On-Board Charger (OBC) Single-Stage Converter

Abstract

The present application discloses an on-board charger (OBC) single-stage converter. An on-board charger for charging a battery, such as a traction battery of an electric vehicle, includes an AC / DC converter and a pulsation buffer (PB) converter. The AC / DC converter is configured to convert an AC input from a mains power supply into an output having a DC voltage and current ripple. The PB converter is connected to the AC / DC converter and is configured to process the output of the AC / DC converter to reduce or minimize its current ripple and transform the output of the AC / DC converter into a battery level DC output for charging the battery.

Description

Technical Field

[0001] The invention relates to an electrical architecture of an on-board charger and a corresponding control strategy. background

[0002] An on-board charger (OBC) of an electric vehicle is used to charge the traction battery of the vehicle. The OBC converts power absorbed from an AC power source into DC power and charges the battery with the DC power.

[0003] Overview

[0004] An on-board charger (OBC) for charging a battery, such as a traction battery of an electric vehicle, is provided. The OBC includes an AC / DC converter and a pulsation buffer (PB) converter. The AC / DC converter is configured to convert an AC input from a mains supply into an output having a DC voltage and a current ripple. The PB converter is connected to the AC / DC converter and is configured to process the output of the AC / DC converter to reduce or minimize its current ripple and transform the output of the AC / DC converter into a battery level DC output for charging the battery.

[0005] In an embodiment, the AC / DC converter includes a rectifier and a converter portion. The rectifier is configured to rectify an AC input from a mains power supply into a rectified AC input, and the converter portion is configured to convert the rectified AC input into an output of the AC / DC converter. In an embodiment, the converter portion includes a primary side power switch bridge on the primary side of the transformer and a secondary side power switch bridge on the secondary side of the transformer. The primary side power switch bridge has a first pair of power switches and a second pair of power switches, and the secondary side power switch bridge has a first pair of power switches and a second pair of power switches.

[0006] In an embodiment, the rectifier may be a full-bridge diode rectifier or a full-bridge active rectifier, such as a MOSFET rectifier.

[0007] In an embodiment, the OBC further comprises at least one additional AC / DC converter. Each additional AC / DC converter is configured to convert an AC input from a mains power supply into an additional output having a DC voltage and current ripple. The PB converter is individually connected to each additional AC / DC converter and is configured to process the output of each additional AC / DC converter to reduce or minimize its current ripple, and transform the output of each additional AC / DC converter into a battery level DC output for charging the battery.

[0008] In an embodiment, a PB converter includes a storage capacitor and an inductor and a pair of power switches.

[0009] In an embodiment, the AC / DC converter lacks a power factor corrector (PFC), and lacks a DC link capacitor between the AC / DC converter and the PB converter.

[0010] Another OBC for charging a battery (e.g., a traction battery of an electric vehicle) is provided. The OBC includes an electronic assembly including an AC / DC converter and a ripple buffer (PB) converter connected to the AC / DC converter. The OBC also includes a controller configured to control the AC / DC converter to convert an AC input from a mains power supply into an output having a DC voltage and current ripple, and to control the PB converter to process the output of the AC / DC converter to reduce or minimize its current ripple, and to transform the output of the AC / DC converter into a battery level DC output for charging the battery.

[0011] In an embodiment, an AC / DC converter includes a rectifier configured to rectify an AC input from a mains power supply into a rectified AC input, and the AC / DC converter also includes a dual active power switch bridge assembly having a primary side power switch bridge located on the primary side of a transformer and a secondary side power bridge located on the secondary side of the transformer. The primary side power switch bridge has two pairs of primary side power switches, and the secondary side power switch bridge has two pairs of secondary side power switches. The controller is also configured to alternately turn on and off the power switches of the primary side power switch bridge and the secondary side power switch bridge according to an AC / DC converter control strategy, so that the AC / DC converter converts the rectified AC input into the output of the AC / DC converter.

[0012] The controller may include a microcontroller and a comparator component. The microcontroller is configured to generate a positive reference signal and a negative reference signal based on the difference between the rectified AC input and the expected rectified AC input. The comparator component is configured to compare the output current generated by the primary side power switch bridge from the rectified AC input with the positive reference signal, turn on the first pair of primary side power switches and the first pair of secondary side power switches when the output current is equal to the positive reference signal, and turn off the second pair of primary side power switches and the second pair of secondary side power switches, and turn on the second pair of primary side power switches and the second pair of secondary side power switches when the output current is equal to the negative reference signal, so that the AC / DC converter generates the output of the AC / DC converter.

[0013] In an embodiment, the comparator component includes a first comparator that receives a positive reference signal and a sensed value of an output current and switches its output when the output current is equal to the positive reference signal; and the comparator component also includes a second comparator that receives a negative reference signal and a sensed value of the output current and switches its output when the output current is equal to the negative reference signal.

[0014] In an embodiment, the comparator component also includes a digital two-state change circuit (e.g., a digital flip-flop circuit) and a digital driver circuit, which work together with the outputs of the first comparator and the second comparator to keep the first pair of primary-side power switches and the first pair of secondary-side power switches turned on, and keep the second pair of primary-side power switches and the second pair of secondary-side power switches turned off until the output current is equal to a negative reference signal, and keep the first pair of primary-side power switches and the first pair of secondary-side power switches turned off, and keep the second pair of primary-side power switches and the second pair of secondary-side power switches turned on until the output current is equal to a positive reference signal, thereby causing the AC / DC converter to generate the output of the AC / DC converter.

[0015] In an embodiment, the PB converter includes a storage capacitor and an inductor and a pair of power switches. The controller is also configured to alternately turn on and off the power switch of the PB converter according to the PB converter control strategy, so that the PB converter processes the output of the AC / DC converter to reduce or minimize its current ripple, and converts the output of the AC / DC converter into a battery level DC output for charging the battery.

[0016] In an embodiment, the controller includes a microcontroller and a comparator component. The microcontroller is configured to generate a positive reference signal and a negative reference signal based on the difference between (i) the output current of the PB converter and (ii) the target output current. The comparator component is configured to compare the buffer current absorbed by the PB converter from the DC output with ripple with the positive reference signal, and when the PB converter buffer current is equal to the positive reference signal, turn on the first power switch of the PB converter and turn off the second power switch of the PB converter, and when the PB converter buffer current is equal to the negative reference signal, turn off the first power switch of the PB converter and turn on the second power switch of the PB converter, so that the PB converter processes the output of the AC / DC converter to reduce or minimize its current ripple, and convert the output of the AC / DC converter into a battery level DC output for charging the battery.

[0017] In an embodiment, the comparator component includes a first comparator that receives a positive reference signal and a sensed value of the PB converter buffer current and switches its output when the PB converter buffer current is equal to the positive reference signal; and the comparator component also includes a second comparator that receives a negative reference signal and a sensed value of the PB converter buffer current and switches its output when the PB converter buffer current is equal to the negative reference signal.

[0018] In an embodiment, the comparator component also includes a digital two-state change circuit and a digital driver circuit, which work together with the outputs of the first comparator and the second comparator to keep the first power switch of the PB converter turned on, and keep the second power switch of the PB converter turned off until the PB converter buffer current is equal to the negative reference signal, and keep the first power switch of the PB converter turned off, and keep the second power switch of the PB converter turned on until the PB converter buffer current is equal to the positive reference signal, so that the PB converter processes the output of the AC / DC converter to reduce or minimize its current ripple, and converts the output of the AC / DC converter into a battery level DC output for charging the battery.

