Bridge resonant converter and bidirectional bridge resonant converter

Abstract

The present application provides a bridge resonant converter and a bidirectional bridge resonant converter. A bidirectional blocking switch is additionally provided in a bridge unit of the bridge resonant converter such that a primary-side winding or a secondary-side winding of a transformer can be short-circuited, and on the basis of whether the gain between an output voltage and an input voltage is greater than or equal to 1, the short-circuit time is determined in different modes. The bridge resonant converter can be achieved only on the basis of two sampling signals of the input voltage and the output voltage which are necessary for controlling the bridge resonant converter, and a sampling circuit does not need to be additionally provided, such that the control is simple, and the influence of the error of the sampling signals, which are specially used for controlling the short-circuit time, on the control in the prior art is avoided, such that the control is more accurate.

Description

Bridge resonant converter and bidirectional bridge resonant converter Technical Field

[0001] The present application relates to the field of power supplies, and in particular to a bridge resonant converter and a bidirectional bridge resonant converter. Background Art

[0002] The bridge resonant converter is an extremely attractive isolated DC-DC converter. Since it can achieve soft switching within the full load range, it can reduce switching losses, improve converter efficiency, reduce size, and increase power density, and is therefore widely used in various fields.

[0003] Bridge resonant converters typically employ variable frequency control, controlling the operating frequency of the switches within the bridge resonant converter. This presents a challenge in applications with wide input voltage ranges or output voltage ranges. This is because a wide input voltage range or output voltage range increases the switching frequency range of the bridge resonant converter. Therefore, increasing the switching frequency range that the controller can provide and the switching frequency range that the switches within the bridge resonant converter can withstand requires higher-performance controllers or switching devices, which undoubtedly increases the cost of the bridge resonant converter. Furthermore, a wider switching frequency range can cause devices to operate at their limits, resulting in poorer device performance. For example, this can cause greater interference with other devices, leading to poor converter reliability. This also increases device losses, reducing converter efficiency.

[0004] With the development of technology and market demand for diversified products, bridge resonant converters with a wide input voltage range or a wide output voltage range are needed and expected.

[0005] Therefore, providing a high-efficiency and high-reliability bridge resonant converter has become the focus of industry research.

[0006] Summary of the Invention

[0007] The present application provides a bridge resonant converter, comprising: a first bridge unit; a transformer, comprising a primary winding and a secondary winding, one end of the first bridge unit being connected to the primary winding, and the other end being used to receive an input voltage; a second bridge unit, one end of the second bridge unit being connected to the secondary winding, and the other end being used to provide an output voltage, and further comprising a bidirectional blocking switch, the bidirectional blocking switch being connected between the two ends of the secondary winding; a resonant unit, connected between the first bridge unit and the primary winding or between the second bridge unit and the secondary winding; a controller, receiving the input voltage and the output voltage, and outputting a switch drive signal for controlling the bidirectional blocking switch according to a gain between the output voltage and the input voltage, so that the bidirectional blocking switch is turned on within a first time.

[0008] Furthermore, each half switching cycle of the bridge resonant converter includes the first time.

[0009] Furthermore, the switch tube in the second bridge unit is delayed in turning off for a second time relative to the switch tube in the first bridge unit working synchronously therewith.

[0010] Furthermore, when the gain is greater than or equal to 1 and when the gain is less than 1, the lengths of the first time and the second time are set differently.

[0011] Furthermore, when the gain is greater than or equal to 1, the lengths of the first time and the second time are configured according to a first relationship; when the gain is less than 1, the lengths of the first time and the second time are configured according to a second relationship.

[0012] Furthermore, in the first relationship, the first time is related to the conduction time of the switch tube in the first bridge unit within half a switching cycle, the gain and the second time, and the second time is related to the conduction time of the switch tube in the first bridge unit within half a switching cycle; in the second relationship, the first time is related to the conduction time of the switch tube in the first bridge unit within half a switching cycle, and the second time is related to the conduction time of the switch tube in the first bridge unit within half a switching cycle and the gain.

[0013] Furthermore, the first bridge unit is configured as a half-bridge topology, and the two ends of the primary winding are respectively connected to the common node of the two bridge arms in the first bridge unit.

[0014] Furthermore, the second bridge unit is configured as a half-bridge topology, a full-bridge topology or a three-level half-bridge topology.

[0015] The present application also provides a bidirectional bridge resonant converter, comprising: a first bridge unit, comprising a first bidirectional blocking switch; a transformer, comprising a first winding and a second winding, wherein one end of the first bridge unit is connected to the first winding, and the other end is used to receive or output a first voltage, and the first bidirectional blocking switch is connected between the two ends of the first winding; a second bridge unit, wherein one end of the second bridge unit is connected to the second winding, and the other end is used to output or receive a second voltage correspondingly, and further comprises a second bidirectional blocking switch, and the second bidirectional blocking switch is connected between the two ends of the second winding; a resonant unit, connected between the first bridge unit and the first winding or between the second bridge unit and the between the second winding; a controller, receiving the first voltage and the second voltage, wherein when the bidirectional bridge resonant converter is used to convert the first voltage into the second voltage, the controller outputs a switch drive signal for controlling the second bidirectional blocking switch according to a first gain between the second voltage and the first voltage, so that the second bidirectional blocking switch is turned on within a first time; when the bidirectional bridge resonant converter is used to convert the second voltage into the first voltage, the controller outputs a switch drive signal for controlling the first bidirectional blocking switch according to a second gain between the first voltage and the second voltage, so that the first bidirectional blocking switch is turned on within a third time.

