Dual-active bridge type conversion circuit and converter thereof
By dynamically adjusting the inductance value through the inductor switching module, the problem of high current stress in the dual active bridge converter over a wide voltage range is solved, thus achieving efficient operation of the converter.
Patent Information
- Application Number
- CN202520087516.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-14
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2035-01-14
AI Technical Summary
Existing dual active bridge converters cannot guarantee high current stress over a wide voltage range, leading to a decrease in converter efficiency.
An inductor switching module is used to switch inductor units through control signals to adjust the inductance value, thereby achieving dynamic adjustment of the inductance value to adapt to different input voltage conditions.
Optimize soft-switching characteristics over a wide input voltage range to improve converter efficiency.
Smart Images
Figure CN223729645U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The embodiment of the utility model relates to active bridge converter field, in particular to a kind of dual active bridge conversion circuit and its converter. BACKGROUND
[0002] Dual Active Bridge (DAB) converter, with high power density, input-output electrical isolation, energy bidirectional flow and other advantages, in power electronic transformer, electric vehicle, renewable energy generation and energy storage and other occasions have important applications.The commonly used control method has single phase shift (SPS) modulation, dual phase shift (DPS) modulation, extended phase shift (EPS) modulation and triple phase shift (TPS) control, etc.The above multiple modulation modes are all realized by controlling the relative phase shift of driving signal between bridge arms in DAB converter to control transmission power.
[0003] Whether using single phase shift control (SPS), dual phase shift control (DPS), extended phase shift control (EPS) or triple phase shift control (TPS), the control target is to reduce the effective value and peak value of inductance current by control strategy, thereby reducing the current stress of converter, optimizing the soft switching range of converter and improving the efficiency of converter.For different working voltages, the inductance of inductance is different.Especially when input voltage is relatively high, to realize the soft switching of MOS tube, the inductance of inductance L needs to be relatively large.Most of the current DAB converter inductance is fixed, when input voltage changes in a wide range, it is impossible to guarantee that the converter works in the optimal state. UTILITY MODEL CONTENT
[0004] The technical problem solved by the embodiment of the utility model is to provide a dual active bridge conversion circuit and its converter, which can guarantee that the current stress of the converter is large in a wide voltage range.
[0005] To solve the above technical problems, one technical scheme of the utility model is to provide a dual active bridge conversion circuit, comprising: a first bridge arm module for converting a first direct current voltage into a first alternating current voltage; a second bridge arm module for converting a second alternating current voltage into a second direct current voltage; a transformer module arranged between the first bridge arm module and the second bridge arm module, for converting the first alternating current voltage into the second alternating current voltage; and an inductance switching module connected in series with the transformer module, comprising at least two inductance units, configured to switch the access state of the at least two inductance units in response to the control signal of the controller, to obtain different equivalent inductance values.
[0006] In some embodiments, the inductance switching module comprises: a magnetic core having a predetermined inductance coefficient; windings forming the at least two inductance units on the magnetic core, wherein a tap is provided between adjacent inductance units.
[0007] In some embodiments, the inductance switching module further comprises a switching unit electrically connected with the tap, for changing the effective number of turns of the windings.
[0008] In some embodiments, the switching unit comprises a plurality of switching devices, each of which is electrically connected with a tap.
[0009] In some embodiments, the switching device is a relay or a semiconductor switching device.
[0010] In some embodiments, the first bridge arm module comprises a switching tube Q1, a switching tube Q2, a switching tube Q3, a switching tube Q4 and a capacitor C1, the drain of the switching tube Q1 and the first end of the capacitor C1 and the drain of the switching tube Q2, the source of the switching tube Q1 and the drain of the switching tube Q3 are connected to form a first connection point, the source of the switching tube Q2 and the drain of the switching tube Q4 are connected to form a second connection point, the source of the switching tube Q3 and the source of the switching tube Q4 and the second end of the capacitor C1 are connected, and the first end and the second end of the capacitor C1 are respectively connected to a first alternating voltage port to receive the first alternating voltage.