[0019] In an embodiment, the OBC further comprises an additional AC / DC converter connected to the PB converter. The controller is further configured to control the additional AC / DC converter to convert the AC input from the mains power supply into an output having a DC voltage and current ripple, and control the PB converter to process the output of the additional AC / DC converter to reduce or minimize its current ripple, and transform the output of the additional AC / DC converter into a battery level DC output for charging the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A block diagram of an electrical system having an on-board charger (OBC) is shown;

[0021] Figure 2 A block diagram of an OBC is shown, wherein the OBC is a three-phase OBC;

[0022] Figure 3 An electrical schematic diagram of an OBC according to an embodiment is shown, wherein the OBC is a single-phase OBC;

[0023] Figure 4 shows an electrical schematic diagram of an OBC according to another embodiment, wherein the OBC is a three-phase OBC;

[0024] Figure 5 shows an electrical schematic diagram of an OBC according to another embodiment, wherein the OBC is a three-phase OBC;

[0025] Figure 6 An electrical schematic diagram of an OBC track is shown, wherein voltage / current waveform diagrams are respectively associated with a mains power supply of an electrical system, a primary side power switch bridge and a secondary side power switch bridge of an AC / DC converter of the OBC, a ripple buffer (PB) converter of the OBC, and a traction battery of the electrical system;

[0026] Fig. 7A The controller shows how to control the PB converter to extract and buffer the voltage (v b) is associated with the necessary amount of buffer current (i b ) and thereby generate details of the target battery voltage / current;

[0027] Figure 7B shows the buffer current (i b ) is an enlarged graph of

[0028] Figure 7C The schematic block diagram of the controller includes a first microcontroller and a first hysteresis comparator component, which are used to control the PB converter to extract the buffer voltage (v b ) is associated with the necessary amount of buffer current (i b ), and thereby generate a target battery voltage / current;

[0029] Fig. 8A The diagram shows how the controller controls the primary side power switch bridge of the AC / DC converter to generate the desired primary side output voltage / current (v op ) / (i op ) and how to control the secondary-side power switch bridge of an AC / DC converter from the desired primary-side output voltage / current (v op ) / (i op ) to generate the desired secondary side input voltage / current (v os ) / (i os ) details;

[0030] Figure 8B shows the primary side output current (i op ) is an enlarged graph of

[0031] Figure 8C A schematic block diagram of a controller is shown, which includes a second microcontroller and a second hysteresis comparator component, which are used to control the primary side power switch bridge together to generate a desired primary side output voltage / current (v op ) / (i op ), and in combination controls the secondary side power switch bridge to output the desired primary side voltage / current (v op ) / (i op ) to generate the desired secondary side input voltage / current (v os ) / (i os );as well as

[0032] Fig. 9 shows how the controller generates the target rectifier output current (i p,目标 ) details, the target rectifier output current (i p,目标) is used to control the primary side power switch bridge to generate the desired primary side output voltage / current (v op ) / (i op ), and in combination controls the secondary side power switch bridge to output the desired primary side voltage / current (v op ) / (i op ) to generate the desired secondary side input voltage / current (v os ) / (i os ). Detailed Description

[0033] Detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely examples of the present invention, which may be embodied in various forms and alternative forms. The drawings are not necessarily drawn to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, the specific structural and functional details disclosed herein should not be interpreted as limiting, but merely as a representative basis for teaching those skilled in the art to utilize the present invention in various ways.

[0034] Reference now Figure 1 , a block diagram of an electrical system 10 having an on-board charger (OBC) 12 is shown. The OBC 12 is "onboard" an electric vehicle. The term "electric vehicle" herein includes any type of vehicle that uses electric power for vehicle propulsion, and includes pure battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), etc. The OBC 12 is used to charge a traction battery 14 of the electric vehicle. The traction battery 14 is a high voltage (HV) DC traction battery in accordance with the electric energy requirements of the electric vehicle propulsion.

[0035] The electrical system 10 also includes an AC power source, such as a mains power source 16 of an electrical grid. The OBC 12 charges the traction battery 14 using power from the mains power source 16. The OBC 12 has an input terminal connected to the mains power source 16 through an external electric vehicle supply equipment (EVSE) 18 to absorb power from the mains power source. The OBC 12 has an output terminal connected to the traction battery 14. The OBC 12 converts the power absorbed from the mains power source 16 into DC power and charges the traction battery 14 with the DC power.

[0036] The controller 20 is associated with the OBC 12. The controller 20 is an electronic device loaded on the electric vehicle, such as a processor, a microcontroller, etc. (e.g., a computer) (e.g., the controller 20 is a vehicle controller). The controller 20 communicates with the OBC 12 to control the operation of the OBC. The controller 20 controls the OBC 12 to convert the power from the main power supply 16 into DC power and charge the traction battery 14 with the DC power. For example, the controller 20 appropriately controls the switching and switching duration of the power switch of the OBC 12 for converting the power from the main power supply 16 into a selected amount of DC power. The controller 20 is operable to communicate and control other nodes of the electrical system 10 and the electric vehicle including nodes involved in charging applications.

[0037] A common OBC has a dual stage architecture, including a power factor corrector (PFC) and a DC / DC converter. The PFC and the DC / DC converter are connected via a capacitive energy buffer, which is called a "DC link capacitor". The PFC can be connected to the mains power supply, and the DC / DC converter is connected to the traction battery. The PFC handles the AC / DC conversion and is controlled by a controller to ensure a high power factor at the input. The DC / DC converter is controlled by the controller to convert the high voltage stable input at the DC link capacitor to a DC battery level for the traction battery. In this regard, the DC / DC converter adapts the output voltage / current to the requirements of the traction battery. In summary, the PFC acts as a grid front end and the DC / DC converter adapts the output to the range of the traction battery.

[0038] The PFC includes one or more bulky and high-cost inductors. The energy conversion scheme of a conventional OBC essentially requires an energy storage element to store / provide the difference between the instantaneous input power, which is a sinusoidal curve that complies with EMC standards, and the output power, which is expected to be constant. Currently, due to the high power requirements, the energy storage element of choice is a configuration of electrolytic capacitors (i.e., DC link capacitors). The required high capacitance results in a large capacitor (i.e., DC link capacitor), which reduces the power density (e.g., about 30% by volume) and has a significant impact on the maximum operating temperature and estimated life (MTBF).

[0039] In addition, each rail of the OBC has one PFC and one DC / DC converter. Therefore, a three-phase ordinary OBC includes three groups of PFC and DC / DC converters. As described above, each group includes several energy storage elements. That is, each rail includes one or more inductors at the PFC stage and multiple electrolytic capacitors at the DC / DC converter stage, which leads to relatively poor power density and relatively poor MTBF as well as increased cost.

[0040] Now refer to Figure 2 , and continue to refer to Figure 1 , Figure 2 1 shows a block diagram of an OBC 12. The OBC 12 is an n-phase OBC, where n is an integer of at least 1. For example, Figure 2 As shown, the OBC 12 is a three-phase OBC having a first rail 22a, a second rail 22b, and a third rail 22c.

[0041] The rails 22a, 22b, 22c have the same type of circuitry in the form of a "modular converter", including AC / DC converters 24a, 24b, 24c, respectively. Each AC / DC converter 24a, 24b, 24c is a single-stage topology. Thus, unlike a conventional OBC having a two-stage architecture including a PFC, a DC link capacitor, and a DC / DC converter for each rail, the OBC 12 has a single-stage architecture including an AC / DC converter for each rail.

[0042] The OBC 12 also includes a ripple buffer (PB) converter 26. The PB converter 26 is shared by the AC / DC converters 24a, 24b, 24c. Figure 2 As shown, the AC / DC converters 24a, 24b, 24c are individually cascading-connected to the PB converter 26. The AC / DC converters 24a, 24b, 24c are connectable to the mains power supply 16 at their input terminals and to the input terminals of the PB 26 at their output terminals. The output terminals of the PB converter 26 are connected to the traction battery 14. The AC / DC converters 24a, 24b, 24c are used together with the PB converter 26 to convert the power from the mains power supply 16 into DC power for charging the traction battery 14. More specifically, the controller 20 controls the operation of the AC / DC converters 24a, 24b, 24c and the operation of the PB converter 26 according to the control strategy of the OBC 12 to convert the power from the mains power supply 16 into DC power for charging the traction battery 14.

[0043] The AC / DC converters 24a, 24b, 24c include the same type of circuits and function the same. Therefore, only the AC / DC converter 24a will be described in more detail. Generally speaking, the AC / DC converter 24a has a converter topology that ignores the use of a classic PFC and its associated inductor. The AC / DC converter 24a is combined with the use of a ripple buffer (PB) converter 26 that maximizes the use of a storage capacitor (in parallel with the traction battery 14), significantly reducing the track capacitor size requirements.

