Power supply circuit and method thereof, and on-board charger

Abstract

The present disclosure provides a power supply circuit and a method thereof, and a vehicle charger. The power supply circuit includes a first bridge circuit configured to invert direct current into alternating current and output the alternating current to a resonant cavity, the first bridge circuit including controllable switching elements, the resonant cavity configured to receive the alternating current from the first bridge circuit to resonate and output the resonated alternating current to a second bridge circuit, the second bridge circuit configured to rectify the resonated alternating current into direct current for output, the power supply circuit having a low-gain mode, the controllable switching elements of the first bridge circuit configured to, in response to the power supply circuit being in the low-gain mode, maintain a switching frequency of the controllable switching elements of the first bridge circuit at a predetermined switching frequency and adjust a length of a dead time of the controllable switching elements of the first bridge circuit to be negatively correlated with an output power output by the power supply circuit.

Description

Technical Field

[0001] This invention relates to electronic circuits, and more particularly to power supply circuits and methods thereof, and on-board chargers. Background Technology

[0002] The on-board charger (OBC) is a crucial component of electric vehicles. It converts alternating current (AC) from the grid into direct current (DC) to efficiently and safely charge the vehicle's battery cells (e.g., the battery pack). The OBC enables AC / DC power conversion, ensuring stable power delivery, and optimizes the charging process through intelligent voltage and current regulation, thereby extending battery life and improving overall vehicle energy management efficiency. In the context of the rapid development of electric vehicles, the performance of the OBC significantly impacts charging speed, system reliability, and vehicle range, making it a key technology driving electric vehicle development. However, in low-gain mode, OBCs may experience issues such as large output current ripple and low output efficiency.

[0003] Therefore, a solution is desired that can reduce output current ripple and improve output efficiency in low-gain mode. Summary of the Invention

[0004] According to at least one embodiment of the present disclosure, a power supply circuit is provided, including a first bridge circuit, a resonant cavity, and a second bridge circuit. The first bridge circuit is configured to invert direct current (DC) to alternating current (AC) and output the AC to the resonant cavity. The first bridge circuit includes a controllable switching element. The resonant cavity is configured to receive the AC from the first bridge circuit for resonance and output the resonant AC to the second bridge circuit. The second bridge circuit is configured to rectify the resonant AC to DC for output. The power supply circuit has a low-gain mode. The controllable switching element of the first bridge circuit is configured such that, in response to the power supply circuit being in the low-gain mode, the switching frequency of the controllable switching element of the first bridge circuit is maintained at a predetermined switching frequency, and the dead time length of the controllable switching element of the first bridge circuit is adjusted to be negatively correlated with the output power of the power supply circuit.

[0005] For example, in a power supply circuit according to at least one embodiment of the present disclosure, the controllable switching element of the first bridge circuit is configured to: control the length of the dead time to decrease as the output power increases, and control the length of the dead time to increase as the output power decreases, in response to the power supply circuit being in the low gain mode.

[0006] For example, in a power supply circuit according to at least one embodiment of the present disclosure, wherein the power supply circuit has a high-gain mode, the controllable switching element of the first bridge circuit is further configured to: maintain the dead time of the controllable switching element in the first bridge circuit at a predetermined length in response to the power supply circuit being in a high-gain mode, and control the switching frequency of the controllable switching element in the first bridge circuit to be negatively correlated with the output power.

[0007] For example, in a power supply circuit according to at least one embodiment of the present disclosure, in response to the power supply circuit being in the high-gain mode, the switching frequency of the controllable switching element in the first bridge circuit is controlled to decrease as the output power increases, and the switching frequency of the controllable switching element in the first bridge circuit is controlled to increase as the output power decreases.

[0008] For example, in a power supply circuit according to at least one embodiment of the present disclosure, the first bridge circuit is configured to: in response to the power supply circuit being in the low-gain mode and the output power increasing to a first predetermined power, the first bridge circuit performs a first switching operation to switch from the low-gain mode to the high-gain mode; and in response to the power supply circuit being in the high-gain mode and the output power decreasing to a second predetermined power, the first bridge circuit performs a second switching operation to switch from the high-gain mode to the low-gain mode, wherein the second predetermined power is less than the first predetermined power.

[0009] For example, according to at least one embodiment of the power supply circuit of this disclosure, the second predetermined power is equal to the output power of the first bridge circuit corresponding to the maximum permissible switching frequency in the high-gain mode.

[0010] For example, in a power supply circuit according to at least one embodiment of the present disclosure, the first bridge circuit is further configured to increase the switching frequency of the controllable switching element in the first bridge circuit by a first predetermined rate of change when performing the first switching operation; the first bridge circuit is further configured to decrease the switching frequency of the controllable switching element in the first bridge circuit by the first predetermined rate of change when performing the second switching operation.

[0011] For example, according to a power supply circuit of at least one embodiment of the present disclosure, the first bridge circuit is further configured such that the output power remains constant during at least one of the first switching operation and the second switching operation performed by the first bridge circuit.

[0012] For example, according to a power supply circuit of at least one embodiment of the present disclosure, the controllable switching element in the first bridge circuit is further configured such that, during at least one of the first switching operation and the second switching operation, the first bridge circuit determines the length of the dead time of the controllable switching element in the first bridge circuit based on the following: determining the output current of the power supply circuit based on the output power; determining the length of the conduction time of the controllable switching element in the first bridge circuit based on the output current and the switching frequency; and determining the length of the dead time based on the length of the conduction time.

[0013] For example, in a power supply circuit according to at least one embodiment of the present disclosure, the predetermined switching frequency is within a predetermined frequency range that includes half of the resonant frequency of the resonant cavity.

[0014] For example, according to at least one embodiment of the power supply circuit of this disclosure, the first bridge circuit includes one of a full-bridge circuit and a half-bridge circuit; and the second bridge circuit includes one of a full-bridge circuit and a half-bridge circuit.

[0015] For example, according to at least one embodiment of the power supply circuit of this disclosure, the first bridge circuit includes a first switch bridge arm, including a first upper switch and a first lower switch connected in series, the second bridge circuit includes a second switch bridge arm, the second switch bridge arm including a second upper switch and a second lower switch connected in series, wherein the first upper switch and the second upper switch are controlled to be on and off simultaneously, the first lower switch and the second lower switch are controlled to be on and off simultaneously, and the first upper switch and the first lower switch are controlled to be complementaryly turned on except for the dead time, wherein the dead time of the controllable switching element of the first bridge circuit is defined as the time during which the first upper switch and the first lower switch are simultaneously in the off state, and the first upper switch, the first lower switch, the second upper switch and the second lower switch are controllable switching elements.

