Resonant converter and method and system for controlling the same

Abstract

The application provides a resonant converter and a control method and system thereof. The resonant converter comprises a controller, a resonant circuit, a first bridge arm and a second bridge arm in parallel, and a third bridge arm and a fourth bridge arm in parallel. Each of the first bridge arm, the second bridge arm, the third bridge arm and the fourth bridge arm comprises an upper bridge arm switch and a lower bridge arm switch in series. When the upper bridge arm switch of the third bridge arm and the lower bridge arm switch of the fourth bridge arm are turned off, a resonant inductor in the resonant circuit forms a resonant network with a junction capacitance inside each bridge arm switch in the first bridge arm and the second bridge arm. In order to break the resonant network, the controller can control the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm to be turned on after a first preset time length after the upper bridge arm switch of the third bridge arm and the lower bridge arm switch of the fourth arm are turned off, so that the voltage gain of the resonant converter when working in a high frequency band can be ensured to decrease with the increase of the frequency and have monotonicity, the cost is lower, and the adaptability is stronger.

Description

Technical Field

[0001] This application relates to the field of electronic power technology, and in particular to a resonant converter and its control method and system. Background Technology

[0002] LLC circuits (a type of bidirectional DC-DC converter) utilize the zero-crossing point generated by the resonant network at high-frequency resonance to achieve zero-voltage turn-on (i.e., soft-switching) of power devices. This reduces the switching losses of the power devices, improves the operating efficiency of the LLC circuit, and gives it a wider operating voltage range. However, when the LLC circuit operates at high frequencies, problems arise such as non-monotonic voltage gain and abnormal soft-switching states of the power devices.

[0003] In existing technologies, an LC resonant network (composed of a resonant inductor and a resonant capacitor) is typically added to the existing LLC circuit. This involves placing one LC resonant network on both the input and output sides of the LLC circuit. This ensures a wide zero-voltage turn-on operating range for both forward and reverse operation, broadens the input voltage range during reverse operation, and solves the problem of abnormal soft-switching states in power devices. However, using two resonant networks in this LLC circuit leads to excessive cost, and the voltage gain of the LLC circuit is not monotonic during operation, limiting its applicability. Summary of the Invention

[0004] This application provides a resonant converter, its control method, and a system that can ensure that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating at high frequencies (such as forward or reverse operation), while also being lower in cost and more adaptable.

[0005] In a first aspect, this application provides a resonant converter, which includes a controller, a resonant circuit, a first bridge arm and a second bridge arm connected in parallel, and a third bridge arm and a fourth bridge arm connected in parallel. The midpoints of the first and second bridge arms are respectively connected to two first connection terminals of the resonant circuit, and the midpoints of the third and fourth bridge arms are respectively connected to two second connection terminals of the resonant circuit. Each of the first, second, third, and fourth bridge arms includes an upper bridge arm switch and a lower bridge arm switch connected in series. The series connection point of the upper and lower bridge arm switches is the bridge arm midpoint, and the series connection point of the upper and lower bridge arm switches in each bridge arm can also serve as the bridge arm midpoint of each bridge arm. The upper and lower bridge arm switches in each bridge arm are complementary in conduction; that is, for each bridge arm, when the upper bridge arm switch is on, the lower bridge arm switch is off, and vice versa. The controller can turn on the lower arm switch of the first arm and the upper arm switch of the second arm after a first preset time period following the disconnection of the upper arm switch of the third arm and the lower arm switch of the fourth arm.

[0006] The first preset duration can be greater than or equal to 0 and less than or equal to the dead time between the upper and lower bridge arm switches in the third or fourth bridge arm. Specifically, the first preset duration can be greater than or equal to 0 and less than or equal to the dead time between the upper and lower bridge arm switches in the third bridge arm, or the first preset duration can be greater than or equal to 0 and less than or equal to the dead time between the upper and lower bridge arm switches in the fourth bridge arm. The dead time between the upper and lower bridge arm switches in the third bridge arm can be understood as the duration between the turn-off time of the upper bridge arm switch and the turn-on time of the lower bridge arm switch in the third bridge arm. Similarly, the dead time between the upper and lower bridge arm switches in the fourth bridge arm can be understood as the duration between the turn-off time of the lower bridge arm switch and the turn-on time of the upper bridge arm switch in the fourth bridge arm.

[0007] In this application, when the upper bridge arm switch of the third bridge arm and the lower bridge arm switch of the fourth bridge arm are disconnected, the current of the resonant inductor in the resonant circuit gradually shifts from the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm to the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm. During this current transfer process, the resonant inductor forms a resonant network with the junction capacitance inside each bridge arm switch in the first and second bridge arms. Furthermore, the controller promptly controls the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm to turn on after a first preset time period following the disconnection of the upper bridge arm switch of the third bridge arm and the lower bridge arm switch of the fourth bridge arm. This disrupts the resonant network formed by the resonant inductor and the junction capacitance inside each bridge arm switch in the first and second bridge arms, thereby ensuring that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating at high frequencies (such as forward or reverse operation), thus widening the operating voltage range of the resonant converter. In addition, this resonant converter uses fewer components (such as a set of resonant circuits), has a simpler structure and lower cost, and can also reduce the overall size of the resonant converter, making it highly adaptable.

[0008] In conjunction with the first aspect, in a first possible implementation, the controller includes a sampling unit and a control unit. The sampling unit may include, but is not limited to, a voltage sampling circuit (also called a voltage detection circuit), a voltage divider resistor sampling circuit, or a voltage Hall sensor. The sampling unit and the control unit can establish wired or wireless communication to transmit voltage data (such as the first midpoint voltage and the second midpoint voltage described below). The sampling unit can acquire the first midpoint voltage of the midpoint of the first bridge arm and the second midpoint voltage of the midpoint of the second bridge arm in real time. Then, the control unit can obtain the switching status signals of the upper and lower bridge arm switches in each of the first and second bridge arms based on the first and second midpoint voltages. Further, the control unit can also generate driving signals for the upper and lower bridge arm switches in each of the first and second bridge arms based on the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms, and the switching status signals of the upper and lower bridge arm switches in each of the first and second bridge arms.

[0009] After generating the drive signal, the control unit can also, based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, control the lower bridge arm switch in the first bridge arm and the upper bridge arm switch in the second bridge arm to turn on after a first preset time period following the disconnection of the upper bridge arm switch in the third bridge arm and the lower bridge arm switch in the fourth bridge arm. Since the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms change continuously over time, and the switch state signals of the upper and lower bridge arm switches in each of the first and second bridge arms change in real time with changes in the voltage values ​​of the first and second midpoint voltages, the control unit can generate more precise drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms. Furthermore, the aforementioned control unit can quickly turn on the lower bridge arm switch in the first bridge arm and the upper bridge arm switch in the second bridge arm after the current transfer of the resonant inductor based on a more precise drive signal, thereby disrupting the resonant network. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating at high frequencies, while also improving the dynamic response speed of the control unit and making it more adaptable.

[0010] In conjunction with the first possible implementation of the first aspect, in the second possible implementation, during the generation of the drive signal, the control unit can invert the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms, thereby obtaining the blanking signals of the upper and lower bridge arm switches in each of the first and second bridge arms. Inverting the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms can be understood as follows: when the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms are high, the blanking signals of the upper and lower bridge arm switches in each of the first and second bridge arms are low; conversely, when the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms are low, the blanking signals of the upper and lower bridge arm switches in each of the first and second bridge arms are high.

[0011] Furthermore, the aforementioned control unit can also generate drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms based on the blanking signals and switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms. Since the blanking signals for the upper and lower bridge arm switches in each of the first and second bridge arms are obtained by inverting the drive signals for the upper and lower bridge arm switches in each of the third and fourth bridge arms, the blanking signals change in real time with the changes in the drive signals, thus ensuring the real-time performance and accuracy of the blanking signals. Furthermore, the aforementioned control unit can combine the real-time changing blanking signals and switch status signals to generate more accurate and real-time changing drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms, thereby ensuring the real-time performance and accuracy of the drive signals and enhancing applicability.

[0012] In conjunction with the second possible implementation of the first aspect, in the third possible implementation, after disrupting the resonant network formed by the resonant inductor and the junction capacitance inside each bridge arm switch in the first and second bridge arms, the control unit can further control the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm to disconnect based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, after a second preset time period following the conduction of the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm. The second preset time period can be greater than or equal to 0 and less than or equal to the conduction time of the lower bridge arm switch of the third bridge arm or the conduction time of the upper bridge arm switch of the fourth bridge arm, wherein the conduction time of the lower bridge arm switch of the third bridge arm is equal to the conduction time of the upper bridge arm switch of the fourth bridge arm. It is understandable that after the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm are turned on, the resonant inductor will not form a resonant network with the junction capacitance inside each bridge arm switch in the first and second bridge arms. Therefore, the control unit will immediately or delay turning off the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm after the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm are turned on. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating at high frequencies (such as forward and reverse operation), thereby widening the operating voltage range of the resonant converter and making it more applicable.

[0013] In a fourth possible implementation, combining the second or third possible implementation of the first aspect, the control unit includes a first comparator and a first AND gate. The positive input of the first comparator is connected to a second midpoint voltage, the output of the first comparator is connected to the first input of the first AND gate, and the second input of the first AND gate is connected to the blanking signal of the lower bridge arm switch in the first bridge arm and the blanking signal of the upper bridge arm switch in the second bridge arm. When the blanking signal is high, the first comparator can output a high level to the first AND gate when the second midpoint voltage is greater than a first reference voltage, indicating that the switching state signal of the lower bridge arm switch in the first bridge arm and the switching state signal of the upper bridge arm switch in the second bridge arm are both high. The first reference voltage can be the voltage that characterizes the reverse recovery of the freewheeling diode inside the bridge arm switch (such as the upper or lower bridge arm switch).

[0014] Furthermore, when the switching state signals of the lower bridge arm switch in the first bridge arm and the upper bridge arm switch in the second bridge arm are both high, and when the blanking signals of the lower and upper bridge arm switches in the first and second bridge arms are both high, the first AND gate outputs a high level as the driving signal for the lower and upper bridge arm switches of the first and second bridge arms. This allows the lower and upper bridge arm switches of the first and second bridge arms to quickly turn on after the freewheeling diodes inside the bridge arm switches complete their reverse recovery. Since the driving signals of the lower and upper bridge arm switches change in real time with the corresponding blanking and switching state signals, the first comparator and the first AND gate can work together to ensure the real-time performance and accuracy of the driving signals, making the system more versatile.

[0015] In conjunction with the fourth possible implementation of the first aspect, in the fifth possible implementation, when the blanking signal is low, the first AND gate can also output a low level as the drive signal for the lower arm switch of the first bridge arm and the upper arm switch of the second bridge arm when the switch state signal of the lower arm switch in the first bridge arm and the switch state signal of the upper arm switch of the second bridge arm are high, and the blanking signal of the lower arm switch in the first bridge arm and the blanking signal of the upper arm switch of the second bridge arm are low. Since the drive signals of the lower arm switch of the first bridge arm and the upper arm switch of the second bridge arm change in real time with the change of their corresponding blanking signal and switch state signal, the first comparator and the first AND gate can work together to ensure the real-time performance and accuracy of the drive signals, making it more versatile.

[0016] In a sixth possible implementation, combining any one of the second to fifth possible implementations of the first aspect, the control unit can further control the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm to be turned on or off based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, after a third preset time period following the disconnection of the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm. The third preset time period can be greater than or equal to 0, and less than or equal to the dead time between the upper and lower bridge arm switches in the third or fourth bridge arm. When the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm are turned on, it can be ensured that the voltage gain of the resonant converter decreases with increasing frequency when operating in the high-frequency range (such as forward and reverse operation), and the monotonicity of the voltage gain is better, resulting in wider applicability. With the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm open, the voltage gain of the resonant converter at high frequency (such as forward and reverse operation) decreases with increasing frequency and has monotonicity, thereby widening the operating voltage range of the resonant converter and making it more applicable.

[0017] In conjunction with the sixth possible implementation of the first aspect, in the seventh possible implementation, the control unit further includes a second comparator and a second AND gate. The positive input of the second comparator can be connected to a first midpoint voltage, the output of the second comparator can be connected to the first input of the second AND gate, and the second input of the second AND gate can be connected to the blanking signal of the upper bridge arm switch and the blanking signal of the lower bridge arm switch in the first bridge arm. When the blanking signal is high, the second comparator can output a high level to the second AND gate when the first midpoint voltage is greater than the second reference voltage, indicating that the switching state signal of the upper bridge arm switch and the switching state signal of the lower bridge arm switch are both high. The second reference voltage can be the voltage characterizing the reverse recovery of the freewheeling diode inside the bridge arm switch, and the second reference voltage and the first reference voltage can be the same or different.

[0018] Furthermore, the aforementioned second AND gate can output a high level as the drive signal for the upper arm switch of the first bridge arm and the lower arm switch of the second bridge arm when the switch state signals of the upper arm switch and the lower arm switch of the first bridge arm are both high, and when the blanking signals of the upper arm switch and the lower arm switch of the second bridge arm are both high. Since the drive signals for the upper arm switch and the lower arm switch of the first bridge arm change in real time with their corresponding blanking signals and switch state signals, the second comparator and the second AND gate can work together to ensure the real-time performance and accuracy of the drive signals, thus enhancing applicability.

