Integrated charger

Abstract

Disclosed is an integrated charger, comprising: a first insulation type charger that converts an AC voltage input from the outside into a first DC voltage for charging a first battery and provides same to the first battery; and a second insulation type charger including a transformer that has a first winding connected to a switching circuit on the first battery side of the first insulation type charger and a second winding electromagnetically coupled to the first winding so as to convert and output the magnitude of the voltage of the first winding, and a rectifier circuit that rectifies a voltage of the second winding, converts the rectified voltage into a second DC voltage having a magnitude smaller than that of the first DC voltage, and provides same to a second battery.

Description

Integrated charger

[0001] The present invention relates to an integrated charger, and more particularly, to an integrated charger capable of reducing the number of parts and miniaturizing the product size.

[0002] Electric vehicles, powered by motors that convert electrical energy into kinetic energy instead of engines that generate power by burning fossil fuels, are equipped with various batteries. For example, electric vehicles have high-voltage, high-capacity batteries that store the electrical energy used to drive the motors, generating vehicle power, and low-voltage batteries that power the vehicle's electrical systems.

[0003] High-voltage batteries can be charged using a power converter, commonly called an onboard charger (OBC). An OBC converts alternating current (AC) power from an external grid into direct current (DC) power of sufficient voltage to charge the high-voltage battery.

[0004] Low voltage batteries can be charged using a low voltage DC-DC converter (LDC) that converts the voltage magnitude of the DC power charged to the high voltage battery into an appropriate low voltage.

[0005] In this way, since a typical electric vehicle is equipped with an OBC and an LDC, a large number of components are required to implement a device for charging a high-voltage battery and a low-voltage battery, and the size thereof is also difficult to miniaturize.

[0006] In order to overcome the shortcomings of the prior art described above, the present invention has as a technical task the provision of an integrated charger that can reduce the total number of parts and also miniaturize the size of the product itself by having the OBC and LDC share parts.

[0007] As a means for solving the above technical problem, the present invention,

[0008] A first insulated charger that converts an externally input AC voltage into a first DC voltage for charging a first battery and provides the converted AC voltage to the first battery; and

[0009] A second insulated charger having a transformer having a first winding connected to a switching circuit connected to the first battery of the first insulated charger, a second winding electromagnetically coupled to the first winding for converting and outputting the magnitude of the voltage of the first winding, and a rectifier circuit for rectifying the voltage of the second winding to convert it into a second DC voltage having a magnitude smaller than the first DC voltage and providing the second DC voltage to the second battery;

[0010] It provides an integrated charger that includes:

[0011] In an embodiment of the present invention, the AC voltage is a multi-phase AC voltage having multiple phases, the first insulated charger includes a plurality of insulated AC-DC conversion circuits connected in parallel to the first battery for converting each phase of the multi-phase AC voltage, and the second insulated charger can generate the first winding-side voltage through switching control of switching elements included in a switching circuit connected to the first battery provided in any two insulated AC-DC conversion circuits among the plurality of insulated AC-DC conversion circuits.

[0012] In an embodiment of the present invention, the switching circuit connected to the first battery includes a first leg including a first switching element and a second switching element connected to both ends of the first battery and connected in series with each other, and a third switching element and a fourth switching element connected to both ends of the first battery and connected in series with each other, and the connection nodes of the first switching element and the second switching element and the connection nodes of the third switching element and the fourth switching element can be connected to both ends of the first winding, respectively.

[0013] In an embodiment of the present invention, the rectifier circuit of the second insulated charger includes a first diode having a cathode connected to one end of the second winding; a second diode having a cathode connected to the other end of the second winding and an anode connected to the anode of the first diode; and an inductor having one end connected to the center end of the second winding, and both ends of the second battery can be connected between the other end of the inductor and the anode of the second diode.

[0014] In an embodiment of the present invention, the rectifier circuit of the second insulated charger includes a fifth switching element and a sixth switching element, each of which has one end connected to one end of the second winding; a seventh switching element and an eighth switching element, each of which has one end connected to the other end of the second winding; and the other end of the fifth switching element and the other end of the seventh switching element may be connected to one end of the second battery, and the other end of the sixth switching element and the other end of the eighth switching element may be connected to the other end of the second battery.