[0016] For example, according to at least one embodiment of the power supply circuit of this disclosure, the first bridge circuit includes a first switch bridge arm, including a first upper switch and a first lower switch connected in series, wherein the first upper switch and the first lower switch are controlled to be complementaryly turned on except for the dead time, wherein the dead time of the controllable switching element of the first bridge circuit is defined as the time during which the first upper switch and the first lower switch are simultaneously in the off state, and the second bridge circuit includes a second switch bridge arm and a third switch bridge arm connected in parallel, wherein the switching elements in the second switch bridge arm and the third switch bridge arm are uncontrollable switching elements.

[0017] For example, according to at least one embodiment of the power supply circuit of this disclosure, the resonant cavity includes one of an LLC type resonant cavity, an SRC type resonant cavity, and a CLLC type resonant cavity.

[0018] For example, according to at least one embodiment of the power supply circuit of the present disclosure, the voltage of the DC power output by the power supply circuit remains constant.

[0019] According to at least one embodiment of the present disclosure, an on-board charger is provided, including: a controller, and a power supply circuit as described above, wherein the controller is configured to send a control signal to the power supply circuit to control a controllable switching element of a first bridge circuit.

[0020] According to at least one embodiment of the present disclosure, a vehicle is provided, including a power supply circuit and an on-board charger as described above.

[0021] According to at least one embodiment of the present disclosure, a method for a power supply circuit is provided, the power supply circuit including a first bridge circuit, a resonant cavity, and a second bridge circuit, wherein the first bridge circuit is configured to invert direct current (DC) to alternating current (AC) and output the AC to the resonant cavity, the first bridge circuit including a controllable switching element, the resonant cavity being configured to receive the AC from the first bridge circuit for resonance and output the resonant AC to the second bridge circuit, the second bridge circuit being configured to rectify the resonant AC to DC for output, wherein the power supply circuit has a low-gain mode, the method comprising: in response to the power supply circuit being in a low-gain mode, maintaining the switching frequency of the controllable switching element in the first bridge circuit at a predetermined switching frequency, and adjusting the length of the dead time of the controllable switching element in the first bridge circuit to be negatively correlated with the output power of the power supply circuit.

[0022] The power supply circuit, on-board charger, vehicle, and method for power supply circuit according to at least one embodiment of the present disclosure can reduce output current ripple and improve output efficiency in low-gain mode. Furthermore, the power supply circuit, on-board charger, vehicle, and method for power supply circuit according to at least one embodiment of the present disclosure are low in cost and low in complexity. Attached Figure Description

[0023] The above and other aspects, features, and advantages of specific embodiments of the present disclosure will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0024] Figure 1 A schematic diagram of a power supply circuit according to at least one embodiment of the present disclosure is shown.

[0025] Figure 2AA power supply circuit and a schematic diagram of its operation according to at least one embodiment of the present disclosure are shown.

[0026] Figure 2B A power supply circuit and a schematic diagram of its operation according to at least one embodiment of the present disclosure are shown.

[0027] Figure 2C A power supply circuit and a schematic diagram of its operation according to at least one embodiment of the present disclosure are shown.

[0028] Figure 3A A schematic diagram of a half-bridge circuit according to at least one embodiment of the present disclosure is shown.

[0029] Figure 3B A schematic diagram of a rectifier bridge circuit according to at least one embodiment of the present disclosure is shown.

[0030] Figure 4A A resonant cavity according to at least one embodiment of the present disclosure is shown.

[0031] Figure 4B A resonant cavity according to at least one embodiment of the present disclosure is shown.

[0032] Figure 5 A schematic diagram showing the conduction timing of a first bridge circuit and a second bridge circuit according to at least one embodiment of the present disclosure is provided.

[0033] Figure 6A The process of switching a power supply circuit from a low-gain mode to a high-gain mode according to at least one embodiment of the present disclosure is illustrated.

[0034] Figure 6B The process of switching a power supply circuit from a high-gain mode to a low-gain mode according to at least one embodiment of the present disclosure is illustrated.

[0035] Figure 7 A schematic diagram showing the conduction angle and discharge angle according to at least one embodiment of the present disclosure is provided.

[0036] Figure 8 An on-board charger according to at least one embodiment of the present disclosure is shown.

[0037] Figure 9 A vehicle according to at least one embodiment of the present disclosure is shown.

[0038] Figure 10 A method according to at least one embodiment of the present disclosure is shown. Detailed Implementation

[0039] Before proceeding with the detailed description below, it may be advantageous to define certain words and phrases used throughout this disclosure. The terms “comprising” and “including” and their derivatives mean including but not limited to. The term “or” is inclusive, meaning and / or. The phrase “associated with” and its derivatives mean including, comprising, interconnecting, containing, contained within, connected or connected to, coupled or coupled to, communicating with, cooperating, intertwining, juxtaposing, proximate, binding or bound to, having, possessing attributes, having a relationship or being related to, etc. The term “controller” means any device, system, or part thereof that controls at least one operation. Such a controller may be implemented in hardware, or a combination of hardware and software and / or firmware. The functionality associated with any particular controller may be centralized or distributed, local or remote. The phrase “at least one,” when used with a list of items, means that different combinations of one or more of the listed items may be used, and that only one item from the list may be required. For example, "at least one of A, B, and C" includes any one of the following combinations: A, B, C, A and B, A and C, B and C, A and B and C.

[0040] Definitions of other specific words and phrases are provided throughout this disclosure. Those skilled in the art will understand that, in many, if not most, cases, such definitions apply to the prior and future use of the words and phrases thus defined.

[0041] The various embodiments of the principles of this disclosure described below with reference to the accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this disclosure in any way. Those skilled in the art will understand that the principles of this disclosure can be implemented in any suitably arranged system or device. In some cases, the actions described in the specification may be performed in a different order and the desired result may still be achieved. Furthermore, the processes depicted in the drawings do not necessarily require a specific order or sequential sequence to achieve the desired result. In certain embodiments, multitasking and parallel processing may be advantageous.

