC units are adjusted by adjusting the control parameters of the AC / DC module, wherein the first component is less than or equal to the maximum withstand bias voltage.

[0033] Preferably, the output voltage deviation is divided into a first component and a second component, including:

[0034] The output voltage deviation is divided into a first component and a second component according to a preset ratio.

[0035] Preferably, the output voltage deviation is divided into a first component and a second component, including:

[0036] The output voltage deviation is divided into a first component and a second component, wherein the first component is the maximum withstand bias voltage of the DC / DC module, and the second component is the difference between the output voltage deviation and the maximum withstand bias voltage.

[0037] Preferably, the DC / DC unit with a larger output voltage among the two DC / DC units is used as the first DC / DC unit, and the DC / DC unit with a smaller output voltage among the two DC / DC units is used as the second DC / DC unit;

[0038] The control step comprises:

[0039] Step S321, determining whether the first DC / DC unit meets the phase shift condition, if yes, executing step S322; if no, executing step S323;

[0040] Step S322, reducing the conduction angle of the inverter circuit of the first DC / DC unit, and then executing step S321;

[0041] Step S323, determining whether the output voltage deviation is greater than the maximum bias voltage of the DC / DC module, if so, executing step S324;

[0042] Step S324, calculating the difference between the output voltage deviation and the maximum bias voltage of the DC / DC module to obtain a bias voltage difference;

[0043] Step S325, determining the maximum bias voltage of the AC / DC module;

[0044] Step S326, determining whether the bias voltage difference is less than or equal to the maximum bias voltage of the AC / DC module, if so, executing step S327;

[0045] Step S327: adjusting the input voltages of the two DC / DC units by adjusting the control parameters of the AC / DC module according to the bias voltage difference.

[0046] Preferably, the step S327 includes:

[0047] The optimal input voltage of the DC / DC module is determined, and the control parameters of the AC / DC module are adjusted according to the optimal input voltage and the bias voltage difference, so as to adjust the input voltages of the two DC / DC units.

[0048] The present invention also constructs a power supply device, including a control module, an AC / DC module and a DC / DC module connected thereto, wherein the DC / DC module includes two DC / DC units, and the control module includes a processor and a memory storing a computer program, and the processor block implements the steps of the output voltage equalization control method described above when executing the computer program.

[0049] Through the technical solution of the present application, when the output voltage deviation of the two DC / DC units is large (the output voltage deviation is greater than the first voltage value), a unique software algorithm is used to adjust the output voltage and / or input voltage of the DC / DC unit by controlling the control parameters of at least one DC / DC unit and / or the control parameters of the AC / DC module, thereby reducing the output voltage deviation of the two DC / DC units. This software-based voltage balancing control method not only reduces the cost and volume of the power supply device, but also improves the reliability of voltage balancing control. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0051] Figure 1 It is a circuit diagram of an existing power supply device;

[0052] Figure 2 is a circuit diagram of a DC / DC module of a power supply device in one embodiment of the present invention;

[0053] Figure 3 It is a flow chart of an embodiment of an output voltage equalization control method of a power supply device of the present invention;

[0054] Figure 4A is a circuit diagram of an inverter circuit in an LLC converter according to an embodiment of the present invention;

[0055] Figure 4B yes Figure 4A Schematic diagram of the midpoint voltage of the inverter circuit before phase shift;

[0056] Figure 4C yes Figure 4A Schematic diagram of the midpoint voltage of the inverter circuit after phase shift;

[0057] Figure 5A It is a schematic diagram of adjusting the working duration of the wave in one embodiment of the present invention;

[0058] Figure 5B It is a schematic diagram of adjusting the duration of stopping the wave transmission in one embodiment of the present invention;

[0059] Figure 6 It is a flow chart of an embodiment of a control step in the output voltage equalization control method of a power supply device of the present invention. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0061] Figure 3 1 is a flow chart of an embodiment of an output voltage balancing control method of a power supply device of the present invention. The output voltage balancing control method of this embodiment is applied to a control module of a power supply device. Figure 1 The power supply device also includes an AC / DC module and a DC / DC module connected to each other. The DC / DC module includes two DC / DC units. The DC / DC unit is, for example, an LLC converter.