[0016] Furthermore, each half switching cycle of the bidirectional bridge resonant converter includes the first time or the third time.

[0017] Furthermore, the switch tube in the bridge unit at the output end is delayed in turning off for a second time relative to the switch tube in the bridge unit at the input end working synchronously therewith.

[0018] Furthermore, when the first gain is greater than or equal to 1 and when the first gain is less than 1, the length setting method of the first time and the second time is different; when the second gain is greater than or equal to 1 and when the second gain is less than 1, the length setting method of the third time and the second time is different.

[0019] Furthermore, when the first gain is greater than or equal to 1, the length of the first time and the second time is configured according to a first relationship; when the first gain is less than 1, the length of the first time and the second time is configured according to a second relationship; when the second gain is greater than or equal to 1, the length of the third time and the second time is configured according to the first relationship; when the second gain is less than 1, the length of the third time and the second time is configured according to the second relationship.

[0020] Furthermore, when the bidirectional bridge resonant converter is used to convert the first voltage into the second voltage, the first time in the first relationship is related to the on-time of the switch in the first bridge unit within half a switching cycle, the first gain, and the second time, and the second time is related to the on-time of the switch in the first bridge unit within half a switching cycle; in the second relationship, the first time is related to the on-time of the switch in the first bridge unit within half a switching cycle, and the second time is related to the on-time of the switch in the first bridge unit within half a switching cycle and the first gain; when the bidirectional bridge resonant converter is used to convert the second voltage into the first voltage, the third time in the first relationship is related to the on-time of the switch in the second bridge unit within half a switching cycle, the second gain, and the second time, and the second time is related to the on-time of the switch in the second bridge unit within half a switching cycle; in the second relationship, the first time is related to the on-time of the switch in the second bridge unit within half a switching cycle, and the second time is related to the on-time of the switch in the second bridge unit within half a switching cycle and the second gain.

[0021] Furthermore, the first bridge unit is configured as a half-bridge topology, and the two ends of the first winding are respectively connected to the common nodes of the two bridge arms in the first bridge unit.

[0022] Furthermore, the second bridge unit is configured as a half-bridge topology, a full-bridge topology or a three-level half-bridge topology.

[0023] The features and technical advantages of the present disclosure have been summarized quite broadly above so that the detailed description disclosed below may be better understood. Additional features and advantages of the present disclosure will be described below, which form the subject matter of the claims of the present disclosure. It will be appreciated by those skilled in the art that the concepts and specific embodiments disclosed herein may be readily used as a basis for modifying or designing other structures or processes for achieving the same purposes of the present disclosure. It will also be appreciated by those skilled in the art that such equivalent structures do not depart from the spirit and scope of the present disclosure as set forth in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description in conjunction with the accompanying drawings, in which:

[0025] FIG1 shows a schematic diagram of a bridge resonant converter according to an embodiment of the present application;

[0026] FIG2 shows a schematic diagram of a bridge resonant converter circuit according to an embodiment of the present application;

[0027] FIG3 shows a schematic diagram of operating waveforms of the bridge resonant converter in FIG2 ;

[0028] FIG4 shows a schematic diagram of a controller module according to an embodiment of the present application;

[0029] FIG5 shows a module diagram of a time generating unit in a controller according to an embodiment of the present application;

[0030] FIG6 shows a schematic diagram of a bidirectional bridge resonant converter according to an embodiment of the present application;

[0031] FIG7 shows a schematic diagram of a bidirectional bridge resonant converter circuit according to an embodiment of the present application.

[0032] Corresponding symbols in the different figures generally refer to corresponding parts unless otherwise indicated. These figures are drawn to clearly illustrate the relevant aspects of the various embodiments and are not necessarily drawn to scale. DETAILED DESCRIPTION

[0033] The following is a clear and complete description of the technical solutions in this application in conjunction with the accompanying drawings. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0034] An embodiment of the present application provides a bridge resonant converter. Referring to FIG1 , a schematic diagram of a bridge resonant converter according to an embodiment of the present application is shown, comprising:

[0035] a first bridge unit 110;

[0036] The transformer 130 includes a primary winding Lp and a secondary winding Ls. One end of the first bridge unit 110 is connected to the primary winding Lp, and the other end is used to receive an input voltage Vin.

[0037] a second bridge unit 120, one end of which is connected to the secondary winding Ls, and the other end of which is used to provide an output voltage Vo, and further comprising a bidirectional blocking switch Sa, the bidirectional blocking switch Sa being connected between the two ends of the secondary winding Ls;

[0038] a resonant unit 140 connected between the first bridge unit 110 and the primary winding Lp or between the second bridge unit 120 and the secondary winding Ls;

[0039] The controller 200 receives the input voltage Vin and the output voltage Vo, and outputs a switch driving signal for controlling the bidirectional blocking switch Sa according to a gain M between the output voltage Vo and the input voltage Vin, so that the bidirectional blocking switch Sa is turned on within a first time Ta.