[0044] In operation, the AC / DC converter 24a converts the input AC from the mains power supply 16 directly into a DC voltage and a positive oscillating current (i.e., "current ripple"). As will be appreciated, the input AC from the mains power supply 16 is sinusoidal. The output of the AC / DC converter 24a is a DC voltage and current ripple. The PB converter 26 post-processes the DC voltage and current ripple output of the AC / DC converter 24a to preferably eliminate or substantially eliminate (or minimize or at least reduce) the current ripple, and converts the output of the AC / DC converter 24a into a battery level DC output.

[0045] Reference now Figure 3 , continue to refer to Figure 1 and Figure 2 , Figure 3 An electrical schematic diagram of the OBC 12 is shown, wherein the OBC is a single-phase OBC. Figure 3 The depiction of OBC 12 in FIG. 1 represents a single-phase direct OBC implementation (one-way). Figure 3 As shown, the OBC 12 includes an AC / DC converter 24 and a ripple buffer (PB) converter 26. The AC / DC converter 24 is connected to the mains power source 16. The PB converter 26 is connected to the traction battery 14.

[0046] like Figure 3As further shown, the AC / DC converter 24 includes a set of four diodes that form a full diode bridge rectifier 28 at the front end of the AC / DC converter. The rectifier 28 is connected to the mains power supply 16 to rectify the AC input of the AC / DC converter 24. The AC / DC converter 24 also includes a first set of four power switches that form a primary side power switch bridge 30 on the primary side of the transformer Tx. The AC / DC converter 24 also includes a second set of four power switches that form a secondary side power switch bridge 32 on the secondary side of the transformer Tx. In a modification, multiple secondary side power switch bridges 32 (each preferably having a separate secondary coil of Tx) can be provided on the secondary side of the transformer Tx. The secondary side power switch bridges 32 can be connected in series, each bridge including a set of four power switches. In this way, lower voltage or other lower specification (and possibly cheaper) components can be used for the power switch bridge 32 to provide an equivalent output voltage from the OBC 12. (This connection of multiple power switch bridges can also be used on each leg of a three-phase version of the OBC 12, which will be described below.)

[0047] The AC / DC converter 24 having a primary side power switch bridge 30 and a secondary side power switch bridge 32 on each side of the transformer Tx has a structure based on a dual active bridge (DAB) topology. The controller 20 controls the power switch bridges 30, 32 to convert the rectified voltage input from the rectifier 28 into a DC voltage and current ripple output. The DC voltage and current ripple output is output from the AC / DC converter 24 to the PB converter 26.

[0048] like Figure 3 As further shown, the PB converter 26 includes a pair of power switches 34, an inductor Lr, and a storage capacitor Cb. Therefore, the PB converter 26 has a current ripple processing based on a ripple snubber topology. The PB converter 26 receives the current ripple output from the AC / DC converter 24. The controller 20 controls the pair of power switches 34 to eliminate the current ripple and convert the output of the AC / DC converter 24 into a battery level DC output for charging the traction battery 14.

[0049] like Figure 3 As shown, the power switches of the primary side power switch bridge 30 and the secondary side power switch bridge 32 of the AC / DC converter 24 and the power switches of the power switch pair 34 of the PB converter 26 are all MOSFETs.

[0050] Compared to the conventional OBC as described above, the OBC 12 does not have a conventional PFC converter, thereby avoiding the need for a bulky and expensive inductor coil. In the OBC 12, there is only one magnetic component, namely the transformer Tx, in the rectifier and DC / DC blocks of the AC / DC converter 24. The PB converter 26 replaces the DC link capacitor compensation function of the conventional OBC. The PB converter 26 compensates for the current ripple output from the AC / DC converter 24 to the PB converter to provide a smooth DC output voltage, thereby significantly reducing the size of the energy storage capacitor Cb of the PB converter.

[0051] Reference now Figure 4 , continue to refer to Figure 1 , Figure 2 and Figure 3 , Figure 4 An electrical schematic diagram of the OBC 12 is shown according to an embodiment, wherein the OBC is a three-phase OBC. Figure 4 The depiction of OBC 12 in FIG. 1 represents a three-phase direct OBC implementation (one-way). Figure 4 As shown, the OBC 12 includes three rails 22a, 22b, 22c, each having an AC / DC converter 24a, 24b, 24c. The AC / DC converters 24a, 24b, 24c are connected in parallel with each other between the mains power supply 16 and the PB converter 26. In this regard, the input terminals of the AC / DC converters 24a, 24b, 24c are connected to the mains power supply 16, while the output terminals of the PB converter 26 are connected to the traction battery 14.

[0052] Each rail 22a, 22b, 22c absorbs power from the mains power supply 16 and converts the power into DC power for charging the traction battery 14. For example, each rail 22a, 22b, 22c can deliver 3.6kW of power for charging the traction battery 14. Thus, in this case, Figure 4 The three-phase OBC 12 shown in FIG. 1 can deliver 10.8 kW (3*3.6 kW) of power for charging the traction battery 14 .

[0053] As described and illustrated, the OBC 12 has a modular implementation that can implement Figure 3 The single-phase OBC implementation and the multi-phase OBC implementation shown, for example Figure 4The three-phase OBC implementation shown. In addition to the benefits of the single-phase OBC implementation mentioned previously, the multi-phase OBC implementation also has the benefit of sharing a single PB converter 26, thereby further realizing cost reduction. In addition, due to the multi-phase OBC implementation, the ripple on the output of the AC / DC converters 24a, 24b, 24c is reduced, thereby enabling the use of smaller inductor Lr and energy storage capacitor Cb components of the PB converter 26 (typically, for a 3-phase OBC implementation, a 3:1 size vs. power reduction).

[0054] As shown, Figure 3 and Figure 4 The OBC 12 shown in each is unidirectional in that the power flow is from the mains power supply 16 to the AC / DC converter 24 to the PB converter 26 to the traction battery 14. However, the OBC 12 can be bidirectional. For example, by using active switches (e.g., MOSFET switches (e.g., Figure 5 As shown)) replaces the diode of the rectifier 28 of the AC / DC converter 24 to make the rectifier bidirectional, Figure 3 and Figure 4 The OBC 12 shown in each of the above can be made bidirectional. Therefore, the topology of the OBC 12 can be implemented using synchronous rectifiers (bidirectional), thereby achieving bidirectional power flow: grid to vehicle (G2V) and vehicle to grid (V2G).

[0055] Reference now Figure 5 , continue to refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 , Figure 5 An electrical schematic diagram of the OBC 12 is shown according to another embodiment, wherein the OBC is a three-phase OBC. Figure 5 The depiction of OBC 12 in FIG. 1 represents a three-phase direct OBC implementation (bidirectional). Figure 5 As shown, the OBC 12 includes three rails 22a, 22b, 22c, each having an AC / DC converter 24a, 24b, 24c. The OBC 12 also includes a PB converter 26x. The PB converter 26x is cascade-connected to the AC / DC converters 24a, 24b, 24c. The AC / DC converters 24a, 24b, 24c are connected in parallel to each other, with their input terminals connected to the main power supply 16, and their output terminals connected to the traction battery 14 together with the PB converter 26x. In operation, all three AC / DC converters 24a, 24b, 24c provide energy to the PB converter 26x, and the PB converter 26x compensates the energy (i.e., compensates the energy output of the AC / DC converter) to provide DC power (i.e., constant voltage, constant current output) for charging the traction battery 14.

[0056] In addition to the benefits mentioned above, Figure 5 This three-phase OBC with cascaded PB converter implementation shown also has the benefit of sharing a single optimized PB converter 26x, thereby increasing the power density of the entire OBC (with some added cost penalty due to the additional semiconductors in the PB converter 26x). Further benefits include maximizing the use of the energy storage capacitor Cb of the PB converter 26x independent of the voltage of the traction battery 14, thereby achieving higher performance. The idea here is that the energy storage capacitor Cb of the PB converter 26x may have a maximum operating voltage that is higher than the required output voltage. Then, using Figure 5 With this topology shown, the storage capacitor Cb can operate at a higher voltage requiring less current (directly related to the losses in this stage).

[0057] Reference now Figure 6 , continue to refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 , Figure 6 An electrical schematic of the rails of the OBC 12 is shown with voltage / current waveform diagrams associated with the mains power source 16 , the primary side power switch bridge 30 and the secondary side power switch bridge 32 of the AC / DC converter 24 , the PB converter 26 , and the traction battery 14 , respectively.