[0019] In conjunction with the seventh possible implementation of the first aspect, in the eighth possible implementation, when the blanking signal is low, the aforementioned second AND gate can also output a low level as the drive signal for the upper arm switch of the first bridge arm and the lower arm switch of the second bridge arm when the switch state signal of the upper arm switch of the first bridge arm and the switch state signal of the lower arm switch of the second bridge arm are high, and the blanking signal of the upper arm switch of the first bridge arm and the blanking signal of the lower arm switch of the second bridge arm are low. Since the drive signals of the upper arm switch of the first bridge arm and the lower arm switch of the second bridge arm change in real time with the change of their corresponding blanking signal and switch state signal, the second comparator and the second AND gate can work together to ensure the real-time performance and accuracy of the drive signals, thus making it more versatile.

[0020] Secondly, this application provides a control method for a resonant converter. This method is applicable to a controller in a resonant converter (such as the resonant converter provided in any of the first to sixth possible embodiments of the first aspect described above). The resonant converter further includes a resonant circuit, a first bridge arm and a second bridge arm connected in parallel, and a third bridge arm and a fourth bridge arm connected in parallel. The midpoints of the first and second bridge arms are respectively connected to two first connection terminals of the resonant circuit. The midpoints of the third and fourth bridge arms are respectively connected to two second connection terminals of the resonant circuit. Each bridge arm includes an upper bridge arm switch and a lower bridge arm switch connected in series. The series connection point of the upper and lower bridge arm switches in each bridge arm can be used as the midpoint of each bridge arm. In this method, the controller can generate drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms. Furthermore, the controller can, based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, control the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm to turn on after a first preset time period following the disconnection of the upper bridge arm switch of the third bridge arm and the lower bridge arm switch of the fourth bridge arm.

[0021] Wherein, the first preset duration is greater than or equal to 0 and less than or equal to the dead time between the upper and lower bridge arm switches in the third or fourth bridge arm, that is, the first preset duration is greater than or equal to 0 and less than or equal to the dead time between the upper and lower bridge arm switches in the third bridge arm, or the first preset duration is greater than or equal to 0 and less than or equal to the dead time between the upper and lower bridge arm switches in the fourth bridge arm. The dead time between the upper and lower bridge arm switches in the third bridge arm can be understood as the duration between the turn-off time of the upper bridge arm switch and the turn-on time of the lower bridge arm switch in the third bridge arm; the dead time between the upper and lower bridge arm switches in the fourth bridge arm can be understood as the duration between the turn-off time of the lower bridge arm switch and the turn-on time of the upper bridge arm switch in the fourth bridge arm.

[0022] In this application, when the upper bridge arm switch of the third bridge arm and the lower bridge arm switch of the fourth bridge arm are disconnected, the current of the resonant inductor in the resonant circuit gradually shifts from the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm to the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm. During this current transfer process, the resonant inductor forms a resonant network with the junction capacitance inside each bridge arm switch in the first and second bridge arms. Furthermore, the controller promptly controls the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm to turn on after a first preset time period following the disconnection of the upper bridge arm switch of the third bridge arm and the lower bridge arm switch of the fourth bridge arm. This disrupts the resonant network formed by the resonant inductor and the junction capacitance inside each bridge arm switch in the first and second bridge arms, thereby ensuring that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating at high frequencies (such as forward or reverse operation). This broadens the operating voltage range of the resonant converter, improves its efficiency, reduces cost, and enhances adaptability.

[0023] In conjunction with the second aspect, in the first possible implementation, during the generation of drive signals, the controller can acquire in real time the first midpoint voltage of the midpoint of the first bridge arm and the second midpoint voltage of the midpoint of the second bridge arm, and obtain the switching state signals of the upper and lower bridge arm switches in each of the first and second bridge arms based on the first and second midpoint voltages. Further, the controller can generate drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms based on the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms, and the switching state signals of the upper and lower bridge arm switches in each of the first and second bridge arms. Since the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms change continuously over time, and the switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms change in real time with the changes in the voltage values ​​of the first and second midpoint voltages, the controller can generate more accurate and real-time changing drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms. This ensures the real-time performance and accuracy of the drive signals and makes the controller more versatile.

[0024] In conjunction with the first possible implementation of the second aspect, in the second possible implementation, during the generation of the switch status signals, the controller can determine that the switch status signal of the upper bridge arm switch of the first bridge arm and the switch status signal of the lower bridge arm switch of the second bridge arm are high-level when the first midpoint voltage is greater than the second reference voltage. Furthermore, the controller can also determine that the switch status signal of the lower bridge arm switch in the first bridge arm and the switch status signal of the upper bridge arm switch of the second bridge arm are high-level when the second midpoint voltage is greater than the first reference voltage. It is understandable that during the process of the current of the resonant inductor in the above resonant circuit gradually transferring from the upper bridge arm switch of the first bridge arm to the lower bridge arm switch of the second bridge arm, the voltage value of the first midpoint voltage will gradually decrease, and the voltage value of the second midpoint voltage will gradually increase. That is, the voltage values ​​of the first midpoint voltage and the second midpoint voltage will continuously change as the current of the resonant inductor gradually transfers. Therefore, the above controller can obtain the real-time changing switch state signal based on the first midpoint voltage and the second midpoint voltage, thereby ensuring the real-time performance and accuracy of the switch state signal and making it more applicable.

[0025] In a third possible implementation, in conjunction with the first or second possible implementation of the second aspect, the controller can invert the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms to obtain the blanking signals of the upper and lower bridge arm switches in each of the first and second bridge arms. Inverting the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms can be understood as follows: when the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms are high, the blanking signals of the upper and lower bridge arm switches in each of the first and second bridge arms are low; conversely, when the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms are low, the blanking signals of the upper and lower bridge arm switches in each of the first and second bridge arms are high.

[0026] Furthermore, the aforementioned controller can generate drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms based on the blanking signals and switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms. Since the blanking signals for the upper and lower bridge arm switches in each of the first and second bridge arms are obtained by inverting the drive signals for the upper and lower bridge arm switches in each of the third and fourth bridge arms, the blanking signals change with the drive signals, thus ensuring the real-time performance of the blanking signals. Furthermore, the aforementioned controller can combine the real-time changing blanking signals and switch status signals to generate more accurate and real-time changing drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms, thereby ensuring the real-time performance and accuracy of the drive signals and enhancing applicability.

[0027] In conjunction with the third possible implementation of the second aspect, in the fourth possible implementation, during the process of generating the drive signal based on the aforementioned blanking signal and switch state signal, when the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms include the drive signal of the lower bridge arm switch of the first bridge arm and the drive signal of the upper bridge arm switch of the second bridge arm, the controller can determine that the drive signal of the lower bridge arm switch of the first bridge arm and the drive signal of the upper bridge arm switch of the second bridge arm are high when the switch state signal of the lower bridge arm switch of the first bridge arm and the switch state signal of the upper bridge arm switch of the second bridge arm are high, and the blanking signal of the lower bridge arm switch of the first bridge arm and the blanking signal of the upper bridge arm switch of the second bridge arm are high. Since the drive signal of the lower bridge arm switch of the first bridge arm and the drive signal of the upper bridge arm switch of the second bridge arm change in real time with the change of their corresponding blanking signal and switch state signal, the real-time performance and accuracy of the drive signal can be guaranteed, and the applicability is stronger.

[0028] In a fifth possible implementation, in conjunction with the third or fourth possible implementation of the second aspect, the controller can, based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, control the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm to disconnect after a second preset time period following the conduction of the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm. The second preset time period can be greater than or equal to 0 and less than or equal to the conduction time of the lower bridge arm switch of the third bridge arm or the conduction time of the upper bridge arm switch of the fourth bridge arm, wherein the conduction time of the lower bridge arm switch of the third bridge arm is equal to the conduction time of the upper bridge arm switch of the fourth bridge arm. It is understandable that after the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm are turned on, the aforementioned resonant inductor will not form a resonant network with the junction capacitance inside each bridge arm switch in the first and second bridge arms. Therefore, after the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm are turned on, the controller will immediately disconnect or delay disconnecting the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating at high frequencies (such as forward and reverse operation), thereby widening the operating voltage range of the resonant converter to improve its efficiency and make it more applicable.

[0029] In conjunction with the fifth possible implementation of the second aspect, in the sixth possible implementation, when the drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms also include the drive signal for the upper bridge arm switch of the first bridge arm and the drive signal for the lower bridge arm switch of the second bridge arm, the controller can determine that the drive signals for the upper and lower bridge arm switches of the first and second bridge arms are high when the switch state signals for the upper and lower bridge arm switches of the first and second bridge arms are high, and the blanking signals for the upper and lower bridge arm switches of the first and second bridge arms are also high. Since the drive signals for the upper and lower bridge arm switches of the first and second bridge arms change in real time with changes in their corresponding blanking and switch state signals, the real-time performance and accuracy of the drive signals can be guaranteed, resulting in greater applicability.

[0030] In a seventh possible implementation, combining any one of the third to sixth possible implementations of the second aspect, the controller can further control the upper arm switch of the first bridge arm and the lower arm switch of the second bridge arm to be turned on or off based on the drive signals of the upper and lower arm switches in each of the first and second bridge arms, after a third preset time period following the disconnection of the lower arm switch of the third bridge arm and the upper arm switch of the fourth bridge arm. The third preset time period can be greater than or equal to 0 and less than or equal to the dead time between the upper and lower arm switches in the third or fourth bridge arm. When the upper arm switch of the first bridge arm and the lower arm switch of the second bridge arm are turned on, it can be ensured that the voltage gain of the resonant converter decreases with increasing frequency when operating at high frequencies (such as forward and reverse operation), and the monotonicity of the voltage gain is better, resulting in wider applicability. With the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm open, the voltage gain of the resonant converter at high frequency (such as forward and reverse operation) decreases with increasing frequency and has monotonicity, thereby widening the operating voltage range of the resonant converter and making it more applicable.

[0031] In conjunction with the seventh possible implementation of the second aspect, in the eighth possible implementation, when the drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms also include the drive signal for the upper bridge arm switch of the first bridge arm and the drive signal for the lower bridge arm switch of the second bridge arm, the controller can determine that the drive signals for the upper and lower bridge arm switches of the first and second bridge arms are high when the switch state signals for the upper and lower bridge arm switches of the first and second bridge arms are high, and the blanking signals for the upper and lower bridge arm switches of the first and second bridge arms are also high. Since the drive signals for the upper and lower bridge arm switches of the first and second bridge arms change in real time with changes in their corresponding blanking and switch state signals, the real-time performance and accuracy of the drive signals can be guaranteed, resulting in greater applicability.

[0032] In conjunction with the eighth possible implementation of the second aspect, in the ninth possible implementation, the controller can further determine that the drive signal of the upper bridge arm switch of the first bridge arm and the drive signal of the lower bridge arm switch of the second bridge arm are low when the switch state signal of the upper bridge arm switch of the first bridge arm and the switch state signal of the lower bridge arm switch of the second bridge arm are high, and the blanking signal of the upper bridge arm switch of the first bridge arm and the blanking signal of the lower bridge arm switch of the second bridge arm are low. Since the drive signals of the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm change in real time with the changes in their corresponding blanking signals and switch state signals, the real-time performance and accuracy of the drive signals can be guaranteed, and the applicability is strengthened.

[0033] Thirdly, this application provides a DC power supply system, which includes a DC source and a switching power supply connected to the DC source. The switching power supply contains a resonant converter as provided in any of the first to sixth possible embodiments described above. Under normal AC mains power supply conditions, the DC source can convert the AC mains power into a DC voltage and perform power factor correction to obtain a DC voltage, which is then output to the switching power supply. At this time, the resonant converter inside the switching power supply can control the operation of its internal switching devices, thereby converting the DC voltage to a target DC voltage to supply power to the DC load. During the process of supplying power to the DC load, since the voltage gain of the resonant converter decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, the operating voltage range of the entire DC power supply system can be widened, thereby improving the system's power supply efficiency. Furthermore, since the resonant converter is small in size and low in cost, the overall size of the DC power supply system can be reduced, while simultaneously lowering the system's power supply cost, making it highly applicable.

[0034] Fourthly, this application provides a power system, which includes, but is not limited to, a power battery and a resonant converter connected to the power battery as provided in any of the first to sixth possible embodiments described above. The power system is applicable to electric devices, including but not limited to: electric vehicles, electric amusement equipment, electric trains, electric bicycles, golf carts, or other electric devices. Since the voltage gain of the resonant converter decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, the operating voltage range of the entire power system can be widened, thereby improving the efficiency of the power system. Furthermore, because the resonant converter is small in size and low in cost, the overall size of the power system can be reduced, thus lowering the cost and making it highly adaptable.

[0035] Fifthly, this application provides a power supply system including a photovoltaic array and a resonant converter connected to the photovoltaic array, as provided in any of the first to sixth possible embodiments described above. During the power supply to a DC load or DC grid, the resonant converter can supply power to the DC load or DC grid based on the DC voltage provided by the photovoltaic array. Throughout the power supply process, since the voltage gain of the resonant converter decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, the operating voltage range of the entire power supply system can be widened, thereby improving the system's power supply efficiency. Furthermore, because the resonant converter is small in size and low in cost, the overall size of the power supply system can be reduced, simultaneously lowering the system's power supply cost and making it highly applicable.

[0036] In conjunction with the fifth aspect, in a first possible implementation, the power supply system further includes a photovoltaic inverter, which can be connected to the AC power grid. During the supply of power to the AC power grid, the resonant converter can output a target DC voltage to the photovoltaic inverter based on the DC voltage provided by the photovoltaic array. At this time, the photovoltaic inverter can convert the DC voltage input to the resonant converter into an AC voltage and supply power to the AC power grid based on this AC voltage. Throughout the power supply process, since the voltage gain of the resonant converter decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, the operating voltage range of the entire power supply system can be broadened, thereby improving the system's power supply efficiency and broadening its applicability.