[0042] On-board chargers are crucial components of electric vehicles. They are configured to charge the battery. On-board chargers can employ a wide-range output voltage design based on an LLC (inductor-inductor-capacitor) resonant topology and can utilize pulse frequency modulation (PFM) control. The output of the on-board charger can be connected to the battery as a regulated power source. The output power of the on-board charger is primarily achieved by regulating the output current. In the PFM scheme, increasing the control frequency reduces the output gain of the on-board charger; conversely, decreasing the control frequency increases the output gain.

[0043] However, due to the limitations of the LLC topology gain range, when the control frequency reaches its maximum (i.e., the gain reaches its minimum), the on-board charger may still maintain a high power output, while there is a smaller power transmission requirement in actual application scenarios.

[0044] For the aforementioned low-power or light-load operating conditions, intermittent (burst) control and phase-shifting control methods can be employed. In intermittent control, when the on-board charger's gain drops to its minimum and the control frequency reaches its maximum, the on-board charger can intermittently enter a sleep mode to further reduce the gain. However, this control method may lead to a significant increase in output current ripple. Furthermore, in phase-shifting control, asymmetric complementary drive can be used to achieve phase shifting at the highest control frequency. However, this control method suffers from low efficiency, making it difficult to meet users' actual energy efficiency requirements.

[0045] Figure 1 A schematic diagram of a power supply circuit according to at least one embodiment of the present disclosure is shown. Figure 1 As shown, the power supply circuit 1000 may include a first bridge circuit 1100, a resonant cavity 1200, and a second bridge circuit 1300.

[0046] According to at least one embodiment of this disclosure, a first bridge circuit 1100 is configured to invert direct current (DC) to alternating current (AC) and output AC to a resonant cavity. For example, the first bridge circuit 1100 can receive DC and convert it to AC for output to the resonant cavity 1200. According to at least one embodiment of this disclosure, the first bridge circuit includes controllable switching elements. For example, the first bridge circuit 1100 may include a bridge circuit for performing inversion operations. For example, the first bridge circuit 1100 may include one of a full-bridge circuit and a half-bridge circuit, but this disclosure is not limited thereto. Other bridge circuits that can implement the above-described inversion operations are also possible.

[0047] According to at least one embodiment of this disclosure, the resonant cavity 1200 is configured to receive AC power from the first bridge circuit 1100 for resonance and output the resonant AC power to the second bridge circuit 1300. The resonant cavity 1200 may also be referred to as a resonant network. According to at least one embodiment of this disclosure, the resonant cavity 1200 can improve the voltage gain range, improve the soft-switching range, control circulating current, and reduce losses. The resonant cavity 1200 may include one of an LLC-type resonant cavity, an SRC-type resonant cavity, and a CLLC-type resonant cavity, but this disclosure is not limited thereto. Other types of resonant cavities capable of achieving the above-described functions are also possible.

[0048] According to at least one embodiment of this disclosure, the second bridge circuit 1300 is configured to rectify the resonant alternating current into direct current for output. For example, the second bridge circuit 1300 can receive alternating current and convert it into direct current to charge a power battery or the like. For example, the second bridge circuit 1300 may include a bridge circuit for performing rectification operations. For example, the second bridge circuit 1300 may include one of a full-bridge circuit and a half-bridge circuit, but this disclosure is not limited thereto. Other bridge circuits that can implement the above-described rectification operations are also possible.

[0049] According to at least one embodiment of this disclosure, the power supply circuit 1000 has a low-gain mode. The controllable switching elements of the first bridge circuit 1100 are configured such that, in response to the power supply circuit 1000 being in the low-gain mode, the switching frequency of the controllable switching elements of the first bridge circuit is maintained at a predetermined switching frequency, and the length of the dead time of the controllable switching elements of the first bridge circuit is adjusted to be negatively correlated with the output power of the power supply circuit.

[0050] As described above, in the pulse frequency modulation scheme, the output gain of the power supply circuit 1000 can be reduced by increasing the control frequency; conversely, the output gain of the power supply circuit 1000 can be increased by decreasing the control frequency. However, according to at least one embodiment of this disclosure, in response to the power supply circuit 1000 being in a low-gain mode, the switching frequency of the controllable switching element of the first bridge circuit can be no longer adjusted, thereby remaining fixed.

[0051] According to at least one embodiment of this disclosure, in low-gain mode, the output power of the control power supply circuit 1000 is negatively correlated with the dead time length of the controllable switching elements of the first bridge circuit 1100. In this way, the dead time length of the controllable switching elements included in the first bridge circuit 1100 is adjusted according to the output power of the power supply circuit 1000 to achieve gain regulation of the power supply circuit 1000 and prevent the power supply circuit 1000 from entering an intermittent control mode.

[0052] The power supply circuit according to at least one embodiment of the present disclosure can reduce output current ripple and improve output efficiency in low-gain mode. Furthermore, the power supply circuit according to at least one embodiment of the present disclosure is low in cost and low in complexity.

[0053] Figure 2A A power supply circuit and a schematic diagram of its operation according to at least one embodiment of the present disclosure are shown. Figure 2B A power supply circuit and a schematic diagram of its operation according to at least one embodiment of the present disclosure are shown. Figure 2C A power supply circuit and a schematic diagram of its operation according to at least one embodiment of the present disclosure are shown. Figures 2A-2CAs shown, the power supply circuit 2000 may include a first bridge circuit 2100, a resonant cavity 2200, and a second bridge circuit 2300. Although not shown, the power supply circuit may further include a controller to control the on and off of the controllable switching elements in the power supply circuit.

[0054] According to at least one embodiment of this disclosure, the first bridge circuit 2100 can be configured to invert direct current (providing input power) into alternating current (AC) and output AC power to the resonant cavity 2200. The resonant cavity 2200 can be configured to receive AC power from the first bridge circuit 2100 for resonance and output the resonant AC power to the second bridge circuit 2200. The second bridge circuit 2200 can be configured to rectify the resonant AC power into direct current (providing output power) for output. According to at least one embodiment of this disclosure, the power supply circuit 2000 can be a voltage regulator. For example, the voltage of the DC power output by the power supply circuit 2000 can remain constant to charge devices such as power batteries.