[0015] In an embodiment of the present invention, the rectifier circuit of the second insulated charger may include a third diode having an anode connected to one end of the second winding; a fourth diode having a cathode connected to one end of the second winding; a fifth diode having an anode connected to the other end of the second winding; a sixth diode having a cathode connected to the other end of the second winding; and a non-insulated DC-DC converter circuit configured to convert the magnitude of a voltage between the cathode of the third diode and the anode of the fourth diode and provide the converted voltage to the second battery.

[0016] In an embodiment of the present invention, the first switching element and the second switching element alternately switch with the same period and duty as each other, the third switching element and the fourth switching element alternately switch with the same period and duty as each other as the first switching element, and the voltage at both ends of the first winding can be determined through phase difference control of the first switching element and the third switching element.

[0017] In an embodiment of the present invention, the voltage between the connection node of the third switching element and the fourth switching element and the negative electrode of the first battery may be fixed to occur during half of the switching period of the first to fourth switching elements.

[0018] According to the integrated charger of the present invention, the switching circuit (rectifier circuit) of the direct current of the conventional OBC and the switching circuit (inverter circuit) of the high voltage side (input side) of the conventional LDC are integrated into one, thereby reducing the number of components, making it possible to miniaturize the product and reduce the manufacturing cost, and there is an excellent effect of improving energy efficiency by reducing the steps for converting power.

[0019] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to facilitate a better understanding of the technical idea of ​​the present invention. Therefore, the present invention should not be interpreted as being limited to the matters described in the following drawings.

[0020] Figures 1 and 2 are circuit diagrams showing the structure of a conventional onboard charger and low-voltage converter.

[0021] FIG. 3 is a circuit diagram of an integrated charger according to one embodiment of the present invention.

[0022] FIG. 4 is a circuit diagram of an integrated charger according to another embodiment of the present invention.

[0023] FIG. 5 is a circuit diagram showing a more specific circuit configuration of an integrated charger according to another embodiment of the present invention.

[0024] FIG. 6 is a waveform diagram showing a switching state when the first insulated charger and the second insulated charger are operated simultaneously in the embodiment of FIG. 5.

[0025] FIG. 7 and FIG. 8 are circuit diagrams illustrating further embodiments of the present invention, and are circuit diagrams illustrating embodiments in which the rectifier circuit of the second insulated charger is configured differently.

[0026] Hereinafter, an integrated charger according to various embodiments of the present invention will be described in detail with reference to the attached drawings.

[0027] The specific structural or functional descriptions of the embodiments described below are disclosed for illustrative purposes only and may be modified and implemented in various forms. Accordingly, the embodiments are not limited to the specific disclosed form, and the scope of this specification includes modifications, equivalents, or alternatives that fall within the technical concept.

[0028] Although terms such as "first" or "second" may be used to describe various components, these terms should be interpreted solely to distinguish one component from another. For example, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

[0029] When it is said that a component is "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but there may also be other components in between.

[0030] Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "has" should be understood to indicate the presence of a described feature, number, step, operation, component, part, or combination thereof, but not to exclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0031] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art. Terms defined in commonly used dictionaries should be interpreted to have a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0032] First, to help understand the present invention, the structure of a conventional on-board charger (OBC) and a low voltage DC-DC converter (LDC) will be briefly described.

[0033] Figures 1 and 2 are circuit diagrams illustrating the structure of a conventional onboard charger and low-voltage converter. More specifically, Figure 1 is a circuit diagram of a structure in which the OBC and LDC are separate, and Figure 2 is a circuit diagram of a structure in which the OBC and LDC share a transformer.