[0040] As shown in FIG1 , a bidirectional blocking switch Sa is connected between the two ends of a secondary winding Ls. When the bidirectional blocking switch Sa is turned on within a first time t1, the secondary winding Ls of the transformer is short-circuited. During this period, the resonant current in the resonant unit 140 gradually increases, and the output current of the bridge resonant converter is zero. Energy is stored in the resonant circuit, and after the first time t1, the energy in the resonant circuit can be released, forming a boost stage. This allows voltage regulation within a certain range and reduces the switching frequency range. In particular, for bridge resonant converters with a wide input voltage range or a wide output voltage range, when the input voltage Vin is relatively low, the resonant current can be increased, and the gain of the resonant unit can be made greater than one, thus achieving a boost stage and reducing the switching frequency range.

[0041] As described above, the present application outputs a switch drive signal Sa for controlling the bidirectional blocking switch Sa solely based on the gain M between the output voltage Vo and the input voltage Vin. The output voltage Vo and the input voltage Vin are essential sampling signals for controlling the bridge resonant converter. This means that the present application does not require additional sampling circuitry to achieve its functionality. This functionality can be achieved solely by utilizing the existing controller 200 in the bridge resonant converter to sample the existing output voltage Vo and input voltage Vin. This eliminates the need for a dedicated sampling circuit for controlling the bidirectional blocking switch.

[0042] Furthermore, no additional sampling is required, and the adverse effects of sampling delay and sampling error on the control are avoided, making the control more accurate and improving the reliability of the bridge resonant converter.

[0043] Specifically, please refer to the schematic diagram of the bridge resonant converter circuit according to an embodiment of the present application shown in FIG2 . The first bridge unit 110 and the second bridge unit 120 are both configured as a half-bridge topology, with the two ends of the primary winding Lp correspondingly connected to the common node of the two bridge arms in the first bridge unit 110, and the two ends of the secondary winding Ls correspondingly connected to the common node of the two bridge arms in the second bridge unit 120.

[0044] Specifically, as shown in FIG2 , the first bridge unit 110 includes a first switching arm formed by a first upper tube S1 and a first lower tube S2 connected in series, and a first capacitor C1 and a second capacitor C2 connected in series. The first switching arm and the first capacitor C1 are connected in parallel to receive an input voltage Vin. The two ends of the primary winding Lp are connected to the common node of the first upper tube S1 and the first lower tube S2 in the first switching arm and the common node of the first capacitor C1 and the second capacitor C2 in the first capacitor C1 and the second capacitor C2 in the first capacitor C2, respectively. The second bridge unit 120 includes a third switching arm formed by a third upper tube S3 and a fourth lower tube S4 connected in series, and a fourth capacitor C3 and a fourth capacitor C4 connected in series. The third switching arm and the fourth capacitor C4 are connected in parallel to provide an output voltage Vo. The two ends of the secondary winding Ls are connected to the common node of the third upper tube S3 and the fourth lower tube S4 in the third switching arm and the common node of the third capacitor C3 and the fourth capacitor C4 in the fourth capacitor C3 and the fourth capacitor C4, respectively.

[0045] As shown in FIG2 , the resonant unit 140 is configured as an LC series resonant unit formed by connecting a resonant inductor Lr and a resonant capacitor Cr in series. As shown in FIG2 , the LC series resonant unit is connected between the first bridge unit 110 and the primary winding Lp. In practical applications, the LC series resonant unit can also be connected between the second bridge unit 120 and the secondary winding Ls. Of course, the resonant unit 140 can also have other structures, such as an LLC resonant unit, the resonant capacitor Cr shares the capacitance in the bridge arm of the bridge unit, etc., as long as a resonant cavity is formed between the first bridge unit 110 and the primary winding Lp or between the second bridge unit 120 and the secondary winding Ls.

[0046] The principles of the present application are explained below using the half-bridge resonant converter shown in FIG2 . Please refer to FIG3 for the schematic diagram of operating waveforms of the bridge resonant converter in FIG2 . It should be noted that the controller 200 also outputs switch drive signals to control the first upper tube S1 , the first lower tube S2 , the third upper tube S3 , and the fourth lower tube S4 .

[0047] As we know, for variable frequency control, a sampling-based feedback loop controls the switching frequency of the switching tubes. At the corresponding switching frequency, each switching tube operates with a duty cycle slightly less than 50%, and the upper and lower tubes in the same bridge arm operate in a complementary manner with a dead zone in between. At least one switching tube in the second bridge unit 120 forms a synchronously operating switching tube with at least one switching tube in the first bridge unit 110. As shown in Figures 2 and 3, the first upper tube S1 and the third upper tube S3 form a pair of synchronously operating switching tubes. Similarly, the first lower tube S2 and the fourth lower tube S4 also form a pair of synchronously operating switching tubes. As shown in Figure 3, the on-time of a switching tube (such as the on-time Ts of the first upper tube S1) constitutes half a switching cycle of the bridge resonant converter. Therefore, controlling the on-time of a switching tube (such as the on-time Ts of the first upper tube S1) is equivalent to controlling the switching frequency of the bridge resonant converter.