[0011] In some embodiments, the second bridge arm module comprises a switching tube Q5, a switching tube Q6, a switching tube Q7, a switching tube Q8 and a capacitor C2, the drain of the switching tube Q6 and the first end of the capacitor C2 and the drain of the switching tube Q5, the source of the switching tube Q6 and the drain of the switching tube Q8 are connected to form a third connection point, the source of the switching tube Q5 and the drain of the switching tube Q7 are connected to form a fourth connection point, the source of the switching tube Q8 and the source of the switching tube Q7 and the second end of the capacitor C2 are connected, and the first end and the second end of the capacitor C2 are respectively connected to a second alternating voltage port to output the second alternating voltage.
[0012] In some embodiments, the transformer module comprises a transformer TX, a primary side first end of the transformer TX is connected with the first connection point, a primary side second end of the transformer TX is connected with the second connection point, a secondary side first end of the transformer TX is connected with the fourth connection point, and a secondary side second end of the transformer TX is connected with the third connection point.
[0013] In some embodiments, the inductance switching module is connected between the first end of the primary side of the transformer TX and the first connection point; or the inductance switching module is connected between the first end of the secondary side of the transformer TX and the fourth connection point.
[0014] To solve the above technical problems, another technical scheme adopted by the utility model is to provide a dual active bridge converter, comprising: the dual active bridge conversion circuit as described above.
[0015] The utility model embodiment has the advantages that: different from the prior art, the dual active bridge conversion circuit can dynamically adjust the inductance value according to the input voltage by adopting the inductance switching module scheme. Small inductance is adopted at low voltage to ensure the power output capability, and large inductance is adopted at high voltage to reduce the current stress, so that the soft switching characteristic is optimized in the wide input voltage range, and the converter efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 is the circuit principle diagram of the conventional dual active bridge converter;
[0017] Figure 2 is the soft switching range waveform diagram of the conventional dual active bridge converter;
[0018] Figure 3 is the structural schematic diagram of the dual active bridge conversion circuit provided by the utility model;
[0019] Figure 4 is the circuit principle diagram of the dual active bridge conversion circuit provided by the utility model;
[0020] Figure 5 is the circuit principle diagram of another dual active bridge conversion circuit provided by the utility model. DETAILED DESCRIPTION
[0021] In order to facilitate the understanding of the utility model, the utility model will be described in more detail below in combination with the drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element or one or more intervening elements can be present therebetween. When an element is described as being "connected" to another element, it can be directly connected to the other element or one or more intervening elements can be present therebetween. The terms "vertical", "horizontal", "left", "right" and similar expressions used in the specification are only for the purpose of illustration.
[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. The use herein of terms such as "and / or" includes a combination of one or more of the associated listed items, in any of their possible permutations.
[0023] A conventional circuit structure of a dual active bridge converter is shown in Figure 1 As shown in FIG. 1, the switch Q1, the switch Q2, the switch Q3 and the switch Q4 form the primary side inverter bridge H1, and the switch Q5, the switch Q6, the switch Q7 and the switch Q8 form the secondary side inverter bridge H2. The primary side inverter bridge H1 and the secondary side inverter bridge H2 are connected through a magnetic network. The inductance LX is the equivalent inductance of the transformer leakage inductance L_leakage and the additional auxiliary inductance Lr; the transformer turns ratio is n:1. The AC side voltage of the primary side inverter bridge H1 is Vp, and the AC side voltage of the secondary side inverter bridge H2 is Vs; the voltage of port 1 is V1, and the voltage of port 2 is V2.