[0055] According to at least one embodiment of this disclosure, such as Figures 2A-2C As shown, the first bridge circuit 2100 may include a full-bridge circuit and may include controllable switching elements, but this disclosure is not limited thereto. The first bridge circuit 2100 may include a first switching bridge arm, which may include a first upper switch (i.e., upper switch 2110) and a first lower switch (i.e., lower switch 2120) connected in series. The first bridge circuit 2100 may also include a fourth switching bridge arm connected in parallel with the first switching bridge arm, which may include a fourth upper switch (i.e., upper switch 2130) and a fourth lower switch (i.e., lower switch 2140) connected in series. The upper switch 2110, lower switch 2120, upper switch 2130, and lower switch 2140 may be controllable switching elements, such as metal-oxide-semiconductor field-effect transistors (MOSFETs) and insulated-gate bipolar transistors (IGBTs), but this disclosure is not limited thereto.

[0056] According to at least one embodiment of this disclosure, such as Figures 2A-2CAs shown, the second bridge circuit 2300 may include a full-bridge circuit and may include controllable switching elements, but this disclosure is not limited thereto. The second bridge circuit 2300 may include a second switching bridge arm, which may include a second upper switch (i.e., upper switch 2310) and a second lower switch (i.e., lower switch 2320) connected in series. The second bridge circuit 2200 may also include a third switching bridge arm connected in parallel with the third switching bridge arm, which may include a third upper switch (i.e., upper switch 2330) and a third lower switch (i.e., lower switch 2340) connected in series. The upper switch 2310, lower switch 2320, upper switch 2330, and lower switch 2340 may be controllable switching elements, such as MOSFETs and IGBTs, but this disclosure is not limited thereto.

[0057] Figure 3A A schematic diagram of a half-bridge circuit according to at least one embodiment of the present disclosure is shown. Figure 3B A schematic diagram of a rectifier bridge circuit according to at least one embodiment of the present disclosure is shown.

[0058] According to at least one embodiment of this disclosure, such as Figure 3A As shown, the first bridge circuit may include a half-bridge circuit 3100 and may include controllable switching elements, but this disclosure is not limited thereto. The first bridge circuit may include a first switching bridge arm, which may include a first upper switch (i.e., upper switch 3110) and a first lower switch (i.e., lower switch 3120) connected in series. The first bridge circuit may include a first capacitor bridge arm connected in parallel with the first switching bridge arm, which may include a first upper capacitor (i.e., capacitor 3130) and a first lower capacitor (i.e., capacitor 3140) connected in series. The upper switch 3310 and the lower switch 3320 may be controllable switching elements, such as MOSFETs and IGBTs, but this disclosure is not limited thereto.

[0059] According to at least one embodiment of this disclosure, such as Figure 3A As shown, the second bridge circuit may include a half-bridge circuit and may include controllable switching elements, but this disclosure is not limited thereto. The second bridge circuit may include a second switching bridge arm, which may include a second upper switch (i.e., upper switch 3110) and a second lower switch (i.e., lower switch 3120) connected in series. The second bridge circuit may include a second capacitor bridge arm connected in parallel with the second switching bridge arm, which may include a second upper capacitor (i.e., capacitor 3130) and a second lower capacitor (i.e., capacitor 3140) connected in series. The upper switch 3310 and the lower switch 3320 may be controllable switching elements, such as MOSFETs and IGBTs, but this disclosure is not limited thereto.

[0060] According to at least one embodiment of this disclosure, such as Figure 3B As shown, the second bridge circuit may include uncontrollable switching elements, but this disclosure is not limited thereto. The second bridge circuit may include a second switching arm, which may include a second upper switch (i.e., upper switch 3210) and a second lower switch (i.e., lower switch 3220) connected in series. The second bridge circuit may include a third switching arm connected in parallel with the second switching arm, which may include a third upper switch (i.e., upper switch 3230) and a third lower switch (i.e., lower switch 3240) connected in series. The upper switch 3210, lower switch 3220, upper switch 3230, and lower switch 3240 may be uncontrollable switching elements, such as diodes, but this disclosure is not limited thereto.

[0061] For example, according to at least one embodiment of this disclosure, the resonant cavity 2200 may include one of an LLC type resonant cavity, an SRC type resonant cavity, and a CLLC type resonant cavity, but this disclosure is not limited thereto, and other types of resonant cavities are also possible. Figures 2A-2C According to at least one embodiment of this disclosure, the resonant cavity 2200 may include a CLLC-type resonant cavity. For example, the CLLC-type resonant cavity 2200 may include an inductor 2210, a capacitor 2220, an inductor 2230, a transformer 2240, an inductor 2250, and a capacitor 2260. Inductor 2250 may represent the magnetizing inductor of transformer 2240. Inductors 2210 and 2230 may represent resonant inductors, and capacitors 2220 and 2260 may represent resonant capacitors.

[0062] Figure 4A A resonant cavity according to at least one embodiment of the present disclosure is shown.

[0063] According to at least one embodiment of this disclosure, the resonant cavity 4100 can be an LLC type resonant cavity. Specifically, the resonant cavity 4100 may include an inductor 4110, an inductor 4120, a capacitor 4130, and a transformer 4140. The inductor 4110 can be a resonant inductor, the inductor 4120 can be the magnetizing inductor of the transformer 4140, and the capacitor 4130 can be a resonant capacitor.

[0064] Figure 4B A resonant cavity according to at least one embodiment of the present disclosure is shown.

[0065] According to at least one embodiment of this disclosure, the resonant cavity 4200 can be an SRC type resonant cavity. Specifically, the resonant cavity 4200 may include an inductor 4210, a capacitor 4220, and a transformer 4230. The inductor 4210 can be a resonant inductor, and the capacitor 4220 can be a resonant capacitor.

[0066] Figure 5A schematic diagram showing the conduction timing of a first bridge circuit and a second bridge circuit according to at least one embodiment of the present disclosure is illustrated. Refer to Figure 2 for further explanation. Figure 5 The symbol shown is T sw It can indicate the switching period and T of the first bridge circuit and the second bridge circuit. d It can indicate the dead time, T on The on-time can be indicated (e.g., the shaded square area marked "H" corresponds to the on-time of the upper switch in the corresponding switch arm, and the shaded square area marked "L" corresponds to the on-time of the lower switch in the corresponding switch arm), T f This can refer to the freewheeling or discharging time, i Lr It can indicate the resonant current of the resonant cavity, V Cr The resonant voltage of the resonant cavity can be indicated. According to at least one embodiment of this disclosure, the dead time can refer to the time when both the upper and lower switches in the corresponding switch arm are turned off.