[0037] In conjunction with the first possible implementation of the fifth aspect, in the second possible implementation, the power supply system further includes a box-type transformer, through which the photovoltaic inverter can be connected to the AC power grid. During the supply of power to the AC power grid, the resonant converter can output a target DC voltage to the photovoltaic inverter based on the DC voltage provided by the photovoltaic array, and the photovoltaic inverter can output AC voltage to the box-type transformer based on the DC voltage input to the resonant converter; furthermore, the box-type transformer can supply power to the AC power grid based on the AC voltage input to the photovoltaic inverter. Throughout the power supply process, since the voltage gain of the resonant converter decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, the operating voltage range of the entire power supply system can be broadened, thereby improving system power supply efficiency and enhancing applicability.

[0038] In conjunction with the fifth aspect, in a third possible implementation, the power supply system further includes a DC bus and a DC / AC converter. This resonant converter can be connected to the input of the DC / AC converter via the DC bus, and its output can be connected to an AC power grid or an AC load. During the power supply process to the AC power grid or AC load, the resonant converter can convert the DC voltage provided by the photovoltaic array into a target DC voltage and output the target DC voltage to the DC / AC converter via the DC bus. The DC / AC converter can then convert the target DC voltage into an AC voltage and supply power to the AC power grid or AC load based on this AC voltage. Throughout the power supply process, because the voltage gain of the resonant converter decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, the operating voltage range of the entire power supply system can be broadened, thereby improving system power supply efficiency and enhancing its applicability.

[0039] In conjunction with the third possible implementation of the fifth aspect, in the fourth possible implementation, in a photovoltaic-storage hybrid power supply application scenario, the above-mentioned power supply system further includes an energy storage module and a DC / DC converter connected to the energy storage module. This DC / DC converter can be connected to the input terminal of a DC / AC converter via a DC bus. During the process of supplying power to the AC grid or AC load, the DC / DC converter can convert the DC voltage provided by the energy storage module into a target DC voltage and output the target DC voltage to the DC / AC converter via the DC bus. At this time, the DC / AC converter can convert the target DC voltage input to the resonant converter and the target DC voltage input to the DC / DC converter into an AC voltage, and supply power to the AC grid or AC load based on this AC voltage. Throughout the power supply process, since the voltage gain of the resonant converter decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, the operating voltage range of the entire power supply system can be widened, thereby improving the system's power supply efficiency and enhancing its flexibility and applicability.

[0040] In conjunction with the third or fourth possible implementation of the fifth aspect, in the fifth possible implementation, the power supply system further includes a generator and an AC / DC converter connected to the generator. The AC / DC converter is connected to its input terminal via a DC bus. During the process of supplying power to the AC grid or AC load, the AC / DC converter can convert the AC voltage provided by the generator into a DC voltage and output a target DC voltage to the DC / AC converter via the DC bus. At this time, the DC / AC converter can convert the target DC voltage input to the resonant converter and the DC voltage input to the AC / DC converter into an AC voltage, and supply power to the AC grid or AC load based on this AC voltage, thereby improving the system's power supply efficiency and flexibility. Optionally, the DC / AC converter can also supply power to the AC grid or AC load based on the DC voltage provided by the photovoltaic array, the DC voltage provided by the energy storage module, and / or the AC voltage provided by the generator, further improving the system's power supply efficiency and flexibility, and enhancing its applicability.

[0041] In this application, the controller promptly turns on the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm after the current transfer of the resonant inductor. This quickly disrupts the resonant network formed by the resonant inductor and the junction capacitances within the switches of the first and second bridge arms. This ensures that the voltage gain of the resonant converter decreases monotonicly with increasing frequency during high-frequency operation, thereby widening the operating voltage range of the resonant converter. Furthermore, this resonant converter uses fewer components (e.g., it includes a set of resonant circuits), resulting in a simpler structure, lower cost, and a smaller overall size, making it more adaptable. Attached Figure Description

[0042] Figure 1 This is a schematic diagram illustrating the application scenario of the resonant converter provided in this application;

[0043] Figure 2 This is a schematic diagram of the resonant converter provided in this application;

[0044] Figure 3 This is another structural schematic diagram of the resonant converter provided in this application;

[0045] Figure 4 This is another structural schematic diagram of the resonant converter provided in this application;

[0046] Figure 5 This is another structural schematic diagram of the resonant converter provided in this application;

[0047] Figure 6 This is another structural schematic diagram of the resonant converter provided in this application;

[0048] Figure 7 This is a schematic diagram of the waveform generation timing of the bridge arm switch in the resonant converter provided in this application;

[0049] Figure 8 This is a schematic diagram of the DC power supply system provided in this application;

[0050] Figure 9 This is a structural schematic diagram of the power supply system provided in this application;

[0051] Figure 10 This is another structural schematic diagram of the power supply system provided in this application;

[0052] Figure 11 This is another structural schematic diagram of the power supply system provided in this application;

[0053] Figure 12 This is another structural schematic diagram of the power supply system provided in this application;

[0054] Figure 13 This is another structural schematic diagram of the power supply system provided in this application;

[0055] Figure 14 This is a flowchart illustrating the control method for the resonant converter provided in this application. Detailed Implementation

[0056] The resonant converter provided in this application is applicable to various fields, including new energy smart microgrids, power transmission and distribution, new energy (such as photovoltaic grid connection and wind power grid connection), photovoltaic power generation (such as powering household appliances (such as refrigerators and air conditioners) or the power grid), wind power generation, high-power converters (such as converting DC voltage to high-power high-voltage AC), electric motors (such as power systems in electric equipment), and power supplies (such as switching power supplies). The specific application can be determined according to the actual application scenario, and no restrictions are imposed here.

[0057] The resonant converter provided in this application is adaptable to different application scenarios, such as electric vehicle applications, photovoltaic power supply applications, wind power grid-connected power supply applications, or other application scenarios. The following explanation uses the electric vehicle application scenario as an example; please refer to [link / reference]. Figure 1 , Figure 1 This is a schematic diagram illustrating an application scenario of the resonant converter provided in this application. For example... Figure 1As shown, an electric vehicle includes a motor and a power system. The power system includes, but is not limited to, a power battery, a resonant converter, and a DC / AC converter. The power battery is connected to the input of the DC / AC converter via the resonant converter, and the output of the DC / AC converter is connected to the motor. During electric vehicle operation, the resonant converter outputs a target DC voltage to the DC / AC converter based on the DC voltage provided by the power battery. The DC / AC converter then converts the target DC voltage into an AC voltage, which drives the motor and thus propels the electric vehicle. However, when the resonant converter operates at high frequencies, its voltage gain is not monotonic, thus narrowing its operating voltage range and reducing its efficiency. To improve the efficiency of the resonant converter, its internal switching devices can be controlled to achieve monotonicity of its voltage gain, thereby widening its operating voltage range and improving its efficiency, which in turn improves the motor drive efficiency of the power system. Furthermore, because the resonant converter is small and inexpensive, the overall size of the power system can be reduced, lowering its cost and making it more versatile.

[0058] The following will combine Figures 2 to 13 This application provides illustrative examples of the resonant converter, DC power supply system, power supply system, and their working principles.

[0059] See Figure 2 , Figure 2 This is a schematic diagram of the resonant converter provided in this application. Figure 2 As shown, the resonant converter includes a controller 10, a resonant circuit 20, parallel first bridge arms 30a and 30b, and parallel third and fourth bridge arms 30c and 30d. The midpoint A of the first bridge arm 30a and the midpoint B of the second bridge arm 30b are respectively connected to the two first connection terminals of the resonant circuit 20. The midpoint C of the third bridge arm 30c and the midpoint D of the fourth bridge arm are respectively connected to the two second connection terminals of the resonant circuit 20. Each of the first, second, third, and fourth bridge arms 30a, 30b, 30c, and 30d includes an upper bridge arm switch and a lower bridge arm switch connected in series, and the series connection point of the upper and lower bridge arm switches in each bridge arm can be used as the midpoint of each bridge arm. In each of the bridge arms, the upper bridge arm switch and the lower bridge arm switch are complementary in conduction. That is, for each bridge arm, when the upper bridge arm switch is on, the lower bridge arm switch is off, and vice versa.

[0060] Furthermore, the upper and lower bridge arm switches in each of the aforementioned bridge arms may include, but are not limited to, metal-oxide-semiconductor field-effect transistors (MOSFETs) and insulated-gate bipolar transistors (IGBTs). MOSFETs can be simply referred to as metal-oxide-semiconductor field-effect transistors or MOSFETs. The specific switching types of the upper and lower bridge arm switches can be determined by the actual circuit topology of the resonant converter. This resonant converter circuit topology may include, but is not limited to, LLC circuits, circuit topologies with synchronous transistors, circuit topologies with ZVS (zero-voltage turn-on) switching transistors, and other types of bidirectional DC-DC converter circuits. For example, such as... Figure 2 As shown, when the circuit topology of the resonant converter is an LLC circuit, the upper and lower bridge arm switches in each of the first bridge arm 30a, the second bridge arm 30b, the third bridge arm 30c and the fourth bridge arm 30d are all MOSFETs.

[0061] The first bridge arm 30a includes an upper bridge arm switch Q1 and a lower bridge arm switch Q2 connected in series. The series connection point of the upper bridge arm switch Q1 and the lower bridge arm switch Q2 can be used as the midpoint A of the first bridge arm 30a, and the upper bridge arm switch Q1 and the lower bridge arm switch Q2 are complementary conductors. The second bridge arm 30b includes an upper bridge arm switch Q3 and a lower bridge arm switch Q4 connected in series. The series connection point of the upper bridge arm switch Q3 and the lower bridge arm switch Q4 can be used as the midpoint B of the second bridge arm 30b, and the upper bridge arm switch Q3 and the lower bridge arm switch Q4 are complementary conductors. The third bridge arm 30c includes an upper bridge arm switch Q5 and a lower bridge arm switch Q6 connected in series. The series connection point of the upper bridge arm switch Q5 and the lower bridge arm switch Q6 can be used as the midpoint C of the third bridge arm 30c, and the upper bridge arm switch Q5 and the lower bridge arm switch Q6 are complementary conductors. The aforementioned fourth bridge arm 30d includes an upper bridge arm switch Q7 and a lower bridge arm switch Q8 connected in series. The connection point of the upper bridge arm switch Q7 and the lower bridge arm switch Q8 can be used as the midpoint D of the fourth bridge arm 30d, and the upper bridge arm switch Q7 and the lower bridge arm switch Q8 are complementary in conduction.

[0062] In some feasible implementations, the controller 10 can turn on the lower arm switch Q2 of the first bridge arm 30a and the upper arm switch Q3 of the second bridge arm 30b after a first preset time period following the disconnection of the upper arm switch Q5 of the third bridge arm 30c and the lower arm switch Q8 of the fourth bridge arm 30d. The upper arm switch Q5 and the lower arm switch Q8 can be understood as the main switches in the resonant converter. The first preset time period is greater than or equal to 0 and less than or equal to the dead time between the upper arm switch and the lower arm switch in the third bridge arm 30c or the fourth bridge arm 30d, i.e., the first preset time period is greater than or equal to 0 and less than or equal to the dead time between the upper arm switch Q5 and the lower arm switch Q6 in the third bridge arm 30c, or the first preset time period is greater than or equal to 0 and less than or equal to the dead time between the upper arm switch Q7 and the lower arm switch Q8 in the fourth bridge arm 30d. The dead time between the upper arm switch Q5 and the lower arm switch Q6 can be understood as the duration between the turn-off time of the upper arm switch Q5 and the turn-on time of the lower arm switch Q6. Similarly, the dead time between the upper arm switch Q7 and the lower arm switch Q8 can be understood as the duration between the turn-off time of the lower arm switch Q8 and the turn-on time of the upper arm switch Q7.

[0063] It is understandable that when the upper bridge arm switch Q5 and the lower bridge arm switch Q8 are disconnected, the current of the resonant inductor in the resonant circuit 20 will gradually transfer from the upper bridge arm switch Q1 and the lower bridge arm switch Q4 to the lower bridge arm switch Q2 and the upper bridge arm switch Q3. During this current transfer process, the resonant inductor will form a resonant network with the junction capacitance (i.e. the capacitance connected in parallel across the source and drain terminals of the bridge arm switch) inside each of the upper bridge arm switches Q1, Q2, Q3, and Q4. Furthermore, the controller 10 promptly turns on the lower bridge arm switch Q2 and the upper bridge arm switch Q3 after a first preset time period following the opening of the upper bridge arm switch Q5 and the lower bridge arm switch Q8. This disrupts the resonant network formed by the resonant inductor and the junction capacitances within each of the upper, lower, and upper bridge arm switches Q1, Q2, Q3, and Q4. This ensures that the voltage gain of the resonant converter decreases monotonically with increasing frequency during high-frequency operation (e.g., forward or reverse operation), thereby widening the operating voltage range of the resonant converter. Additionally, this resonant converter uses fewer components (e.g., it includes a set of resonant circuits 20), resulting in a simpler structure, reduced overall size, lower cost, and greater adaptability.

[0064] In some feasible implementations, when the first preset duration is equal to 0, the controller 10 can immediately turn on the lower bridge arm switch Q2 of the first bridge arm 30a and the upper bridge arm switch Q3 of the second bridge arm 30b after the upper bridge arm switch Q5 of the third bridge arm 30c and the lower bridge arm switch Q8 of the fourth bridge arm 30d are turned off. This quickly destroys the resonant network formed by the resonant inductor and the junction capacitance inside each of the upper bridge arm switches Q1, Q2, Q3 and Q4. This ensures that the voltage gain of the resonant converter decreases with increasing frequency when operating at high frequencies, and enhances the monotonicity of the voltage gain of the resonant converter, thereby widening the operating voltage range of the resonant converter and making it more applicable.