[0058] In operation, the mains power supply 16 inputs a voltage / current to the OBC 12. The voltage / current waveform diagram 40 represents the voltage / current input from the mains power supply 16 to the OBC 12. The input voltage / current includes an input voltage (v ac ) and an input current (i ac ).

[0059] The rectifier 28 of the AC / DC converter 24 receives an input voltage / current from the mains power supply 16 and rectifies the input voltage / current into a rectified voltage / current. The voltage / current waveform diagram 42 represents the rectified voltage / current output from the rectifier 28. The rectified output voltage / current includes a rectified output voltage (v p ) and a rectified output current (i p ).

[0060] The primary side power switch bridge 30 of the AC / DC converter 24 on the DC / DC primary side of the transformer Tx receives the rectified output voltage / current from the rectifier 28. As will be described in more detail below, the controller 20 controls the operation of the primary side power switch bridge 30 to draw the necessary amount of rectified output current associated with the rectified output voltage from the rectifier 28, and thereby generate a primary side output voltage / current on the primary side of the transformer Tx. The voltage / current waveform diagram 44 represents the primary side output voltage / current. The primary side output voltage / current includes a primary side output voltage (v op ) and the primary side output current (i op ).

[0061] As will be further described below, in conjunction with controlling the operation of the primary side power switch bridge 30 to generate a primary side output voltage / current (v op ) / (i op ), the controller 20 accordingly controls the operation of the secondary-side power switch bridge 32 of the AC / DC converter 24 to switch the secondary side of the transformer Tx according to the primary-side voltage / current (v op ) / (i op ) generates a secondary side input voltage / current. The voltage / current waveform diagram 46 represents the secondary side input voltage / current. The secondary side input voltage / current includes a secondary side input voltage (v os ) and the secondary side input current (i os ).

[0062] exist Figure 6 In the embodiment of the OBC 12 shown, the OBC also includes a capacitor Cs connected in parallel between the secondary side power switch bridge 32 and the PB converter 26. The capacitor Cs is connected by the secondary side input voltage / current (v os ) / (i os ) is charged to thereby provide a secondary side output voltage / current. The voltage / current waveform diagram 48 represents the secondary side output voltage / current. The secondary side output voltage / current includes a positive DC source voltage (v s )48a and the rectified sinusoidal source current (i s )48b.

[0063] The PB converter 26 draws a buffer current associated with the buffer voltage from the capacitor Cs. As will be described in more detail below, the controller 20 controls the operation of a pair of power switches 34 of the PB converter 26 so that the PB converter draws a necessary amount of buffer current associated with the buffer voltage and thereby generates a target battery voltage / current. The target battery voltage / current is output from the PB converter 26 to charge the traction battery 14.

[0064] Voltage / current waveform diagram 50 shows the buffer current (i b ) and the associated buffer voltage (v b ). Buffer voltage (v b ) is the positive DC offset sinusoidal voltage 50a, the buffer current (i b ) has a sinusoidal peak current waveform 50b.

[0065] The voltage / current waveform 52 represents the battery voltage / current actually output from the PB converter 26 to charge the traction battery 14. The battery voltage / current output from the PB converter 26 includes a positive DC voltage (v 电池 )52a and positive DC current (i 电池 )52b.

[0066] Reference now Fig. 7A , Figure 7B and Figure 7C , continue to refer to Figure 6 , Fig. 7A , Figure 7B and Figure 7C The control strategy operation executed by the controller 20 for controlling the PB converter 26 to draw and buffer the voltage (v b ) is associated with the necessary amount of buffer current (i b ), and thereby generate the target battery voltage / current.

[0067] Fig. 7A Details 72 related to the operation of these control strategies are shown. As depicted therein, the controller 20 modulates the pair of power switches 34 of the PB converter 26 ("PB modulation") based on (i) the battery current (i 电池 ) and (ii) the target battery current expected to be output from the PB converter (i 电池,目标 ) The controller 20 controls the switch 34 of the PB converter 26 according to the PB modulation so that the PB converter draws the voltage (v b ) is associated with the necessary amount of buffer current (i b ), and thereby generates the target battery voltage / current. That is, this PB modulation of the power switch 34 of the PB converter 26 causes the PB converter to draw a current having a sinusoidal peak current waveform 50b and having a voltage with a buffer voltage (v b ) is associated with the necessary amount of buffer current (i b ), and thereby generate the target battery voltage / current.

[0068] Fig. 7AThe details 72 shown in FIG. 7 relate to how the controller 20 controls the PB converter 26 so that the PB converter draws the necessary amount of buffer current (i b The inputs for this determination are (i) the battery current output from the PB converter 26 (i 电池 ) and (ii) target battery current (i 电池，目标 The battery current (i ) output from the PB converter 26 is measured using a sensor. 电池 The output of this determination is the peak target buffer current (i b,峰值,目标 ). Peak target buffer current (i b,峰值,目标 ) defines a PB modulation, according to which the controller 20 controls the power switch 34 of the PB converter 26. In particular, as described below with reference to Figure 7B and Figure 7C As described, the peak target buffer current (i b,峰值,目标 ) represents a sinusoidal peak current waveform 50b, which in turn represents the necessary amount of buffer current (i b ). For reference, see below Figure 7C As further described, the peak target buffer current (i b,峰值,目标 ) is input to the high-speed (hardware) conversion stage of the controller 20 (ie, Figure 7C The first microcontroller 76 shown is used to control the PB converter 26 accordingly to draw the necessary amount of buffer current (i b ).

[0069] Figure 7B The buffer current (i b ) is an enlarged graph 74. As shown in the enlarged graph 74, the buffer current (i b ) consists of a triangular current waveform that oscillates at a frequency much higher than the frequency of the sinusoidal peak current waveform 50b. The triangular current waveform is generated by the controller 20 alternately turning on and off the power switch 34 of the PB converter 26 according to the PB modulation, for causing the PB converter to draw the necessary amount of buffer current (i b ), and generate the target battery voltage / current.

[0070] Figure 7C FIG. 2 shows a schematic block diagram of a first microcontroller 76 and a first hysteresis comparator component 78 of the controller 20. The first microcontroller 76 and the first comparator component 78 are used together to control the operation of the PB converter 26 so that the PB converter draws a necessary amount of buffer current (i ) having a sinusoidal peak current waveform 50 b from the AC / DC converter 24. b ), and thereby generate the target battery voltage / current.

[0071] In operation, the first microcontroller 76 generates a first reference signal ("Ref_H") 80 and a second reference signal ("Ref_L") 82. Figure 7B and Figure 7C It can be seen from the comparison that the first reference signal 80 corresponds to the positive half-cycle sinusoidal peak current waveform component of the sinusoidal peak current waveform 50b, and the second reference signal 82 corresponds to the negative half-cycle sinusoidal peak current waveform component of the sinusoidal peak current waveform 50b. Figure 7C As shown, the first microcontroller 76 generates a buffer current based on the peak target buffer current (i b,峰值,目标 )'s corresponding downstream adjustments generate each of the first reference signal 80 and the second reference signal 82.

[0072] The first comparator component 78 is used to generate a control (ie, trigger) signal to alternately turn on and off the power switch 34 of the PB converter 26. The first comparator component 78 generates a control signal based on the buffer current (i b ) is compared with each of the first reference signal 80 and the second reference signal 82 to generate a control signal. Figure 7B and Figure 7C , when the buffer current (i b ) is equal to the value of the first reference signal 80 (ie, when the buffer current (i b ) intersects the positive half-cycle sinusoidal peak current waveform component of the sinusoidal peak current waveform 50b), the first comparator component 78 generates a control signal to turn off one of the power switches 34 (for example, turn off the power switch (M H )), and turn on the other of the power switch pair 34 (eg, turn on the power switch (M L )). Similarly, further reference Figure 7B and Figure 7C , when the buffer current (i b ) is equal to the value of the second reference signal 82 (ie, when the buffer current (i b ) intersects the negative half-cycle sinusoidal peak current waveform component of the sinusoidal peak current waveform 50b), the first comparator component 78 generates a control signal to turn on one of the power switches 34 (i.e., turn on the power switch (M H )), and turn off the other of the power switch pair 34 (ie, turn off the power switch (M L )).