[0048] Specifically, as shown in Figure 3, starting at time t1, controller 200 turns on the first high-side switch S1 for a duration of Ts, until time t4. At time t2 within the Ts period, controller 200 turns on the bidirectional blocking switch Sa for a first duration Ta, until time t3. As shown in Figure 3, the output current io of this device is zero, and the slope of the rising resonant current ir increases. Starting at time t3, controller 200 turns on the third high-side switch S3, until time t5. Time t5 is later than time t4 by a second duration Tb. Therefore, between time t4 and time t5, the synchronously operating third high-side switch S3 is turned off a second duration Tb later than the first high-side switch S1. This constitutes the first half of the switching cycle.

[0049] In the second half of the switching cycle, the second lower tube S2, the fourth lower tube S4, and the bidirectional blocking switch Sa working synchronously are turned on. The turn-on timing of the first lower tube S2, the fourth lower tube S4, and the bidirectional blocking switch Sa is the same as the turn-on timing of the first upper tube S1, the third upper tube S3, and the bidirectional blocking switch Sa in the first half of the switching cycle, and will not be repeated here.

[0050] Specifically, a dead time may be included between the switching actions of the switch tube in the first bridge unit 110, and a dead time may be included between the switching actions of the switch tube in the second bridge unit 120 to ensure reliable operation of the bridge resonant converter. Please note that the above description ignores the dead time.

[0051] In this way, each half switching cycle of the bridge resonant converter includes the first time Ta, so that the secondary winding Ls of the transformer is short-circuited, and energy is stored in the resonant tank.

[0052] Furthermore, to improve the efficiency of the bridge resonant converter, it is desired that the switch tube in the second bridge unit 120 of the bridge resonant converter achieves ZCS. As shown in FIG3 , the switch tube in the second bridge unit 120 (e.g., the third switch tube S3) is delayed in turning off for a second time Tb relative to the switch tube in the first bridge unit 110 (e.g., the first switch tube S1) operating synchronously therewith. This delay allows the output current to cross zero and reverse during the second time Tb. Thereafter, the switch tube in the second bridge unit 120 is turned off at the end of the second time Tb. This allows the switch tube in the second bridge unit 120 to achieve ZCS, thereby improving the efficiency of the bridge resonant converter.

[0053] To ensure that the bridge resonant converter has the aforementioned first time Ta boost phase, and also to ensure that the switch tube within the second bridge unit 120 of the bridge resonant converter achieves ZCS, the ideal operating waveform of the bridge resonant converter is shown in Figure 3. To ensure that the operating waveform of the bridge resonant converter is as shown in Figure 3, the inventors have discovered, based on the operating waveforms in Figure 3, that the first time Ta and the second time Tb are related to the gain of the bridge resonant converter. Specifically, when the gain of the bridge resonant converter is greater than or equal to 1 and when it is less than 1, the lengths of the first time Ta and the second time Tb are set differently.

[0054] More specifically, when the gain of the bridge resonant converter is greater than or equal to 1, the lengths of the first time Ta and the second time Tb are configured according to the first relationship; when the gain of the bridge resonant converter is less than 1, the lengths of the first time Ta and the second time Tb are configured according to the second relationship.

[0055] More specifically, the first time Ta in the first relational expression is related to the on-time Ts of the switch in the first bridge unit 110 of the bridge resonant converter during half a switching cycle, the gain of the bridge resonant converter, and the turn-off delay time (i.e., the second time Tb) of the switch in the second bridge unit 120 relative to the switch in the first bridge unit 110 operating synchronously therewith. The second time Tb is related to the on-time Ts of the switch in the first bridge unit 110 of the bridge resonant converter during half a switching cycle. In the second relational expression, the first time Ta is related to the on-time Ts of the switch in the first bridge unit 110 of the bridge resonant converter during half a switching cycle, and the second time Tb is related to the on-time Ts of the switch in the first bridge unit 110 of the bridge resonant converter during half a switching cycle and the gain of the bridge resonant converter.

[0056] Specifically, taking the bridge resonant converter shown in Figure 2 as an example, and considering its ability to operate under the ideal waveform conditions shown in Figure 3, the first upper tube S1 and the first lower tube S2 in the first bridge unit 110 have the same on-time, Ts, within half a switching cycle. The bidirectional blocking switch Sa in the second bridge unit 120 has a first on-time, Ta, which precedes the third upper tube S3 or the fourth lower tube S4. The third upper tube S3 and the fourth lower tube S4 in the second bridge unit 120 have the same on-time, but lag the first upper tube S1 and the first lower tube S2, respectively, by a second time, Tb. The turns ratio of the primary and secondary windings of the transformer 130 is n, and A = Ta / Ts and B = Tb / Ts, meaning that A and B represent the lengths of the first time Ta and the second time Tb, respectively. The inventors have discovered that when the gain M (M = n * Vo / Vin) of the bridge resonant converter is greater than or equal to 1, A and B must be configured according to the first relationship.

[0057] Specifically, in one embodiment, in the first relationship, B = b1 + k1. b1 is a constant, typically ranging from 0.01 to 0.05. Of course, this application does not limit the specific value of b1, which is related to the specific circuit of the bridge resonant converter. k1 is a correction factor used to correct the value of B. It can be adjusted based on the parameters of the components within the bridge resonant converter, or after the bridge resonant converter is designed, it can be corrected based on multiple experiments to obtain a correction factor k1 suitable for the bridge resonant converter. Since B = Tb / Ts, then Tb = B*Ts. That is, the second time Tb obtained according to the first relationship is related to the on-time Ts of the switch tube within the first bridge unit 110 within half a switching cycle, specifically the product of the on-time Ts and a coefficient, which is B (B = b1 + k1).