[0024] When the single phase shift (SPS) is used, the power expression is as follows (where n is the transformer turns ratio, V1 is the voltage of port 1, V2 is the voltage of port 2, f S is the working frequency of the converter, is the phase angle difference between Vp and Vs, the positive and negative of which determines the flow direction of the power):
[0025]
[0026] When , the maximum output current is:
[0027]
[0028] It can be seen that the inductance L determines the size of the maximum output current. When the input voltage is fixed, the output current and the output voltage are irrelevant, and only related to the phase shift angle; when the output voltage is fixed, the input current and the input voltage are irrelevant, and only related to the phase shift angle:
[0029]
[0030] Let the power reference value be:
[0031]
[0032] Figure 2 The relationship between the inductance and the different input voltages and the transmission power is shown:
[0033] When the transformer ratio is determined, the larger the inductance L, the smaller the output power of the converter, and the smaller the inductance, the stronger the power output capability of the converter. Generally, when designing the inductance, the inductance L is designed according to the working voltage range of the product and the maximum working current. By I oMax The expression shows that the maximum output current is proportional to the input voltage, so as long as the maximum current can be output at the lowest input voltage, the input voltage range can meet the requirements.
[0034] When the input voltage is the lowest:
[0035]
[0036] The inductance ensures the maximum output current of the converter and the output capability of the converter at low input voltage. However, when the input voltage increases and the input range is wide, the inductance is obviously small, resulting in an increase in inductance peak current, an increase in current stress of the device, an increase in converter loss, and an increase in converter efficiency. The inductance current peak value is calculated as follows:
[0037]
[0038] Analysis shows that if soft switching is to be achieved, the necessary condition is that during the time when the lower tube is turned off and the upper tube is turned on, the current needs to flow into the bridge arm midpoint to realize the charging and discharging process of the upper and lower tube junction capacitor. In order to ensure that the switch tube realizes soft switching as much as possible, it is necessary to ensure that the energy stored in the inductor can completely extract the charge on the parasitic capacitor of the MOS tube, and the inductor needs to meet the following requirements:
[0039]
[0040] Therefore, for different working voltages, the inductance of the inductor needs to be different. Especially when the input voltage is relatively high, to realize soft switching of the MOS tube, the inductance of the inductor L needs to be large. Most of the current DAB converter inductors have fixed inductance, and when the input voltage changes in a wide range, the converter cannot work in the optimal state.
[0041] In order to improve the efficiency of the converter, the embodiment provides a dual active bridge converter circuit, which comprises a first bridge arm module 100, a transformer module 200, a second bridge arm module 300 and an inductor switching module 400.
[0042] The main function of the first bridge arm module 100 is to convert the first direct current into the first alternating current. The main function of the second bridge arm module 300 is to convert the second alternating current into the second direct current. The transformer module 200 is arranged between the first bridge arm module 100 and the second bridge arm module 300, and is used to realize conversion of the first alternating current to the second alternating current.
[0043] The key technical feature lies in setting an inductance switching module 400 in series with the voltage transformation module 200. The inductance switching module 400 contains at least two inductance units, which can selectively access or disconnect different inductance units in response to the control signal of the controller, thereby obtaining different equivalent inductance values.
[0044] Specifically, the inductance switching module includes a magnetic core with a predetermined inductance coefficient and a winding, and the winding is wound on the magnetic core to form at least two inductance units, wherein a tap is arranged between adjacent inductance units.
[0045] Further, the inductance switching module further includes a switching unit electrically connected with the tap for changing the effective number of turns of the winding. The switching unit includes a plurality of switching devices, each of which is electrically connected with a tap.
[0046] By way of example but not limitation, the switching device is a relay or a semiconductor switching device.
[0047] Through the above technical solution, the inductance value can be adjusted according to the change of the input voltage, and the working characteristics of the converter are optimized. The ability to switch inductance values in different working states lays a foundation for high-efficiency operation of the converter in a wide input voltage range.
