Circuit and method for controlling a bidirectional cllc converter

Abstract

A bidirectional power converter includes a first switching circuit coupled to a second switching circuit via a transformer, wherein the first switching circuit is configured to transfer power to the second switching circuit during a charging mode; the second switching circuit is configured to transfer power to the first switching circuit during a discharging mode, and the first switching circuit is configured to operate in a half-bridge configuration during a first portion of the charging mode.

Description

Technical Field

[0001] The present invention relates generally to bidirectional CLLC converters, and more specifically to circuitry and methods for controlling bidirectional CLLC converters during charging and discharging modes. Background Technology

[0002] Power applications, such as battery chargers, electric vehicles (EVs), renewable energy, uninterruptible power supplies (UPS), and smart grid power systems, utilize bidirectional DC-DC converters to interface between devices and / or power sources that can both consume and provide DC power.

[0003] The trend in power conversion systems for EVs and energy storage is toward higher efficiency, higher power density, and bidirectional operation. Bidirectional CLLC converters have become very popular in bidirectional DC-DC power conversion applications because of their zero-voltage switching (ZVS) operation in bidirectional mode, as discussed by Wei Chen et al. in “Snubberless Bidirectional DC-DC Converter With New CLLC Resonant Tank Featuring Minimized Switching Loss”, published in IEEE Transactions on Industrial Electronics, Volume 57, No. 9, September 2010. As used herein, “CLLC” refers to a resonant combination of circuit elements including capacitors (C) and inductors (L). In some cases, for such circuits, ZVS operation and thus the reduction in switching losses may only apply to on-switching, and hard switching (e.g., with corresponding switching losses) may still exist during off-switching.

[0004] To achieve high efficiency, good thermal performance, and reduced electromagnetic interference (EMI), it can be useful to properly design the turns ratio of the transformer used in a CLLC bidirectional converter to minimize the converter's switching frequency and shutdown current under heavy load conditions, even when the gain is less than the gain at the resonant frequency. However, in some applications, such as EV on-board chargers (OBCs), the required output voltage range of the DC-DC converter can vary considerably when operating in charging mode. Furthermore, both vehicle-to-grid (V2G) operation (e.g., where the EV can supply power to the grid) and vehicle-to-load (V2L) operation (e.g., where the EV can supply power to a connected load) can have wide DC input voltage ranges, and the required output voltage range of the DC-DC converter can also be wide. As a result, designing the transformer's turns ratio to support applications with such a wide range of variations can be challenging.

[0005] Previous studies have investigated two-stage architectures, such as the one involving a CLLC converter following a buck / boost converter or vice versa, as discussed by Liu Hao et al. in their paper "Urban Rail Transit Power System Integrated with Electric Vehicles Based on CLLC Resonant and Buck-boost Converter," presented at the 2018 IEEE International Conference on Electrical Systems for Aircraft, Railway, Ship Propulsion and Road Vehicles & International Transportation Electrification Conference (ESARS-ITEC). However, adding a buck / boost converter can increase system cost and negatively impact system efficiency and power density.

[0006] Relay-based flexible control has also been studied in adapter applications, such as the paper "High-Efficiency Single-Stage LLC Resonant Converter for Wide-Input-Voltage Range" published by Chong-Eun Kim et al. in IEEE Transactions on Power Electronics, Volume 33, Issue 9, September 2018. In these devices, mechanical relays can be used to change the transformer turns ratio in different operating modes. However, relay-based methods also increase system cost and affect system efficiency and power density. Summary of the Invention

[0007] According to some embodiments of the present invention, a bidirectional power converter includes: a first switching circuit coupled to a second switching circuit via a transformer, wherein the first switching circuit is configured to transfer power to the second switching circuit during a charging mode; the second switching circuit is configured to transfer power to the first switching circuit during a discharging mode, and the first switching circuit is configured to operate in a half-bridge configuration during a first portion of the charging mode.

[0008] In some embodiments, the first switching circuit is further configured to operate as a full-bridge synchronous rectifier during a first portion of the discharge mode.

[0009] In some embodiments, the second switching circuit is configured to operate as a full-bridge synchronous rectifier during the first portion of the charging mode.

[0010] In some embodiments, the first switch (e.g., Q4) and the second switch (e.g., Q3) of the first switching circuit are configured to be active simultaneously during a portion of the first part of the charging mode.

[0011] In some embodiments, the first switch (e.g., Q4) is configured to transition from the deactivated state to the activated state at substantially the same time as the second switch (e.g., Q3) is configured to transition from the deactivated state to the activated state during a first portion of the charging mode.

[0012] In some embodiments, the first switch (e.g., Q4) is configured to transition from the active state to the deactivated state at substantially the same time as the second switch (e.g., Q3) is configured to transition from the active state to the deactivated state during a first portion of the charging mode.

[0013] In some embodiments, during a first portion of the charging mode, a first switch (e.g., Q4) performs pulse width modulation at a first frequency having a first duty cycle, and a second switch (e.g., Q3) performs pulse width modulation at a second frequency having a second duty cycle, the first frequency and the second frequency being substantially the same, and the durations of the first duty cycle and the second duty cycle being different.

[0014] In some embodiments, the first switch (e.g., Q4) and the third switch (e.g., Q1) of the first switching circuit are configured to be active simultaneously during another part of the first part of the charging mode.

[0015] In some embodiments, the fourth switch (e.g., Q7) and the fifth switch (e.g., Q8) of the second switching circuit are configured to be active simultaneously during a portion of the first part of the discharge mode.

[0016] In some embodiments, the fourth switch (e.g., Q7) is configured to transition from the deactivated state to the activated state at substantially the same time during the first part of the discharge mode, when the fifth switch (e.g., Q8) is configured to transition from the deactivated state to the activated state.

[0017] In some embodiments, the fourth switch (e.g., Q7) is configured to transition from the active state to the deactivated state at substantially the same time that the fifth switch (e.g., Q8) is configured to transition from the active state to the deactivated state during the first portion of the discharge mode.

[0018] In some embodiments, during the first part of the discharge mode, a fourth switch (e.g., Q7) performs pulse width modulation at a fourth frequency with a fourth duty cycle, and a fifth switch (e.g., Q8) performs pulse width modulation at a fifth frequency with a fifth duty cycle, the fourth frequency and the fifth frequency being substantially the same, and the durations of the fourth duty cycle and the fifth duty cycle being different.

[0019] In some embodiments, the fourth switch (e.g., Q7) and the sixth switch (e.g., Q6) of the second switching circuit are configured to be active simultaneously during another part of the first part of the discharge mode.

[0020] In some embodiments, the switch (e.g., Q2) of the first switching circuit is configured to be turned on during the duration of the first part of the charging mode.

[0021] In some embodiments, the switch (e.g., Q5) of the second switching circuit is configured to be turned on during the duration of the first part of the discharge mode.

[0022] In some embodiments, the first switching circuit includes: a first switch (e.g., Q1) having a first terminal coupled to a first terminal of an input port and a second terminal coupled to a first terminal of a first winding of a transformer; a second switch (e.g., Q2) having a first terminal coupled to a first terminal of an input port and a second terminal coupled to a second terminal of a first winding of a transformer; a third switch (e.g., Q3) having a first terminal coupled to a first terminal of a first winding of a transformer and a second terminal coupled to a second terminal of an input port; and a fourth switch (e.g., Q4) having a first terminal coupled to a second terminal of a first winding of a transformer and a second terminal coupled to a second terminal of an input port.

[0023] In some embodiments, the first switching circuit includes: a fifth switch (e.g., Q5) having a first terminal coupled to a first terminal of an output port and a second terminal coupled to a first terminal of a second winding of a transformer; a sixth switch (e.g., Q6) having a first terminal coupled to a first terminal of an output port and a second terminal coupled to a second terminal of a second winding of a transformer; a seventh switch (e.g., Q7) having a first terminal coupled to a first terminal of a second winding of a transformer and a second terminal coupled to a second terminal of an output port; and an eighth switch (e.g., Q8) having a first terminal coupled to a second terminal of a second winding of a transformer and a second terminal coupled to a second terminal of an output port.

[0024] According to some embodiments of the present invention, a bidirectional power converter includes: a first switching circuit coupled to a second switching circuit via a transformer, wherein the first switching circuit is configured to transfer power to the second switching circuit during a charging mode; the second switching circuit is configured to transfer power to the first switching circuit during a discharging mode, and a first switch (e.g., Q2) of the first switching circuit is configured to be turned on for most of the duration of the charging mode.