[0065] In some feasible implementations, such as Figure 2 As shown, the V1 side of the resonant converter includes a positive connection and a negative connection. The positive connection on V1 side can be connected to the drains of upper bridge arm switches Q1 and Q3, and the negative connection on V1 side can be connected to the sources of lower bridge arm switches Q4 and Q5. Similarly, the V2 side of the resonant converter also includes a positive connection and a negative connection. The positive connection on V2 side can be connected to the drains of upper bridge arm switches Q5 and Q7, and the negative connection on V2 side can be connected to the sources of lower bridge arm switches Q6 and Q8. When the resonant converter is in reverse operation (i.e., the resonant converter operates in reverse), the V1 side connection can be used as the input terminal, and the V2 side connection can be used as the output terminal. When the resonant converter is in forward operation (i.e., the resonant converter operates forward), the V1 side connection can be used as the output terminal, and the V2 side connection can be used as the input terminal.

[0066] In some feasible implementations, the resonant circuit 20 may include, but is not limited to, a resonant inductor, a resonant capacitor, a transformer, and a DC blocking capacitor. The specific structure of the resonant circuit 20 can be determined by the actual circuit topology and actual operating state (such as reverse or forward operation) of the resonant converter, and is not limited here. For ease of description, the following explanation will use an LLC circuit as an example of the resonant converter's circuit topology. The specific circuit structure of the resonant circuit 20 can be found in [reference needed]. Figure 3 , Figure 3 This is another schematic diagram of the resonant converter provided in this application. When the resonant converter is in reverse operation, the specific circuit structure of the resonant circuit 20 is as follows: Figure 3 As shown in 3a above, Figure 2 The resonant circuit 20 shown includes a resonant inductor Lr1, a resonant capacitor Cr1, a transformer T1, and a DC blocking capacitor Cb1. Optionally, the above... Figure 2The resonant converter shown also includes an output capacitor Co1 connected in parallel with the fourth bridge arm 30d, and the voltage across the output capacitor Co1 is voltage V2.

[0067] The first bridge arm 30a, the second bridge arm 30b, the resonant inductor Lr1, the resonant capacitor Cr1, and the transformer T1 constitute the input circuit of the resonant converter. The third bridge arm 30c, the fourth bridge arm 30d, and the output capacitor Co1 constitute the output circuit of the resonant converter. The DC blocking capacitor Cb1 can be used to isolate the input and output circuits of the resonant converter. When the transformer T1 includes a primary winding Np1 and a secondary winding Ns1, the midpoint A of the first bridge arm 30a can be connected to the same-name pin of the primary winding Np1 through the resonant inductor Lr1 and the resonant capacitor Cr1. The midpoint B of the second bridge arm 30b can be connected to the opposite-name pin of the primary winding Np1. The midpoint C of the third bridge arm 30c can be connected to the same-name pin of the secondary winding Ns1 through the DC blocking capacitor Cb1. The midpoint D of the fourth bridge arm 30d can be connected to the opposite-name pin of the secondary winding Ns1.

[0068] In some feasible implementations, when the resonant converter is in reverse operation (i.e., the resonant converter operates in reverse), the parallel connection terminals of the first bridge arm 30a and the second bridge arm 30b can serve as the input terminals of the resonant converter (i.e., the connection terminals on the V1 side) to connect to a DC source, and the parallel connection terminals of the third bridge arm 30c and the fourth bridge arm 30d can serve as the output terminals of the resonant converter (i.e., the connection terminals on the V2 side) to connect to a battery. The DC source may include, but is not limited to, photovoltaic strings, energy storage batteries, and alternating current (AC) / direct current (DC) rectified power supplies. At this time, the power flow of the resonant converter is from the V2 side to the V1 side (i.e., energy flows from the output terminal to the input terminal). The controller 10 can control the operation of each bridge arm from the first bridge arm 30a to the fourth bridge arm 30d, thereby converting the voltage V2 provided by the battery into voltage V1 to supply power to the DC source.

[0069] In some feasible implementations, when the resonant converter is in the forward operating state, the specific circuit structure of the resonant circuit 20 is as follows: Figure 3 As shown in 3b above, Figure 2 The resonant circuit 20 shown includes a resonant inductor Lr2, a resonant capacitor Cr2, a transformer T2, and a DC blocking capacitor Cb2. Optionally, the above... Figure 2The resonant converter shown also includes an output capacitor Co2 connected in parallel with the first bridge arm 30a, and the voltage across the output capacitor Co2 is voltage V1. The first bridge arm 30a, the second bridge arm 30b, and the output capacitor Co2 constitute the output side circuit of the resonant converter. The third bridge arm 30c, the fourth bridge arm 30d, the resonant inductor Lr2, the resonant capacitor Cr2, and the transformer T2 constitute the input side circuit of the resonant converter. The DC blocking capacitor Cb2 can be used to isolate the input side circuit and the output side circuit of the resonant converter. In the case that transformer T2 includes primary winding Np2 and secondary winding Ns2, the midpoint A of the first bridge arm 30a can be connected to the opposite-named pin of the secondary winding Ns2, the midpoint B of the second bridge arm 30b can be connected to the same-named pin of the secondary winding Ns2 through the DC blocking capacitor Cb2, the midpoint C of the third bridge arm 30c can be connected to the opposite-named pin of the primary winding Np2, and the midpoint D of the fourth bridge arm 30d can be connected to the same-named pin of the primary winding Np2 through the resonant inductor Lr2 and the resonant capacitor Cr2.

[0070] In some feasible implementations, when the resonant converter is in forward operation (i.e., the resonant converter is operating in the forward direction), the parallel connection terminals of the first bridge arm 30a and the second bridge arm 30b can serve as the output terminals of the resonant converter (i.e., the connection terminals on the V1 side) to connect to the load, and the parallel connection terminals of the third bridge arm 30c and the fourth bridge arm 30d can serve as the input terminals of the resonant converter (i.e., the connection terminals on the V2 side) to connect to the DC source. At this time, the power flow direction of the resonant converter is from the V2 side to the V1 side (i.e., energy flows from the input terminal to the output terminal). The controller 10 can control the operation of each bridge arm from the first bridge arm 30a to the fourth bridge arm 30d, thereby converting the voltage V2 provided by the DC source into voltage V1 to supply power to the load.

[0071] In some feasible implementations, during the process of controlling the operation of each bridge arm from the first bridge arm 30a to the fourth bridge arm 30d to supply power to the DC source or load, the controller 10 can also promptly control the lower bridge arm switch Q2 and the upper bridge arm switch Q3 to conduct after a first preset time after the upper bridge arm switch Q5 and the lower bridge arm switch Q8 are turned off. This disrupts the resonant network formed by the resonant inductor and the junction capacitance inside each bridge arm switch (Q1, Q2, Q3, and Q4), thereby ensuring that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity during both forward and reverse operation, thus widening the operating voltage range of the resonant converter. Furthermore, the resonant converter uses fewer components, has a simpler structure, and lower cost. The transformer (such as the aforementioned transformer T1 or transformer T2) is also smaller, reducing the overall size of the resonant converter and making it more adaptable. For ease of description, the following explanation will use the resonant converter operating in reverse as an example; please refer to [reference needed]. Figure 4 , Figure 4 This is another schematic diagram of the resonant converter provided in this application.

[0072] In some feasible implementations, such as Figure 4 As shown above, Figure 3 The controller 10 shown in 3a includes a sampling unit 101 and a control unit 102. The sampling unit 101 may include, but is not limited to, a voltage sampling circuit (also called a voltage detection circuit), a voltage divider resistor sampling circuit, or a voltage Hall sensor. The sampling unit 101 and the control unit 102 can establish wired or wireless communication to transmit voltage data (such as the first midpoint voltage V described below). A Second midpoint voltage V B The sampling unit 101 described above can acquire the first midpoint voltage V at the midpoint A of the first bridge arm 30a in real time. A The second midpoint voltage V at the midpoint B of the second bridge arm 30b B and outputs the first midpoint voltage V to the control unit 102. A Second midpoint voltage V B At this point, the control unit 102 can base its decisions on the first midpoint voltage V. A Second midpoint voltage V B The switching status signals of the upper and lower bridge arm switches in each of the first bridge arm 30a and the second bridge arm 30b are obtained.

[0073] Furthermore, the control unit 102 can generate drive signals for the upper and lower bridge arm switches in each of the third bridge arm 30c and the fourth bridge arm 30d, and the switch state signals for the upper and lower bridge arm switches in each of the first bridge arm 30a and the second bridge arm 30b, based on the drive signals of the upper and lower bridge arm switches in each of the third bridge arm 30c and the fourth bridge arm 30d. At this time, the control unit 102 can also generate drive signals for the upper and lower bridge arm switches in each of the first bridge arm 30a and the second bridge arm 30b, based on the drive signals of the upper and lower bridge arm switches (e.g., ...). Figure 4 The drive signals Q1-Q4 shown in the figure control the lower arm switch Q2 in the first arm 30a and the upper arm switch Q3 in the second arm 30b to turn on after a first preset time period after the upper arm switch Q5 in the third arm 30c and the lower arm switch Q8 in the fourth arm 30d are turned off.

[0074] It is understandable that during the process of the current in the resonant inductor Lr1 gradually shifting from the upper bridge arm switch Q1 and the lower bridge arm switch Q4 to the lower bridge arm switch Q2 and the upper bridge arm switch Q3, the first midpoint voltage V A The voltage value will gradually decrease, and the second midpoint voltage V B The voltage value will gradually increase, that is, the first midpoint voltage VA The voltage value and the second midpoint voltage V B The voltage value will continuously change as the current in the resonant inductor Lr1 gradually shifts. Therefore, the control unit 102 can be based on the first midpoint voltage V. A Second midpoint voltage V B By obtaining real-time changing switch state signals, more precise drive signals are generated for the upper and lower bridge arm switches in each of the first bridge arm 30a and the second bridge arm 30b. Furthermore, the control unit 102 can quickly turn on the lower bridge arm switch Q2 and the upper bridge arm switch Q3 after the current transfer in the resonant inductor Lr1 based on these more precise drive signals, thereby disrupting the resonant network. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and exhibits monotonicity during high-frequency operation, while simultaneously improving the dynamic response speed of the control unit 102 and enhancing its adaptability.

[0075] In some feasible implementations, the control unit 102 can invert the drive signals of the upper and lower bridge arm switches in each of the third bridge arm 30c and the fourth bridge arm 30d, thereby obtaining blanking signals for the upper and lower bridge arm switches in each of the first bridge arm 30a and the second bridge arm 30b. Here, the blanking signal refers to a signal used to shield the control unit 102 from the induced voltage pulse generated at the moment the bridge arm switch is turned on, in order to avoid erroneous signals. Specifically, inverting the drive signals of the upper and lower bridge arm switches in each of the third bridge arm 30c and the fourth bridge arm 30d can be understood as follows: when the drive signals of the upper and lower bridge arm switches in each of the third bridge arm 30c and the fourth bridge arm 30d are at a high level, the blanking signals of the upper and lower bridge arm switches in each of the first bridge arm 30a and the second bridge arm 30b are at a low level; conversely, when the drive signals of the upper and lower bridge arm switches in each of the third bridge arm 30c and the fourth bridge arm 30d are at a low level, the blanking signals of the upper and lower bridge arm switches in each of the first bridge arm 30a and the second bridge arm 30b are at a high level.

[0076] Furthermore, the control unit 102 can generate drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms 30a and 30b based on the blanking signals and switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms 30a and 30b. At this time, the control unit 102 can also, based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms 30a and 30b, control the lower bridge arm switch Q2 in the first bridge arm 30a and the upper bridge arm switch Q3 in the second bridge arm 30b to turn on after a first preset time period following the disconnection of the upper bridge arm switch Q5 in the third bridge arm 30c and the lower bridge arm switch Q8 in the fourth bridge arm 30d.

[0077] It is understandable that since the blanking signals of the upper and lower bridge arm switches in each of the first and second bridge arms 30a and 30b are obtained by inverting the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms 30c and 30d, the blanking signals will change in real time with the change of the drive signals, thus ensuring the real-time performance and accuracy of the blanking signals. Furthermore, the control unit 102 can combine the real-time changing blanking signals and switch state signals to generate more precise drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms 30a and 30b, so as to quickly turn on the lower bridge arm switch Q2 and the upper bridge arm switch Q3 after the current transfer of the resonant inductor Lr1 to destroy the resonant network. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating at high frequencies (such as forward and reverse operation), while improving the dynamic response speed of the control unit 102 and making it more adaptable.

[0078] In some feasible implementations, after disrupting the resonant network formed by the resonant inductor Lr1 and the junction capacitances within each of the upper and lower bridge arm switches Q1, Q2, Q3, and Q4, the control unit 102 can further, based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms 30a and 30b, control the lower bridge arm switch Q6 of the third bridge arm 30c and the upper bridge arm switch Q7 of the fourth bridge arm 30d to disconnect after a second preset time following their conduction. The second preset time can be greater than or equal to 0 and less than or equal to the conduction time of the lower bridge arm switch Q6 of the third bridge arm 30c or the conduction time of the upper bridge arm switch Q7 of the fourth bridge arm 30d, wherein the conduction time of the lower bridge arm switch Q6 is equal to the conduction time of the upper bridge arm switch Q7.

[0079] It is understandable that after the lower bridge arm switch Q6 and the upper bridge arm switch Q7 are turned on, the resonant inductor Lr1 will not form a resonant network with the junction capacitance inside each of the upper bridge arm switches Q1, Q2, Q3, and Q4. Therefore, the control unit 102 will immediately turn off or delay turning off the lower bridge arm switch Q2 and the upper bridge arm switch Q3 after the lower bridge arm switch Q6 and the upper bridge arm switch Q7 are turned on. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating at high frequencies (such as forward and reverse operation), thereby widening the operating voltage range of the resonant converter to improve its efficiency and make it more applicable.