[0062] like Figure 3 As shown, the output voltage equalization control method of this embodiment includes:

[0063] Acquisition step S10: acquiring output voltages of two DC / DC units, and calculating output voltage deviations of the two DC / DC units;

[0064] Determining step S20: determining whether the output voltage deviation is greater than a preset first voltage value, if so, executing step S30;

[0065] Control step S30: adjusting the output voltage of the corresponding DC / DC unit by adjusting the control parameters of at least one DC / DC unit, and / or adjusting the input voltage of the two DC / DC units by adjusting the control parameters of the AC / DC module.

[0066] Through the technical solution of this embodiment, when the output voltage deviation of the two DC / DC units is large (the output voltage deviation is greater than the first voltage value), a unique software algorithm is used to adjust the output voltage and / or input voltage of the DC / DC unit by controlling the control parameters of at least one DC / DC unit and / or the control parameters of the AC / DC module, thereby reducing the output voltage deviation of the two DC / DC units. This software-based voltage balancing control method not only reduces the cost and volume of the power supply device, but also improves the reliability of voltage balancing control.

[0067] Further, in an optional embodiment, the DC / DC unit is an LLC converter, combined with Figure 2 Each LLC converter includes an inverter circuit (such as a full-bridge inverter circuit), a resonant cavity, a transformer, and a rectifier circuit connected to each other. In step S30, the output voltage of the corresponding DC / DC unit is adjusted by adjusting the control parameters of at least one DC / DC unit, including:

[0068] adjusting the output voltage of the corresponding DC / DC unit by adjusting the conduction angle of the inverter circuit in at least one DC / DC unit; and / or,

[0069] The output voltage of the corresponding DC / DC unit is adjusted by adjusting the driving density of the inverter circuit in at least one DC / DC unit.

[0070] In a specific embodiment, when adjusting the output voltage of the DC / DC unit by adjusting the conduction angle of the inverter circuit in the DC / DC unit (LLC converter) (i.e., by phase shifting), a conduction angle adjustment loop can be established in the control logic, with the conduction angle as the adjustment object and the output voltage as the feedback object, and the purpose of adjusting the output voltage is achieved by adjusting the conduction angle of the inverter circuit. The adjustment principle of the conduction angle is described below:

[0071] Combination Figure 4A , 4B , 4C, the inverter circuit in the LLC converter is an inverter full-bridge circuit. In a switching cycle, when there is no phase shift, the two diagonal switch tubes of the inverter circuit are turned on and off at the same time. At this time, the conduction angle α is 180°, and the output voltage (midpoint voltage) of the inverter full-bridge circuit is V in , as shown in formula 1; when the phase is shifted, the two sets of diagonal switch tubes of the inverter circuit are no longer turned on and off at the same time. At this time, the conduction angle α is less than 180°, and the lagging bridge arm delays the leading bridge arm by 180°-α, that is, the phase shift angle is 180°-α, and the midpoint voltage of the inverter full-bridge circuit is V′ in, as shown in Formula 2. Regarding the conduction angle α, it should be noted that since the sum of the conduction angle α and the phase shift angle is half a switching cycle, that is, 180°, the larger the phase shift angle, the smaller the conduction angle; and vice versa.

[0072]

[0073] Among them, V i is the input voltage of the DC / DC unit, is also the output voltage of the AC / DC module, and α is the conduction angle. Figure 4B , 4C As shown, based on the midpoint voltage of the inverter full-bridge circuit before phase shifting, the midpoint voltage after phase shifting needs to be multiplied by a coefficient less than 1, that is, sin(α / 2). Therefore, by controlling the conduction angle, the midpoint voltage can be adjusted, that is, the output voltage of the inverter circuit can be adjusted. Of course, the adjustment of the conduction angle α will also have certain constraints. The basis for judging whether it can be adjusted includes but is not limited to: device current stress (mainly primary inverter devices), device temperature rise, working mode (soft switching), etc.

[0074] In a specific embodiment, when adjusting the output voltage of the DC / DC unit, it can be achieved by adjusting the driving density of the inverter circuit in the DC / DC unit, and the driving density is related to the wave-generating working time and the wave-generating stopping time. Therefore, the output voltage of the DC / DC unit can be adjusted by adjusting the wave-generating working time and / or the wave-generating stopping time. Figure 5A As shown, when the wave-generating working time of the DC / DC unit is adjusted from T1 to T2, the output voltage of the DC / DC unit can be reduced; Figure 5B As shown, when the wave generation stop time of the DC / DC unit is adjusted from T3 to T4, the output voltage of the DC / DC unit can be reduced.