[0025] In some embodiments, the first switch (e.g., Q5) of the second switching circuit is configured to be turned on during the duration of the discharge mode.

[0026] In some embodiments, the second switch (e.g., Q4) of the first switching circuit is configured to be operated so that it is active during a portion of the duty cycle of the third switch (e.g., Q3) of the first switching circuit.

[0027] In some embodiments, the second switch (e.g., Q4) of the first switching circuit is configured to be operated so that it is active during a portion of the duty cycle of the third switch (e.g., Q3) and the fourth switch (e.g., Q1) of the first switching circuit.

[0028] In some embodiments, the second switch (e.g., Q7) of the second switching circuit is configured to be operated so that it is active during a portion of the duty cycle of the third switch (e.g., Q8) of the second switching circuit.

[0029] In some embodiments, the second switch (e.g., Q7) of the second switching circuit is configured to be operated so that it is active during a portion of the duty cycle of the third switch (e.g., Q8) and the fourth switch (e.g., Q6) of the second switching circuit.

[0030] In some embodiments, the first switching circuit includes a first full-bridge switching circuit, and the second switching circuit includes a second full-bridge switching circuit.

[0031] In some embodiments, the first switch (e.g., Q2) of the first switching circuit is configured to be turned on throughout the entire duration of the charging mode.

[0032] According to some embodiments of the present invention, a bidirectional power converter includes: a first switching circuit coupled to a second switching circuit via a transformer, wherein the first switching circuit includes a first switch (e.g., Q1), a second switch (e.g., Q2), a third switch (e.g., Q3), and a fourth switch (e.g., Q4) and is configured to transfer power to the second switching circuit during a charging mode; the second switching circuit includes a fifth switch (e.g., Q5), a sixth switch (e.g., Q6), a seventh switch (e.g., Q7), and an eighth switch (e.g., Q8) and is configured to transfer power to the first switching circuit during a discharging mode, wherein the third switch (e.g., Q3) and the fourth switch (e.g., Q4) are configured to be active simultaneously during a portion of the charging mode, the fourth switch (e.g., Q4) and the third switch (e.g., Q3) are configured to be controlled by their respective pulse width modulation (PWM) signals, and the first PWM signal of the fourth switch (e.g., Q4) has a pulse width with a different duration than the second PWM signal of the third switch (e.g., Q3).

[0033] In some embodiments, the first switching circuit is configured to operate as a full-bridge synchronous rectifier during a portion of the discharge mode.

[0034] In some embodiments, the second switching circuit is configured to operate as a full-bridge synchronous rectifier during a portion of the charging mode.

[0035] In some embodiments, the fourth switch (e.g., Q4) is configured to transition from the deactivated state to the activated state at substantially the same time that the third switch (e.g., Q3) is configured to transition from the deactivated state to the activated state.

[0036] In some embodiments, the fourth switch (e.g., Q4) is configured to transition from the active state to the deactivated state at substantially the same time that the third switch (e.g., Q3) is configured to transition from the active state to the deactivated state.

[0037] In some embodiments, a fourth switch (e.g., Q4) performs pulse width modulation at a first frequency, and a third switch (e.g., Q3) performs pulse width modulation at a second frequency, and the first frequency and the second frequency are substantially the same.

[0038] In some embodiments, the fourth switch (e.g., Q4) and the first switch (e.g., Q1) of the first switching circuit are configured to be active simultaneously during another part of the charging mode.

[0039] In some embodiments, the seventh switch (e.g., Q7) and the eighth switch (e.g., Q8) of the second switching circuit are configured to be active simultaneously during a portion of the discharge mode.

[0040] In some embodiments, the seventh switch (e.g., Q7) is configured to transition from the deactivated state to the activated state at substantially the same time that the eighth switch (e.g., Q8) is configured to transition from the deactivated state to the activated state.

[0041] In some embodiments, the seventh switch (e.g., Q7) is configured to transition from the active state to the deactivated state at substantially the same time that the eighth switch (e.g., Q8) is configured to transition from the active state to the deactivated state.

[0042] In some embodiments, a seventh switch (e.g., Q7) performs pulse width modulation at a fourth frequency having a fourth duty cycle, and an eighth switch (e.g., Q8) performs pulse width modulation at a fifth frequency having a fifth duty cycle, the fourth frequency being substantially the same as the fifth frequency, and the duration of the fourth duty cycle being different from that of the fifth duty cycle.

[0043] In some embodiments, the seventh switch (e.g., Q7) and the sixth switch (e.g., Q6) of the second switching circuit are configured to be active simultaneously during another part of the discharge mode.

[0044] In some embodiments, the second switch (e.g., Q2) of the first switching circuit is configured to be turned on during the duration of the charging mode.

[0045] In some embodiments, the fifth switch (e.g., Q5) of the second switching circuit is configured to be turned on during the duration of the discharge mode.

[0046] In some embodiments, the second switch (e.g., Q2) of the first switching circuit is configured to be controlled by a third PWM signal during the charging mode, such that the second switch (e.g., Q2) is activated when the fourth switch (e.g., Q4) is inactive.

[0047] In some embodiments, the fifth switch (e.g., Q5) of the second switching circuit is configured to be controlled by a fourth PWM signal during the discharge mode, such that the fifth switch (e.g., Q5) is activated when the seventh switch (e.g., Q7) is inactive.

[0048] According to some embodiments of the present invention, a method of operating a bidirectional power converter includes: providing a first switching circuit having a full-bridge configuration, the first switching circuit being coupled to a second switching circuit via a transformer; operating the first switching circuit having a full-bridge configuration of the bidirectional power converter in a half-bridge configuration during a first portion of a charging mode; and transferring power from the first switching circuit to the second switching circuit via the transformer during the charging mode.

[0049] In some embodiments, the method further includes operating a second switching circuit during the discharge mode of the bidirectional power converter to transfer power to the first switching circuit.

[0050] In some embodiments, the method further includes operating a first switching circuit during a first portion of a discharge mode to operate in a full-bridge synchronous rectifier configuration.

[0051] In some embodiments, the method further includes operating a second switching circuit as a full-bridge synchronous rectifier during a first portion of the charging mode.

[0052] In some embodiments, operating the first switching circuit during a first portion of the charging mode includes operating a first switch (e.g., Q4) and a second switch (e.g., Q3) of the first switching circuit to be active simultaneously during a portion of the first portion of the charging mode.

[0053] In some embodiments, operating the first switch circuit during a first portion of the charging mode further includes operating the first switch (e.g., Q4) to transition from a deactivated state to an activated state at substantially the same time that the second switch (e.g., Q3) transitions from a deactivated state to an activated state during the first portion of the charging mode.

[0054] In some embodiments, operating the first switch circuit during a first portion of the charging mode further includes operating the first switch (e.g., Q4) to transition from the active state to the deactivated state at substantially the same time that the second switch (e.g., Q3) transitions from the active state to the deactivated state during the first portion of the charging mode.

[0055] In some embodiments, operating the first switching circuit during a first portion of the charging mode further includes operating a first switch (e.g., Q4) and a third switch (e.g., Q1) of the first switching circuit to be active simultaneously during another portion of the first portion of the charging mode.

[0056] In some embodiments, operating the first switching circuit during a first portion of the charging mode further includes operating a switch (e.g., Q2) of the first switching circuit to be turned on during the duration of the first portion of the charging mode.

[0057] Further features, advantages, and details of the invention will be appreciated by those skilled in the art from reading the figures and the following detailed description of preferred embodiments, which are merely illustrative of the invention.

[0058] It should be noted that the various aspects of the invention described with respect to one embodiment can be incorporated into different embodiments, although their contents are not specifically described. That is, all embodiments and / or features of any embodiment can be combined in any manner and / or combination. These and other objects and / or aspects of the invention will be explained in detail in the following description. Attached Figure Description

[0059] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate some embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0060] Figure 1 This is a circuit diagram illustrating a bidirectional CLLC converter including a controller configured to operate as control circuitry, according to some embodiments of the present invention.

[0061] Figure 2 The illustrations depict some embodiments of the present invention. Figure 1 A circuit diagram showing how a bidirectional CLLC converter can operate as a half-bridge CLLC converter with full-bridge synchronous rectification in charging mode.