[0080] In some feasible implementations, the control unit 102 can also control the upper bridge arm switch Q1 of the first bridge arm 30a and the lower bridge arm switch Q4 of the second bridge arm 30b to be turned on or off based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms 30a and 30b, after a third preset time period following the disconnection of the lower bridge arm switch Q6 of the third bridge arm 30c and the upper bridge arm switch Q7 of the fourth bridge arm 30d. Here, the upper bridge arm switch Q1 and the lower bridge arm switch Q4 can be understood as synchronous transistors in the resonant converter; the third preset time period can be greater than or equal to 0 and less than or equal to the dead time between the upper and lower bridge arm switches in the third bridge arm 30c or the fourth bridge arm 30d. When the upper bridge arm switch Q1 and the lower bridge arm switch Q4 are turned on, it can be ensured that the voltage gain of the resonant converter decreases with increasing frequency when operating in the high-frequency range (such as forward and reverse operation), and the monotonicity of the voltage gain is better, making it more applicable. With the upper bridge arm switch Q1 and the lower bridge arm switch Q4 disconnected, the voltage gain of the resonant converter operating at high frequencies (such as forward and reverse operation) decreases monotonicly with increasing frequency. This broadens the operating voltage range of the resonant converter, improving its efficiency and broadening its applicability. Please refer to [further details omitted]. Figure 5 , Figure 5 This is another schematic diagram of the resonant converter provided in this application.

[0081] In some feasible implementations, such as Figure 5 As shown above, Figure 4 The control unit 102 shown includes a first comparator U1 and a first AND gate U2, wherein the positive input terminal of the first comparator U1 is connected to the second midpoint voltage V. B The output of the first comparator U1 can be connected to the first input of the first AND gate U2, and the second input of the first AND gate U2 can be connected to the blanking signal of the lower bridge arm switch Q2 in the first bridge arm 30a and the blanking signal of the upper bridge arm switch Q3 in the second bridge arm 30b. Optionally, the control unit 102 further includes a logic control subunit 1021, a proportional-integral (PI) control subunit 1022, a wave generator subunit 1023, and a drive control subunit 1024. The logic control subunit 1021, the PI control subunit 1022, the wave generator subunit 1023, and the drive control subunit 1024 can be software control logic or hardware circuits integrated on the control unit 102. The specific implementation can be determined according to the actual application scenario and is not limited here.

[0082] In some feasible implementations, the aforementioned PI control subunit 1022 can output modulation waves of each of the upper bridge arm switches Q5, Q6, Q7, and Q8 to the wave-generating subunit 1023 based on hardware feedback. The hardware feedback may include, but is not limited to, voltage V1, current on V1 side, voltage V2, current on V2 side, current flowing through resonant inductor Lr1, and current flowing through DC blocking capacitor Cb1. Then, the wave-generating subunit 1023 can generate drive signals (which can be simply referred to as...) for each of the upper bridge arm switches Q5, Q6, Q7, and Q8 based on the modulation waves of each switch. Figure 5 The logic control subunit 1021 outputs the drive signals of each bridge arm switch to the logic control subunit 1021, which inverts the drive signals of each bridge arm switch to obtain the blanking signals of each of the upper bridge arm switches Q1, lower bridge arm switches Q2, upper bridge arm switches Q3 and lower bridge arm switches Q4. The logic control subunit 1021 then outputs the blanking signal of the lower bridge arm switch Q2 and the blanking signal of the upper bridge arm switch Q3 to the first AND gate U2. The blanking signal may be a high level or a low level.

[0083] In some feasible implementations, the first comparator U1 described above can be at the second midpoint voltage V B Greater than the first reference voltage V ref1 At this time, the switch status signal of the lower bridge arm switch Q2 in the first bridge arm 30a and the switch status signal of the upper bridge arm switch Q3 in the second bridge arm 30b are output to the first AND gate U2 at a high level. The first reference voltage V... ref1 This can be used to provide the reverse recovery voltage for the freewheeling diode inside the bridge arm switch (such as the upper or lower bridge arm switch). Further, the first AND gate U2 can output a high level when the switch state signal of the lower bridge arm switch Q2 in the first bridge arm 30a and the switch state signal of the upper bridge arm switch Q3 in the second bridge arm 30b are both high, and when the blanking signal of the lower bridge arm switch Q2 in the first bridge arm 30a and the blanking signal of the upper bridge arm switch Q3 in the second bridge arm 30b are both high. This outputs a high level as the drive signal for the lower bridge arm switch Q2 in the first bridge arm 30a and the drive signal for the upper bridge arm switch Q3 in the second bridge arm 30b. Since the drive signals for the lower bridge arm switch Q2 and the upper bridge arm switch Q3 change in real time with the changes in their corresponding blanking signals and switch state signals, the first comparator U1 and the first AND gate U2 can work together to ensure the real-time performance and accuracy of the drive signals, thus increasing applicability.

[0084] Furthermore, the aforementioned drive control subunit 1024 can, based on the drive signals of the lower bridge arm switch Q2 and the upper bridge arm switch Q3, control the lower bridge arm switch Q2 and the upper bridge arm switch Q3 to turn on after a first preset time period following the opening of the upper bridge arm switch Q5 and the lower bridge arm switch Q8. It can be understood that the aforementioned first comparator U1, first AND gate U2, and drive control subunit 1024 can work collaboratively, by controlling the second midpoint voltage V... B and the first reference voltage V ref1 By comparing the reverse recovery of the freewheeling diode inside the bridge arm switch, the lower bridge arm switch Q2 and the upper bridge arm switch Q3 are quickly turned on. This can destroy the resonant network formed by the resonant inductance in the resonant circuit 20 and the junction capacitance inside each bridge arm switch (upper bridge arm switch Q1, lower bridge arm switch Q2, upper bridge arm switch Q3, and lower bridge arm switch Q4). This ensures that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating at high frequencies (such as forward and reverse operation). This widens the operating voltage range of the resonant converter, improves its efficiency, and enhances its adaptability.

[0085] In some feasible implementations, the aforementioned first AND gate U2 can also be used to detect the switching status signal of the lower bridge arm switch Q2 in the first bridge arm 30a and the switching status signal of the upper bridge arm switch Q3 in the second bridge arm 30b (which can be simply referred to as...). Figure 5 The switching status signals of Q2 and Q3 in the first bridge arm 30a are high, and the switching status signal of the lower bridge arm switch Q2 in the first bridge arm 30a and the blanking signal of the upper bridge arm switch Q3 in the second bridge arm 30b (which can be simply referred to as...) are also high. Figure 5 When the blanking signals of Q2 and Q3 in the first bridge arm 30a are low, a low level is output as the drive signal for the lower bridge arm switch of the first bridge arm 30a and the upper bridge arm switch of the second bridge arm 30b. Since the drive signals of the lower bridge arm switch Q2 and the upper bridge arm switch Q3 change in real time with the changes of their corresponding blanking signals and switch state signals, the first comparator U1 and the first AND gate U2 can work together to ensure the real-time performance and accuracy of the drive signals, making them more versatile.

[0086] Furthermore, the aforementioned drive control subunit 1024 can be based on the drive signal of the lower bridge arm switch Q2 and the drive signal of the upper bridge arm switch Q3 (which can be simply referred to as...). Figure 5 The drive signals of Q2 and Q3 in the above (i.e., the drive signals of Q2 and Q3) control the lower bridge arm switch Q2 and the upper bridge arm switch Q3 to open after a second preset time after the upper bridge arm switch Q5 and the lower bridge arm switch Q8 are turned on. It can be understood that the aforementioned first comparator U1, first AND gate U2, and drive control subunit 1024 can work together to control the second midpoint voltage V. B and the first reference voltage V ref1The comparison is used to obtain the drive signal (such as low level) for quickly disconnecting the lower bridge arm switch Q2 and the upper bridge arm switch Q3. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating in the high-frequency range, thereby widening the operating voltage range of the resonant converter to improve its efficiency and make it more applicable.

[0087] In some feasible implementations, such as Figure 5 As shown above, Figure 4 The control unit 102 shown also includes a second comparator U3 and a second AND gate U4, wherein the positive input terminal of the second comparator U3 can be connected to the first midpoint voltage V. A The output of the second comparator U3 can be connected to the first input of the second AND gate U4, and the second input of the second AND gate U4 can be connected to the blanking signal of the upper bridge arm switch Q1 in the first bridge arm 30a and the blanking signal of the lower bridge arm switch Q4 in the second bridge arm 30b. The logic control subunit 1021 can also output the blanking signals of the upper bridge arm switch Q1 and the lower bridge arm switch Q4 to the first AND gate U2, where the blanking signals include a high level or a low level. The second comparator U3 can be connected to the first midpoint voltage V. A Greater than the second reference voltage V ref2 At this time, the switch status signal of the upper bridge arm switch Q1 of the first bridge arm 30a and the switch status signal of the lower bridge arm switch Q4 of the second bridge arm 30b are output to the second AND gate U4 at a high level. The second reference voltage V... ref2 The voltage that characterizes the freewheeling diode inside the bridge arm switch to complete reverse recovery, and the second reference voltage V ref2 and the aforementioned first reference voltage V ref1 They can be the same or different.

[0088] Furthermore, when the blanking signal is high, the second AND gate U4 can output a high level as the drive signal for the upper arm switch Q1 of the first bridge arm 30a and the lower arm switch Q4 of the second bridge arm 30b when both the switch state signal of the upper arm switch Q1 in the first bridge arm 30a and the blanking signal of the lower arm switch Q4 in the second bridge arm 30b are high. Since the drive signals for the upper arm switch Q1 and the lower arm switch Q4 change in real time with their corresponding blanking signals and switch state signals, the second comparator U3 and the second AND gate U4 can work together to ensure the real-time performance and accuracy of the drive signals, thus enhancing applicability. After receiving the drive signal, the drive control subunit 1024 can control the upper bridge arm switch Q1 and the lower bridge arm switch Q4 to turn on after a third preset time after the lower bridge arm switch Q6 and the upper bridge arm switch Q7 are turned off, based on the drive signal of the upper bridge arm switch Q1 and the drive signal of the lower bridge arm switch Q4. This ensures that the voltage gain of the resonant converter decreases as the frequency increases when it operates in the high frequency range, and the monotonicity of the voltage gain is better, making it more applicable.

[0089] In some feasible implementations, when the blanking signal is low, the second AND gate U4 can also respond to the switching state signal of the upper bridge arm switch Q1 of the first bridge arm 30a and the switching state signal of the lower bridge arm switch Q4 of the second bridge arm 30b (which can be simply referred to as...). Figure 5 The switch status signals of Q1 and Q4 in the first bridge arm 30a are high, and the blanking signal of the upper bridge arm switch in the first bridge arm 30a and the blanking signal of the lower bridge arm switch in the second bridge arm 30b (which can be simply referred to as...) are also high. Figure 5 When the blanking signals of Q1 and Q4 in the above-mentioned bridge arm 30a are low, the output is low as the drive signal for the upper bridge arm switch of the first bridge arm 30a and the lower bridge arm switch of the second bridge arm 30b. Since the drive signals of the upper bridge arm switch Q1 and the lower bridge arm switch Q4 change in real time with the changes of their corresponding blanking signals and switch state signals, the second comparator U3 and the second AND gate U4 can work together to ensure the real-time performance and accuracy of the drive signals, making them more versatile. After obtaining the drive signals, the drive control subunit 1024 can also use the drive signals of the upper bridge arm switch Q1 and the lower bridge arm switch Q4 (which can be simply referred to as the drive signals for the upper bridge arm switch Q1 and the lower bridge arm switch Q4) as the drive signals for the upper bridge arm switch Q1 and the lower bridge arm switch Q4. Figure 5 The drive signals of Q1 and Q4 in the middle control the upper bridge arm switch Q1 and the lower bridge arm switch Q4 to open after the third preset time after the lower bridge arm switch Q6 and the upper bridge arm switch Q7 are opened. This ensures that the voltage gain of the resonant converter decreases with the increase of frequency when it is working in the high frequency range and has monotonicity, thereby widening the operating voltage range of the resonant converter and making it more applicable.

[0090] Optionally, in some feasible implementations, if the software sampling speed and calculation speed of the control unit 102 meet the control requirements, the control logic corresponding to the comparators (such as the first comparator U1 and the second comparator U3 mentioned above) and AND gates (such as the first AND gate U2 and the second AND gate U4 mentioned above) can be integrated into the control unit 102. This eliminates the need to set up comparators and AND gates in the control unit 102, resulting in fewer components used in the resonant converter and lower cost. In this case, the specific structure of the control unit 102 can be found in [reference needed]. Figure 6 , Figure 6 This is another structural schematic diagram of the resonant converter provided in this application. For example... Figure 6 As shown above, Figure 4 The control unit 102 shown includes a logic control subunit 1021, a PI control subunit 1022, a wave generation subunit 1023, and a drive control subunit 1024. The logic control subunit 1021, the PI control subunit 1022, the wave generation subunit 1023, and the drive control subunit 1024 can be software control logic integrated on the control unit 102.