[0048] In combination Figure 4 A specific circuit structure of a dual active bridge converter circuit is described in detail. For ease of description, the dual active bridge converter circuit composed of an inductance switching module including two inductance units is described in this embodiment:
[0049] The first bridge arm module 100 includes the switching tube Q1, the switching tube Q2, the switching tube Q3, the switching tube Q4, and the capacitor C1. The drain of the switching tube Q1 is connected with the first end of the capacitor C1 and the drain of the switching tube Q2, and the source of the switching tube Q1 is connected with the drain of the switching tube Q3 to form a first connection point. The source of the switching tube Q2 is connected with the drain of the switching tube Q4 to form a second connection point. The source of the switching tube Q3 is connected with the source of the switching tube Q4 and the second end of the capacitor C1. The first end and the second end of the capacitor C1 are respectively connected with the first alternating voltage port for receiving the first direct current voltage V1.
[0050] The second bridge arm module 300 includes the switching tube Q5, the switching tube Q6, the switching tube Q7, the switching tube Q8, and the capacitor C2. The drain of the switching tube Q6 is connected with the first end of the capacitor C2 and the drain of the switching tube Q5, and the source of the switching tube Q6 is connected with the drain of the switching tube Q8 to form a third connection point. The source of the switching tube Q5 is connected with the drain of the switching tube Q7 to form a fourth connection point. The source of the switching tube Q8 is connected with the source of the switching tube Q7 and the second end of the capacitor C2. The first end and the second end of the capacitor C2 are respectively connected with the second alternating voltage port for outputting the second direct current voltage V2.
[0051] The transformer TX has a primary side first end connected to the first connection point and a primary side second end connected to the second connection point. The transformer TX has a secondary side first end connected to the fourth connection point and a secondary side second end connected to the third connection point.
[0052] The inductance switching module 400 is connected between the primary side first end of the transformer TX and the first connection point. The inductance switching module includes an inductance LX with a middle tap, the inductance LX being provided with an A tap and a B tap, and having a number of turns n1 and n2 respectively. The A tap and the B tap are controlled by switches K1 and K2. When a smaller inductance value is needed, K1 is closed, the inductance LX corresponds to the number of turns n1, and the inductance LX corresponds to the inductance (n1) 2 *Al; when a larger inductance value is needed, K2 is closed, the inductance LX corresponds to the number of turns (n1+n2), and the inductance LX corresponds to the inductance (n1+n2) 2 *Al.
[0053] In the embodiment of the present application, the inductance switching module 400 specifically includes the inductance LX, the control switch K1 and the control switch K2, the first end of the control switch K1 and the first end of the control switch K2 are connected to the first connection point, the second end of the control switch K1 and the B tap of the inductance LX are connected, the second end of the control switch K2 and the A tap of the inductance LX are connected, and the inductance LX is connected to the primary side first end of the transformer TX.
[0054] By way of example but not limitation, the control switch K1 and the control switch K2 can be implemented by using a relay or a back-to-back MOS tube respectively, or can be implemented by using a single-pole double-throw switch simultaneously.
[0055] In this embodiment, according to the size of the input voltage V1, by controlling the conduction state of the switches K1 and K2, the effective number of turns of the inductance LX can be changed, thereby realizing dynamic adjustment of the inductance value, so that the converter can maintain good working characteristics under different input voltage conditions. In order to widen the input voltage range, the 2-tap can be expanded to a 3-tap, a 4-tap to a multi-tap structure.
[0056] It should be noted that the inductance switching module 400 can also be connected between the secondary side first end of the transformer TX and the fourth connection point, as shown in Figure 5 In the embodiment of the present application, the inductance switching module 400 specifically includes the inductance LX, the control switch K1 and the control switch K2, the first end of the control switch K1 and the first end of the control switch K2 are connected to the fourth connection point, the second end of the control switch K1 and the B tap of the inductance LX are connected, the second end of the control switch K2 and the A tap of the inductance LX are connected, and the inductance LX is connected to the secondary side first end of the transformer TX.