[0067] Reference Figure 5 The system controls the first upper switch in the first switch arm of the first bridge circuit and the second upper switch in the second switch arm of the second bridge circuit to be simultaneously open and closed. Similarly, it controls the first lower switch in the first switch arm of the first bridge circuit and the second lower switch in the second switch arm of the second bridge circuit to be simultaneously open and closed. Furthermore, except for the dead time, the first upper switch and the first lower switch are complementary in conduction. Complementary conduction means that when the first upper switch is in the on state, the first lower switch is in the off state; and when the first upper switch is in the off state, the first lower switch is in the on state. The dead time of the controllable switching element in the first bridge circuit can be defined as the time during which both the first upper switch and the first lower switch are in the off state. It is understood that, given the above control strategy, the switching frequencies of the controllable switching elements in the first bridge circuit and the second bridge circuit are the same.

[0068] According to at least one embodiment of this disclosure, when both the first bridge circuit and the second bridge circuit are full-bridge circuits, refer to Figure 5 and Figure 2A During the first conduction time T from left to right on During this period, the first upper switch of the first switch arm, the fourth lower switch of the fourth switch arm, the second upper switch of the second switch arm, and the third lower switch of the third switch arm can be controlled to be turned on. During the aforementioned on-time T... on During this period, the resonant current i Lr Increase, and the resonant voltage V Cr Increase. Furthermore, such as Figure 2A As shown, during the aforementioned conduction time T onDuring this period, the input current flows through the upper switch 2110, the resonant cavity 2200, and the lower switch 2140, while the output current flows through the lower switch 2340, the resonant cavity 2200, and the upper switch 2310.

[0069] According to at least one embodiment of this disclosure, referring to Figure 5 In the first dead time T from left to right d During this period, the switching elements in the first, fourth, second, and third switch arms can be controlled to turn off. During the aforementioned dead time T... d During this period, the resonant current i Lr Remain stable, and the resonant voltage V Cr Maintain stability. Furthermore, during the aforementioned dead time T... d Discharge time T f During this period, the switching elements in the first, fourth, second, and third switch arms can be controlled to turn off, but the input and output currents can freewheel through the body diodes in these switching elements. Specifically, as shown... Figure 2C As shown, during the aforementioned discharge time T f During this period, the input current flows through the body diode of the lower switch 2120, the resonant cavity 2200, and the body diode of the upper switch 2130, while the output current flows through the body diode of the lower switch 2340, the resonant cavity 2200, and the body diode of the upper switch 2310.

[0070] According to at least one embodiment of this disclosure, referring to Figure 5 and Figure 2B During the second conduction time T from left to right on During this period, the first lower switch of the first switch arm, the fourth upper switch of the fourth switch arm, the second lower switch of the second switch arm, and the third upper switch of the third switch arm can be controlled to be turned on. During the aforementioned on-time T... on During this period, the resonant current i Lr Increase (e.g., during the first conduction time T mentioned above) on (during which the flow directions are opposite), and the resonant voltage V Cr Reduce. Furthermore, such as Figure 2B As shown, during the aforementioned conduction time T on During this period, the input current flows through the upper switch 2130, the resonant cavity 2200, and the lower switch 2120, while the output current flows through the lower switch 2320, the resonant cavity 2200, and the upper switch 2330.

[0071] According to at least one embodiment of this disclosure, referring to Figure 5 In the second dead time T from left to right dDuring this period, the switching elements in the first, fourth, second, and third switch arms can be controlled to turn off. During the aforementioned dead time T... d During this period, the resonant current i Lr Remain stable, and the resonant voltage V Cr Maintain stability. Furthermore, during the aforementioned dead time T... d Discharge time T f During this period, the switching elements in the first, fourth, second, and third switching arms can be controlled to turn off, but the input and output currents can freewheel through the body diodes in these switching elements. Details will not be repeated here to avoid redundancy. It is understood that when the first and / or second bridge circuits are half-bridge circuits, the timing of the controllable switching elements in the corresponding switching arms will be different from... Figure 5 The timing sequence of the corresponding controllable switching elements shown is the same, and the details will not be repeated here to avoid redundancy.

[0072] Return to reference Figures 2A-2C According to at least one embodiment of this disclosure, in response to the power supply circuit being in a low-gain mode, the length of the dead time of the first bridge circuit decreases as the output power increases, and the length of the dead time of the first bridge circuit increases as the output power decreases. As described above, in the low-gain mode, the switching frequencies of the first and second bridge circuits are maintained at a predetermined switching frequency. The dead time of the first bridge circuit is adjusted according to the output power of the second bridge circuit; when the output power increases, the length of the dead time of the first bridge circuit decreases accordingly; when the output power decreases, the length of the dead time of the first bridge circuit increases accordingly, thereby adjusting the gain of the power supply circuit 1000 and reducing the ripple of the output current. According to at least one embodiment of this disclosure, the predetermined switching frequency can be within a predetermined frequency range including half of the resonant frequency of the resonant cavity 2200. That is, the predetermined switching frequency can be approximately half of the resonant frequency, but this disclosure is not limited thereto, and other predetermined switching frequencies are also possible.

[0073] According to at least one embodiment of this disclosure, the power supply circuit 2000 can have a high-gain mode and a low-gain mode, thereby flexibly charging devices such as power batteries. For example, the controllable switching element in the first bridge circuit 2100 can be further configured to: in response to the power supply circuit 2000 being in a high-gain mode, maintain the dead time of the controllable switching element in the first bridge circuit at a predetermined length, and control the switching frequency of the controllable switching element in the first bridge circuit to be negatively correlated with the output power. For example, in the high-gain mode, the dead time of the switching elements in the first bridge circuit 2100 and the second bridge circuit 2300 is maintained at a minimum dead time, but this disclosure is not limited to this, and other predetermined lengths are also possible. According to at least one embodiment of this disclosure, the switching frequencies of the first bridge circuit 2100 and the second bridge circuit 2300 are controlled based on the output power of the second bridge circuit. When the output power of the second bridge circuit increases, the switching frequencies of the first bridge circuit 2100 and the second bridge circuit 2300 are controlled to decrease accordingly; when the output power of the second bridge circuit decreases, the switching frequencies of the first bridge circuit 2100 and the second bridge circuit 2300 are controlled to increase accordingly. According to at least one embodiment of this disclosure, in high-gain mode, the power supply circuit can employ a pulse frequency modulation control method, but this disclosure is not limited thereto.