[0062] Figure 3 The illustrations depict some embodiments of the present invention. Figure 1 A circuit diagram showing how a bidirectional CLLC converter can operate as a half-bridge CLLC converter with full-bridge synchronous rectification in discharge mode.

[0063] Figure 4 This is a circuit diagram illustrating signals applied to control the switching of a bidirectional CLLC converter according to some embodiments of the present invention when operating in charging mode.

[0064] Figure 5 This is a circuit diagram illustrating signals applied to control the switching of a bidirectional CLLC converter according to some embodiments of the present invention when operating in discharge mode.

[0065] Figure 6 This is a circuit diagram illustrating an additional embodiment of a bidirectional CLLC converter according to some embodiments of the present invention when operating in charging mode.

[0066] Figure 7 This is a circuit diagram illustrating an additional embodiment of a bidirectional CLLC converter according to some embodiments of the present invention when operating in discharge mode.

[0067] Figures 8A to 8H This is a timing diagram illustrating various operating modes of a bidirectional CLLC converter according to some embodiments of the present invention.

[0068] Figures 9A to 9F This is a circuit diagram of an additional configuration of the resonant tank of a bidirectional CLLC converter according to some embodiments of the present invention. Detailed Implementation

[0069] The invention will now be described more fully with reference to the accompanying drawings, which illustrate exemplary embodiments of the invention. In the drawings, the relative dimensions of various regions or features may be exaggerated for clarity. However, the invention can be embodied in many different forms and should not be construed as limited to the embodiments described herein; rather, these embodiments are provided to make the disclosure of the invention thorough and complete, and to fully convey the scope of the invention to those skilled in the art.

[0070] According to embodiments of the present invention, a bidirectional CLLC converter is provided, which is configured to be driven such that a first switching circuit of the bidirectional CLLC converter is configured to operate in a half-bridge configuration during at least a portion of a charging mode and in a full-bridge configuration during at least a portion of a discharging mode, in order to increase the gain range of the system while reducing and / or minimizing switching losses. In some embodiments, the duty cycle and / or frequency of the switches in the bidirectional CLLC converter can be manipulated to provide concurrent activation time for one or more switches in order to provide ZVS for the switches during charging and / or discharging operations.

[0071] Figure 1 A bidirectional CLLC converter according to some embodiments of the present invention is illustrated. For example, the design of a bidirectional CLLC converter was discussed by Jee-Hoon Jung et al. in “Design Methodology of Bidirectional CLLC Resonant Converter for High-Frequency Isolation of DC Distribution Systems”, published in IEEE Transactions on Power Electronics, Volume 28, No. 4, April 2013, the contents of which are incorporated herein by reference. The operation of the bidirectional CLLC converter is determined in part based on the control of various switching elements (e.g., switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8) controlled by controller 110. Controller 110 (e.g., a digital controller) may be coupled to switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8, and may provide signals for activating switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8.

[0072] Switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 are in Figure 1The diagram shows a MOSFET transistor switch. However, it is understood that other types of switches, such as bipolar junction transistors (BJTs), junction field-effect transistors (JFETs), thyristors, and / or other devices, can replace or supplement MOSFET switches. In this discussion, switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 are described as “activated / active” and “inactive / deactivated”. As used herein, activating switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 means turning switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 on. Similarly, deactivating switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 means turning switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 off. It is understood that switches Q1, Q2, Q3, Q4, Q5, Q6, Q7 and Q8 can be implemented as normally open or normally closed devices without departing from the present invention.

[0073] Each of switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 in Figure 1 The diodes are shown in parallel with the circuit. This diode can be an explicit external diode in the circuit, and / or it can be an implicit internal body diode of switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8. The "body diode" of a MOSFET is the PN junction between the drain terminal and the substrate. As long as the source is more positive than the drain, current can flow through the internal body diode (in an N-channel MOSFET) because there is also a direct connection between the source terminal and the substrate.

[0074] Figure 1 The bidirectional full-bridge CLLC resonant converter shown has a primary inverter stage 120, whose full-bridge symmetrical structure is coupled to a secondary rectifier stage 130 via a symmetrical high-frequency transformer T1. During charging mode, power switches Q1, Q2, Q3, and Q4 in the primary inverter stage 120 convert the input power (whose voltage signal is represented by Vbus) from DC to AC, transferring the power to the secondary rectifier stage 130 via transformer T1 during the charging mode. The converter can then use this transformer T1 to output power (whose voltage signal is represented by Vbattery), achieving current isolation between the primary stage 120 and the secondary stage 130. During discharging mode, the circuit operates in the opposite manner. That is, power switches Q5, Q6, Q7, and Q8 in the secondary stage 130 convert the input power (whose voltage signal is represented by Vbattery) from DC to AC, transferring the power to the primary stage 120 via transformer T1.

[0075] In a conventional bidirectional full-bridge CLLC resonant converter, the device is controlled such that during charging mode, the primary side acts as a full-bridge converter and the secondary side acts as a synchronous rectifier; and during discharging mode, the secondary side acts as a full-bridge converter and the primary side acts as a synchronous rectifier. Embodiments of the present invention propose modifying the control of the device (e.g., via controller 110) to change the operation of the switches, making them different from those used in conventional bidirectional full-bridge CLLC resonant converters. The bidirectional CLLC resonant converter according to embodiments of the present invention operates in a different manner to provide improved performance.

[0076] In conventional control schemes, the controller can set the duty cycles of switches Q1, Q2, Q3, and Q4 to approximately 50%, and can adjust the switching frequency to adjust the voltage gain of the CLLC converter during charging mode. As used herein, the duty cycle of a switch refers to the duty cycle of the signal provided to activate the switch. For example, the switch can be a transistor, and the signal provided to activate the switch can be a power signal with voltage or current applied to the gate (or base) of the transistor. In some embodiments, the signal applied to the switch can be a pulse-width modulated signal, and the duty cycle refers to the duty cycle of the signal pulses. Similarly, the frequency of the signal pulses can be used to adjust the switching frequency of the switch.

[0077] The gain of a bidirectional CLLC converter in charging mode (e.g., the increase in power from input to output) can be adjusted based on several operating factors, including but not limited to the turns ratio of transformer T1, the switching frequency, the resonant frequency of the circuit, and the ratio between the resonant inductance and the magnetizing inductance. For example, the gain of the bidirectional CLLC converter may be one value at the switching frequency of the primary stage 120, but another value at the second switching frequency. Therefore, the gain of the bidirectional CLLC converter can be changed based on several adjustable factors. Generally, the range of factors that can be adjusted to adjust the gain of the circuit can extend from a lower limit and / or value represented by a to an upper limit and / or value represented by b (where a... <b)。

[0078] The switching frequencies of switches Q5, Q6, Q7, and Q8 can be adjusted to control the voltage gain in discharge mode. Similar to charging mode, the gain of the CLLC converter is also adjustable in discharge mode. The adjustable factor of the circuit in discharge mode can range from c to d (where c... <d)。

[0079] The turns ratio of transformer T1 can be expressed as the number of turns in the primary winding relative to the number of turns in the secondary winding: n1 / n2. Therefore, the available Vbattery range in charging mode (e.g., the output voltage signal in charging mode) is shown in Equation 1, and the available Vbus voltage range in discharging mode (e.g., the output voltage signal in discharging mode) is shown in Equation 2.

[0080]

[0081]

[0082] In embodiments of the invention, the duty cycles and switching frequencies of switches Q1 and Q3 can be adjusted to adjust the voltage gain of the CLLC converter in charging mode. In some embodiments, the duty cycles of switches Q1 and Q3 can be set to approximately 50%. The duty cycle of switch Q2 can also be set to zero (e.g., always off during charging mode), while the duty cycle of switch Q4 can be set to 100% (e.g., always on during charging mode). Then, as... Figure 2 As shown, during the charging mode, the primary side of the CLLC converter can operate as a half-bridge CLLC, while the secondary side of the CLLC converter operates as a full-bridge synchronous rectifier.

[0083] exist Figure 2 In the configuration shown, the available Vbattery range in charging mode is illustrated by Equation 3.

[0084]

[0085] As shown in Equation 3, the revised configuration reduces the low range of Vbattery gain in charging mode.