[0034] First, the conventional OBC and LDC circuit illustrated in FIG. 1 may include one OBC (100) having an input terminal connected to a grid, an output terminal connected to a high-voltage battery (300), and a structure in which the input and output terminals are mutually insulated by a transformer (T1), and one LDC (200) having an input terminal connected to a high-voltage battery (300), an output terminal connected to a low-voltage battery (400), and a structure in which the input and output terminals are mutually insulated by a transformer (T2). A bridge circuit having switching elements connected to the primary coil and the secondary coil of each of the transformers (T1) and (T2) may be connected. The OBC (100) illustrated in FIG. 1 shows an example of a 2-stage structure having a stage for AC-DC conversion and a DC converter stage that converts a DC voltage generated by a link capacitor at the output terminal of the block for AC-DC conversion, but this can be replaced with a 1-stage structure that directly connects a bridge circuit to a system input terminal into which AC is input and transfers energy to the output terminal through a transformer.

[0035] As illustrated in Fig. 1, the conventional OBC and LDC circuits are individually prepared for the circuit to form the OBC (100) and the circuit to form the LDC (200), so a large number of elements and parts are required for circuit implementation, and since the stages for power conversion are implemented in multiple stages, there is a disadvantage of low efficiency.

[0036] In addition, the conventional OBC and LDC circuit illustrated in Fig. 2 has a structure in which the OBC (100) and the LDC (200) integrate a transformer (T3). The OBC (100) of Fig. 2 illustrates an output terminal connected to a high-voltage battery (300) from a DC link terminal at the rear end of the DC-AC conversion stage.

[0037] The conventional OBC and LDC circuits illustrated in Fig. 2 attempted to reduce price and volume by integrating the transformer (T3), but had the disadvantage of not being able to substantially reduce the size of the entire circuit or reduce manufacturing costs due to a reduction in parts due to increased complexity and size of the transformer design.

[0038] FIG. 3 is a circuit diagram of an integrated charger according to one embodiment of the present invention, and FIG. 4 is a circuit diagram of an integrated charger according to another embodiment of the present invention.

[0039] Referring to FIGS. 3 and 4, an integrated charger according to an embodiment of the present invention may be configured to include a first insulated charger (10-1, 10-2) that converts an AC voltage input from an external source, such as a grid, into a first DC voltage for charging a first battery (300), which corresponds to a high-voltage battery, and provides the first DC voltage to the first battery (300), a transformer (T1) of the first insulated charger (10-1, 10-2) and a first battery-side switching circuit (11), a transformer (T4) having a second coil that is electromagnetically coupled to the first coil and converts and outputs the magnitude of the voltage of the first coil, and a second insulated charger (20) having a rectifier circuit (21) that rectifies the voltage of the second coil and converts it into a second DC voltage having a voltage smaller than the first DC voltage and provides the second DC voltage to the second battery (400), which corresponds to a low-voltage battery. Here, the first insulated charger (10-1, 10-2) may correspond to the OBC, and the second insulated charger (20) may correspond to the LDC.

[0040] The embodiments of FIGS. 3 and 4 have differences in the configuration of the first insulated charger corresponding to the OBC circuit. FIG. 3 is an embodiment having a first insulated charger of a two-stage configuration, and FIG. 4 is an embodiment having a first insulated charger of a one-stage configuration.

[0041] The first insulated charger (10-1) illustrated in FIG. 3 may include an AC-DC conversion stage (13) that converts an external AC voltage into a DC link voltage, an AC-side inverter unit (14) connected between the AC-DC conversion stage (13) and a transformer (T1), a transformer (T1), and a rectifier unit (11) connected between the transformer (T1) and an output terminal to convert a voltage whose magnitude is converted by the transformer (T1) into a DC voltage. The DC voltage converted by the rectifier unit (11) may be provided to a high-voltage battery (300).

[0042] The first insulated charger (10-2) illustrated in Fig. 4 is a charger having an input / output terminal structure in which a single-stage AC-side inverter unit (12) and a rectifier unit (11) and a transformer (T1) connected therebetween are insulated. The AC-side inverter unit (12) and the rectifier unit (11) can be implemented as a switching circuit such as a bridge circuit composed of switching elements, and the AC-type voltage whose magnitude is converted by the transformer (T1) can be converted by the rectifier unit (11) and provided to a high-voltage battery (300).

[0043] The embodiments illustrated in FIGS. 3 and 4 have in common a rectifier (11) connected between the secondary side of the transformer (T1) and the high-voltage battery (300). The rectifier (11) can be implemented as a switching circuit in the form of a bridge circuit having a plurality of legs including two switching elements connected between both ends of the high-voltage battery (300).