[0074] The power supply circuit 2000 disclosed herein can adjust the switching frequency according to the output power in high-gain mode and adjust the dead time according to the output power in low-gain mode. Furthermore, the power supply circuit 2000 can switch between high-gain and low-gain modes. The switching process can be completed in a very short time period, for example, on the order of milliseconds, but this disclosure is not limited to this and the switching process can be completed in an even shorter time.

[0075] Figure 6A The process of switching a power supply circuit from a low-gain mode to a high-gain mode according to at least one embodiment of the present disclosure is illustrated.

[0076] like Figure 6A As shown, Fs_max can be the maximum allowable switching frequency in high-gain mode, DT_max can be the maximum allowable dead time in low-gain mode, Fs_min can be the predetermined switching frequency in low-gain mode, and DT_min can be the minimum allowable dead time in high-gain mode. Figure 6A As shown, the power supply circuit can adjust the switching frequency according to the output power in high-gain mode, and adjust the dead time according to the output power in low-gain mode.

[0077] According to at least one embodiment of the present disclosure, the first bridge circuit can be configured to perform a first switching operation to switch from a low-gain mode to a high-gain mode in response to the power supply circuit being in a low-gain mode and the output power increasing to a first predetermined power.

[0078] Please note that, although Figure 6A The shaded portion in the diagram illustrates the first switching operation as a power broadening, but this is for the purpose of clearly showing the changes in dead time and switching frequency during the first switching operation. According to at least one embodiment of this disclosure, during the first switching operation of the first bridge circuit, the output power of the power supply circuit can remain constant, and the switching frequency can be increased from a predetermined switching frequency (e.g., half the resonant frequency of the resonant cavity) to Fs_max. For example, according to at least one embodiment of this disclosure, the first bridge circuit can be further configured to increase the switching frequency of the controllable switching elements in the first bridge circuit at a first predetermined rate of change during the first switching operation. That is, the switching frequency can change linearly during the first switching operation, but this disclosure is not limited thereto, and other changes are possible, wherein the rate of change of the switching frequency during the first switching operation is greater than the rate of change of the switching frequency in high-gain mode.

[0079] According to at least one embodiment of the present disclosure, during the first switching operation of the first bridge circuit, the output power of the power supply circuit can remain constant, and the dead time can be gradually reduced to DT_min, wherein the rate of change of the dead time during the first switching operation is greater than the rate of change of the dead time in the low gain mode.

[0080] Figure 6B This illustrates the process of a power supply circuit according to at least one embodiment of the present disclosure switching from a high-gain mode to a low-gain mode. The meanings of Fs_max, DT_max, Fs_min, and DT_min are... Figure 6A The same applies here, so it will not be described again to avoid redundancy. For example... Figure 6B As shown, the power supply circuit can adjust the switching frequency according to the output power in high-gain mode, and adjust the dead time according to the output power in low-gain mode.

[0081] According to at least one embodiment of this disclosure, the first bridge circuit can be configured to perform a second switching operation to switch from a high-gain mode to a low-gain mode in response to the power supply circuit being in a high-gain mode and the output power decreasing to a second predetermined power. The second predetermined power is, for example, the power value of the power supply circuit when it enters an intermittent mode using a conventional intermittent control mode.

[0082] Please note that, although Figure 6BThe shaded portion in the diagram illustrates the second switching operation as a power broadening, but this is for the purpose of clearly showing the changes in dead time and switching frequency during the second switching operation. According to at least one embodiment of this disclosure, the first bridge circuit can be further configured such that the output power of the power supply circuit remains constant during the second switching operation performed by the first bridge circuit. Furthermore, the switching frequency can be reduced from Fs_max to Fs_min (e.g., half the resonant frequency of the resonant cavity).

[0083] For example, according to at least one embodiment of this disclosure, the first bridge circuit may be further configured to reduce the switching frequency of the controllable switching element in the first bridge circuit by a first predetermined rate of change when performing the second switching operation. That is, the switching frequency may change linearly during the second switching operation, but this disclosure is not limited thereto, and other changes are also possible. The rate of change of the switching frequency during the second switching operation is greater than the rate of change of the switching frequency in the high-gain mode.

[0084] According to at least one embodiment of this disclosure, during the second switching operation of the first bridge circuit, the output power of the power supply circuit can remain constant, and the dead time can gradually increase. The rate of change of the dead time during the second switching operation is greater than the rate of change of the dead time in the low-gain mode.

[0085] According to at least one embodiment of this disclosure, the second predetermined power may be less than the first predetermined power. For example, the second predetermined power may be equal to the output power corresponding to the maximum permissible switching frequency of the first bridge circuit in high-gain mode. According to at least one embodiment of this disclosure, the first predetermined power may be 500W higher than the second predetermined power, but this disclosure is not limited thereto; the first predetermined power may be significantly more or less than the second predetermined power.

[0086] According to at least one embodiment of this disclosure, as described above, the output power of the first bridge circuit remains constant during at least one of the first and second switching operations, and the switching frequency changes linearly. Furthermore, the trend of the dead time length during at least one of the first and second switching operations can be determined based on the output power and the switching frequency.

[0087] Figure 7 A schematic diagram showing the conduction angle and discharge angle according to at least one embodiment of the present disclosure is provided. Figure 7 Chinese V CrN i represents the normalized capacitor voltage value of the resonant cavity in the above power supply circuit. LrN This represents the normalized current value of the resonant cavity in the aforementioned power supply circuit.

[0088] like Figure 7As shown, from (-V CrN0 ,0) A solid arc connecting to point A represents, for example Figure 2A The resonant current rise corresponding to the conduction time shown is connected from point A to (V CrN0 A solid-line arc (0) represents, for example... Figure 2C The discharge time corresponds to the decrease in resonant current. Furthermore, angle AO1O2 is θ1, and angle AO2O1 is θ2. The relationship between θ1 and θ2 and the conduction and discharge times can be found in equations (1) and (2):

[0089] θ1=w*t1(1)

[0090] θ2=w*t2(2)

[0091] Where w is the resonant angular frequency of the resonant cavity in the power supply circuit, t1 is the conduction time, and t2 is the discharge time.