[0075] Regarding the above embodiment, it should be noted that when the output voltage deviation is too large, three adjustments can be made: phase shift, input voltage adjustment, and drive density adjustment. In specific applications, one or more of these adjustment methods can be selected, and when multiple adjustment methods are selected, different combinations can be made.

[0076] In an alternative embodiment, if Figure 6 As shown, the control step S30 of this embodiment includes:

[0077] Step S311, determining whether the first DC / DC unit meets the phase shift condition, if yes, executing step S312; if no, executing step S313;

[0078] Step S312, reducing the conduction angle of the inverter circuit of the first DC / DC unit, and then executing step S316;

[0079] Step S313, obtaining the current input voltages of the two DC / DC units, and determining whether the input voltage adjustment condition is met according to the current input voltages, if so, executing step S314; if not, executing step S315;

[0080] Step S314, adjusting the control parameters of the AC / DC module to reduce the input voltage of the first DC / DC unit and / or increase the input voltage of the second DC / DC unit, and then executing step S316;

[0081] Step S315, reducing the driving density of the inverter circuit of the first DC / DC unit;

[0082] Step S316, obtaining the current output voltages of the two DC / DC units, calculating the current output voltage deviation of the two DC / DC units, and determining whether the current output voltage deviation is less than a preset second voltage value, the second voltage value is less than or equal to the first voltage value, if so, executing step S317; if not, executing step S311;

[0083] Step S317, maintaining control parameters of the two DC / DC units and the AC / DC module.

[0084] In this embodiment, combined Figure 2 , due to V o1 >V o2 , and satisfy |V o1 -V o2 |=ΔV o ≥V ref_out_max , start the voltage-balanced regulation loop. At this time, first determine whether the conduction angle α of the inverter circuit of the first DC / DC unit meets the phase shift condition. If the phase shift condition is met, adjust the conduction angle α corresponding to the first DC / DC unit to reduce the input voltage of the resonant cavity in the first DC / DC unit and adjust the output voltage of the first DC / DC unit; if the phase shift condition is not met, determine whether the input voltage adjustment condition is met, for example, determine whether the input voltage deviation satisfies: ΔV i <V ref_in_max , where ΔV i =|V i1 -V i2 | is the input voltage deviation of the two DC / DC units, V ref_in_max The maximum deviation allowed can be a fixed value or can vary with the output voltage. For example, from the perspective of device withstand voltage, as the output voltage increases, the second voltage value decreases. When the input voltage adjustment condition is met, the control parameters of the AC / DC module are adjusted to reduce the input voltage V of the first DC / DC unit.i1 , increase the input voltage V of the second DC / DC unit i2 , but it is necessary to maintain V i1 +V i2 =V i , to meet the system requirements. When the input voltage adjustment condition is not met, the drive density is adjusted to reduce the drive density of the first DC / DC unit. Regardless of the adjustment method, after adjustment, it is determined again whether the output voltage deviation is less than the second voltage value, that is, whether it satisfies: ΔV o <V ref_out_min If it is satisfied, the adjustment is ended and the control parameters are maintained; if it is not satisfied, a new round of adjustment is started again.

[0085] In this embodiment, the three adjustment modes are combined and applied by setting the entry conditions of the three adjustment modes. Specifically, the phase shift adjustment is performed first, followed by the input voltage adjustment, and finally the drive density adjustment. Moreover, during the adjustment, the control parameters of the front-stage AC / DC module and the rear-stage DC / DC module are adjusted together, thereby increasing the adjustable range of the bias voltage.

[0086] In an optional embodiment, the control step S30 of this embodiment includes:

[0087] Obtaining the required power of the power supply device, and determining whether the current load is light, heavy, or no load according to the required power;

[0088] When the load is light, the output voltage of the corresponding DC / DC unit is adjusted by adjusting the conduction angle of the inverter circuit in at least one DC / DC unit and / or adjusting the driving density of the inverter circuit in at least one DC / DC unit;

[0089] When the load is heavy, the output voltage of the corresponding DC / DC unit is adjusted by adjusting the conduction angle of the inverter circuit in at least one DC / DC unit, and / or the input voltage of the two DC / DC units is adjusted by adjusting the control parameters of the AC / DC module;

[0090] When the system is unloaded, the output voltage of the corresponding DC / DC unit is adjusted by adjusting the driving density of the inverter circuit in at least one DC / DC unit.