[0091] In some feasible implementations, the control unit 102 can control the logic control subunit 1021, the PI control subunit 1022, and the wave generation subunit 1023 to work together to obtain blanking signals for each of the upper bridge arm switches Q1, Q2, Q3, and Q4, wherein the blanking signals include high or low levels. It should be noted that the specific working principles of the logic control subunit 1021, the PI control subunit 1022, and the wave generation subunit 1023 can be found in the above description. Figure 5 The description in the corresponding embodiment will not be repeated below. After obtaining the blanking signal of the lower bridge arm switch Q2 and the blanking signal of the upper bridge arm switch Q3 (which can be simply referred to as the blanking signals of Q2 and Q3), the control unit 102 can adjust the second midpoint voltage V. B Greater than the first reference voltage V ref1 (can be represented as V) B >V ref1 When the switch is activated, the switch status signals of the lower bridge arm switch Q2 and the upper bridge arm switch Q3 (which can be simply referred to as the switch status signals of Q2 and Q3) are high.

[0092] Furthermore, when the blanking signal is high, the control unit 102 can perform an AND logic 1 calculation on the switch state signals of Q2 and Q3 and the blanking signals of Q2 and Q3. Thus, when both the switch state signals of Q2 and Q3 and the blanking signals of Q2 and Q3 are high, the drive signals of the lower bridge arm switch Q2 and the upper bridge arm switch Q3 (which can be simply referred to as the drive signals of Q2 and Q3) are both high. At this time, the control unit 102 can drive the control subunit 1024 to quickly turn on the lower bridge arm switch Q2 and the upper bridge arm switch Q3 after a first preset time period following the opening of the upper bridge arm switch Q5 and the lower bridge arm switch Q8, thereby disrupting the resonant network. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, thereby widening the operating voltage range of the resonant converter to improve its efficiency, lower cost, and greater adaptability.

[0093] In some feasible implementations, when the blanking signal is low, the control unit 102 can perform an AND logic 1 calculation on the switch state signals of Q2 and Q3 and the blanking signals of Q2 and Q3, so that when the switch state signals of Q2 and Q3 are high and the blanking signals of Q2 and Q3 are low, the drive signals of Q2 and Q3 are both low. Furthermore, the control unit 102 can, through the drive control subunit 1024, quickly disconnect the lower bridge arm switch Q2 and the upper bridge arm switch Q3 after a second preset time after the upper bridge arm switch Q5 and the lower bridge arm switch Q8 are turned on, based on the drive signals of Q2 and Q3. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating at high frequencies, thereby widening the operating voltage range of the resonant converter, resulting in higher efficiency and wider applicability.

[0094] In some feasible implementations, after obtaining the blanking signals of the upper arm switch Q1 and the lower arm switch Q4 (which can be simply referred to as the blanking signals of Q1 and Q4), the control unit 102 can adjust the first midpoint voltage V. A Greater than the second reference voltage V ref2 (can be represented as V) A >V ref2When the switch state signals of the upper arm switch Q1 and the lower arm switch Q4 (hereinafter referred to as the switch state signals of Q1 and Q4) are high, the control unit 102 can perform an AND logic 2 calculation on the switch state signals of Q1 and Q4 and the blanking signals of Q1 and Q4, so that when the switch state signals of Q1 and Q4 and the blanking signals of Q1 and Q4 are both high, the drive signals of the upper arm switch Q1 and the drive signals of the lower arm switch Q4 (hereinafter referred to as the drive signals of Q1 and Q4) are both high. At this time, the control unit 102 can drive the control subunit 1024 to quickly turn on the upper bridge arm switch Q1 and the lower bridge arm switch Q4 after the third preset time after the lower bridge arm switch Q6 and the upper bridge arm switch Q7 are turned off, based on the drive signals of Q1 and Q4. This ensures that the voltage gain of the resonant converter decreases as the frequency increases when it is working in the high frequency band, and the monotonicity of the voltage gain is better and the applicability is stronger.

[0095] In some feasible implementations, when the blanking signal is low, the control unit 102 can perform an AND logic 2 calculation on the switch state signals of Q1 and Q4 and the blanking signals of Q1 and Q4, so that when the switch state signals of Q1 and Q4 are high and the blanking signals of Q1 and Q4 are low, the drive signals of Q1 and Q4 are both low. Furthermore, the control unit 102 can, through the drive control subunit 1024, quickly disconnect the upper bridge arm switch Q1 and the lower bridge arm switch Q4 after a third preset time period following the disconnection of the lower bridge arm switch Q6 and the upper bridge arm switch Q7, based on the drive signals of Q1 and Q4. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, thereby widening the operating voltage range of the resonant converter and enhancing its applicability.

[0096] In some feasible implementations, at the first reference voltage V ref1 With the second reference voltage V ref2 Under the same conditions, the timing sequence of the upper and lower bridge arm switches in each of the first bridge arm 30a, second bridge arm 30b, third bridge arm 30c, and fourth bridge arm 30d can be found in [reference needed]. Figure 7 , Figure 7 This is a schematic diagram of the waveform generation timing of the bridge arm switches in the resonant converter provided in this application. For example... Figure 7 As shown, the first reference voltage V ref1 Equal to the second reference voltage V ref2 Equal to reference voltage V ref , can be represented as V ref1 =V ref2 =V refAt time t0, the drive signals of Q5 and Q8 will change from high level (e.g., 1) to low level (e.g., 0), and the blanking signals of Q2 and Q3 will change from low level to high level. After the first preset time after time t0 (i.e., time t1), the second midpoint voltage V... B Greater than the reference voltage V ref (That is, the switching state signals of Q2 and Q3 are high level) and the blanking signals of Q2 and Q3 are high level, so the driving signals of Q2 and Q3 are high level (that is, the switching state of Q2 and Q3 is on). Therefore, the control unit 102 will control the lower bridge arm switch Q2 and the upper bridge arm switch Q3 to be on at time t1.

[0097] Wherein, reference voltage V ref The magnitude of the reference voltage V determines the conduction time (i.e., time t1) of the lower bridge arm switch Q2 and the upper bridge arm switch Q3. Therefore, the control unit 102 can select a suitable reference voltage V. ref To ensure that the lower bridge arm switch Q2 and the upper bridge arm switch Q3 are turned on in a timely manner, at the reference voltage V ref The smaller the frequency, the earlier the lower bridge arm switch Q2 and upper bridge arm switch Q3 turn on, resulting in better voltage gain monotonicity of the resonant converter. For example, the voltage gain monotonicity of the resonant converter is best when the lower bridge arm switch Q2 and upper bridge arm switch Q3 turn on at time t0. Furthermore, it allows the voltage gain of the resonant converter to decrease with increasing frequency, thus broadening its applicability. At time t2, the drive signals of Q6 and Q7 change from low to high, and the blanking signals of Q2 and Q3 are high. After the second preset time (i.e., time t3) following time t2, the second midpoint voltage V... B Greater than the reference voltage V ref (That is, the switching state signals of Q2 and Q3 change from low level to high level) and the blanking signals of Q2 and Q3 will change from high level to low level. It can be seen that the driving signals of Q2 and Q3 are low level (that is, the switching state of Q2 and Q3 is open). Therefore, the control unit 102 will control the lower bridge arm switch Q2 and the upper bridge arm switch Q3 to open at time t3. This ensures that the voltage gain of the resonant converter decreases with the increase of frequency and has monotonicity when operating in the high frequency range. This widens the operating voltage range of the resonant converter, improves its working efficiency, and makes it more applicable.

[0098] In some feasible implementations, at time t4, the drive signals of Q6 and Q7 will change from high level to low level, and the blanking signals of Q1 and Q4 will change from low level to high level; after a third preset time period following time t4 (i.e., at time t5), the first midpoint voltage V A Greater than the reference voltage V ref(That is, the switching state signals of Q1 and Q4 are high level) and the blanking signals of Q1 and Q4 are high level, so the drive signals of Q1 and Q4 are high level (that is, the switching state of Q1 and Q4 is on). Therefore, the control unit 102 will control the upper bridge arm switch Q1 and the lower bridge arm switch Q4 to turn on at time t5. Wherein, the reference voltage V... ref The magnitude of the reference voltage V determines the conduction time (i.e., time t5) of the upper bridge arm switch Q1 and the lower bridge arm switch Q4. Therefore, the control unit 102 can select a suitable reference voltage V. ref This ensures that the upper bridge arm switch Q1 and the lower bridge arm switch Q4 are turned on in a timely manner, which can further enhance the voltage gain monotonicity of the resonant converter and make it more versatile.

[0099] In the resonant converter provided in this application, the controller 10 can promptly turn on the lower bridge arm switch Q2 and the upper bridge arm switch Q3 after the current transfer of the resonant inductor, thereby quickly destroying the resonant network formed by the resonant inductor (such as the aforementioned resonant inductor Lr1 or resonant inductor Lr2) and the junction capacitance inside each of the upper bridge arm switches Q1, Q2, Q3, and Q4. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating in the high-frequency range, thereby widening the operating voltage range of the resonant converter to improve its operating efficiency. The resonant converter is also smaller and lower in cost. After the lower bridge arm switch Q6 and the upper bridge arm switch Q7 are turned on, the resonant inductor Lr1 will not form a resonant network with the junction capacitance inside each of the aforementioned bridge arm switches. Therefore, the controller 10 will immediately disconnect or delay disconnecting the lower bridge arm switch Q2 and the upper bridge arm switch Q3, thereby ensuring that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating in the high-frequency range, thus widening the operating voltage range of the resonant converter. In addition, the controller 10 can also promptly turn on or off the upper bridge arm switch Q1 and the lower bridge arm switch Q4 after the lower bridge arm switch Q6 and the upper bridge arm switch Q7 are turned off, thereby enhancing the monotonicity of the voltage gain of the resonant converter, further widening the operating voltage range of the resonant converter, and making it more adaptable.

[0100] In some feasible implementation methods, the following will be combined Figure 8 Please refer to the following for an explanation of the DC power supply system and its working principle. Figure 8 , Figure 8 This is a schematic diagram of the DC power supply system provided in this application. Figure 8 As shown, the DC power supply system 4 includes a DC source 41 and a switching power supply 42 connected to the DC source 41. The switching power supply 42 contains a resonant converter 420 (as described above). Figures 2 to 7(The resonant converter shown). Under normal AC mains power supply, DC source 41 can convert AC mains power and perform power factor correction to obtain DC voltage, and output this DC voltage to switching power supply 42. At this time, the resonant converter 420 inside the switching power supply 42 can control the operation of its internal switching devices, thereby converting the DC voltage to the target DC voltage to supply power to the DC load. During the process of supplying power to the DC load, since the voltage gain of the resonant converter 420 decreases with increasing frequency and has monotonicity when operating in the high-frequency range, the operating voltage range of the entire DC power supply system 4 can be widened, thereby improving the system power supply efficiency; in addition, since the resonant converter 420 is small in size and low in cost, the size of the entire DC power supply system 4 can be reduced, and the system power supply cost can be reduced, making it highly applicable.

[0101] In some feasible implementation methods, the following will be combined Figure 9 Please refer to the following for an explanation of the power supply system and its working principle. Figure 9 , Figure 9 This is a structural schematic diagram of the power supply system provided in this application. For example... Figure 9 As shown, the power supply system 5 includes a photovoltaic array 50 and a resonant converter 51 connected to the photovoltaic array 50 (as described above). Figures 2 to 7 The resonant converter 51 shown can be connected to a DC load or a DC grid at its output. During the power supply process to the DC load or DC grid, the resonant converter 51 converts the DC voltage provided by the photovoltaic array 50 into a target DC voltage, and supplies power to the DC load or DC grid based on this target DC voltage. Throughout the power supply process, since the voltage gain of the resonant converter 51 decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, the operating voltage range of the entire power supply system 5 can be widened, thereby improving the system's power supply efficiency. Furthermore, due to the small size and low cost of the resonant converter 51, the overall size of the power supply system 5 can be reduced, thus lowering the system's power supply cost and making it highly adaptable. Please refer to... Figure 10 , Figure 10 This is another structural schematic diagram of the power supply system provided in this application.

[0102] In some feasible implementations, in photovoltaic power supply application scenarios, such as Figure 10 As shown above, Figure 9The power supply system 5 shown also includes a photovoltaic inverter 52. The photovoltaic array 50 can be connected to the input terminal of the photovoltaic inverter 52 via a resonant converter 51, and the output terminal of the photovoltaic inverter 52 can be connected to the AC power grid. During the process of supplying power to the AC power grid, the resonant converter 51 can output a target DC voltage to the photovoltaic inverter 52 based on the DC voltage provided by the photovoltaic array 50. At this time, the photovoltaic inverter 52 can convert the DC voltage input to the resonant converter 51 into an AC voltage and supply power to the AC power grid based on this AC voltage. Throughout the power supply process, since the voltage gain of the resonant converter 51 decreases with increasing frequency and has monotonicity when operating at high frequencies, the operating voltage range of the entire power supply system 5 can be widened, thereby improving the system's power supply efficiency and broadening its applicability. Please refer to [link to relevant documentation]. Figure 11 , Figure 11 This is another structural schematic diagram of the power supply system provided in this application.

[0103] In some feasible implementations, such as Figure 11 As shown above, Figure 10 The power supply system 5 shown also includes a box-type transformer 53, through which the aforementioned photovoltaic inverter 52 can be connected to the AC power grid. The box-type transformer 53 refers to a substation (or distribution station) that combines high-voltage switchgear, distribution transformers, and low-voltage distribution equipment according to a specific wiring scheme and installs them within a box-type enclosure. During the AC power supply process, the aforementioned resonant converter 51 can output a target DC voltage to the photovoltaic inverter 52 based on the DC voltage provided by the photovoltaic array 50. At this time, the photovoltaic inverter 52 can output AC voltage to the box-type transformer 53 based on the DC voltage input to the resonant converter 51. Furthermore, the aforementioned box-type transformer 53 can supply power to the AC power grid based on the AC voltage input to the photovoltaic inverter 52. Throughout the power supply process, since the voltage gain of the resonant converter 51 decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, the operating voltage range of the entire power supply system 5 can be widened, thereby improving the system's power supply efficiency and broadening its applicability. Please refer to... Figure 12 , Figure 12 This is another structural schematic diagram of the power supply system provided in this application.