[0044] The second insulated charger (20) may include a transformer (T4) whose primary winding is connected to a switching circuit corresponding to the rectifier (11) of the first insulated charger (10), and a rectifier (21) connected to the secondary winding of the transformer (T4).

[0045] The second insulated charger (20) can charge the low-voltage battery (400) by converting the voltage magnitude of the direct current power of the high-voltage battery (300) and providing it to the low-voltage battery (400). The switching circuit (11) corresponding to the direct current side of the first insulated charger (10), i.e., the rectifier connected to the high-voltage battery, can function as an inverter that provides an alternating current voltage to the primary side of the transformer (T4) of the second insulated charger (20).

[0046] The transformer (T4) converts (steps down) the magnitude of the voltage input to the primary side according to the turns ratio of the primary side winding and the secondary side winding and provides it to the secondary side winding, and the voltage of the secondary side winding is converted into direct current by the rectifier circuit (21) and can be provided to the low-voltage battery (400).

[0047] FIG. 5 is a circuit diagram showing a more specific circuit configuration of an integrated charger according to one embodiment of the present invention.

[0048] Referring to Fig. 5, the AC voltage input from the outside is a three-phase AC voltage having a constant phase difference, and the first insulated charger corresponding to the OBC may have a structure including a plurality of insulated AC-DC conversion circuits (ADC1 to ADC3) connected in parallel to a high-voltage battery (300) to convert each phase of the multi-phase AC voltage. Each of the plurality of insulated AC-DC conversion circuits (ADC1 to ADC3) may include a transformer (T1) and may each include a rectifier connected between each transformer (T1) and the high-voltage battery (300).

[0049] In an example having the structure of the first insulated charger, any two legs (LEG1, LEG2) among one leg included in each rectifier may be respectively connected to both ends of the primary winding of the transformer (T4) of the second insulated charger, so as to become an inverter circuit of the LDC implemented by the second insulated charger. In the embodiment of Fig. 5, the leg (LEG1) included in the first insulated AC-DC conversion circuit (ADC1) and the leg (LEG2) included in the second insulated AC-DC conversion circuit (ADC2) may each be connected to both ends of the primary winding of the transformer (T4). More specifically, the connection node of the switching elements (S1, S2) included in the leg (LEG1) can be connected to one end of the primary winding of the transformer (T4), and the connection node of the switching elements (S3, S4) included in the leg (LEG2) can be connected to the other end of the primary winding of the transformer (T4).

[0050] In addition, the embodiment of FIG. 5 can be implemented in the form of a PSFB (Phase Shift Full Bridge) converter in which a rectifier circuit (21) connected to the secondary winding of the transformer (T4) of the second insulated charger operates in a PWM manner.

[0051] More specifically, in the embodiment of FIG. 5, the rectifier circuit (21) of the second insulated charger includes a first diode (D1) having a cathode connected to one end of a second winding of a transformer (T4), a second diode (D2) having a cathode connected to the other end of the second winding of the transformer (T4) and an anode connected to the anode of the first diode (D1), and an inductor (L1) having one end connected to the center end of the second winding of the transformer (T4), and a low-voltage battery (400) can be connected between the other end of the inductor (L1) and the anode of the second diode (D2).

[0052] FIG. 6 is a waveform diagram showing a switching state when the first insulated charger and the second insulated charger are operated simultaneously in the embodiment of FIG. 5.

[0053] As shown in Fig. 6, the switching elements (S1, S2) of the first leg (LEG1) and the switching elements (S3, S4) of the second leg (LEG2) are turned on / off with the same cycle and duty, and the switching elements within each leg can be turned on / off alternately. In particular, in the embodiment of the present invention, a phase difference (φ) is provided between the switching elements (S1, S2) of the first leg (LEG1) and the switching elements (S3, S4) of the second leg (LEG2), so that the voltage (V) between the connection nodes of the two switching elements (S1, S2) and the connection nodes of the two switching elements (S3, S4) ab ) is determined, and the voltage (V) between the connection node of the two switching elements (S3, S4) and the negative pole of the high voltage battery (300) is determined. bn ) can be fixed to occur during half of the switching cycle of the switching elements (S1 to S4), thereby enabling charging of the high-voltage battery (200) and supply of power to the second insulated charger to occur simultaneously.