[0091] In this embodiment, the bias voltages at no load, light load and heavy load can be respectively solved by combining three groups of adjustment methods.

[0092] In an optional embodiment, the control step S30 of this embodiment includes:

[0093] When the output voltage deviation is greater than the maximum withstand bias voltage of the DC / DC module, the output voltage deviation is divided into a first component and a second component, and the DC / DC module is borne by the first component, and according to the second component, the input voltages of the two DC / DC units are adjusted by adjusting the control parameters of the AC / DC module, wherein the first component is less than or equal to the maximum withstand bias voltage.

[0094] In this embodiment, when the bias voltage cannot be completely eliminated, the bias voltage can be shared by the front and rear stages of the power supply device to further expand the tolerance range of the bias voltage.

[0095] Further, in a specific example, dividing the output voltage deviation into a first component and a second component includes: dividing the output voltage deviation into a first component and a second component according to a preset ratio. In this embodiment, ΔVo and ΔVi are adjusted according to a certain ratio (eg, 0.5:0.5).

[0096] Further, in a specific example, the output voltage deviation is divided into a first component and a second component, including: dividing the output voltage deviation into a first component and a second component, wherein the first component is the maximum withstand bias voltage of the DC / DC module, and the second component is the difference between the output voltage deviation and the maximum withstand bias voltage. In this embodiment, the DC / DC module first withstands the bias voltage, and the excess portion is then borne by the AC / DC module.

[0097] Furthermore, in a specific embodiment, the controlling step includes:

[0098] Step S321, using the DC / DC unit with a larger output voltage among the two DC / DC units as a first DC / DC unit, and using the DC / DC unit with a smaller output voltage among the two DC / DC units as a second DC / DC unit;

[0099] The control step comprises:

[0100] Step S321, determining whether the first DC / DC unit meets the phase shift condition, if yes, executing step S322; if no, executing step S323;

[0101] Step S322, reducing the conduction angle of the inverter circuit of the first DC / DC unit, and then executing step S321;

[0102] Step S323, determining whether the output voltage deviation is greater than the maximum bias voltage of the DC / DC module, if so, executing step S324;

[0103] Step S324, calculating the difference between the output voltage deviation and the maximum bias voltage of the DC / DC module to obtain a bias voltage difference;

[0104] Step S325, determining the maximum bias voltage of the AC / DC module;

[0105] Step S326, determining whether the bias voltage difference is less than or equal to the maximum bias voltage of the AC / DC module, if so, executing step S327;

[0106] Step S327: adjusting the input voltages of the two DC / DC units by adjusting the control parameters of the AC / DC module according to the bias voltage difference.

[0107] In this embodiment, if the output voltage bias ΔVo is within the tolerance range of the DC / DC module, only the DC / DC module will bear it, and the AC / DC module will not bear it. If the output voltage bias ΔVo exceeds the tolerance range of the DC / DC module, the excess part will be borne by the AC / DC module. Specifically:

[0108] First, determine whether the first DC / DC unit can shift phase. If yes, perform phase shift according to step S322. If no, determine whether the output voltage deviation is greater than the maximum bias voltage of the DC / DC module, that is, determine whether: ΔV o >ΔV o_max =2V o1_max -V o If so, it means that the output voltage deviation has exceeded the tolerance range of the DC / DC module. o1_max is the maximum voltage that the output capacitor Co1 can withstand. This value is a known quantity and is mainly determined by the device stress. It is usually V o1_max =V o2_max ; V o_max is the current output voltage V o The maximum offset voltage that the DC / DC module can withstand under certain conditions.