[0073] In detail, Figure 7C As shown, the first comparator component 78 includes a first analog comparator circuit 84 and a second analog comparator circuit 86, a digital trigger circuit 88, and a digital driver circuit 90. The first comparator circuit 84 receives a first reference signal ("Ref_H") 80 and a buffer current (ib ) as input. The second comparator circuit 86 receives the second reference signal ("Ref_L") 82 and the buffer current (i b ) as input. The first comparator circuit 84 buffers the current (i b ) is equal to the value of the first reference signal 80 (ie, when the buffer current (i b ) is a value that constitutes the outer amplitude envelope of the first reference signal 80. The second comparator circuit 86 switches its output when the buffer current (i b ) is equal to the value of the second reference signal 82 (ie, when the buffer current (i b ) is the value of the outer amplitude envelope constituting the second reference signal 82) switches its output.

[0074] The trigger circuit 88 and the driver circuit 90 are accordingly used to cause a pulse width modulation (PWM) control signal to be provided to the power switch 34 of the PB converter 26. The PWM control signal specifies that when the buffer current (i b ) is equal to the second reference signal 82, the first of the power switches is turned off, the second of the power switches is turned on, and the first power switch remains turned off and the second power switch remains turned on until the buffer current (i b ) is equal to the first reference signal 80. Similarly, the PWM control signal stipulates that when the buffer current (i b ) is equal to the first reference signal 80, the first power switch is turned on and the second power switch is turned off, and the first power switch remains turned on and the second power switch remains turned off until the buffer current (i b ) is equal to the second reference signal 82.

[0075] The first microcontroller 76 is relatively low cost because it generates a digital external slow loop (i.e., the first reference signal 80 and the second reference signal 82). The first comparator component 78 is a low cost analog fast current control loop. In summary, the first microcontroller 76 is based on (i) the battery current (i 电池 ) and (ii) target battery current (i 电池，目标 ) generates reference signals 80 and 82; and the first comparator component 78 (ie, hardware) is based on the buffer current (i drawn by the PB converter 26 b ) and the reference signals 80, 82 to control the switching of the power switch of the PB converter 26. In this way, the first microcontroller 76 allocates a high-level software control loop that generates a waveform input to the hardware circuit (ie, the first comparator component 78).

[0076] Unlike conventional methods, the first microcontroller 76 does not directly measure, perform control actions, and / or generate control signals. The first microcontroller 76 thus avoids high resource utilization and timing constraints. That is, the first microcontroller 76 does not calculate the buffer current (i b ) will encounter a vertex of the first reference signal 80 or the second reference signal 82. Therefore, the first microcontroller 76 does not generate a control signal for controlling the power switch. Figure 7B As shown, since the apex occurs relatively quickly, such control signals require relatively fast processing. Instead of generating such control signals, the first microcontroller 76 generates a first reference signal 80 and a second reference signal 82. The generation of the reference signals 80, 82 employs millisecond processing. Accordingly, the first microcontroller 76 operates at a relatively low speed (e.g., milliseconds) rather than a relatively high speed (e.g., nanoseconds).

[0077] Reference now Fig. 8A , Figure 8B and Figure 8C , continue to refer to Figure 6 , Fig. 8A , Figure 8B and Figure 8C The control strategy operation performed by the controller 20 for controlling the primary side power switch bridge 30 to generate the desired primary side output voltage / current (v op ) / (i op ), and in combination controls the secondary side power switch bridge 32 to output the desired primary side voltage / current (v op ) / (i op ) to generate the desired secondary side input voltage / current (v os ) / (i os ).

[0078] Fig. 8A Details 92 related to the operation of these control strategies are shown. As depicted therein, the modulation (“DC-DC modulation”) of the power switches of the power switch bridges 30, 32 by the controller 20 is based on (i) the rectified output current (i) drawn by the primary side power switch bridge 30 p ) and (ii) to be drawn by the primary side power switch bridge to generate the desired primary side output current (i op ) of the target rectified output current (i p,目标 ) between the rectified output voltage (v p ) is associated with the rectified output current (i p ) to generate the desired primary-side output voltage / current (v op ) / (i opIn combination, the controller 20 controls the power switches of the secondary-side power switch bridge 32 according to the DC-DC modulation so that the secondary-side power switch bridge outputs the desired primary-side output voltage / current (v op ) / (i op ) to generate the desired secondary side input voltage / current (v os ) / (i os ).

[0079] Fig. 8A The details 92 shown in FIG. 9 relate to how the controller 20 controls the primary side power switch bridge 30 to generate the desired primary side output current (i op The inputs for this determination are (i) the rectified input current drawn by the primary side power switch bridge 30 (i p ) and (ii) the desired primary side output current (i op ) of the target rectifier output current (i p,目标 A sensor is used to measure the rectified input current (i p ). The controller 20 generates a target rectifier output current (i p,目标 ), which will refer to Fig. 9 The output of this determination is the peak target primary-side output current (i op,峰值,目标 ). Peak target primary side output current (i op,峰值,目标 ) defines a DC-DC modulation, according to which the controller 20 controls the power switches of the power switch bridges 30 and 32, so that in the power switch bridges 30 and 32, the primary side output current (i op ) and the secondary side input current (i os ) are equal (i.e., i op =i os ).

[0080] In particular, as shown below Figure 8B and Figure 8C As described, the peak target primary-side output current (i op,峰值,目标 ) represents the expected primary side output current (i op ) is a mirror image of the sinusoidal peak current waveform 44b. Figure 8C As described, the peak target primary-side output current (i op,峰值,目标 ) is input to the high-speed (hardware) conversion stage of the controller 20 (ie, Figure 8C The second microcontroller 94 is used to control the power switch bridges 30 and 32 accordingly to generate the desired primary side output current (i op ) and the secondary side input current (i os ), where i op =ios .

[0081] Figure 8B The primary side output current (i op ) is an enlarged graph 91. As shown in the enlarged graph 91, the primary side output current (i op ) consists of a triangular current waveform that oscillates at a much higher frequency than the mirrored sinusoidal peak current waveform 44b. Since the controller 20 alternately turns on and off each pair of power switches of the primary side power switch bridge 30 according to the DC-DC modulation, the primary side power switch bridge is changed from being in phase with the rectified output voltage (v p ) is associated with the rectified output current (i p ) to generate the desired primary-side output voltage / current (v op ) / (i op ), so a triangular current waveform is generated.

[0082] The controller 20 alternately turns on and off the power switch pairs of the primary-side power switch bridge 30 while alternately turning on and off the corresponding power switch pairs of the secondary-side power switch bridge 32, so as to make the secondary-side power switch bridge output a desired primary-side output voltage / current (v op ) / (i op ) to generate the desired secondary side input voltage / current (v os ) / (i os For example, the controller 20 turns on a pair of primary-side power switches (eg, turns on the power switch (M p,H1 ) and (M p,L2 )) and simultaneously turn on the corresponding pair of secondary-side power switches (i.e., turn on the power switch (M s,L1 ) and (M s,H2 )), while turning off the other pair of primary-side power switches (for example, turning off the power switch (M p,L1 ) and (M p,H2 )) and simultaneously turn off the corresponding pair of secondary-side power switches (i.e., turn off the power switch (M s,H1 ) and (M s,L2 )). This is because the AC / DC converter 26 has a dual active bridge (DAB) topology. In this way, the secondary side power switch bridge 32 outputs a voltage / current (v op ) / (i op ) generates secondary side voltage / current (v os ) / (i os ).

[0083] Figure 8CFIG. 2 shows a schematic block diagram of a second microcontroller 94 and a second hysteresis comparator component 95 of the controller 20. The second microcontroller 94 and the second comparator component 95 together control the operation of the primary side power switch bridge 30 to generate a desired primary side output voltage / current (V op ) / (i op ), and in combination with the operation of the secondary side power switch bridge 32, according to the desired primary side output voltage / current (v op ) / (i op ) to generate the desired secondary side input voltage / current (v os ) / (i os ).