[0057] Different from the prior art, the dual active bridge conversion circuit can dynamically adjust the inductance value according to the input voltage by adopting the scheme of the inductance switching module.
[0058] Based on the dual active bridge conversion circuit provided in the above embodiment, the embodiment of the application further provides a dual active bridge converter, which comprises the dual active bridge conversion circuit as described above.
[0059] It should be noted that the specification and drawings of the utility model provide the preferred embodiments of the utility model, however, the utility model can be realized by many different forms, and is not limited to the embodiments described in the specification, the embodiments do not serve as additional limitation on the content of the utility model, and the purpose of providing these embodiments is to make the understanding of the disclosure of the utility model more thorough and comprehensive.Also, the above technical features continue to combine, form various embodiments not listed above, and are all regarded as the range of the specification of the utility model; further, for those skilled in the art, the above description can be improved or transformed, and all these improvements and transformations should belong to the protection scope of the claims of the utility model.
Claims
1. A dual active bridge conversion circuit, characterized by include: The first bridge arm module is used to convert the first DC voltage into the first AC voltage; The second bridge arm module is used to convert the second AC voltage into a second DC voltage; A transformer module is disposed between the first bridge arm module and the second bridge arm module, and is used to convert the first AC voltage into the second AC voltage. And an inductor switching module, connected in series with the transformer module, including at least two inductor units, configured to switch the access state of the at least two inductor units in response to the control signal of the controller, so as to obtain different equivalent inductance values.
2. The circuit of claim 1, wherein, The inductor switching module includes: The magnetic core has a predetermined inductance coefficient; The winding forms at least two inductor units on the magnetic core, wherein taps are provided between adjacent inductor units.
3. The circuit of claim 2, wherein, The inductor switching module further includes a switching unit, which is electrically connected to the tap and is used to change the effective number of turns of the winding.
4. The circuit of claim 3, wherein, The switching unit includes multiple switching devices, each of which is electrically connected to one of the taps.
5. The circuit of claim 4, wherein, The switching device is a relay or a semiconductor switching device.
6. The circuit of claim 1, wherein, The first bridge arm module includes switching transistors Q1, Q2, Q3, and Q4, and capacitor C1. The drain of the switching transistor Q1, the first terminal of the capacitor C1, and the drain of the switching transistor Q2 are connected to form a first connection point. The source of the switching transistor Q1 and the drain of the switching transistor Q3 are connected to form a second connection point. The source of the switching transistor Q3 and the source of the switching transistor Q4 are connected to the second terminal of the capacitor C1. The first and second terminals of the capacitor C1 are respectively connected to a first AC voltage port to receive the first AC voltage.
7. The circuit of claim 6, wherein, The second bridge arm module includes switching transistors Q5, Q6, Q7, and Q8, and capacitor C2. The drain of the switching transistor Q6, the first terminal of the capacitor C2, and the drain of the switching transistor Q5 are connected to form a third connection point. The source of the switching transistor Q6 and the drain of the switching transistor Q8 are connected to form a fourth connection point. The source of the switching transistor Q8, the source of the switching transistor Q7, and the second terminal of the capacitor C2 are connected. The first and second terminals of the capacitor C2 are respectively connected to the second AC voltage port to output the second AC voltage.
8. The circuit of claim 7, wherein, The transformer module includes a transformer TX. The primary side of the transformer TX is connected to the first connection point, the primary side of the transformer TX is connected to the second connection point, the secondary side of the transformer TX is connected to the fourth connection point, and the secondary side of the transformer TX is connected to the third connection point.
9. The circuit of claim 8, wherein, The inductor switching module is connected between the first end of the primary side of the transformer TX and the first connection point; or the inductor switching module is connected between the first end of the secondary side of the transformer TX and the fourth connection point.
10. A dual active bridge converter, characterized by include: The dual active bridge converter circuit as described in any one of claims 1-9.