[0086] Similarly, in embodiments of the invention, the duty cycles and switching frequencies of switches Q6 and Q8 can be adjusted to adjust the voltage gain of the CLLC converter in discharge mode. In some embodiments, the duty cycles of switches Q6 and Q8 can be set to approximately 50%. The duty cycle of switch Q5 can also be set to zero (e.g., always off during discharge mode), while the duty cycle of switch Q7 can be set to 100% (e.g., always on during discharge mode). The CLLC converter can then operate in discharge mode as a half-bridge CLLC converter with a full-bridge synchronous rectifier, such as... Figure 3 As shown in the image.

[0087] The available Vbus voltage range in the discharge mode is shown by Equation 4.

[0088]

[0089] As shown in Equation 4, the revised configuration reduces the low range of Vbus gain in discharge mode.

[0090] In some embodiments, the controller 110 (e.g., a digital controller) may adjust the signal provided to activate switch Q4 in charging mode or to activate switch Q7 in discharging mode (see [link]). Figure 5 The duty cycle and phase shift (e.g., compared to the signals supplied to other switches Q1, Q3) are adjusted to further reduce the gain of the CLLC converter. For example, as... Figure 4 As shown, during charging mode, a pulse width modulation (PWM) signal can be applied to control switch Q4. Similarly, as... Figure 5 As shown, during discharge mode, a pulse width modulation (PWM) signal can be applied to control switch Q7. In some embodiments, the PWM signal can be applied to the gate of the MOSFET. Although Figure 4 and Figure 5 The diagrams illustrate the PWM signals applied to individual switches, but it is understood that each of switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 can be coupled to a signal that controls its activation (also shown in...). Figure 1 (in the middle). Therefore, controller 110 can be configured to collectively control the activation and deactivation of switches Q1, Q2, Q3, Q4, Q5, Q6, Q7 and Q8 (e.g., via pulse width modulation signals).

[0091] exist Figure 4 and Figure 5 In this configuration, one switch remains inactive for the duration of the charging mode, and another switch remains inactive for the duration of the discharging mode (e.g., switch Q2 in charging mode and switch Q5 in discharging mode). When switch Q4 is off, current can freewheeling via the internal body diode of switch Q2. In some embodiments, switch Q2 can be activated (e.g., turned on) during the freewheeling mode to minimize conduction losses on the internal body diodes of switches Q2 (during charging mode) and Q5 (during discharging mode). Figure 6 and Figure 7 An embodiment is illustrated in which switch Q2 (in charging mode) and switch Q5 (in discharging mode) are activated (e.g., turned on) to reduce and / or minimize the conduction losses of switches Q2 and Q5.

[0092] For example, such as Figure 6 As shown, during charging mode, switch Q2 can be activated in a complementary manner to switch Q4. That is, the duty cycle of switch Q2 can be opposite to that of switch Q4. Figure 6As shown, both switches Q2 and Q4 can be controlled via a PWM signal, although the PWM signal applied to Q2 may be different from the PWM signal applied to Q4. Therefore, when switch Q4 is active (e.g., on), switch Q2 may be inactive (e.g., off), and when switch Q4 is inactive, switch Q2 may be active. In some embodiments, this will result in a duty cycle of switch Q2 that is less than / less than that of switch Q4.

[0093] Similarly, such as Figure 7 As shown, during discharge mode, switch Q5 can be activated in a complementary manner to switch Q7. That is, the duty cycle of switch Q5 can be opposite to that of switch Q7. Figure 6 As shown, both switches Q5 and Q7 can be controlled via a PWM signal, although the PWM signal applied to Q5 may be different from the PWM signal applied to Q7. Therefore, when switch Q7 is active (e.g., on), switch Q5 may be inactive (e.g., off), and when switch Q7 is inactive, switch Q5 may be active. In some embodiments, this will result in the duty cycle of switch Q5 being less than / less than that of switch Q7. Figure 6 and Figure 7 In this embodiment, switches Q2 and Q5 can achieve ZVS, and the conduction losses of switches Q2 and Q5 can be reduced and / or minimized. Therefore, the system efficiency of the bidirectional CLLC converter can be improved.

[0094] Figures 8A to 8H The illustrations are of some embodiments of the present invention. Figure 1 Timing diagrams for various operating modes of a bidirectional CLLC converter. Figures 8A to 8H The timing diagram illustrates activation signals that can be applied to each of switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 during charging and discharging modes, respectively. In some embodiments, these signals may be signals applied to the gate of a transistor (such as a MOSFET), although the invention is not limited thereto.

[0095] Reference Figure 8A and Figure 1 The operation method of the present invention may include deactivating switch Q2 and activating switch Q4, at least for most of the time in the charging mode. For example, during the charging mode, switch Q2 may be biased to deactivate switch Q2, and switch Q4 may be biased to activate switch Q4. In this embodiment, also Figure 4 and Figure 5As illustrated and discussed herein, switches Q1 and Q3 can be activated during charging mode according to their respective pulse width modulation signals to operate as a half-bridge CLLC (e.g., transferring power from the primary side to the secondary side of transformer T1). In some embodiments, the duty cycle of the signals provided to switches Q1 and Q3 can be approximately 50%.

[0096] Furthermore, during charging mode, switches Q5, Q6, Q7, and Q8 can be activated according to their respective pulse width modulation signals to operate as synchronous rectifiers. The operation of synchronous rectification on the secondary side is merely an example, and rectification can be implemented using other signal patterns without departing from the invention.

[0097] Still refer to Figure 8A In discharge mode, for at least most of the discharge mode, switch Q5 can be biased to deactivate switch Q5, and switch Q7 can be biased to activate switch Q7. Switches Q6 and Q8 can be activated during discharge mode according to their respective pulse width modulation signals to operate as a half-bridge CLLC (e.g., transferring power from the secondary side to the primary side of transformer T1). In some embodiments, the duty cycle of the signals provided to switches Q6 and Q8 can be approximately 50%.

[0098] Furthermore, during discharge mode, switches Q1, Q2, Q3, and Q4 can be activated according to their respective pulse width modulation signals to operate as synchronous rectifiers. The operation of synchronous rectification on the primary side is merely an example, and rectification can be implemented using other signal patterns without departing from the invention. As discussed herein with respect to Equations 3 and 4, Figure 8A This configuration can be used to reduce the low range of device gain.

[0099] In some embodiments, power can be transferred to the load during charging mode (e.g., from the primary side to the secondary side, or from...). Figure 8A (From the left side of the circuit to the right side of the circuit). In some embodiments, the longer switches Q1 and Q4 are simultaneously on, the higher the gain of the device in the charging direction. Similarly, power can be transferred in the discharging mode (e.g., from the secondary side to the primary side, or from...). Figure 8A (From the right side of the circuit to the left side of the circuit). In some embodiments, the longer the switches Q6 and Q7 are simultaneously turned on, the higher the gain of the device in the discharge direction.

[0100] Figure 8B It is for operation according to some embodiments of the present invention. Figure 1 Timing diagram of an additional method for a bidirectional CLLC converter. (Refer to...) Figure 8B and Figure 1The operation method of the present invention may include deactivating switch Q2 for at least most of the time in the charging mode and activating switch Q4 according to a pulse width modulation signal. For example, as Figure 8B As shown, during at least a portion of the charging mode, switch Q4 can be turned on at the same time as switch Q3 (e.g., transitioning from a deactivated state to an active state). Switch Q4 can be activated by a signal (e.g., a PWM signal) having the same frequency as the signals activating switches Q1 and Q3, respectively. In some embodiments, the PWM signal provided to switch Q4 can have a different duty cycle than the PWM signal provided to switch Q3. For example, the pulse width of the pulse modulation signal provided to switch Q4 can have a longer duration than the pulse width of the pulse modulation signal provided to switch Q3. In some embodiments, switch Q4 can be active at the same time as switch Q3 during at least a portion of the charging mode (e.g., simultaneously active). By adjusting the duty cycle of switch Q4, the gain of the half-bridge CLLC converter with full-bridge synchronous rectification can be further adjusted, which can provide a wider gain range for the device during the charging mode. Figure 8B The operating method may not be able to achieve ZVS for switches Q1, Q3 and Q4.

[0101] Switches Q1 and Q3 can be activated during charging mode according to their respective pulse width modulation signals to transfer power from the primary side to the secondary side of transformer T1. In some embodiments, the duty cycle of the signals provided to switches Q1 and Q3 can be approximately 50%. Furthermore, during charging mode, switches Q5, Q6, Q7, and Q8 can be activated according to their respective pulse width modulation signals to operate as synchronous rectifiers.