[0092] According to at least one embodiment of this disclosure, the values ​​of cos(θ1) and cos(θ2) can be obtained with reference to the following equations (3) and (4):

[0093] (3)

[0094] (4)

[0095] Among them, nV oN This represents the normalized output voltage of the power supply circuit, V. CrN0 This represents the normalized initial voltage value of the resonant cavity capacitor.

[0096] According to at least one embodiment of this disclosure, the average current output by the power supply circuit can be obtained by the following equation (5):

[0097] (5)

[0098] Among them, i AvrN i is the normalized output current of the power supply circuit. LrN T is the normalized resonant current of the resonant cavity. sw For the switching period, T on Let be the conduction time. By substituting equations (3) and (4) into equation (5), we can obtain equation (6).

[0099] (6)

[0100] Among them, i AvrN i is the normalized output current of the power supply circuit. LrN T is the normalized resonant current of the resonant cavity. sw For the switching period, T onFor the conduction time, nV oN This represents the normalized output voltage of the power supply circuit, V. CrN0 The normalized initial voltage value of the resonant cavity is represented by ω, where ω is the resonant angular frequency of the resonant cavity in the power supply circuit, and T is the resonant capacitance value. on =T1+T2, where T1=t1 is the conduction time and T2=t2 is the discharge time.

[0101] According to at least one embodiment of this disclosure, as described above, the output power of the first bridge circuit remains constant during at least one of the first switching operation and the second switching operation. Furthermore, as described above, the voltage of the DC current output by the power supply circuit remains constant. Therefore, the output power of the power supply circuit is primarily affected by the magnitude of the DC current output by the power supply circuit. According to equation (6), the output current, i.e., is the normalized output current i of the power supply circuit. AvrN Subject to T sw and V CrN0 Influence.

[0102] According to at least one embodiment of this disclosure, during at least one of the first and second switching operations performed by the first bridge circuit, the output current of the power supply circuit can be determined based on the output power (e.g., a power that remains constant during switching). Further, based on the output current and a switching frequency determined based on a predetermined rate of change, the normalized initial capacitor voltage V of the resonant cavity can be determined using equation (6). CrN0 By using V CrN0 Substituting into equation (3), we can obtain the value of cos(θ1), and thus the value of θ1. By substituting θ1 into equation (2), we can obtain the length of the conduction time. Based on the length of the conduction time and the switching period T... sw The length of the dead time can be determined. In this way, a smooth transition can be achieved when switching gain modes, without generating excessive current ripple, etc.

[0103] Figure 8 An on-board charger according to at least one embodiment of the present disclosure is shown. For example... Figure 8 As shown, the on-board charger 8000 may include a power supply circuit 8100 and a controller 8200.

[0104] According to at least one embodiment of this disclosure, the power supply circuit 8100 may include the power supply circuit described above. According to at least one embodiment of this disclosure, the controller 8200 may include, but is not limited to, a central processing unit (CPU), a digital signal processor (DSP), a graphics processing unit (GPU), or other forms of processing units with data processing capabilities and / or program execution capabilities, such as a field-programmable gate array (FPGA), an electronic controller (ECU), a microcontroller unit (MCU), a domain controller (DCU), etc.

[0105] The controller 8200 can be configured to send control signals to the power supply circuit 8100 to control the controllable switching elements of the first bridge circuit and the second bridge circuit to turn on or off, but this disclosure is not limited thereto.

[0106] Although an example of an on-board charger has been shown, those skilled in the art will understand that the power supply circuit 8100 described above may be included in other electronic devices, such as, but not limited to, DC charging piles, DC chargers, etc., and this disclosure is not limited thereto.

[0107] Figure 9 A vehicle according to at least one embodiment of the present disclosure is shown.

[0108] Vehicle 9000 may include, but is not limited to, cars, tractor-trailers (with or without trailers), buses, recreational vehicles, minivans, or sport utility vehicles (SUVs).

[0109] like Figure 9 As shown, vehicle 9000 may include device 9100, which may be one or more of the power supply circuit and on-board charger described above.

[0110] Figure 10 A method according to at least one embodiment of the present disclosure is shown.

[0111] Figure 10 The illustrated method 100 can be used in a power supply circuit. The power supply circuit includes a first bridge circuit, a resonant cavity, and a second bridge circuit. The first bridge circuit is configured to invert direct current (DC) to alternating current (AC) and output the AC to the resonant cavity. The first bridge circuit includes a controllable switching element. The resonant cavity is configured to receive the AC from the first bridge circuit for resonance and output the resonant AC to the second bridge circuit. The second bridge circuit is configured to rectify the resonant AC into DC for output.

[0112] According to at least one embodiment of this disclosure, the power supply circuit has a low-gain mode.

[0113] like Figure 10 As shown, method 100 may include steps S101 and S102.

[0114] In step S101, in response to the power supply circuit being in low gain mode, the switching frequency of the controllable switching element in the first bridge circuit is maintained at a predetermined switching frequency.

[0115] In step S102, the dead time of the controllable switching element in the first bridge circuit is adjusted to be negatively correlated with the output power of the power supply circuit.

[0116] The power supply circuit, on-board charger, vehicle, and method for power supply circuit according to at least one embodiment of the present disclosure can reduce output current ripple and improve output efficiency in low-gain mode. Furthermore, the power supply circuit, on-board charger, electronic device, vehicle, and method for power supply circuit according to at least one embodiment of the present disclosure are low in cost and low in complexity.

[0117] Although this disclosure has been described with reference to exemplary embodiments, various changes and modifications may be suggested to those skilled in the art. This disclosure is intended to cover such changes and modifications that fall within the scope of the appended claims.

[0118] Any description in this invention should not be construed as implying that any particular element, step, or function is an essential element that must be included within the scope of the claims. The scope of the patent subject matter is defined only by the claims.