[0058] Specifically, in one embodiment, in the first equation, A = (M-1) / M+2*B+k2, where k2 is a correction factor used to correct the value of A. This correction factor can be adjusted based on the parameters of the components within the bridge resonant converter, or can be modified after the bridge resonant converter is designed and tested multiple times to obtain a correction factor suitable for the bridge resonant converter. Since A = Ta / Ts, then Ta = A*Ts = ((M-1) / M+2*B+k2)*Ts. That is, the first time Ta obtained according to the first equation is related to the on-time Ts of the switch in the first bridge unit 110 during half a switching cycle, the gain M of the bridge resonant converter, and the turn-off delay time (i.e., the second time Tb) of the switch in the second bridge unit 120 relative to the switch in the first bridge unit 110 operating synchronously therewith. Specifically, it is the product of the on-time Ts and (M-1) / M+2*B+k2.

[0059] Specifically, in one embodiment, in the second relationship, B = (1-M) / 2 + k3. Similarly, k3 is a correction factor used to correct the value of B. This correction factor can be adjusted based on the parameters of the components within the bridge resonant converter. Alternatively, after the bridge resonant converter is designed, the correction factor k3 suitable for the bridge resonant converter can be obtained through multiple experiments. Since B = Tb / Ts, Tb = B*Ts. That is, the second time Tb obtained according to the second relationship is related to the on-time Ts of the switch tube within the first bridge unit 110 during half a switching cycle and the gain M of the bridge resonant converter. Specifically, it is the product of the on-time Ts and (1-M) / 2 + k3.

[0060] Specifically, in one embodiment, in the second relationship, A = b2 + k4. b2 is a constant whose value is typically close to zero. Of course, this application does not limit the specific value of b2, which is related to the specific circuit of the bridge resonant converter. k4 is a correction factor used to correct the value of A. It can be adjusted based on the parameters of the components within the bridge resonant converter, or after the bridge resonant converter is designed, it can be corrected based on multiple experiments to obtain a correction factor k4 suitable for the bridge resonant converter. From A = Ta / Ts, then Ta = (b2 + k4) * Ts. That is, the first time Ta obtained according to the first relationship is related to the on-time Ts of the switch tube within the first bridge unit 110 within half a switching cycle. Specifically, it is the product of the on-time Ts and a coefficient, which is A (A = b2 + k4).

[0061] In a specific implementation, please refer to the controller module schematic diagram of an embodiment of the present application shown in FIG4 . As shown in FIG4 , the controller 200 includes an on-time Ts calculation unit 210, which receives an output sampling signal Sc from the bridge resonant converter and a reference signal Sref corresponding to the output sampling signal Sc. The unit is configured to calculate the on-time Ts of the switch tube in the first bridge unit 110 within half a switching cycle based on the output sampling signal Sc and the reference signal Sref. Specifically, the on-time Ts calculation unit 210 includes a calculation unit for calculating the difference between the output sampling signal Sc and the reference signal Sref, and a PID operation unit for obtaining the on-time Ts based on the difference signal. The output sampling signal Sc here can be any signal representing the output signal of the bridge resonant converter, such as an output voltage signal, an output current signal, or an output power signal. The corresponding reference signal Sref can be a voltage reference signal, a current reference signal, a power reference signal, or the like. Any method can be used as long as the on-time Ts can be obtained based on the sampling signal Sc and the reference signal Sref.

[0062] As shown in FIG4 , the controller 200 further includes a time generating unit 220 for receiving the on-time Ts, the input voltage Vin and the output voltage Vo to obtain a first time Ta and a second time Tb according to the on-time Ts, the input voltage Vin and the output voltage Vo.

[0063] As shown in FIG4 , the controller 200 further includes a drive signal generating unit 230 for receiving a first time Ta and a second time Tb to output a switch drive signal for driving the first upper tube S1, the first lower tube S2, the third upper tube S3, the fourth lower tube S4, and the bidirectional blocking switch Sa in the bridge resonant converter, so that the operating waveform thereof approaches the rational operating waveform shown in FIG3 .

[0064] More specifically, please refer to the module schematic diagram of the time generation unit in the controller shown in Figure 5. As shown in Figure 5, the time generation unit 220 includes a gain calculation unit 221, which is used to receive the input voltage Vin and the output voltage Vo to calculate the gain M of the bridge resonant converter. Specifically, the gain M can be calculated according to the formula M=n*Vo / Vin, where n is the turns ratio of the transformer 130 winding.

[0065] As shown in FIG5 , the time generating unit 220 further includes a gain determining unit 222 for determining whether the gain M is greater than or equal to 1 and outputting a gain representative signal CM.

[0066] As shown in FIG5 , the time generation unit 220 further includes a time parameter generation unit 223 for receiving the gain characterization signal CM and outputting time parameters A and B. Specifically, the time parameters A and B are configured using either a first relational expression or a second relational expression based on the gain characterization signal CM. The first and second relational expressions can be found in the above description and are not further elaborated here.

[0067] As shown in FIG5 , the time generating unit 220 further includes a time calculating unit 224 for obtaining a first time Ta and a second time Tb according to time parameters A and B and the on-time Ts, where A=Ta / Ts and B=Tb / Ts.