[0102] Still refer to Figure 8B In discharge mode, switch Q5 can be biased to be deactivated at least for most of the discharge mode time, and switch Q7 can be pulse-width modulated to be turned on at the same time as switch Q8 (e.g., transitioning from a deactivated state to an active state). Switch Q7 can be activated by a PWM signal having the same frequency as the signal activating switch Q8. In some embodiments, the PWM signal provided to switch Q7 can have a different duty cycle than the PWM signal provided to switch Q8. For example, the pulse width of the pulse-modulated signal provided to switch Q7 can have a longer duration than the pulse width of the pulse-modulated signal provided to switch Q8. In some embodiments, switch Q7 can be active at the same time as switch Q8 for at least a portion of the discharge mode time (e.g., simultaneously active). By adjusting the duty cycle of switch Q7, the gain of the half-bridge CLLC converter with full-bridge synchronous rectification can be further adjusted during discharge mode, which can provide a wider gain range for the device. Figure 8BThe operating method may not be able to achieve ZVS for switches Q6, Q7, and Q8.

[0103] Switches Q6 and Q8 can be activated during discharge mode according to their respective pulse width modulation signals to transfer power from the secondary side to the primary side of transformer T1. In some embodiments, the duty cycle of the signals provided to switches Q6 and Q8 can be approximately 50%. Furthermore, during discharge mode, switches Q1, Q2, Q3, and Q4 can be activated according to their respective pulse width modulation signals to operate as synchronous rectifiers.

[0104] Figure 8C It is for operation according to some embodiments of the present invention. Figure 1 Timing diagram of an additional method for a bidirectional CLLC converter. (Refer to...) Figure 8C and Figure 1 The operation method of the present invention may include deactivating switch Q2 for at least most of the time in the charging mode and activating switch Q4 according to a pulse width modulation signal. For example, as Figure 8C As shown, during at least a portion of the charging mode, switch Q4 may be turned off at the same time as switch Q3 (e.g., transitioning from an active state to a deactivated state). Switch Q4 may be activated by a signal (e.g., a PWM signal) having the same frequency as the respective signals activating switches Q1 and Q3, but the PWM signal provided to switch Q4 may have a different duty cycle than the PWM signal provided to switch Q3. For example, the pulse width of the pulse modulation signal provided to switch Q4 may have a longer duration than the pulse width of the pulse modulation signal provided to switch Q3. In some embodiments, switch Q4 may be active at the same time as switch Q3 for at least a portion of the charging mode (e.g., simultaneously active). By adjusting the duty cycle of switch Q4, the gain of the half-bridge CLLC converter with full-bridge synchronous rectification can be further adjusted during the charging mode. Figure 8C The operation method can achieve ZVS for switches Q1 and Q3, but cannot guarantee ZVS for switch Q4.

[0105] Switches Q1 and Q3 can be activated during charging mode according to their respective pulse width modulation signals to transfer power from the primary side to the secondary side of transformer T1. In some embodiments, the duty cycle of the signals provided to switches Q1 and Q3 can be approximately 50%. Furthermore, during charging mode, switches Q5, Q6, Q7, and Q8 can be activated according to their respective pulse width modulation signals to operate as synchronous rectifiers.

[0106] Still refer to Figure 8CIn discharge mode, switch Q5 can be biased to deactivate switch Q5 for at least a majority of the discharge mode time, and switch Q7 can be pulse-width modulated to be turned off at the same time as switch Q8 (e.g., transitioning from an active state to a deactivated state). Switch Q7 can be activated by a PWM signal having the same frequency as the signal activating switch Q8, but can have a different duty cycle than the PWM signal provided to switch Q8. For example, the pulse width of the pulse-modulated signal provided to switch Q7 can have a longer duration than the pulse width of the pulse-modulated signal provided to switch Q8. In some embodiments, switch Q7 can be active at the same time as switch Q8 for at least a portion of the discharge mode time (e.g., simultaneously active). By adjusting the duty cycle of switch Q7, the gain of the half-bridge CLLC converter with full-bridge synchronous rectification can be further adjusted during discharge mode. Figure 8C The operation method can achieve ZVS for switches Q6 and Q8, but cannot guarantee ZVS for switch Q7.

[0107] Switches Q6 and Q8 can be activated during discharge mode according to their respective pulse width modulation signals to transfer power from the secondary side to the primary side of transformer T1. In some embodiments, the duty cycle of the signals provided to switches Q6 and Q8 can be approximately 50%. Furthermore, during discharge mode, switches Q1, Q2, Q3, and Q4 can be activated according to their respective pulse width modulation signals to operate as synchronous rectifiers.

[0108] Figure 8D It is for operation according to some embodiments of the present invention. Figure 1 Timing diagram of an additional method for a bidirectional CLLC converter. (Refer to...) Figure 8D and Figure 1 The operation method of the present invention may include deactivating switch Q2 for at least most of the time in the charging mode and activating switch Q4 according to a pulse width modulation signal. For example, as Figure 8DAs shown, during at least a portion of the charging mode, switch Q4 may be turned off at the same time as switch Q3 (e.g., transitioning from an active state to a deactivated state). Switch Q4 may be activated by a signal (e.g., a PWM signal) having a different frequency than the respective signals activating switches Q1 and Q3, and the PWM signal provided to switch Q4 may have a different duty cycle than the PWM signal provided to switch Q3. In some embodiments, the switching frequency of the signal provided to switch Q4 may be less than the switching frequency of the respective signals provided to switches Q1 and Q3. For example, the pulse width of the pulse modulation signal provided to switch Q4 may have a longer duration than the pulse width of the pulse modulation signal provided to switch Q3. In some embodiments, switch Q4 may be active at the same time as switch Q3 and at the same time as switch Q1 during at least a portion of the charging mode (e.g., simultaneously active). By adjusting the duty cycle of switch Q4, the gain of the half-bridge CLLC converter with full-bridge synchronous rectification can be further adjusted during the charging mode. Figure 8D The operating method enables ZVS for switches Q1 and Q3. Furthermore, since switch Q4 is pulse-width modulated at a lower switching frequency, the switching losses of switch Q4 can be reduced and / or minimized.

[0109] Switches Q1 and Q3 can be activated during charging mode according to their respective pulse width modulation signals to transfer power from the primary side to the secondary side of transformer T1. In some embodiments, the duty cycle of the signals provided to switches Q1 and Q3 can be approximately 50%. Furthermore, during charging mode, switches Q5, Q6, Q7, and Q8 can be activated according to their respective pulse width modulation signals to operate as synchronous rectifiers.

[0110] Still refer to Figure 8DIn discharge mode, switch Q5 can be biased to deactivate switch Q5 for at least a majority of the discharge mode time, and switch Q7 can be pulse-width modulated to be turned off at the same time as switch Q8 (e.g., transitioning from an active state to a deactivated state). Switch Q7 can be activated by a PWM signal having a different frequency than the respective signals activating switches Q6 and Q8, and the PWM signal provided to switch Q7 can have a different duty cycle than the PWM signal provided to switch Q8. In some embodiments, the switching frequency of the signal provided to switch Q7 can be less than the switching frequency of the respective signals provided to switches Q6 and Q8. For example, the pulse width of the pulse-modulated signal provided to switch Q7 can have a longer duration than the pulse width of the pulse-modulated signal provided to switch Q8. In some embodiments, switch Q7 can be active at the same time as switch Q6 and at the same time as switch Q8 for at least a portion of the charging mode time (e.g., simultaneously active). By adjusting the duty cycle of switch Q7, the gain of the half-bridge CLLC converter with full-bridge synchronous rectification can be further adjusted during discharge mode. Figure 8D The operating method enables ZVS for switches Q6 and Q8. Furthermore, since switch Q7 performs pulse width modulation at a lower switching frequency, the switching loss of Q7 can be reduced and / or minimized.

[0111] Switches Q6 and Q8 can be activated during discharge mode according to their respective pulse width modulation signals to transfer power from the secondary side of transformer T1 to the primary stage 120. In some embodiments, the duty cycle of the signals provided to switches Q6 and Q8 can be approximately 50%. Furthermore, during discharge mode, switches Q1, Q2, Q3, and Q4 can be activated according to their respective pulse width modulation signals to operate as synchronous rectifiers.