[0084] In operation, the second microcontroller 94 generates a third reference signal ("Ref_H") 96 and a fourth reference signal ("Ref_L") 98. Figure 8B and Figure 8C As can be seen from the comparison, the third reference signal 96 corresponds to the positive cycle of the mirrored sinusoidal peak current waveform 44b, and the fourth reference signal 98 corresponds to the negative cycle of the mirrored sinusoidal peak current waveform 44b. Figure 8C As shown, the second microcontroller 94 generates a current based on the peak target primary side output current (i op,峰值,目标 )'s corresponding downstream adjustments generate each of the third reference signal 96 and the fourth reference signal 98.

[0085] The second comparator component 95 is used to generate a control (ie, trigger) signal for alternately turning on and off the corresponding power switch pairs of the primary-side power switch bridge 30 and the secondary-side power switch bridge 32. The second comparator component 95 is based on the primary-side output current (i op ) is compared with each of the third reference signal 96 and the fourth reference signal 98 to generate a control signal. Figure 8B and Figure 8C , when the primary side output current (i op ) is equal to the value of the third reference signal 96 (ie, when the primary side output current (i op ) intersects the positive cycle of the mirrored sinusoidal peak current waveform 44b), the second comparator component 95 generates a control signal to turn off a pair of primary side power switches (eg, turn off the power switch (M p,H1 ) and (M p,L2 )) and turn on another pair of primary-side power switches (eg, turn on power switch (M p,L1 ) and (M p,H2 )). Similarly, further reference Figure 8B and Figure 8C , when the primary side output current (i op ) is equal to the value of the fourth reference signal 98 (ie, when the primary side current (i op) intersects the negative cycle of the mirrored sinusoidal peak current waveform 44b), the second comparator component 95 generates a control signal to turn on a pair of primary side power switches (i.e., turn on the power switch (M p,H1 ) and (M p,L2 )) and turn off the other pair of primary-side power switches (ie, turn off the power switches (M p,L1 ) and (M p,H2 )).

[0086] Just like the first comparator assembly 78, the second comparator assembly 95 includes the same type of arrangement of first and second analog comparator circuits, digital trigger circuits, and digital driver circuits, such as Figure 8C The operation of the second microcontroller 94 and the second comparator assembly 95 is similar to the operation of the first microcontroller 76 and the first comparator assembly 78 described above.

[0087] The first microcontroller 76 and the second microcontroller 94 may be implemented as separate microcontrollers as described or as a single microcontroller. The first microcontroller 76 and the second microcontroller 94 may be part of the controller 20 as described, or may be part of other controllers.

[0088] Reference now Fig. 9 , continue to refer to Figure 6 and Figure 8C , Fig. 9 shows how the controller 20 generates the target rectifier output current (i p,目标 ) related details 100. The input to this determination is (i) the buffer voltage (v b ) and (ii) the peak target buffer voltage (v b,峰值,目标 The buffer voltage (v b ), for example, measured periodically every 10 milliseconds (100 Hz). The output of this determination is the peak target rectifier output current (i b,峰值,目标 ). The controller 20 uses the peak target rectifier output current (i b,峰值,目标 ) as input to generate the target rectifier output current (i p,目标 ). In particular, the target rectifier output current (i p,目标 )According to (i p,目标 )=PI_Function(v b,峰值,目标 ,v b ) to generate. In addition, the target rectifier output current (i p,目标 ) According to the i from the system 电池,目标 consigned and saturated (restricted), the i 电池,目标 According to the charging power requirement (i电池,目标 ,v 电池,感测 ) determines the maximum input current. Again, this is a low speed calculation performed in the microcontroller of the controller 20.

[0089] In summary, for each phase of OBC 12:

[0090] -From vehicle system: v 电池,目标 ,i 电池,目标 ;

[0091] -If v 电池,感测 >v 电池,目标 , then i 电池,目标 =0;

[0092] -i b,峰值,目标 =PI_Function(i 电池,目标 ,i 电池 );

[0093] -v b,峰值,目标 is a constant value determined by design (the capacitor C of the PB buffer 26 b The maximum voltage that can be tolerated);

[0094] -v 电池 (=v s ) and v b Being measured;

[0095] –v p is the rectified v ac (Standard Process);

[0096] -When M H When in the on state: i s =i 电池 +i b ;and

[0097] -when i op =i os , M p,H1 、M pH2 、M pL1 、M pL2 、M sH1 、M sH2 、M sL1 and M sL2 Controlled by the same high-speed signal (consider switching alternation and dead times to avoid “H” and “L” being on at the same time).

[0098] For the three-phase interleaved OBC 12, the battery current is divided into three phases:

[0099] -i 电池＝ i 电池_1 +i电池_2 +i 电池_3 (3-phase interleaved OBC); and

[0100] -i 电池_n =pi / (2*sqrt(2))*(i rms_n *v ac_rms_n ) / v 电池 )n=1..3(active phase).

[0101] Although exemplary embodiments have been described above, it is not intended that these embodiments describe all possible forms of the present invention. On the contrary, the words used in the specification are descriptive rather than restrictive, and it is understood that various changes may be made without departing from the spirit and scope of the present invention. In addition, the features of various implementation embodiments may be combined to form other embodiments of the present invention.

[0102] Aspects of the present disclosure may be implemented in one or more of the following embodiments.

[0103] 1) A vehicle charger for charging a battery, comprising:

[0104] an AC / DC converter configured to convert an AC input from a mains power supply to an output having a DC voltage and current ripple; and

[0105] A ripple-buffered PB converter is connected to the AC / DC converter and is configured to process the output of the AC / DC converter to minimize its current ripple and convert the output of the AC / DC converter into a battery-level DC output for charging the battery.

[0106] 2) The vehicle charger according to 1), wherein:

[0107] The AC / DC converter includes a rectifier configured to rectify an AC input from the mains power supply into a rectified AC input and a converter portion configured to convert the rectified AC input into an output of the AC / DC converter.

[0108] 3) The vehicle charger according to 2), wherein:

[0109] The converter portion includes a primary side power switch bridge on the primary side of the transformer and a secondary side power switch bridge on the secondary side of the transformer, wherein the primary side power switch bridge has a first pair of power switches and a second pair of power switches, and the secondary side power switch bridge has a first pair of power switches and a second pair of power switches.

[0110] 4) The vehicle charger according to 2), wherein:

[0111] The rectifier is a full-bridge diode rectifier, or a full-bridge active rectifier.

[0112] 5) The vehicle charger according to 1), further comprising:

[0113] at least one additional AC / DC converter, each additional AC / DC converter configured to convert an AC input from the mains power supply to an additional output having a DC voltage and current ripple; and

[0114] The PB converter is individually connected to each additional AC / DC converter and is configured to process the additional output of each additional AC / DC converter to reduce or minimize current ripple from each additional AC / DC converter, and convert the additional output of each additional AC / DC converter into a battery level DC output for charging the battery.

[0115] 6) The vehicle charger according to 1), wherein:

[0116] The PB converter includes a storage capacitor and an inductor and a pair of power switches.

[0117] 7) The vehicle charger according to 1), wherein:

[0118] The AC / DC converter lacks a power factor corrector.

[0119] 8) The vehicle charger according to 1), wherein:

[0120] A DC link capacitor is missing between the AC / DC converter and the PB converter.

[0121] 9) A vehicle charger for charging a battery, comprising:

[0122] an electronic assembly including an AC / DC converter and a PB converter connected to the AC / DC converter; and

[0123] a controller configured to control the AC / DC converter to convert an AC input from a mains power supply into an output having a DC voltage and current ripple, and to control the PB converter to process the output of the AC / DC converter to reduce or minimize its current ripple, and to transform the output of the AC / DC converter into a battery level DC output for charging the battery.

[0124] 10) The vehicle charger according to 9), wherein:

[0125] The AC / DC converter includes a rectifier configured to rectify an AC input from the mains power supply into a rectified AC input, and the AC / DC converter further includes a dual active power switch bridge assembly having a primary side power switch bridge located on a primary side of a transformer and a secondary side power switch bridge located on a secondary side of the transformer, the primary side power switch bridge having two pairs of primary side power switches, and the secondary side power switch bridge having two pairs of secondary side power switches; and

[0126] The controller is further configured to alternately turn on and off the power switches of the primary side power switch bridge and the secondary side power switch bridge according to an AC / DC converter control strategy so that the AC / DC converter converts the rectified AC input into the output of the AC / DC converter.