[0068] More specifically, as shown in FIG3 , without considering the dead time, the duty cycle of the first upper tube S1 and the first lower tube S2 in the first bridge unit 110 is 50%, the duty cycle of the bidirectional blocking switch Sa and the third upper tube S3 together is 50%, and the duty cycle of the bidirectional blocking switch Sa and the fourth lower tube S4 together is 50%, and in each half switching cycle, the bidirectional blocking switch Sa is turned on before the third upper tube S3 or the fourth lower tube S4.

[0069] Based on the same principle as the above-mentioned bridge resonant converter, the present application further provides a bidirectional bridge resonant converter, which can be seen in FIG6 as a schematic diagram of a bidirectional bridge resonant converter according to an embodiment of the present application, including:

[0070] The first bridge unit 110 includes a first bidirectional blocking switch Sa1;

[0071] The transformer 130 includes a first winding Lp and a second winding Ls. One end of the first bridge unit 110 is connected to the first winding Lp, and the other end is used to receive or output a first voltage V1. The first bidirectional blocking switch Sa1 is connected between the two ends of the first winding Lp.

[0072] a second bridge unit 120, one end of the second bridge unit 120 being connected to the second winding Ls, and the other end being configured to output or receive a second voltage V2, and further comprising a second bidirectional blocking switch Sa1, wherein the second bidirectional blocking switch Sa2 is connected between the two ends of the second winding Ls;

[0073] a resonant unit 140 connected between the first bridge unit 110 and the first winding Lp or between the second bridge unit 120 and the second winding Ls;

[0074] The controller 200 receives the first voltage V1 and the second voltage V2, wherein

[0075] When the bidirectional bridge resonant converter is used to convert the first voltage V1 into the second voltage V2, the controller 200 outputs a switch driving signal for controlling the second bidirectional blocking switch Sa2 according to a first gain M1 between the second voltage V2 and the first voltage V1, so that the second bidirectional blocking switch Sa2 is turned on within a first time Ta.

[0076] When the bidirectional bridge resonant converter is used to convert the second voltage V2 into the first voltage V1, the controller 200 outputs a switch drive signal for controlling the first bidirectional blocking switch Sa1 according to a second gain M2 between the first voltage V1 and the second voltage V2, so that the first bidirectional blocking switch Sa1 is turned on within a third time Ta3.

[0077] When the bidirectional bridge resonant converter is used to convert the first voltage V1 into the second voltage V2, the converter shown in Figure 6 is the same as the bridge resonant converter in Figure 2. At this time, the first voltage V1 is equivalent to the input voltage Vin, the second voltage V2 is equivalent to the output voltage Vo, the first gain M1 is equivalent to the gain M, and the second bidirectional blocking switch Sa2 is equivalent to the bidirectional blocking switch Sa. The principle is the same as above.

[0078] That is, each half switching cycle of the bidirectional bridge resonant converter includes the first time Ta.

[0079] The switch in the output bridge unit (ie, the second bridge unit 120 ) is delayed in turning off by the second time Tb relative to the switch in the input bridge unit (ie, the first bridge unit 110 ) working synchronously therewith.

[0080] When the first gain M1 is greater than or equal to 1 and when the first gain M1 is less than 1, the lengths of the first time Ta and the second time Tb are set differently. More specifically, when the first gain M1 is greater than or equal to 1, the lengths of the first time Ta and the second time Tb are configured according to a first relationship; when the first gain M1 is less than 1, the lengths of the first time Ta and the second time Tb are configured according to a second relationship. More specifically, in the first relationship, the first time Ta is related to the on-time Ts of the switch tube in the first bridge unit 110 within half a switching cycle, the first gain M1, and the second time Tb, and the second time Tb is related to the on-time Ts of the switch tube in the first bridge unit 110 within half a switching cycle; in the second relationship, the first time Ta is related to the on-time Ts of the switch tube in the first bridge unit within half a switching cycle, and the second time Tb is related to the on-time Ts of the switch tube in the first bridge unit within half a switching cycle and the first gain M1. The specific principles are the same as above and will not be repeated here.

[0081] Correspondingly, when the bidirectional bridge resonant converter is used to convert the second voltage V2 into the first voltage V1, the converter shown in Figure 6 is similar to the bridge resonant converter in Figure 2. At this time, the second voltage V2 is equivalent to the input voltage Vin, the first voltage V1 is equivalent to the output voltage Vo, the second gain M2 is equivalent to the gain M, the first bidirectional blocking switch Sa1 is equivalent to the bidirectional blocking switch Sa, and the third time Ta3 is equivalent to the first time Ta. The principle is the same as above.

[0082] That is, the third time Ta3 is included in each half switching cycle of the bidirectional bridge resonant converter.

[0083] The switch in the output bridge unit (ie, the first bridge unit 110 ) is delayed in turning off by the second time Tb relative to the switch in the input bridge unit (ie, the second bridge unit 120 ) working synchronously therewith.