[0112] Figures 8A-8D The illustration shows an embodiment where one switch is inactive during the duration of a charging mode and another switch is inactive during the duration of a discharging mode (e.g., switch Q2 in charging mode and switch Q5 in discharging mode). In some embodiments, as described herein... Figure 6 and Figure 7 The switches discussed (switch Q2 in charging mode and switch Q5 in discharging mode) can be operated during a portion of the duty cycle (e.g., via a PWM signal).

[0113] For example, Figure 8E The diagram illustrates the relationship with Figure 8BSimilar to the embodiment described above. That is, during the charging mode, switch Q4 is controlled to have the same frequency as switch Q3 and transitions from an inactive state to an active state at the same time as switch Q3, but with a different duty cycle. Similarly, switch Q7 is controlled to have the same frequency as switch Q8 and transitions from an inactive state to an active state at the same time as switch Q8, but with a different duty cycle. However, with... Figure 8B The difference is that, in Figure 8E In this embodiment, switch Q2 is controlled by a PWM signal to have a switching pattern complementary to that of switch Q4 in charging mode, and switch Q5 is controlled by a PWM signal to have a switching pattern complementary to that of switch Q7 in discharging mode. Therefore, in charging mode, when switch Q4 is inactive (e.g., off), switch Q2 can be controlled to be active (e.g., on), and when switch Q4 is active, switch Q2 can be controlled to be inactive. Similarly, in charging mode, when switch Q7 is inactive (e.g., off), switch Q5 can be controlled to be active (e.g., on), and when switch Q7 is active, switch Q5 can be controlled to be inactive.

[0114] Figure 8F The diagram illustrates the relationship with Figure 8C Similar to the embodiment described above. That is, during the charging mode, switch Q4 is controlled to have the same frequency as switch Q3 and transitions from an active state to an inactive state at the same time as switch Q3, but with a different duty cycle. Similarly, switch Q7 is controlled to have the same frequency as switch Q8 and transitions from an active state to an inactive state at the same time as switch Q8, but with a different duty cycle. However, with... Figure 8C The difference is that, in Figure 8F In one embodiment, switch Q2 is controlled by a PWM signal to have a switching pattern complementary to switch Q4 in charging mode, and switch Q5 is controlled by a PWM signal to have a switching pattern complementary to switch Q7 in discharging mode.

[0115] Figure 8G The diagram illustrates the relationship with Figure 8D Similar to the embodiments described above. That is, during the charging mode, switch Q4 is controlled to have a duty cycle and frequency different from both switches Q1 and Q3, such that switch Q4 is active during a portion of the duty cycle of switch Q3 and a portion of the duty cycle of switch Q1. Similarly, switch Q7 is controlled to have a duty cycle and frequency different from both switches Q6 and Q8, such that switch Q4 is active during a portion of the duty cycle of switch Q6 and a portion of the duty cycle of switch Q8. However, compared with... Figure 8D The difference is that, in Figure 8GIn one embodiment, switch Q2 is controlled by a PWM signal to have a switching pattern complementary to switch Q4 in charging mode, and switch Q5 is controlled by a PWM signal to have a switching pattern complementary to switch Q7 in discharging mode.

[0116] exist Figures 8A-8G Different methods for operating the switching circuit of the present invention have been illustrated. Figures 8A-8G The diagram illustrates the same switching method applied to the primary stage 120 during the charging mode as the switching method applied to the secondary stage 130 during the discharging mode, but the invention is not limited thereto. Figure 8H It is for operation according to some embodiments of the present invention. Figure 1 Timing diagram of an additional method for a bidirectional CLLC converter. Figure 8H In this embodiment, a different switching method is used during the charging mode compared to the discharging mode. In other words, in some embodiments, the PWM signal applied to switch Q4 during the charging mode may be different from the PWM signal applied to switch Q7 during the discharging mode (e.g., having different frequencies or different duty cycles). Figure 8H In the middle, switch Q4 during charging mode is similar to that about Figure 8C The method is activated (e.g., switch Q4 is deactivated at the same time as switch Q3, but at the same frequency as switch Q3), while switch Q7 is activated during discharge mode at a frequency similar to that of switch Q3. Figure 8D The method is activated (e.g., during a portion of the time when both switches Q6 and Q7 are active, switch Q7 is active, but switching at a different frequency than switches Q6 and Q7). It is understood that different combinations of operations can be utilized in charging and discharging modes without departing from the invention. For example, in some embodiments, switch Q2 can remain in a deactivated state during charging mode (as per the description herein). Figures 8A-8D (As discussed), and switch Q5 can be operated in a complementary manner to switch Q7, as described in this article. Figures 8E-8G The subject of discussion.

[0117] Similarly, although Figures 8A-8H The illustration shows the use of a single switching method during charging and / or discharging modes, but it will be understood that the signal switching mode can be modified during charging and / or discharging modes (e.g., activating the signals of Q4 and / or Q7). For example, in some embodiments, controller 110 may be configured to switch according to a first switching method (e.g., similar to the method described above) within a first portion of the charging mode. Figure 8B The method described above provides a signal to switch Q4, and controller 110 can be configured to, within the second part of the charging mode, according to a second switching method (e.g., similar to the method described above). Figure 8CThe method described herein provides a signal to switch Q4. In some embodiments, controller 110 may be configured to provide a signal to switch Q2 to keep switch Q2 in a deactivated state during the first portion of the charging mode (as described herein). Figures 8A-8D (as discussed), and can be switched to provide a signal to switch Q2 to operate switch Q2 in a manner complementary to switch Q4 in the second part of the charging mode (as discussed in this paper). Figures 8E-8G (As discussed). Understandably, during discharge mode, switch Q7 can be controlled similarly.

[0118] Go back and refer to Figure 1 The controller 110 may be configured to provide activation signals (e.g., pulse width modulation signals) to the switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 described herein. In some embodiments, the controller 110 may be configured to provide activation signals substantially in accordance with... Figures 8A-8H The timing diagram shown is used to control the operation of the device.

[0119] In some embodiments, controller 110 may be configured to sample and / or analyze the output voltage and / or gain of the device to determine whether the gain is sufficient for the current load. In some embodiments, controller 110 may be configured to sample the gain required in a charging mode or a discharging mode (e.g., via a feedback loop). By analyzing the gain required by the device, the operating mode of the device can be shifted. In the following discussion, operation will be discussed with regard to operation during the charging mode, but it will be understood that a similar approach can also be used for the discharging mode. Furthermore, the charging mode and the discharging mode can be controlled independently of each other, such that the control decisions made by controller 110 regarding the charging mode may differ from the control decisions made by controller 110 regarding the discharging mode.

[0120] For example, in a first operating mode, the controller 110 can be configured to operate the device as a conventional full-bridge bidirectional CLLC converter. In a charging mode, the primary side can operate conventionally (e.g., as a full-bridge converter), and the secondary side can operate as a synchronous rectifier. In a discharging mode, similar operation can be utilized, where the secondary side acts as a full-bridge converter and the primary side acts as a synchronous rectifier.

[0121] Controller 110 can analyze the required output voltage and / or gain during device operation. If the required output voltage and / or gain is lower than that supported by full-bridge operation, controller 110 can be configured to switch operation to half-bridge operation on the primary side. For example, controller 110 can modify the control signal according to... Figures 8A-8H One embodiment controls the activation of switch Q4. For example, controller 110 can switch to about Figure 8AThe operation is illustrated in the diagram.

[0122] Controller 110 can continue to analyze the required output voltage and / or gain during device operation. If the required output voltage and / or gain is still lower than... Figure 8A If the operating mode is available, then the controller 110 can be configured to switch the converter's configuration to utilize, for example... Figure 8D The PWM signal shown activates switch Q4.

[0123] The controller can continue to analyze the required output voltage and / or gain during device operation. If the required output voltage and / or gain is still lower than... Figure 8D If the operating mode is available, then the controller 110 can be configured to switch the converter's configuration to utilize... Figure 8C The PWM signal shown activates switch Q4. Although... Figure 8D Compared to the operation method shown, Figure 8C The operating method shown allows for a higher switching frequency for switch Q4, but this is still acceptable. Due to the lower output voltage, the output power may be lower, which may reduce the current stress and power loss of switch Q4.

[0124] Although the foregoing discussion of the operation of controller 110 has focused on the transitions between operating modes of the invention, it should be understood that the invention is not limited thereto. For example, in some embodiments, controller 110 may operate in the manner discussed herein with respect to the controller operation of a bidirectional CLLC converter (e.g., Figures 8A-8H The switching between one of the operating modes and conventional operation. In some embodiments, this switching can be based on the desired gain of the device.