[0109] When the output voltage deviation exceeds the tolerance range of the DC / DC module, the difference between the output voltage deviation and the maximum tolerance bias voltage, i.e., the bias voltage difference, is calculated. The bias voltage difference can be tolerated by the AC / DC module. Then, the maximum tolerance bias voltage of the AC / DC module is determined. For example, the minimum input voltage and the maximum input voltage of each DC / DC unit are determined respectively, and then the maximum tolerance bias voltage of the AC / DC module is determined according to the minimum input voltage and the maximum input voltage. Specifically:

[0110] When determining the minimum input voltage of a DC / DC unit, first obtain V o 、V o_ref 、Vgrid , ΔI p 、V i , P o , P o_ref The value of V o is the current output voltage, V o_ref is the output voltage requirement, V grid Current input grid voltage, P o is the current output power, P o_ref is the output power requirement. Then, according to V grid Determine V i_min1 (PFC is a boost circuit), and then according to V o 、V o_ref Determine V i_min2 (Too low V i Meaning a higher voltage gain, which may cause the system to enter hard switching), finally, the minimum input voltage V of the DC / DC module is determined according to the following formula i_min :V i_min =max(V i_min1 ,V i_min2 ), and the minimum input voltage of each DC / DC unit is: V i_min / 2.

[0111] When determining the maximum input voltage of a DC / DC unit, usually V i1_max =V i2_max , while V i1_max 、V i2_max Determined by device stress, such as C i1 and C i2 The maximum input voltage of the DC / DC module is determined by the withstand voltage, etc. i_max , that is, V i1_max +V i2_max , this value is usually determined during design and can be assumed to be known. The maximum input voltage of each DC / DC unit is: V i_max / 2.

[0112] After the minimum input voltage and maximum input voltage of the DC / DC unit are determined, the maximum bias voltage ΔV of the AC / DC module can be determined according to Formula 3: i_max :

[0113]

[0114] After determining the maximum bias voltage ΔV of the AC / DC module i_max After that, it is determined whether the bias voltage difference is less than or equal to the maximum bias voltage of the AC / DC module, that is, whether it satisfies: ΔV o -(2V o1_max -Vo )≤ΔV i_max If yes, adjust Vi and ΔVi, where ΔV i =ΔV o -ΔV max =ΔV o -(2V o1_max -V o ).

[0115] Furthermore, since ΔV i =ΔV o -ΔV max =ΔV o -(2V o1_max -V o ), there are many Vi of ΔVi, so an optimal Vi can be selected first, and then the input voltage can be adjusted. In an optional embodiment, step S327 includes: determining the optimal input voltage of the DC / DC module, and adjusting the control parameters of the AC / DC module according to the optimal input voltage and the bias voltage difference to adjust the input voltage of the two DC / DC units.

[0116] Preferably, the optimal input voltage V can be determined according to the following method: i_opt : Among them, N p is the number of primary turns of the transformer in the LLC converter, N s is the number of secondary turns of the transformer in the LLC converter.

[0117] The present invention also constructs a power supply device, such as Figure 1 As shown, the power supply device includes a control module (not shown), an AC / DC module and a DC / DC module connected to each other, the DC / DC module includes two DC / DC units, the control module includes a processor and a memory storing a computer program, and the processor block implements the steps of the output voltage equalization control method described above when executing the computer program.

[0118] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the claims of the present application.

Claims

1. A method for controlling output voltage equalization of a power supply device, wherein the power supply device comprises an AC / DC module and a DC / DC module connected to each other, wherein the DC / DC module comprises two DC / DC units, wherein: include: Acquisition step: acquiring the output voltages of the two DC / DC units, and calculating the output voltage deviation of the two DC / DC units; Determining step: determining whether the output voltage deviation is greater than a preset first voltage value; Control step: when the output voltage deviation is greater than the first voltage value, the output voltage of the corresponding DC / DC unit is adjusted by adjusting the control parameters of at least one DC / DC unit, and / or the input voltage of the two DC / DC units is adjusted by adjusting the control parameters of the AC / DC module.

2. The output voltage equalization control method according to claim 1, characterized in that: The DC / DC unit is an LLC converter; The method adjusts the output voltage of the corresponding DC / DC unit by adjusting the control parameter of at least one DC / DC unit, comprising: adjusting the output voltage of the corresponding DC / DC unit by adjusting the conduction angle of the inverter circuit in at least one DC / DC unit; and / or, The output voltage of the corresponding DC / DC unit is adjusted by adjusting the driving density of the inverter circuit in at least one DC / DC unit.