[0104] In some feasible implementations, in photovoltaic power supply application scenarios, such as Figure 12 As shown above, Figure 11The power supply system 5 shown also includes a DC bus 54 and a DC / AC converter 55. The resonant converter 51 can be connected to the input terminal of the DC / AC converter 55 via the DC bus 54, and the output terminal of the DC / AC converter 55 can be connected to the AC power grid or an AC load. During the process of supplying power to the AC power grid or AC load, the resonant converter 51 can convert the DC voltage provided by the photovoltaic array 50 into a target DC voltage and output the target DC voltage to the DC / AC converter 55 via the DC bus 54. Then, the DC / AC converter 55 can convert the target DC voltage into an AC voltage and supply power to the AC power grid or AC load based on this AC voltage. Throughout the power supply process, since the voltage gain of the resonant converter 51 decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, the operating voltage range of the entire power supply system 5 can be widened, thereby improving the system's power supply efficiency and broadening its applicability. Please refer to... Figure 13 , Figure 13 This is another structural schematic diagram of the power supply system provided in this application.

[0105] In some feasible implementations, in photovoltaic-storage hybrid power supply application scenarios, such as Figure 13 As shown in 13a, the above Figure 12 The power supply system shown also includes an energy storage module 56 and a DC / DC converter 57 connected to the energy storage module 56 (as described above). Figures 2 to 7 The resonant converter shown is used. The DC / DC converter 57 can be connected to the input of the DC / AC converter 55 via the DC bus 54. The energy storage module 56 may include at least one battery cluster, which can be composed of multiple battery packs connected in series. This battery pack can be a battery module, which can be composed of one or more battery cells (the voltage of the battery cells is typically between 2.5V and 4.2V) connected in series and parallel to form a minimum energy storage and management unit. During the supply of power to the AC grid or AC load, the DC / DC converter 57 can convert the DC voltage provided by the energy storage module 56 into a target DC voltage and output the target DC voltage to the DC / AC converter 55 via the DC bus 54. At this time, the DC / AC converter 55 can convert the target DC voltage input to the resonant converter 51 and the target DC voltage input to the DC / DC converter 57 into an AC voltage, and supply power to the AC grid or AC load based on this AC voltage. Throughout the power supply process, since the voltage gain of the resonant converter 51 decreases with increasing frequency and has monotonicity when operating at high frequencies, the operating voltage range of the entire power supply system 5 can be widened, thereby improving the system power supply efficiency and enhancing the system power supply flexibility and applicability.

[0106] Optionally, in some feasible implementations, in wind-solar hybrid power supply applications, such as Figure 13As shown in 13b, the above Figure 12 The power supply system shown also includes a generator 58 and an AC / DC converter 59 connected to the generator 58. The AC / DC converter 59 can be connected to the input terminal of a DC / AC converter 55 via a DC bus 54. During the process of supplying power to the AC grid or AC load, the AC / DC converter 59 can convert the AC voltage provided by the generator 58 into a DC voltage and output the target DC voltage to the DC / AC converter 55 via the DC bus 54. At this time, the DC / AC converter 55 can convert the target DC voltage input to the resonant converter 51 and the DC voltage input to the AC / DC converter 59 into an AC voltage, and supply power to the AC grid or AC load based on this AC voltage, thereby improving the system's power supply efficiency and flexibility. Optionally, the DC / AC converter 55 can also supply power to the AC grid or AC load based on the DC voltage provided by the photovoltaic array 50, the DC voltage provided by the energy storage module 56, and / or the AC voltage provided by the generator 58, further improving the system's power supply efficiency and flexibility, and making it more applicable.

[0107] In the power supply system 5 provided in this application, during the entire power supply process, since the voltage gain of the resonant converter 51 decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, the operating voltage range of the entire power supply system 5 can be widened, thereby improving the system power supply efficiency. Furthermore, because the resonant converter 51 is small in size and low in cost, the overall size of the power supply system 5 can be reduced, thus lowering the system power supply cost and enhancing its applicability. In addition, the power supply system 5 can also supply power to the AC grid or AC loads based on the DC voltage provided by the photovoltaic array 50, the DC voltage provided by the energy storage module 56, and / or the AC voltage provided by the generator 58, further improving the system power supply efficiency and flexibility, and enhancing its applicability.

[0108] Please see Figure 14 , Figure 14 This is a flowchart illustrating the control method for the resonant converter provided in this application. This method is applicable to resonant converters (such as those described above). Figures 2 to 7 The controller in the resonant converter shown includes a resonant circuit, a first bridge arm and a second bridge arm connected in parallel, and a third bridge arm and a fourth bridge arm connected in parallel. The midpoints of the first and second bridge arms are respectively connected to the two first terminals of the resonant circuit. The midpoints of the third and fourth bridge arms are respectively connected to the two second terminals of the resonant circuit. Each bridge arm includes an upper bridge arm switch and a lower bridge arm switch connected in series, with the series connection point of the upper and lower bridge arm switches being the midpoint of the bridge arm. Figure 14 As shown, the method includes the following steps S101 to S102:

[0109] Step S101: Generate drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms.

[0110] In some feasible implementations, the controller can acquire in real time the first midpoint voltage of the midpoint of the first bridge arm and the second midpoint voltage of the midpoint of the second bridge arm, and obtain the switching status signals of the upper and lower bridge arm switches in each of the first and second bridge arms based on the first and second midpoint voltages. Specifically, the controller can determine that the switching status signal of the upper bridge arm switch of the first bridge arm and the switching status signal of the lower bridge arm switch of the second bridge arm are high when the first midpoint voltage is greater than the second reference voltage. Furthermore, the controller can also determine that the switching status signal of the lower bridge arm switch in the first bridge arm and the switching status signal of the upper bridge arm switch of the second bridge arm are high when the second midpoint voltage is greater than the first reference voltage. It is understandable that during the process of the current of the resonant inductor in the above resonant circuit gradually transferring from the upper bridge arm switch of the first bridge arm to the lower bridge arm switch of the second bridge arm, the voltage value of the first midpoint voltage will gradually decrease, and the voltage value of the second midpoint voltage will gradually increase. That is, the voltage values ​​of the first midpoint voltage and the second midpoint voltage will continuously change as the current of the resonant inductor gradually transfers. Therefore, the above controller can obtain the real-time changing switch state signal based on the first midpoint voltage and the second midpoint voltage, thereby ensuring the real-time performance and accuracy of the switch state signal and making it more applicable.

[0111] In some feasible implementations, after obtaining the switch status signals, the controller can generate drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms based on the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms, and the switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms. It is understood that since the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms change continuously over time, and the switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms change in real time with changes in the voltage values ​​of the first and second midpoint voltages, the controller can generate more accurate and real-time changing drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms. This ensures the real-time performance and accuracy of the drive signals and enhances their applicability.

[0112] In some feasible implementations, during the generation of drive signals, the controller can invert the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms to obtain the blanking signals of the upper and lower bridge arm switches in each of the first and second bridge arms. Inverting the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms can be understood as follows: when the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms are high, the blanking signals of the upper and lower bridge arm switches in each of the first and second bridge arms are low; conversely, when the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms are low, the blanking signals of the upper and lower bridge arm switches in each of the first and second bridge arms are high.

[0113] Furthermore, the aforementioned controller can generate drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms based on the blanking signals and switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms. It can be understood that since the blanking signals for the upper and lower bridge arm switches in each of the first and second bridge arms are obtained by inverting the drive signals for the upper and lower bridge arm switches in each of the third and fourth bridge arms, the blanking signals change with the drive signals, thus ensuring the real-time performance of the blanking signals. Furthermore, the aforementioned controller can combine the real-time changing blanking signals and switch status signals to generate more accurate and real-time changing drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms, thereby ensuring the real-time performance and accuracy of the drive signals and enhancing their applicability.

[0114] In some feasible implementations, during the process of generating drive signals based on the blanking signal and switch state signal, when the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms include the drive signal of the lower bridge arm switch of the first bridge arm and the drive signal of the upper bridge arm switch of the second bridge arm, the controller can determine that the drive signal of the lower bridge arm switch of the first bridge arm and the drive signal of the upper bridge arm switch of the second bridge arm are high when the switch state signal of the lower bridge arm switch of the first bridge arm and the switch state signal of the upper bridge arm switch of the second bridge arm are high, and the blanking signal of the lower bridge arm switch of the first bridge arm and the blanking signal of the upper bridge arm switch of the second bridge arm are high. Alternatively, the controller can also determine that the drive signals of the lower bridge arm switch and the upper bridge arm switch of the first bridge arm are low when the switch status signal of the lower bridge arm switch in the first bridge arm and the switch status signal of the upper bridge arm switch in the second bridge arm are high, and the blanking signal of the lower bridge arm switch in the first bridge arm and the blanking signal of the upper bridge arm switch in the second bridge arm are low. Therefore, the drive signals of the lower bridge arm switch in the first bridge arm and the upper bridge arm switch in the second bridge arm change in real time with the changes in their corresponding blanking signals (such as high or low levels) and switch status signals, thus ensuring the real-time performance and accuracy of the drive signals and enhancing their applicability.

[0115] In some feasible implementations, when the drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms also include the drive signal for the upper bridge arm switch of the first bridge arm and the drive signal for the lower bridge arm switch of the second bridge arm, the controller may determine that the drive signals for the upper and lower bridge arm switches of the first and second bridge arms are high when the switch status signals for the upper and lower bridge arm switches of the first and second bridge arms are high, and the blanking signals for the upper and lower bridge arm switches of the first and second bridge arms are high. Alternatively, the controller may also determine that the drive signals for the upper and lower bridge arm switches of the first and second bridge arms are low when the switch status signals for the upper and lower bridge arm switches of the first and second bridge arms are high, and the blanking signals for the upper and lower bridge arm switches of the first and second bridge arms are low. Therefore, the drive signals of the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm change in real time with the change of their corresponding blanking signals (such as high level or low level) and switch state signals, thereby ensuring the real-time performance and accuracy of the drive signals and making them more applicable.

[0116] Step S102: Based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, after a first preset time period following the disconnection of the upper bridge arm switch of the third bridge arm and the lower bridge arm switch of the fourth bridge arm, control the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm to be turned on.

[0117] In some feasible implementations, the aforementioned first preset duration can be greater than or equal to 0 and less than or equal to the dead time between the upper and lower bridge arm switches in the third or fourth bridge arm, that is, the first preset duration is greater than or equal to 0 and less than or equal to the dead time between the upper and lower bridge arm switches in the third bridge arm, or the first preset duration is greater than or equal to 0 and less than or equal to the dead time between the upper and lower bridge arm switches in the fourth bridge arm. The dead time between the upper and lower bridge arm switches in the third bridge arm can be understood as the duration between the turn-off time of the upper bridge arm switch and the turn-on time of the lower bridge arm switch in the third bridge arm; the dead time between the upper and lower bridge arm switches in the fourth bridge arm can be understood as the duration between the turn-off time of the lower bridge arm switch and the turn-on time of the upper bridge arm switch in the fourth bridge arm.

[0118] In some feasible implementations, when the upper bridge arm switch of the third bridge arm and the lower bridge arm switch of the fourth bridge arm are disconnected, the current of the resonant inductor in the above-mentioned resonant circuit will gradually transfer from the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm to the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm. During this current transfer process of the resonant inductor, the resonant inductor will form a resonant network with the junction capacitance (i.e. the capacitance connected in parallel across the source and drain terminals of the bridge arm switch) inside each bridge arm switch in the first and second bridge arms. Furthermore, the aforementioned controller will promptly turn on the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm after a first preset time period following the disconnection of the upper bridge arm switch of the third bridge arm and the lower bridge arm switch of the fourth bridge arm. This disrupts the resonant network formed by the resonant inductor and the junction capacitance inside each bridge arm switch in the first and second bridge arms. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating at high frequencies (such as forward or reverse operation). This, in turn, broadens the operating voltage range of the resonant converter, thereby improving its efficiency, reducing costs, and increasing adaptability.

[0119] In some feasible implementations, when the first preset duration is equal to 0, the controller will immediately turn on the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm after the upper bridge arm switch of the third bridge arm and the lower bridge arm switch of the fourth bridge arm are turned off. This quickly disrupts the resonant network formed by the resonant inductor and the junction capacitance inside each bridge arm switch in the first and second bridge arms. This ensures that the voltage gain of the resonant converter decreases with increasing frequency when operating at high frequencies, and enhances the monotonicity of the voltage gain of the resonant converter, further widening the operating voltage range of the resonant converter and making it more applicable.

[0120] In some feasible implementations, the controller can also, based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, control the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm to disconnect after a second preset time period following the conduction of the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm. The second preset time period can be greater than or equal to 0 and less than or equal to the conduction time of the lower bridge arm switch of the third bridge arm or the conduction time of the upper bridge arm switch of the fourth bridge arm, wherein the conduction time of the lower bridge arm switch of the third bridge arm is equal to the conduction time of the upper bridge arm switch of the fourth bridge arm. It is understandable that after the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm are turned on, the aforementioned resonant inductor will not form a resonant network with the junction capacitance inside each bridge arm switch in the first and second bridge arms. Therefore, after the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm are turned on, the controller will immediately disconnect or delay disconnecting the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and has monotonicity when operating at high frequencies (such as forward and reverse operation), thereby widening the operating voltage range of the resonant converter to improve its efficiency and make it more applicable.