[0125] In some embodiments, controller 110 may be or may include one or more programmable general-purpose or special-purpose microprocessors, digital signal processors (DSPs), programmable controllers, application-specific integrated circuits (ASICs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), trusted platform modules (TPMs), or combinations of such or similar devices. In some embodiments, controller 110 may be implemented via circuitry including analog and / or digital circuitry elements.

[0126] As shown in this article, for example in Figures 1-7 In this circuit, both the primary stage 120 and the secondary stage 130 have resonant circuits as part of the circuit. The resonant circuits include capacitors and inductors coupled to transformer T1, and are also part of transformer T1. For example, in... Figure 1In the primary stage 120 and secondary stage 130, the resonant circuits respectively include an inductor and a capacitor connected in series on opposite sides of the windings of transformer T1. Although this is one embodiment of a resonant circuit, those skilled in the art will recognize that other embodiments of the resonant circuit can be utilized without departing from the scope of the invention. Figures 9A to 9F This is a circuit diagram of an additional configuration of the resonant circuit of a bidirectional CLLC converter according to some embodiments of the present invention.

[0127] For example, Figure 9A The diagram illustrates the relationship between... Figures 1-7 The inductor and capacitor are connected in series on opposite sides of the winding of transformer T1 in a similar manner as shown in the diagram. Figures 9B to 9D The diagram illustrates that the arrangement of capacitors and inductors can be reversed on one or both sides of transformer T1. Figure 9E and Figure 9F The diagram shows that a capacitor and an inductor can be connected in series on the same side of transformer T1.

[0128] Figures 9A-9F The embodiments shown are for illustrative purposes only and are not intended to limit the scope of the invention. For example, the arrangement of the resonant circuit in the primary stage 120 may differ from that in the secondary stage 130. Similarly, although a single capacitor and inductor are illustrated in series with transformer T1, it will be understood that any one element can actually be multiple elements (e.g., more than one capacitor and / or more than one inductor), and the individual elements can be arranged in various configurations relative to transformer T1. Other resonant circuit configurations can be utilized within the bidirectional CLLC converter described herein without departing from the scope of the invention.

[0129] This invention enables flexible control using controller 110 based on the device's operating conditions. For example, the gain range of the full-bridge bidirectional CLLC converter becomes wider in both charging and discharging modes. As a result, the transformer ratio and the design of the primary and secondary resonant circuits become simpler. Furthermore, switching turn-off losses can be reduced and / or minimized. Compared to two-stage solutions or relay-based solutions, the embodiments of the invention described herein can improve system efficiency and power density, and system costs can also be reduced. The embodiments described herein can be used in power conversion applications with wide input voltage ranges or wide output voltage ranges, such as, but not limited to, three-phase AC input EV OBCs. In three-phase AC input EV OBCs, full power ratings may be required in the three-phase input charging mode, but derating power may be acceptable in the V2L DC-AC discharging mode. Therefore, even in a half-bridge configuration, the requirements for power switches are not increased compared to full power ratings in a full-bridge configuration.

[0130] Understandably, when a component is referred to as "coupled" or "connected" to another component, it can be directly coupled or connected to the other component, or there may be intermediate components. Conversely, when a component is referred to as "directly coupled" or "directly connected" to another component, there are no intermediate components. Similar terms always refer to similar components.

[0131] For the sake of brevity and / or clarity, well-known features or structures may not be described in detail.

[0132] As used herein, the term "and / or" includes any and all combinations of one or more of the related listed items.

[0133] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that, when used in this specification, the terms “comprising” and / or “comprising of” specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0134] The terms “about,” “basically,” and “approximately” used in this article to refer to values ​​or figures mean that the value or figure can vary by as much as + / - 15% (15%).

[0135] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having meanings consistent with their meanings in the relevant technical context, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0136] It is understood that although the terms first, second, etc., may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. Rather, these terms are only used to distinguish one element, component, region, layer, and / or portion from another. Therefore, the first element, component, region, layer, or portion discussed herein may be referred to as the second element, component, region, layer, or portion without departing from the teachings of the invention. The order of operations (or steps) is not limited to the order presented in the claims or figures unless specifically indicated otherwise.

[0137] Those skilled in the art can make many changes and modifications without departing from the spirit and scope of the invention, taking into account the benefits of this disclosure. Therefore, it must be understood that the illustrated embodiments are merely illustrative and should not be construed as limiting the invention as defined in the appended claims. Thus, the appended claims should be understood to include not only combinations of the literally defined elements but also all equivalent elements that perform substantially the same function in substantially the same manner to obtain substantially the same results. Therefore, the claims should be understood to include the content of the foregoing specific illustrations and descriptions, conceptual equivalents, and content that embodies the basic idea of ​​the invention.

Claims

1. A bidirectional power converter, comprising: The first switching circuit is coupled to the second switching circuit via a transformer. The first switching circuit is configured to transfer power to the second switching circuit during the charging mode. The second switching circuit is configured to transfer power to the first switching circuit during the discharge mode. The first switching circuit is configured to operate in a half-bridge configuration during the first portion of the charging mode. In this circuit, the first switch and the second switch are configured to be active simultaneously during a portion of the first part of the charging mode. During the first portion of the charging mode, the first switch is configured to perform pulse width modulation at a first frequency having a first duty cycle, and the second switch is configured to perform pulse width modulation at a second frequency having a second duty cycle. Wherein, the first frequency and the second frequency are non-zero frequencies, and The first duty cycle is different from the second duty cycle.

2. The bidirectional power converter according to claim 1, wherein, The first switching circuit is further configured to operate as a full-bridge synchronous rectifier during the first portion of the discharge mode.

3. The bidirectional power converter according to claim 1 or claim 2, wherein, The second switching circuit is configured to operate as a full-bridge synchronous rectifier during the first portion of the charging mode.

4. The bidirectional power converter according to claim 1 or claim 2, wherein, The first switch is configured to transition from a deactivated state to an activated state during a first portion of the charging mode at substantially the same time that the second switch is configured to transition from a deactivated state to an activated state.

5. The bidirectional power converter according to claim 1 or claim 2, wherein, The first switch is configured to transition from the active state to the deactivated state during a first portion of the charging mode at substantially the same time that the second switch is configured to transition from the active state to the deactivated state.

6. The bidirectional power converter according to claim 1 or claim 2, in, The first frequency is substantially the same as the second frequency.

7. The bidirectional power converter according to claim 1 or claim 2, wherein, The first switch and the third switch of the first switching circuit are configured to be active simultaneously during another part of the first part of the charging mode.

8. The bidirectional power converter according to claim 2, wherein, The seventh and eighth switches of the second switching circuit are configured to be active simultaneously during a portion of the first part of the discharge mode.

9. The bidirectional power converter according to claim 8, wherein, The seventh switch is configured to transition from the deactivated state to the activated state at substantially the same time during the first part of the discharge mode, when the eighth switch is configured to transition from the deactivated state to the activated state.

10. The bidirectional power converter according to claim 8, wherein, The seventh switch is configured to transition from the active state to the deactivated state at substantially the same time during the first part of the discharge mode, when the eighth switch is configured to transition from the active state to the deactivated state.

11. The bidirectional power converter according to any one of claims 8-10, wherein, During the first portion of the discharge mode, the seventh switch performs pulse width modulation at a fourth frequency with a fourth duty cycle, and the eighth switch performs pulse width modulation at a fifth frequency with a fifth duty cycle. The fourth frequency is substantially the same as the fifth frequency, and The fourth duty cycle has a different duration than the fifth duty cycle.

12. The bidirectional power converter according to claim 8, wherein, The seventh and sixth switches of the second switching circuit are configured to be active simultaneously during another part of the first part of the discharge mode.

13. The bidirectional power converter according to claim 1, wherein, The third switch of the first switching circuit is configured to be turned on during the duration of the first part of the charging mode.

14. The bidirectional power converter according to claim 2, wherein, The fifth switch of the second switching circuit is configured to be turned on during the duration of the first part of the discharge mode.