3. The output voltage equalization control method according to claim 2, characterized in that: The DC / DC unit with a larger output voltage among the two DC / DC units is used as a first DC / DC unit, and the DC / DC unit with a smaller output voltage among the two DC / DC units is used as a second DC / DC unit; The control step comprises: Step S311, determine whether the first DC / DC unit meets the phase shift condition, if so, execute Step S312; if not, execute step S313; Step S312, reducing the conduction angle of the inverter circuit of the first DC / DC unit, and then executing step S316; Step S313, obtaining the current input voltages of the two DC / DC units, and determining whether the input voltage adjustment condition is met according to the current input voltages, if so, executing step S314; if not, executing step S315; Step S314, adjusting the control parameters of the AC / DC module to reduce the input voltage of the first DC / DC unit and / or increase the input voltage of the second DC / DC unit, and then executing step S316; Step S315, reducing the driving density of the inverter circuit of the first DC / DC unit; Step S316, obtaining the current output voltages of the two DC / DC units, calculating the current output voltage deviation of the two DC / DC units, and determining whether the current output voltage deviation is less than a preset second voltage value, the second voltage value is less than or equal to the first voltage value, if so, executing step S317; if not, executing step S311; Step S317, maintaining control parameters of the two DC / DC units and the AC / DC module.

4. The output voltage equalization control method according to claim 2, characterized in that: The control step comprises: Obtaining the required power of the power supply device, and determining whether the current load is light, heavy, or no load according to the required power; When the load is light, the output voltage of the corresponding DC / DC unit is adjusted by adjusting the conduction angle of the inverter circuit in at least one DC / DC unit and / or adjusting the driving density of the inverter circuit in at least one DC / DC unit; When the load is heavy, the output voltage of the corresponding DC / DC unit is adjusted by adjusting the conduction angle of the inverter circuit in at least one DC / DC unit, and / or the input voltage of the two DC / DC units is adjusted by adjusting the control parameters of the AC / DC module; When the system is unloaded, the output voltage of the corresponding DC / DC unit is adjusted by adjusting the driving density of the inverter circuit in at least one DC / DC unit.

5. The output voltage equalization control method according to claim 1, characterized in that: The control step comprises: When the output voltage deviation is greater than the maximum withstand bias voltage of the DC / DC module, a first component and a second component are determined according to the output voltage deviation, and the DC / DC module withstands the first component, and according to the second component, the input voltages of the two DC / DC units are adjusted by adjusting the control parameters of the AC / DC module, wherein the first component is less than or equal to the maximum withstand bias voltage.

6. The output voltage equalization control method according to claim 5, characterized in that: The output voltage deviation is divided into a first component and a second component, including: The output voltage deviation is divided into a first component and a second component according to a preset ratio.

7. The output voltage equalization control method according to claim 5, characterized in that: The output voltage deviation is divided into a first component and a second component, including: The output voltage deviation is divided into a first component and a second component, wherein the first component is the maximum withstand bias voltage of the DC / DC module, and the second component is the difference between the output voltage deviation and the maximum withstand bias voltage.

8. The output voltage equalization control method according to claim 7, characterized in that: The DC / DC unit with a larger output voltage among the two DC / DC units is used as a first DC / DC unit, and the DC / DC unit with a smaller output voltage among the two DC / DC units is used as a second DC / DC unit; The control step comprises: Step S321, determining whether the first DC / DC unit meets the phase shift condition, if yes, executing step S322; if no, executing step S323; Step S322, reducing the conduction angle of the inverter circuit of the first DC / DC unit, and then executing step S321; Step S323, determining whether the output voltage deviation is greater than the maximum bias voltage of the DC / DC module, if so, executing step S324; Step S324, calculating the difference between the output voltage deviation and the maximum bias voltage of the DC / DC module to obtain a bias voltage difference; Step S325, determining the maximum bias voltage of the AC / DC module; Step S326, determining whether the bias voltage difference is less than or equal to the maximum bias voltage of the AC / DC module, if so, executing step S327; Step S327: adjusting the input voltages of the two DC / DC units by adjusting the control parameters of the AC / DC module according to the bias voltage difference.

9. The output voltage equalization control method according to claim 8, characterized in that: The step S327 includes: The optimal input voltage of the DC / DC module is determined, and the control parameters of the AC / DC module are adjusted according to the optimal input voltage and the bias voltage difference, so as to adjust the input voltages of the two DC / DC units.

10. A power supply device, comprising a control module, an AC / DC module and a DC / DC module connected thereto, wherein the DC / DC module comprises two DC / DC units, and the control module comprises a processor and a memory storing a computer program, wherein: The processor block implements the steps of the output voltage equalization control method according to any one of claims 1 to 9 when executing the computer program.

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