[0084] When the second gain M2 is greater than or equal to 1 and when the second gain M2 is less than 1, the lengths of the third time Ta3 and the second time Tb are configured differently. More specifically, when the second gain M2 is greater than or equal to 1, the lengths of the third time Ta3 and the second time Tb are configured according to a first relationship; when the second gain M2 is less than 1, the lengths of the third time Ta3 and the second time Tb are configured according to a second relationship. More specifically, in the first relationship, the third time Ta3 is related to the on-time Ts of the switch in the second bridge unit 120 during half a switching cycle, the second gain M2, and the second time Tb, and the second time Tb is related to the on-time Ts of the switch in the second bridge unit 110 during half a switching cycle. In the second relationship, the third time Ta3 is related to the on-time Ts of the switch in the second bridge unit during half a switching cycle, and the second time Tb is related to the on-time Ts of the switch in the second bridge unit 120 during half a switching cycle and the second gain M2. The specific principles are the same as above and will not be repeated here.

[0085] In one specific embodiment, similar to the bridge resonant converter shown in FIG2 , the first bridge unit 110 and the second bridge unit 120 are both configured in a half-bridge topology. For details, see FIG7 , which shows a schematic circuit diagram of a bidirectional bridge resonant converter according to one embodiment of the present application. The two ends of the first winding Lp are respectively connected to the common node of the two bridge arms in the first bridge unit 110, and the two ends of the second winding Ls are respectively connected to the common node of the two bridge arms in the second bridge unit 120.

[0086] In practical applications, for unidirectional bridge resonant converters and bidirectional bridge resonant converters, their first bridge unit 110 and second bridge unit 120 can also be configured as full-bridge units, that is, the first bridge unit 110 and the second bridge unit 120 each include two switch bridge arms connected in parallel, and each switch bridge arm includes two switch tubes connected in series. For the full-bridge unit, the control principle of the switch tube therein is the same as that in the prior art and will not be repeated here. It is just that the bidirectional blocking switch is turned on for a first time Ta before the switch tube in the full-bridge unit as the output end is turned on, so as to achieve the advantages of the present application. Specifically, the first bidirectional blocking switch Sa1 is turned on for a third time Ta3 before the switch tube in the full-bridge unit as the output end is turned on, or the second bidirectional blocking switch Sa2 is turned on for a third time Ta3 before the switch tube in the full-bridge unit as the output end is turned on.

[0087] Similarly, one of the first bridge unit 110 and the second bridge unit 120 of the bridge resonant converter may be configured as a half-bridge, and the other may be configured as a full-bridge unit. Alternatively, one of the first bridge unit 110 and the second bridge unit 120 of the bridge resonant converter may be configured as a half-bridge, and the other may be configured as a three-level half-bridge. Alternatively, one of the first bridge unit 110 and the second bridge unit 120 of the bridge resonant converter may be configured as a full-bridge, and the other may be configured as a three-level half-bridge.

[0088] That is, the present application does not limit the specific structure of the bridge unit in the bridge resonant converter, as long as the bridge resonant converter includes a bidirectional blocking switch capable of short-circuiting the primary winding Lp (or first winding) of the transformer and / or a bidirectional blocking switch capable of short-circuiting the secondary winding Ls (or second winding) of the transformer.

[0089] The controller 200 is a digital controller, such as a DSP, MCU, etc. That is, the control modules in the controller 200 are all implemented by programming, and the present application does not require the addition of a detection circuit. Therefore, the solution of the present application does not require any changes to the hardware circuit, is low in cost, and is simple to operate.

[0090] In the above embodiment, the bidirectional blocking switch is configured to include two switching transistors connected in series, with a diode connected in parallel across each switching transistor, and the anodes of the two diodes connected together. This bidirectional blocking switch enables both bidirectional conduction and bidirectional blocking. Of course, the bidirectional blocking switch can also be configured in other configurations, as long as it can achieve both bidirectional conduction and bidirectional blocking.

[0091] Furthermore, according to the above description, the bridge resonant converter of the present application determines the conduction time of the bidirectional blocking switch based on the real-time sampled input voltage, output voltage and output sampling signal, so the control timeliness is good, thereby improving the performance of the bridge resonant converter.

[0092] Although the embodiments of the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims.

[0093] Furthermore, the scope of the present application is not intended to be limited to the particular embodiments of the processes, machines, manufacture, compositions of matter, means, methods, and steps described in the specification. As will be readily understood by one of ordinary skill in the art from the disclosure herein, processes, machines, manufacture, compositions of matter, means, methods, or steps that perform substantially the same functions now exist or will later be developed or that achieve substantially the same results as the corresponding embodiments described herein may be utilized in accordance with the present disclosure. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

1. A bridge resonant converter, characterized in that: include: First bridge unit; A transformer, comprising a primary winding and a secondary winding, wherein one end of the first bridge unit is connected to the primary winding, and the other end is used to receive an input voltage; a second bridge unit, one end of which is connected to the secondary winding, and the other end of which is used to provide an output voltage, and further comprising a bidirectional blocking switch connected between the two ends of the secondary winding; a resonance unit connected between the first bridge unit and the primary winding or between the second bridge unit and the secondary winding; The controller receives the input voltage and the output voltage, and outputs a switch driving signal for controlling the bidirectional blocking switch according to a gain between the output voltage and the input voltage, so that the bidirectional blocking switch is turned on within a first time.

2. The bridge resonant converter according to claim 1, characterized in that: The first time is included in each half switching cycle of the bridge resonant converter.