[0054] FIGS. 7 and 8 are circuit diagrams illustrating other embodiments of the present invention, particularly embodiments in which the rectifier circuit of the second insulating charger is configured differently. Since the circuit configuration of the first insulating circuit portion in the embodiments of FIGS. 7 and 8 is substantially the same as that of the embodiment of FIG. 6, a description of the circuit configuration of the first insulating circuit portion will be omitted.

[0055] Referring to Fig. 7, the rectifier circuit (21) of the second insulated charger in the integrated charger according to the embodiment of the present invention may be implemented with the structure of a DAB (Dual Active Bridge) converter. In the embodiment of Fig. 7, the rectifier circuit (21) implemented with the structure of a DAB converter may include a fifth switching element (S5) and a sixth switching element (S6), each of which has one end connected to one end of the second winding of the transformer (T4), and a seventh switching element (S7) and an eighth switching element (S8), each of which has one end connected to the other end of the second winding of the transformer (T4). The other end of the fifth switching element (S5) and the other end of the seventh switching element (S7) may be connected to one end of the second battery (400), and the other end of the sixth switching element (S6) and the other end of the eighth switching element (S8) may be connected to the other end of the second battery (400).

[0056] As in the embodiment illustrated in Fig. 7, the rectifier circuit (21) implemented with the structure of a DAB converter can be controlled in a SPS (Single Phase-Shift) manner. Specifically, among the switching elements provided in the switching circuit of the first insulated charger, the switching elements (S1, S2) of the first leg (LEG1) are alternately switched with the same period and duty, the switching elements (S3, S4) of the second leg (LEG2) are alternately switched with the same period and duty, the first switching element (S1) and the fourth switching element (S4) are switched with the same timing, and the second switching element (S2) and the third switching element (S3) are switched with the same timing.

[0057] Similarly, the fifth switching element (S5) and the eighth switching element (S8) can be switched at the same timing, the sixth switching element (S6) and the seventh switching element (S7) can be switched at the same timing, the fifth switching element (S5) and the sixth switching element (S6) can be switched alternately at the same cycle, and the seventh switching element (S7) and the eighth switching element (S8) can be switched alternately at the same cycle. Here, the first switching element (S1) and the fifth switching element (S5) are switched with a phase difference from each other. By controlling the switching elements with such a phase difference, a voltage difference is generated in the inductor (Ls) connected between the primary winding of the transformer (T4) and the connection node of the first switching element (S1) and the second switching element (S2), and accordingly, an inductor current is generated, so that current can be supplied to the low-voltage battery (400).

[0058] Next, referring to 8, the rectifier circuit (21) of the second insulated charger in the integrated charger according to the embodiment of the present invention may be implemented as a two-stage converter including a diode rectifier and a boost converter structure. In the embodiment of FIG. 8, the rectifier circuit (21) may include a diode (D3) having an anode connected to one end of a second winding of a transformer (T4), a diode (D4) having a cathode connected to one end of the second winding, a third diode (D5) having an anode connected to the other end of the second winding, a diode (D6) having a cathode connected to the other end of the second winding, and a boost converter circuit (211) configured to convert the magnitude of the voltage between the cathode of the diode (D3) and the anode of the diode (D4) and provide the converted voltage to the second battery.

[0059] In the rectifier circuit (21) according to the embodiment illustrated in FIG. 8, among the switching elements provided in the switching circuit of the first insulated charger, the switching elements (S1, S2) of the first leg (LEG1) are alternately switched with the same period and duty, the switching elements (S3, S4) of the second leg (LEG2) are alternately switched with the same period and duty, the first switching element (S1) and the fourth switching element (S4) are switched with the same timing, and the second switching element (S2) and the third switching element (S3) are switched with the same timing. Accordingly, the voltage across the primary coil of the transformer (T4) is determined, and an AC current is generated that is provided to the primary coil by the inductor (Lr) and capacitor (Cr) connected to the primary coil of the transformer (T4). The voltage (Vd) output from the diode bridge circuit of the rectifier circuit (21) can be controlled by a boost converter (211), which is a non-insulated converter, and provided to the second battery (400).