[0127] 11) The vehicle charger according to 10), wherein:

[0128] The PB converter includes a storage capacitor and an inductor and a pair of power switches; and

[0129] The controller is further configured to alternately turn on and off the power switch of the PB converter according to a PB converter control strategy, so that the PB converter processes the output of the AC / DC converter to reduce or minimize its current ripple, and converts the output of the AC / DC converter into a battery-level DC output for charging the battery.

[0130] 12) The vehicle charger according to 10), wherein:

[0131] The controller includes a microcontroller and a comparator component, wherein the microcontroller is configured to generate a positive reference signal and a negative reference signal based on a difference between the rectified AC input and a desired rectified AC input, and the comparator component is configured to compare an output current generated by the primary side power switch bridge from the rectified AC input with the positive reference signal, turn on a first pair of primary side power switches and a first pair of secondary side power switches when the output current is equal to the positive reference signal, and turn off a second pair of primary side power switches and a second pair of secondary side power switches, and turn on the second pair of primary side power switches and the second pair of secondary side power switches when the output current is equal to the negative reference signal, thereby causing the AC / DC converter to generate the output of the AC / DC converter.

[0132] 13) The vehicle charger according to 12), wherein:

[0133] The comparator component includes a first comparator that receives the positive reference signal and a sensed value of the output current and switches its output when the output current is equal to the positive reference signal; and

[0134] The comparator assembly also includes a second comparator that receives the negative reference signal and the sensed value of the output current and switches its output when the output current is equal to the negative reference signal.

[0135] 14) The vehicle charger according to 13), wherein:

[0136] The comparator component also includes a digital two-state change circuit and a digital driver circuit, which work together with the outputs of the first comparator and the second comparator to keep the first pair of primary side power switches and the first pair of secondary side power switches turned on, and keep the second pair of primary side power switches and the second pair of secondary side power switches turned off until the output current is equal to the negative reference signal, and keep the first pair of primary side power switches and the first pair of secondary side power switches turned off, and keep the second pair of primary side power switches and the second pair of secondary side power switches turned on until the output current is equal to the positive reference signal, thereby causing the AC / DC converter to generate the output of the AC / DC converter.

[0137] 15) The vehicle charger according to 9), wherein:

[0138] The PB converter includes a storage capacitor and an inductor and a pair of power switches; and

[0139] The controller is further configured to alternately turn on and off the power switch of the PB converter according to a PB converter control strategy, so that the PB converter processes the output of the AC / DC converter to reduce or minimize its current ripple, and converts the output of the AC / DC converter into a battery-level DC output for charging the battery.

[0140] 16) The vehicle charger according to 15), wherein:

[0141] The controller includes a microcontroller and a comparator component, wherein the microcontroller is configured to generate a positive reference signal and a negative reference signal based on (i) a difference between an output current of the PB converter and (ii) a target output current, and the comparator component is configured to compare a buffer current absorbed by the PB converter from a DC output with a ripple with the positive reference signal, and when the PB converter buffer current is equal to the positive reference signal, turn on a first power switch of the PB converter and turn off a second power switch of the PB converter, and when the PB converter buffer current is equal to the negative reference signal, turn off the first power switch of the PB converter and turn on the second power switch of the PB converter, so that the PB converter processes the output of the AC / DC converter to reduce or minimize its current ripple, and converts the output of the AC / DC converter into a battery-level DC output for charging the battery.

[0142] 17) The vehicle charger according to 16), wherein:

[0143] The comparator component includes a first comparator that receives the positive reference signal and a sensed value of the PB converter buffer current and switches its output when the PB converter buffer current is equal to the positive reference signal; and

[0144] The comparator assembly also includes a second comparator that receives the negative reference signal and a sensed value of the PB converter buffer current and switches its output when the PB converter buffer current is equal to the negative reference signal.

[0145] 18) The vehicle charger according to 17), wherein:

[0146] The comparator component also includes a digital two-state change circuit and a digital driver circuit, which work together with the outputs of the first comparator and the second comparator to keep the first power switch of the PB converter turned on, and keep the second power switch of the PB converter turned off until the PB converter buffer current is equal to the negative reference signal, and keep the first power switch of the PB converter turned off, and keep the second power switch of the PB converter turned on until the PB converter buffer current is equal to the positive reference signal, so that the PB converter processes the output of the AC / DC converter to reduce or minimize its current ripple, and converts the output of the AC / DC converter into a battery level DC output for charging the battery.

[0147] 19) The vehicle charger according to 9), wherein:

[0148] The AC / DC converter lacks a power factor corrector; and

[0149] A DC link capacitor is missing between the AC / DC converter and the PB converter.

[0150] 20) The vehicle charger according to 9) further comprises:

[0151] an additional AC / DC converter connected to the PB converter; and

[0152] The controller is also configured to control the additional AC / DC converters to convert the AC input from the mains power supply into additional outputs having DC voltage and current ripple, and to control the PB converters to process the additional outputs of each additional AC / DC converter to reduce or minimize its current ripple, and to transform the additional outputs of each additional AC / DC converter into battery level DC outputs for charging the battery.

Claims

1. A vehicle charger for charging a battery, comprising: an AC / DC converter configured to convert an AC input from a mains power supply to an output having a DC voltage and current ripple; a ripple-suppressing PB converter connected to the AC / DC converter, and a controller configured to control the AC / DC converter to convert an AC input from a mains power supply into an output having a DC voltage and current ripple, and to control the PB converter to process the output of the AC / DC converter to reduce or minimize its current ripple, and to transform the output of the AC / DC converter into a battery level DC output for charging the battery; The PB converter comprises an energy storage capacitor, an inductor, a first power switch and a second power switch, wherein the first power switch and the second power switch are connected in series between the positive electrode and the negative electrode of the battery, and the series branch of the energy storage capacitor and the inductor is connected in parallel between the series node of the first power switch and the second power switch and the negative electrode of the battery; The controller is further configured to alternately turn on and off the first power switch and the second power switch of the PB converter according to a PB converter control strategy, so that the PB converter processes the output of the AC / DC converter to reduce or minimize its current ripple based on a ripple snubber topology, and converts the output of the AC / DC converter into a battery level DC output for charging the battery; The controller includes a microcontroller and a comparator component, wherein the microcontroller is configured to generate a positive reference signal and a negative reference signal based on (i) a difference between an output current of the PB converter and (ii) a target output current, and the comparator component is configured to compare a buffer current absorbed by the PB converter from a DC output with a ripple with the positive reference signal, and when the PB converter buffer current is equal to the positive reference signal, turn on the first power switch of the PB converter and turn off the second power switch of the PB converter, and when the PB converter buffer current is equal to the negative reference signal, turn off the first power switch of the PB converter and turn on the second power switch of the PB converter, so that the PB converter processes the output of the AC / DC converter to reduce or minimize its current ripple based on the pulsating buffer topology, and convert the output of the AC / DC converter into a battery-level DC output for charging the battery.

2. The vehicle charger according to claim 1, wherein: The AC / DC converter includes a rectifier configured to rectify an AC input from the mains power supply into a rectified AC input and a converter portion configured to convert the rectified AC input into an output of the AC / DC converter.

3. The vehicle charger according to claim 2, wherein: The converter portion includes a primary side power switch bridge on the primary side of the transformer and a secondary side power switch bridge on the secondary side of the transformer, the primary side power switch bridge having a first pair of power switches and a second pair of power switches, and the secondary side power switch bridge having a first pair of power switches and a second pair of power switches.

4. The vehicle charger according to claim 2, wherein: The rectifier is a full-bridge diode rectifier, or a full-bridge active rectifier.

5. The vehicle charger according to claim 1, further comprising: at least one additional AC / DC converter, each additional AC / DC converter configured to convert an AC input from the mains power supply to an additional output having a DC voltage and current ripple; and The PB converter is individually connected to each additional AC / DC converter and is configured to process the additional output of each additional AC / DC converter to reduce or minimize current ripple from each additional AC / DC converter, and convert the additional output of each additional AC / DC converter into a battery level DC output for charging the battery.

6. The vehicle charger according to claim 1, wherein: The comparator component includes a first comparator that receives the positive reference signal and a sensed value of the PB converter buffer current and switches its output when the PB converter buffer current is equal to the positive reference signal; and The comparator assembly also includes a second comparator that receives the negative reference signal and a sensed value of the PB converter buffer current and switches its output when the PB converter buffer current is equal to the negative reference signal.