Claims

1. A power supply circuit, comprising a first bridge circuit, a resonant cavity, and a second bridge circuit, wherein, The first bridge circuit is configured to invert direct current into alternating current and output the alternating current to the resonant cavity. The first bridge circuit includes controllable switching elements. The resonant cavity is configured to receive the alternating current from the first bridge circuit to resonate, and to output the resonant alternating current to the second bridge circuit. The second bridge circuit is configured to rectify the resonant alternating current into direct current for output. The power supply circuit has a low-gain mode. The controllable switching element of the first bridge circuit is configured such that, in response to the power supply circuit being in the low-gain mode, the switching frequency of the controllable switching element of the first bridge circuit is maintained at a predetermined switching frequency, and the length of the dead time of the controllable switching element of the first bridge circuit is adjusted to be negatively correlated with the output power of the power supply circuit.

2. The power supply circuit according to claim 1, wherein, The controllable switching element of the first bridge circuit is configured to: in response to the power supply circuit being in the low-gain mode, The length of the dead time is controlled to decrease as the output power increases, and The length of the dead time is controlled to increase as the output power decreases.

3. The power supply circuit according to claim 1, wherein, The power supply circuit has a high-gain mode. The controllable switching element of the first bridge circuit is further configured to: maintain the dead time of the controllable switching element in the first bridge circuit at a predetermined length in response to the power supply circuit being in a high-gain mode, and control the switching frequency of the controllable switching element in the first bridge circuit to be negatively correlated with the output power.

4. The power supply circuit according to claim 3, wherein, In response to the power supply circuit being in the high-gain mode The switching frequency of the controllable switching element in the first bridge circuit decreases as the output power increases, and The switching frequency of the controllable switching element in the first bridge circuit increases as the output power decreases.

5. The power supply circuit according to claim 3, wherein, The first bridge circuit is configured as follows: In response to the power supply circuit being in the low-gain mode and the output power increasing to a first predetermined power, the first bridge circuit performs a first switching operation to switch from the low-gain mode to the high-gain mode, and In response to the power supply circuit being in the high-gain mode and the output power decreasing to a second predetermined power, the first bridge circuit performs a second switching operation to switch from the high-gain mode to the low-gain mode. Wherein, the second predetermined power is less than the first predetermined power.

6. The power supply circuit according to claim 5, wherein, The second predetermined power is equal to the output power of the first bridge circuit corresponding to the maximum permissible switching frequency in the high-gain mode.

7. The power supply circuit according to claim 5, wherein, The first bridge circuit is further configured to increase the switching frequency of the controllable switching element in the first bridge circuit by a first predetermined rate of change when the first switching operation is performed. The first bridge circuit is further configured to reduce the switching frequency of the controllable switching element in the first bridge circuit by the first predetermined rate of change when performing the second switching operation.

8. The power supply circuit according to claim 5, wherein, The first bridge circuit is further configured such that the output power remains constant during at least one of the first switching operation and the second switching operation performed by the first bridge circuit.

9. The power supply circuit according to claim 8, wherein, The controllable switching element in the first bridge circuit is further configured such that, during at least one of the first switching operation and the second switching operation, the first bridge circuit determines the length of the dead time of the controllable switching element in the first bridge circuit according to the following: The output current of the power supply circuit is determined based on the output power. Based on the output current and the switching frequency, the conduction time of the controllable switching element in the first bridge circuit is determined, and The length of the dead time is determined based on the length of the conduction time.

10. The power supply circuit according to any one of claims 1-9, wherein, The predetermined switching frequency is within a predetermined frequency range that includes half of the resonant frequency of the resonant cavity.

11. The power supply circuit according to any one of claims 1-9, wherein, The first bridge circuit includes one of a full-bridge circuit and a half-bridge circuit; and The second bridge circuit includes one of a full-bridge circuit and a half-bridge circuit.

12. The power supply circuit according to claim 11, wherein, The first bridge circuit includes a first switch arm, comprising a first upper switch and a first lower switch connected in series. The second bridge circuit includes a second switch arm, comprising a second upper switch and a second lower switch connected in series. The first upper switch and the second upper switch are controlled to be simultaneously turned on and off, and the first lower switch and the second lower switch are controlled to be simultaneously turned on and off. Except for the dead time, the first upper switch and the first lower switch are controlled to be complementaryly turned on. The dead time of the controllable switching element of the first bridge circuit is defined as the time during which the first upper switch and the first lower switch are simultaneously in the off state. The first upper switch, the first lower switch, the second upper switch, and the second lower switch are controllable switching elements.

13. The power supply circuit according to claim 11, wherein, The first bridge circuit includes a first switch bridge arm, comprising a first upper switch and a first lower switch connected in series, wherein the first upper switch and the first lower switch are controlled to conduct complementaryly except for the dead time, wherein the dead time of the controllable switching element of the first bridge circuit is defined as the time during which the first upper switch and the first lower switch are simultaneously in the off state. The second bridge circuit includes a second switch bridge arm and a third switch bridge arm connected in parallel, wherein the switching elements in the second switch bridge arm and the third switch bridge arm are uncontrollable switching elements.

14. The power supply circuit according to any one of claims 1-9, wherein, The resonant cavity includes one of the LLC type resonant cavity, the SRC type resonant cavity, and the CLLC type resonant cavity.

15. The power supply circuit according to any one of claims 1-9, wherein, The voltage of the DC power output by the power supply circuit remains constant.

16. An on-board charger, comprising: Controller, and The power supply circuit as described in any one of claims 1-15, The controller is configured to send control signals to the power supply circuit to control the controllable switching elements of the first bridge circuit.

17. A method for a power supply circuit, said power supply circuit comprising a first bridge circuit, a resonant cavity, and a second bridge circuit, wherein, The first bridge circuit is configured to invert direct current (DC) into alternating current (AC) and output the AC to a resonant cavity. The first bridge circuit includes a controllable switching element. The resonant cavity is configured to receive the AC from the first bridge circuit for resonance and output the resonant AC to a second bridge circuit. The second bridge circuit is configured to rectify the resonant AC to DC for output. Wherein, the power supply circuit has a low-gain mode, and the method includes: in response to the power supply circuit being in a low-gain mode, The switching frequency of the controllable switching element in the first bridge circuit is maintained at a predetermined switching frequency, and The dead time of the controllable switching element in the first bridge circuit is adjusted to be negatively correlated with the output power of the power supply circuit.

Images