[0060] As described above, the integrated charger according to various embodiments of the present invention integrates the direct current switching circuit (rectifier circuit) of a conventional OBC and the high voltage side (input side) switching circuit (inverter circuit) of a conventional LDC into one, thereby reducing the number of components, thereby enabling product miniaturization and reducing manufacturing costs, and improving energy efficiency by reducing the steps for converting power. In addition, the technical features of the integrated charger according to various embodiments of the present invention described above can be universally applied to insulated chargers using different circuit structures.

[0061] <Explanation of symbols>

[0062] 10-1, 10-2: First insulated charger

[0063] 11: DC side switching circuit 12: AC side switching circuit

[0064] 20: Second insulated charger 21: Rectifier circuit

Claims

1. A first insulated charger that converts an externally input AC voltage into a first DC voltage for charging a first battery and provides the converted AC voltage to the first battery; and A second insulated charger having a transformer having a first winding connected to a switching circuit connected to the first battery of the first insulated charger, a second winding electromagnetically coupled to the first winding for converting and outputting the magnitude of the voltage of the first winding, and a rectifier circuit for rectifying the voltage of the second winding to convert it into a second DC voltage having a magnitude smaller than the first DC voltage and providing the second DC voltage to the second battery; Integrated charger including.

2. In claim 1, The above AC voltage is a multi-phase AC voltage having multiple phases, and the first insulated charger includes a plurality of insulated AC-DC converter circuits connected in parallel to the first battery to convert each phase of the multi-phase AC voltage. An integrated charger characterized in that the second insulated charger generates the first winding side voltage through switching control of switching elements included in the first battery side switching circuit provided in any two insulated AC-DC conversion circuits among the plurality of insulated AC-DC conversion circuits.

3. In claim 1 or claim 2, The first battery-side switching circuit includes a first leg including a first switching element and a second switching element connected to both ends of the first battery and connected in series with each other, and a third switching element and a fourth switching element connected to both ends of the first battery and connected in series with each other. An integrated charger characterized in that the connection nodes of the first switching element and the second switching element and the connection nodes of the third switching element and the fourth switching element are respectively connected to both ends of the first winding.

4. In claim 3, the rectifier circuit of the second insulated charger, A first diode having a cathode connected to one end of the second winding; A second diode having a cathode connected to the other end of the second winding and an anode connected to the anode of the first diode; and Including an inductor once connected to the center terminal of the second winding, An integrated charger characterized in that both ends of the second battery are connected between the other end of the inductor and the anode of the second diode.

5. In claim 3, the rectifier circuit of the second insulated charger, A fifth switching element and a sixth switching element, one end of which is connected to one end of the second winding; It includes a seventh switching element and an eighth switching element, one end of which is connected to the other end of the second winding, An integrated charger, characterized in that the other terminal of the fifth switching element and the other terminal of the seventh switching element are connected to one end of the second battery, and the other terminal of the sixth switching element and the other terminal of the eighth switching element are connected to the other terminal of the second battery.

6. In claim 3, the rectifier circuit of the second insulated charger, A first diode having an anode connected to one end of the second winding; A second diode having a cathode connected to one end of the second winding; A third diode having an anode connected to the other end of the second winding; A fourth diode having a cathode connected to the other end of the second winding; and An integrated charger characterized by including a non-insulated DC-DC converter circuit configured to convert the magnitude of the voltage between the cathode of the first diode and the anode of the second diode and provide it to the second battery.

7. In claim 3, The first switching element and the second switching element are alternately switched with the same period and duty, The third switching element and the fourth switching element are alternately switched with the same period and duty as the first switching element, An integrated charger characterized in that the voltage at both ends of the first winding is determined by controlling the phase difference between the first switching element and the third switching element.

8. In claim 7, An integrated charger, characterized in that the voltage between the connection node of the third switching element and the fourth switching element and the negative electrode of the first battery is fixed to occur during half of the switching period of the first to fourth switching elements.

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