3. The bridge resonant converter according to claim 1 or 2, characterized in that: The switch tube in the second bridge unit is turned off delayed by a second time relative to the switch tube in the first bridge unit working synchronously therewith.

4. The bridge resonant converter according to claim 3, characterized in that: When the gain is greater than or equal to 1 and when the gain is less than 1, the lengths of the first time and the second time are set differently.

5. The bridge resonant converter according to claim 4, characterized in that: When the gain is greater than or equal to 1, the lengths of the first time and the second time are configured according to a first relational expression; when the gain is less than 1, the lengths of the first time and the second time are configured according to a second relational expression.

6. The bridge resonant converter according to claim 5, characterized in that: In the first relational expression, the first time is related to the conduction time of the switch tube in the first bridge unit in half a switching cycle, the gain and the second time, and the second time is related to the conduction time of the switch tube in the first bridge unit in half a switching cycle; In the second relational expression, the first time is related to the conduction time of the switch tube in the first bridge unit within half a switching cycle, and the second time is related to the conduction time of the switch tube in the first bridge unit within half a switching cycle and the gain.

7. The bridge resonant converter according to claim 1, characterized in that: The first bridge unit is configured as a half-bridge topology, and two ends of the primary winding are respectively connected to common nodes of two bridge arms in the first bridge unit.

8. The bridge resonant converter according to claim 7, characterized in that: The second bridge unit is configured as a half-bridge topology, a full-bridge topology or a three-level half-bridge topology.

9. A bidirectional bridge resonant converter, characterized in that: include: A first bridge unit including a first bidirectional blocking switch; A transformer, comprising a first winding and a second winding, wherein one end of the first bridge unit is connected to the first winding, and the other end is used to receive or output a first voltage, and the first bidirectional blocking switch is connected between the two ends of the first winding; a second bridge unit, one end of which is connected to the second winding, and the other end of which is used to output or receive a second voltage correspondingly, and further comprising a second bidirectional blocking switch, wherein the second bidirectional blocking switch is connected between the two ends of the second winding; a resonance unit connected between the first bridge unit and the first winding or between the second bridge unit and the second winding; A controller receives the first voltage and the second voltage, wherein When the bidirectional bridge resonant converter is used to convert the first voltage into the second voltage, the controller converts the first voltage into the second voltage according to a first gain between the second voltage and the first voltage. outputting a switch driving signal for controlling the second bidirectional blocking switch so that the second bidirectional blocking switch is turned on within a first time; When the bidirectional bridge resonant converter is used to convert the second voltage into the first voltage, the controller outputs a switch drive signal for controlling the first bidirectional blocking switch according to a second gain between the first voltage and the second voltage, so that the first bidirectional blocking switch is turned on within a third time.

10. The bidirectional bridge resonant converter according to claim 9, characterized in that: Each half switching cycle of the bidirectional bridge resonant converter includes the first time or the third time.

11. The bidirectional bridge resonant converter according to claim 9, characterized in that: The switch tube in the bridge unit at the output end is turned off delayed by a second time relative to the switch tube in the bridge unit at the input end working synchronously therewith.

12. The bidirectional bridge resonant converter according to claim 11, characterized in that: Wherein: when the first gain is greater than or equal to 1 and when the first gain is less than 1, the lengths of the first time and the second time are set differently; When the second gain is greater than or equal to 1 and when the second gain is less than 1, the lengths of the third time and the second time are set differently.

13. The bidirectional bridge resonant converter according to claim 12, characterized in that: When the first gain is greater than or equal to 1, the lengths of the first time and the second time are configured according to a first relational expression; when the first gain is less than 1, the lengths of the first time and the second time are configured according to a second relational expression; When the second gain is greater than or equal to 1, the lengths of the third time and the second time are configured according to a first relationship; when the second gain is less than 1, the lengths of the third time and the second time are configured according to a second relationship.

14. The bidirectional bridge resonant converter according to claim 13, characterized in that: When the bidirectional bridge resonant converter is used to convert the first voltage into the second voltage, the first time in the first relational expression is related to the on-time of the switch tube in the first bridge unit within half a switching cycle, the first gain and the second time, and the second time is related to the on-time of the switch tube in the first bridge unit within half a switching cycle; the first time in the second relational expression is related to the on-time of the switch tube in the first bridge unit within half a switching cycle, and the second time is related to the on-time of the switch tube in the first bridge unit within half a switching cycle and the first gain; When the bidirectional bridge resonant converter is used to convert the second voltage into the first voltage, the third time in the first relationship is related to the turn-on time of the switch tube in the second bridge unit within half a switching cycle, the second gain and the second time, and the second time is related to the turn-on time of the switch tube in the second bridge unit within half a switching cycle; in the second relationship, the first time is related to the turn-on time of the switch tube in the second bridge unit within half a switching cycle, and the second time is related to the turn-on time of the switch tube in the second bridge unit within half a switching cycle and the second gain.

15. The bidirectional bridge resonant converter according to claim 9, characterized in that: The first bridge unit is configured as a half-bridge topology, and two ends of the first winding are respectively connected to common nodes of two bridge arms in the first bridge unit.

16. The bidirectional bridge resonant converter according to claim 15, characterized in that: The second bridge unit is configured as a half-bridge topology, a full-bridge topology or a three-level half-bridge topology.

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