[0121] In some feasible implementations, the controller can, based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, control the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm to be turned on or off after a third preset time period following the disconnection of the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm. The third preset time period can be greater than or equal to 0 and less than or equal to the dead time between the upper and lower bridge arm switches in the third or fourth bridge arm. When the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm are turned on, it can be ensured that the voltage gain of the resonant converter decreases with increasing frequency when operating at high frequencies (such as forward and reverse operation), and the monotonicity of the voltage gain is better, resulting in wider applicability. With the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm open, the voltage gain of the resonant converter at high frequency (such as forward and reverse operation) decreases with increasing frequency and has monotonicity, thereby widening the operating voltage range of the resonant converter to improve its efficiency and make it more applicable.

[0122] In specific implementation, further operations performed by the controller in the control method of the resonant converter provided in this application can be found above. Figures 2 to 7 The implementation method of the controller in the resonant converter and its working principle shown will not be described in detail here.

[0123] In the method provided in this application, the controller promptly turns on the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm after the current transfer of the resonant inductor. This quickly disrupts the resonant network formed by the resonant inductor and the junction capacitances inside the switches of the first and second bridge arms. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, thereby widening the operating voltage range of the resonant converter, improving its efficiency, and reducing costs. After the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm are turned on, the resonant inductor will not form a resonant network with the junction capacitances inside the switches. Therefore, the controller immediately disconnects or delays disconnecting the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm. This ensures that the voltage gain of the resonant converter decreases with increasing frequency and exhibits monotonicity when operating at high frequencies, thereby widening the operating voltage range of the resonant converter. In addition, the controller can promptly turn on or off the upper arm switch of the first arm and the lower arm switch of the second arm after the lower arm switch of the third arm and the upper arm switch of the fourth arm are turned off. This can enhance the voltage gain monotonicity of the resonant converter, further broaden the operating voltage range of the resonant converter, and make it more adaptable.

[0124] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A resonant converter, characterized by, The resonant converter includes a controller, a resonant circuit, a first bridge arm and a second bridge arm connected in parallel, and a third bridge arm and a fourth bridge arm connected in parallel. The midpoints of the first bridge arm and the second bridge arm are respectively connected to two first connection terminals of the resonant circuit, and the midpoints of the third bridge arm and the fourth bridge arm are respectively connected to two second connection terminals of the resonant circuit. Each of the first, second, third, and fourth bridge arms includes an upper bridge arm switch and a lower bridge arm switch connected in series, and the series connection point of the upper bridge arm switch and the lower bridge arm switch is the midpoint of the bridge arm. The controller is used to turn on the lower arm switch of the first bridge arm and the upper arm switch of the second bridge arm after a first preset time period following the disconnection of the upper arm switch of the third bridge arm and the lower arm switch of the fourth bridge arm. Wherein, the first preset duration is greater than or equal to 0 and less than or equal to the dead time between the upper and lower bridge arm switches in the third or fourth bridge arm, and the dead time between the upper and lower bridge arm switches in the third bridge arm is the duration between the turn-off time of the upper bridge arm switch and the turn-on time of the lower bridge arm switch.

2. The transformer of claim 1, wherein, The controller includes a sampling unit and a control unit; The sampling unit is used to collect the first midpoint voltage of the midpoint of the first bridge arm and the second midpoint voltage of the midpoint of the second bridge arm; the control unit is used to obtain the switching status signals of the upper bridge arm switch and the lower bridge arm switch in each of the first and second bridge arms based on the first midpoint voltage and the second midpoint voltage. The control unit is further configured to generate drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms based on the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms, and the switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms. The control unit is further configured to, based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, control the lower bridge arm switch in the first bridge arm and the upper bridge arm switch in the second bridge arm to be turned on after a first preset time period following the disconnection of the upper bridge arm switch in the third bridge arm and the lower bridge arm switch in the fourth bridge arm.

3. The transformer of claim 2, wherein, The control unit is used for: The drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms are inverted to obtain the blanking signals of the upper and lower bridge arm switches in each of the first and second bridge arms. Based on the blanking signals and switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms, drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms are generated.

4. The transformer of claim 3, wherein, The control unit is also used for: Based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm are controlled to disconnect after a second preset time after the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm are turned on. Wherein, the second preset duration is greater than or equal to 0 and less than or equal to the conduction duration of the lower bridge arm switch of the third bridge arm or the conduction duration of the upper bridge arm switch of the fourth bridge arm.

5. The transformer of claim 4, wherein, The control unit includes a first comparator and a first AND gate. The positive input terminal of the first comparator is connected to the second midpoint voltage. The output terminal of the first comparator is connected to the first input terminal of the first AND gate. The second input terminal of the first AND gate is connected to the blanking signal of the lower bridge arm switch in the first bridge arm and the blanking signal of the upper bridge arm switch in the second bridge arm. The first comparator is used to output the switch status signal of the lower bridge arm switch in the first bridge arm and the switch status signal of the upper bridge arm switch in the second bridge arm as high level to the first AND gate when the second midpoint voltage is greater than the first reference voltage. The first AND gate is used to output a high level when the switch status signal of the lower bridge arm switch in the first bridge arm and the switch status signal of the upper bridge arm switch in the second bridge arm are both high, and when the blanking signal of the lower bridge arm switch in the first bridge arm and the blanking signal of the upper bridge arm switch in the second bridge arm are both high, so as to serve as the drive signal of the lower bridge arm switch in the first bridge arm and the drive signal of the upper bridge arm switch in the second bridge arm.

6. The transformer of claim 5, wherein, The first AND gate is further configured to output a low level as a drive signal for the lower arm switch of the first arm and the upper arm switch of the second arm when the switch status signal of the lower arm switch in the first arm and the switch status signal of the upper arm switch in the second arm are high, and the blanking signal of the lower arm switch in the first arm and the blanking signal of the upper arm switch in the second arm are low.

7. The variator of any of claims 3 to 6, wherein, The control unit is further configured to, based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, control the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm to be turned on or off after a third preset time period following the disconnection of the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm, wherein the third preset time period is greater than or equal to 0 and less than or equal to the dead time.

8. The variator of claim 7, characterised in that, The control unit further includes a second comparator and a second AND gate. The positive input terminal of the second comparator is connected to the first midpoint voltage. The output terminal of the second comparator is connected to the first input terminal of the second AND gate. The second input terminal of the second AND gate is connected to the blanking signal of the upper bridge arm switch in the first bridge arm and the blanking signal of the lower bridge arm switch in the second bridge arm. The second comparator is used to output the switch status signal of the upper bridge arm switch of the first bridge arm and the switch status signal of the lower bridge arm switch of the second bridge arm to the second AND gate when the first midpoint voltage is greater than the second reference voltage. The second AND gate is used to output a high level as the drive signal for the upper arm switch of the first bridge arm and the lower arm switch of the second bridge arm when the switch status signal of the upper arm switch of the first bridge arm and the switch status signal of the lower arm switch of the second bridge arm are both high, and the blanking signal of the upper arm switch of the first bridge arm and the blanking signal of the lower arm switch of the second bridge arm are both high.

9. The variator of claim 8, characterised in that, The second AND gate is further configured to output a low level as a drive signal for the upper arm switch of the first bridge arm and the lower arm switch of the second bridge arm when the switch status signal of the upper arm switch of the first bridge arm and the switch status signal of the lower arm switch of the second bridge arm are high, and the blanking signal of the upper arm switch of the first bridge arm and the blanking signal of the lower arm switch of the second bridge arm are low, so as to serve as a drive signal for the upper arm switch of the first bridge arm and the lower arm switch of the second bridge arm.

10. A control method of a resonant converter, characterized by, The method is applicable to the controller in the resonant converter, which further includes a resonant circuit, a first bridge arm and a second bridge arm connected in parallel, and a third bridge arm and a fourth bridge arm connected in parallel. The midpoints of the first and second bridge arms are respectively connected to two first connection terminals of the resonant circuit, and the midpoints of the third and fourth bridge arms are respectively connected to two second connection terminals of the resonant circuit. Each of the first, second, third, and fourth bridge arms includes an upper bridge arm switch and a lower bridge arm switch connected in series, with the series connection point of the upper and lower bridge arm switches being the midpoint of the bridge arm. The method includes: Generate drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms; Based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm are turned on after a first preset time after the upper bridge arm switch of the third bridge arm and the lower bridge arm switch of the fourth bridge arm are turned off. The first preset time is greater than or equal to 0 and less than or equal to the dead time between the upper and lower bridge arm switches in the third or fourth bridge arm. The dead time between the upper and lower bridge arm switches in the third bridge arm is the duration between the turn-off time of the upper bridge arm switch and the turn-on time of the lower bridge arm switch.

11. The method according to claim 10, characterized in that, The generation of drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms includes: The first midpoint voltage of the first bridge arm and the second midpoint voltage of the second bridge arm are collected, and the switching status signals of the upper bridge arm switch and the lower bridge arm switch in each of the first and second bridge arms are obtained based on the first midpoint voltage and the second midpoint voltage. Based on the drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms, and the switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms, drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms are generated.

12. The method of claim 11, wherein, The step of obtaining the switching status signals of the upper and lower bridge arm switches in each of the first and second bridge arms based on the first midpoint voltage and the second midpoint voltage includes: When the first midpoint voltage is greater than the second reference voltage, the switch status signal of the upper bridge arm switch of the first bridge arm and the switch status signal of the lower bridge arm switch of the second bridge arm are determined to be high level. When the second midpoint voltage is greater than the first reference voltage, the switching status signal of the lower bridge arm switch in the first bridge arm and the switching status signal of the upper bridge arm switch in the second bridge arm are determined to be at a high level.

13. The method of claim 12, wherein, The process of generating drive signals for the upper and lower bridge arm switches in each of the third and fourth bridge arms, based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, and the switch state signals of the upper and lower bridge arm switches in each of the first and second bridge arms, includes: The drive signals of the upper and lower bridge arm switches in each of the third and fourth bridge arms are inverted to obtain the blanking signals of the upper and lower bridge arm switches in each of the first and second bridge arms. Based on the blanking signals and switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms, drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms are generated.

14. The method of claim 13, wherein, The drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms include the drive signal for the lower bridge arm switch of the first bridge arm and the drive signal for the upper bridge arm switch of the second bridge arm. The step of generating drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms based on the blanking signals and switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms includes: When the switch status signal of the lower bridge arm switch in the first bridge arm and the switch status signal of the upper bridge arm switch in the second bridge arm are both at a high level, and the blanking signal of the lower bridge arm switch in the first bridge arm and the blanking signal of the upper bridge arm switch in the second bridge arm are both at a high level, it is determined that the drive signal of the lower bridge arm switch in the first bridge arm and the drive signal of the upper bridge arm switch in the second bridge arm are both at a high level.

15. The method according to claim 14, characterized in that, The method further includes: Based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, the lower bridge arm switch of the first bridge arm and the upper bridge arm switch of the second bridge arm are controlled to disconnect after a second preset time after the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm are turned on. Wherein, the second preset duration is greater than or equal to 0 and less than or equal to the conduction duration of the lower bridge arm switch of the third bridge arm or the conduction duration of the upper bridge arm switch of the fourth bridge arm.

16. The method of claim 15, wherein, The drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms include the drive signal for the lower bridge arm switch of the first bridge arm and the drive signal for the upper bridge arm switch of the second bridge arm. The step of generating drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms based on the blanking signals and switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms includes: When the switch status signal of the lower bridge arm switch in the first bridge arm and the switch status signal of the upper bridge arm switch in the second bridge arm are high, and the blanking signal of the lower bridge arm switch in the first bridge arm and the blanking signal of the upper bridge arm switch in the second bridge arm are low, it is determined that the drive signal of the lower bridge arm switch in the first bridge arm and the drive signal of the upper bridge arm switch in the second bridge arm are low.

17. The method according to any one of claims 13-16, characterized in that, The method further includes: Based on the drive signals of the upper and lower bridge arm switches in each of the first and second bridge arms, the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm are controlled to be turned on or off after a third preset time after the lower bridge arm switch of the third bridge arm and the upper bridge arm switch of the fourth bridge arm are turned off, wherein the third preset time is greater than or equal to 0 and less than or equal to the dead time.

18. The method of claim 17, wherein, The drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms also include the drive signal for the upper bridge arm switch of the first bridge arm and the drive signal for the lower bridge arm switch of the second bridge arm. The step of generating drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms based on the blanking signals and switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms includes: When the switch status signal of the upper bridge arm switch of the first bridge arm and the switch status signal of the lower bridge arm switch of the second bridge arm are high, and the blanking signal of the upper bridge arm switch of the first bridge arm and the blanking signal of the lower bridge arm switch of the second bridge arm are high, it is determined that the drive signal of the upper bridge arm switch of the first bridge arm and the drive signal of the lower bridge arm switch of the second bridge arm are high.

19. The method of claim 18, wherein, The step of generating drive signals for the upper and lower bridge arm switches in each of the first and second bridge arms based on the blanking signals and switch status signals of the upper and lower bridge arm switches in each of the first and second bridge arms further includes: When the switch status signal of the upper bridge arm switch of the first bridge arm and the switch status signal of the lower bridge arm switch of the second bridge arm are high, and the blanking signal of the upper bridge arm switch of the first bridge arm and the blanking signal of the lower bridge arm switch of the second bridge arm are low, it is determined that the drive signal of the upper bridge arm switch of the first bridge arm and the drive signal of the lower bridge arm switch of the second bridge arm are low.

20. A direct current power supply system characterized by comprising: The DC power supply system includes a DC source and a switching power supply connected to the DC source, wherein the switching power supply is provided with a resonant converter as described in any one of claims 1-9.

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