15. The bidirectional power converter according to claim 1, wherein, The first switching circuit includes: The third switch has a first terminal coupled to a first terminal of the input port and a second terminal coupled to a first terminal of the first winding of the transformer; The fourth switch has a first terminal coupled to a first terminal of the input port and a second terminal coupled to a second terminal of the first winding of the transformer; The second switch has a first terminal coupled to a first terminal of the first winding of the transformer and a second terminal coupled to a second terminal of the input port; and The first switch has a first terminal coupled to a second terminal of a first winding of the transformer and a second terminal coupled to a second terminal of the input port.

16. The bidirectional power converter according to claim 15, wherein, The second switching circuit includes: The fifth switch has a first terminal coupled to a first terminal of the output port and a second terminal coupled to a first terminal of the second winding of the transformer; The sixth switch has a first terminal coupled to a first terminal of the output port and a second terminal coupled to a second terminal of the second winding of the transformer; A seventh switch having a first terminal coupled to a first terminal of the second winding of the transformer and a second terminal coupled to a second terminal of the output port; and The eighth switch has a first terminal coupled to the second terminal of the second winding of the transformer and a second terminal coupled to the second terminal of the output port.

17. A bidirectional power converter, comprising: The first switching circuit is coupled to the second switching circuit via a transformer. The first switching circuit is configured to transfer power to the second switching circuit during the charging mode. The second switching circuit is configured to transfer power to the first switching circuit during the discharge mode. Wherein, the first switch of the first switching circuit is configured to be turned on during most of the duration of the charging mode, and The first switch is configured to be operated so that it is active for a portion of the duration of the charging mode.

18. The bidirectional power converter according to claim 17, wherein, The first switch of the second switching circuit is configured to be turned on for most of the duration of the discharge mode.

19. The bidirectional power converter according to claim 17 or claim 18, wherein, The second switch of the first switching circuit is configured to be operated so that it is active during a portion of the duty cycle of the third switch of the first switching circuit.

20. The bidirectional power converter according to claim 17 or claim 18, wherein, The second switch of the first switching circuit is configured to be operated so that it is active during a portion of the duty cycle of the third and fourth switches of the first switching circuit.

21. The bidirectional power converter according to claim 17 or claim 18, wherein, The second switch of the second switching circuit is configured to be operated so that it is active during a portion of the duty cycle of the third switch of the second switching circuit.

22. The bidirectional power converter according to claim 17 or claim 18, wherein, The second switch of the second switching circuit is configured to be operated so that it is active during a portion of the duty cycle of the third and fourth switches of the second switching circuit.

23. The bidirectional power converter according to claim 17 or claim 18, wherein, The first switching circuit includes a first full-bridge switching circuit, and The second switching circuit includes a second full-bridge switching circuit.

24. A bidirectional power converter, comprising: The first switching circuit is coupled to the second switching circuit via a transformer. The first switching circuit includes a first switch, a second switch, a third switch, and a fourth switch, and is configured to transfer power to the second switching circuit during charging mode. The second switching circuit includes a fifth switch, a sixth switch, a seventh switch, and an eighth switch, and is configured to transfer power to the first switching circuit during a discharge mode. The third switch and the fourth switch are configured to be active simultaneously during a portion of the charging mode. The fourth switch and the third switch are configured to be controlled by their respective pulse width modulation (PWM) signals during the charging mode. Wherein, the first PWM signal of the fourth switch has a longer pulse width duration than the second PWM signal of the third switch, and The fourth switch is configured to transition from an active state to a deactivated state during the charging mode.

25. The bidirectional power converter according to claim 24, wherein, The first switching circuit is configured to operate as a full-bridge synchronous rectifier during a portion of the discharge mode.

26. The bidirectional power converter according to claim 24 or claim 25, wherein, The second switching circuit is configured to operate as a full-bridge synchronous rectifier during a portion of the charging mode.

27. The bidirectional power converter according to claim 24 or claim 25, wherein, The fourth switch is configured to switch from the deactivated state to the activated state at substantially the same time that the third switch is configured to switch from the deactivated state to the activated state.

28. The bidirectional power converter according to claim 24 or claim 25, wherein, The fourth switch is configured to transition from the active state to the deactivated state at substantially the same time that the third switch is configured to transition from the active state to the deactivated state.

29. The bidirectional power converter according to claim 24 or claim 25, wherein, The fourth switch performs pulse width modulation at a first frequency, and the third switch performs pulse width modulation at a second frequency. The first frequency is substantially the same as the second frequency.

30. The bidirectional power converter according to claim 24 or claim 25, wherein, The fourth switch and the first switch of the first switching circuit are configured to be active simultaneously during another part of the charging mode.

31. The bidirectional power converter according to claim 24 or claim 25, wherein, The seventh and eighth switches of the second switching circuit are configured to be active simultaneously during a portion of the discharge mode.

32. The bidirectional power converter according to claim 24 or claim 25, wherein, The seventh switch is configured to transition from the deactivated state to the activated state at substantially the same time that the eighth switch is configured to transition from the deactivated state to the activated state.

33. The bidirectional power converter according to claim 24 or claim 25, wherein, The seventh switch is configured to transition from the active state to the deactivated state at substantially the same time that the eighth switch is configured to transition from the active state to the deactivated state.

34. The bidirectional power converter according to claim 24 or claim 25, wherein, The seventh switch performs pulse width modulation at a fourth frequency with a fourth duty cycle, and the eighth switch performs pulse width modulation at a fifth frequency with a fifth duty cycle. The fourth frequency is substantially the same as the fifth frequency, and The fourth duty cycle has a different duration than the fifth duty cycle.

35. The bidirectional power converter according to claim 24 or claim 25, wherein, The seventh and sixth switches of the second switching circuit are configured to be active simultaneously during another part of the discharge mode.

36. The bidirectional power converter according to claim 24 or claim 25, wherein, The second switch of the first switching circuit is configured to be turned on during the duration of the charging mode.

37. The bidirectional power converter according to claim 24 or claim 25, wherein, The fifth switch of the second switching circuit is configured to be turned on during the duration of the discharge mode.

38. The bidirectional power converter according to claim 24 or claim 25, wherein, The second switch of the first switching circuit is configured to be controlled by a third PWM signal during the charging mode, such that the second switch is activated when the fourth switch is inactive.

39. The bidirectional power converter according to claim 24 or claim 25, wherein, The fifth switch of the second switching circuit is configured to be controlled by a fourth PWM signal during the discharge mode, such that the fifth switch is activated when the seventh switch is inactive.

40. A method of operating a bidirectional power converter, comprising: A first switching circuit with a full-bridge configuration is provided, the first switching circuit being coupled to a second switching circuit via a transformer; During the first part of the charging mode, the first switching circuit of the bidirectional power converter, which has a full-bridge configuration, is operated in a half-bridge configuration. as well as During the charging mode, power is transferred from the first switching circuit to the second switching circuit via the transformer. Operating the first switching circuit during the first portion of the charging mode includes: The first and second switches of the first switching circuit are operated so that they are simultaneously active during a portion of the first part of the charging mode; and The first switch is pulse-width modulated at a first frequency having a first duty cycle, and the second switch is pulse-width modulated at a second frequency having a second duty cycle. Wherein, the first frequency and the second frequency are non-zero frequencies, and The first duty cycle is different from the second duty cycle.

41. The method of claim 40, further comprising operating the second switching circuit to transfer power to the first switching circuit during a discharge mode of the bidirectional power converter.

42. The method of claim 41, further comprising operating the first switching circuit to operate in a full-bridge synchronous rectifier configuration during a first portion of the discharge mode.

43. The method according to any one of claims 40-42, further comprising operating the second switching circuit as a full-bridge synchronous rectifier during a first portion of the charging mode.

44. The method according to any one of claims 40-42, wherein, Operating the first switch circuit during the first portion of the charging mode further includes operating the first switch to switch from the deactivated state to the activated state at substantially the same time that the second switch switches from the deactivated state to the activated state during the first portion of the charging mode.

45. The method according to any one of claims 40-42, wherein operating the first switch circuit during the first portion of the charging mode further comprises operating the first switch to transition from the active state to the deactivated state during the first portion of the charging mode at substantially the same time that the second switch transitions from the active state to the deactivated state.

46. ​​The method according to any one of claims 40-42, wherein operating the first switching circuit during a first portion of the charging mode further comprises operating a first switch and a third switch of the first switching circuit to be active simultaneously during another portion of the first portion of the charging mode.

47. The method according to any one of claims 40-42, wherein, Operating the first switching circuit during the first portion of the charging mode further includes operating a third switch of the first switching circuit to be turned on during the duration of the first portion of the charging mode.

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