7. The vehicle charger according to claim 6, wherein: The comparator component also includes a digital two-state change circuit and a digital driver circuit, which work together with the outputs of the first comparator and the second comparator to keep the first power switch of the PB converter turned on, and keep the second power switch of the PB converter turned off until the PB converter buffer current is equal to the negative reference signal, and keep the first power switch of the PB converter turned off, and keep the second power switch of the PB converter turned on until the PB converter buffer current is equal to the positive reference signal, so that the PB converter processes the output of the AC / DC converter to reduce or minimize its current ripple, and converts the output of the AC / DC converter into a battery level DC output for charging the battery.

8. The vehicle charger according to claim 1, wherein: The AC / DC converter lacks a power factor corrector.

9. The vehicle charger according to claim 1, wherein: A DC link capacitor is missing between the AC / DC converter and the PB converter.

10. A vehicle charger for charging a battery, comprising: an electronic assembly comprising an AC / DC converter and a PB converter connected to the AC / DC converter; as well as a controller configured to control the AC / DC converter to convert an AC input from a mains power supply into an output having a DC voltage and current ripple, and to control the PB converter to process the output of the AC / DC converter to reduce or minimize its current ripple, and to transform the output of the AC / DC converter into a battery level DC output for charging the battery; wherein: The AC / DC converter includes a rectifier configured to rectify an AC input from the mains power supply into a rectified AC input, and the AC / DC converter also includes a dual active power switch bridge assembly having a primary side power switch bridge located on the primary side of a transformer and a secondary side power switch bridge located on the secondary side of the transformer, the primary side power switch bridge having a first pair of primary side power switches M p,L1 ,M p,H2 and the second pair of primary side power switches M p,H1 ,M p,L2 , wherein the first pair of primary side power switches M p,L1 ,M p,H2 The primary side power switch bridge comprises a first power switch M arranged on an isolated arm. p,L1 and the second power switch M p,H2 , wherein the second pair of primary side power switches M p,H1 ,M p,L2 A third power switch M is arranged on the separated arms of the primary side power switch bridge. p,H1 and the fourth power switch M p,L2 , and the secondary side power switch bridge has a first pair of secondary side power switches M s,L1 ,M s,H2 and the second pair of secondary side power switches M s,H1 ,M s,L2 , wherein the first pair of secondary side power switches M s,L1 ,M s,H2 The secondary side power switch bridge comprises a first power switch M arranged on an alternate arm of the secondary side power switch bridge. s,L1 and the second power switch M s,H2 , wherein the second pair of secondary side power switches M s,H1 ,M s,L2 The secondary side power switch bridge comprises a third power switch M arranged on an alternate arm of the secondary side power switch bridge. s,H1 and the fourth power switch M s,L2 ; The controller is further configured to alternately turn on and off the first pair of primary-side power switches M of the primary-side power switch bridge according to an AC / DC converter control strategy. p,L1 ,M p,H2 and the second pair of primary side power switches M p,H1 ,M p,L2 and the first pair of secondary side power switches M of the secondary side power switch bridge s,L1 ,M s,H2 and the second pair of secondary side power switches M s,H1 ,M s,L2 , so that the AC / DC converter converts the rectified AC input into an output of the AC / DC converter; The controller includes a microcontroller and a comparator component, wherein the microcontroller is configured to generate a positive reference signal and a negative reference signal based on a difference between the rectified AC input and a desired rectified AC input, and the comparator component is configured to compare an output current generated by the primary side power switch bridge from the rectified AC input with the positive reference signal, and turn on the first pair of primary side power switches M when the output current is equal to the positive reference signal. p,L1 ,M p,H2 and the first pair of secondary side power switches M s,L1 ,M s,H2 , and turn off the second pair of primary side power switches M p,H1 ,M p,L2 and the second pair of secondary side power switches M s,H1 ,M s,L2 , and when the output current is equal to the negative reference signal, turning off the first pair of primary side power switches M p,L1 ,M p,H2 and the first pair of secondary side power switches M s,L1 ,M s,H2 , and turn on the second pair of primary side power switches M p,H1 ,M p,L2 and the second pair of secondary side power switches M s,H1 ,M s,L2 , so that the AC / DC converter generates the output of the AC / DC converter.

11. The vehicle charger according to claim 10, wherein: The PB converter comprises an energy storage capacitor, an inductor, a first power switch and a second power switch, wherein the first power switch and the second power switch are connected in series between the positive electrode and the negative electrode of the battery, and a series branch of the energy storage capacitor and the inductor is connected in parallel between a series node of the first power switch and the second power switch and the negative electrode of the battery; and The controller is further configured to alternately turn on and off the first power switch and the second power switch of the PB converter according to a PB converter control strategy, so that the PB converter processes the output of the AC / DC converter to reduce or minimize its current ripple based on a pulsating buffer topology, and converts the output of the AC / DC converter into a battery-level DC output for charging the battery.

12. The vehicle charger according to claim 10, wherein: The comparator assembly includes a first comparator that receives the positive reference signal and a sensed value of the output current and switches its output when the output current is equal to the positive reference signal; and The comparator assembly also includes a second comparator that receives the negative reference signal and the sensed value of the output current and switches its output when the output current is equal to the negative reference signal.

13. The vehicle charger according to claim 12, wherein: The comparator component also includes a digital two-state change circuit and a digital driver circuit, which work together with the outputs of the first comparator and the second comparator to keep the first pair of primary side power switches and the first pair of secondary side power switches turned on, and keep the second pair of primary side power switches and the second pair of secondary side power switches turned off until the output current is equal to the negative reference signal, and keep the first pair of primary side power switches and the first pair of secondary side power switches turned off, and keep the second pair of primary side power switches and the second pair of secondary side power switches turned on until the output current is equal to the positive reference signal, thereby causing the AC / DC converter to generate the output of the AC / DC converter.

14. The vehicle charger according to claim 11, wherein: The controller includes a microcontroller and a comparator component, wherein the microcontroller is configured to generate a positive reference signal and a negative reference signal based on (i) a difference between an output current of the PB converter and (ii) a target output current, and the comparator component is configured to compare a buffer current absorbed by the PB converter from a DC output with a ripple with the positive reference signal, and when the PB converter buffer current is equal to the positive reference signal, turn on a first power switch of the PB converter and turn off a second power switch of the PB converter, and when the PB converter buffer current is equal to the negative reference signal, turn off the first power switch of the PB converter and turn on the second power switch of the PB converter, so that the PB converter processes the output of the AC / DC converter to reduce or minimize its current ripple, and converts the output of the AC / DC converter into a battery-level DC output for charging the battery.

15. The vehicle charger according to claim 14, wherein: The comparator component includes a first comparator that receives the positive reference signal and a sensed value of the PB converter buffer current and switches its output when the PB converter buffer current is equal to the positive reference signal; and The comparator assembly also includes a second comparator that receives the negative reference signal and a sensed value of the PB converter buffer current and switches its output when the PB converter buffer current is equal to the negative reference signal.

16. The vehicle charger according to claim 15, wherein: The comparator component also includes a digital two-state change circuit and a digital driver circuit, which work together with the outputs of the first comparator and the second comparator to keep the first power switch of the PB converter turned on, and keep the second power switch of the PB converter turned off until the PB converter buffer current is equal to the negative reference signal, and keep the first power switch of the PB converter turned off, and keep the second power switch of the PB converter turned on until the PB converter buffer current is equal to the positive reference signal, so that the PB converter processes the output of the AC / DC converter to reduce or minimize its current ripple, and converts the output of the AC / DC converter into a battery level DC output for charging the battery.

17. The vehicle charger according to claim 10, wherein: The AC / DC converter lacks a power factor corrector; and A DC link capacitor is missing between the AC / DC converter and the PB converter.

18. The vehicle charger according to claim 10, further comprising: an additional AC / DC converter connected to the PB converter; and The controller is also configured to control the additional AC / DC converters to convert the AC input from the mains power supply into additional outputs having DC voltage and current ripple, and to control the PB converters to process the additional outputs of each additional AC / DC converter to reduce or minimize its current ripple, and to transform the additional outputs of each additional AC / DC converter into battery level DC outputs for charging the battery.

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