High efficiency battery charging circuit

Abstract

To provide a converting circuit for an on-board charging device.SOLUTION: A converting circuit for an on-board charging device according to the present invention includes a first resonance converter, a second resonance converter, a phase shift full-bridge converter that transmits at least part of DC voltage transmitted from an input terminal to an output terminal in accordance with the phase difference between a first control signal and a second control signal, and a control unit that generates a pulse to generate the phase difference between the first control signal and the second control signal.SELECTED DRAWING: Figure 5a

Description

[Technical field]

[0001] The present disclosure relates to a converting circuit, and more particularly to a converting circuit for an on-board charging device. [Background technology]

[0002] Charging methods for electric vehicles (EVs) can be broadly classified into three types.

[0003] The first method is the on-board charger (OBC). An on-board charger is a device that converts the alternating current (AC) power input to a vehicle into direct current (DC) power when charging an electric vehicle slowly or using a portable charger and a household plug. It is similar to an inverter in that it converts AC into DC.

[0004] The second type is the external charger method or standard charging method. An external charger refers to any charging system that has a stand that receives power from an external power supply facility, a cable, and a coupler for single-phase AC connection. An external charger is a type of charger that charges the storage battery using the electric vehicle's on-board charger.

[0005] The third method is the charger station or high speed charging method. A charger station operates by supplying direct current (DC) power directly from the charger to the battery of an electric vehicle.

[0006] Of these, on-board chargers are the standard for electric vehicles due to their convenience of being able to charge the battery pack directly from the AC power source of a utility line, their compact size, and their reasonable price. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Korean Patent Publication No. 10-2012-0134731 Summary of the Invention [Problem to be solved by the invention]

[0008] SUMMARY OF THE DISCLOSURE The present disclosure has been devised to address the above-mentioned background art, and aims to provide a converting circuit for an on-board charging device.

[0009] The technical problems in the present disclosure are not limited to the above-mentioned technical problems, and a person skilled in the art can clearly understand problems other than the above-mentioned technical problems based on the following description. [Means for solving the problem]

[0010] According to an embodiment of the present disclosure for solving the above-mentioned problems, a converting circuit for an on-board charging device is disclosed. The converting circuit for the on-board charging device includes a first resonant converter including at least two first switching elements, and is constant-voltage controlled to follow a predetermined ratio of a minimum voltage of a battery connected to an output terminal based on a first control signal input to the at least two first switching elements, and outputs a first output voltage, a second resonant converter including at least two second switching elements, and is constant-voltage controlled to follow a predetermined ratio of a minimum voltage of the battery based on a second control signal input to the at least two second switching elements, and outputs a second output voltage, and a controller that generates first and second control signals to determine a switching frequency to track a predetermined ratio of a minimum voltage of the battery, and generates a pulse that generates a phase difference between the first and second control signals for constant current control to track a reference current value set corresponding to a charging or discharging section of the battery, or constant voltage control to track a difference value between a maximum voltage and a minimum voltage of the battery.

[0011] In addition, the first resonant converter is connected to an input terminal and transmits at least a portion of a DC voltage transmitted from the input terminal to a first output terminal through a first transformer based on a first control signal input to the at least two first switching elements, the second resonant converter is connected to the input terminal and transmits at least a portion of a DC voltage transmitted from the input terminal to a second output terminal through a second transformer based on a second control signal input to the at least two second switching elements, and the phase-shifted full-bridge converter includes a third transformer and is capable of transmitting at least a portion of a DC voltage transmitted from the input terminal to a third output terminal through the third transformer based on a phase difference between the first control signal and the second control signal and a winding ratio of an input terminal and an output terminal of the third transformer.

[0012] The first resonant converter includes a 1-1 switching element, an operation mode of which is controlled by inputting the first control signal to a gate node thereof, the drain node of which is connected to one end of the input terminal and the source node of which is connected to one end of the phase shift full bridge converter; a 1-2 switching element, an operation mode of which is controlled by inputting the first control signal to a gate node thereof, the drain node of which is connected to a source node of the 1-1 switching element and the source node of which is connected to a ground node; a 1-1 resonant inductor, one end of which is connected to the drain node of the 1-1 switching element; a 1-2 resonant inductor, one end of which is connected to the other end of the 1-1 resonant inductor and connected in parallel to an input end of the first transformer; a first resonant capacitor, the other end of which is connected to one end of the 1-2 resonant inductor and the other end of which is connected to the source node of the 1-1 switching element; and the first transformer, an input end of which is connected in parallel to the 1-2 resonant inductor and an output end of which is connected to the first output terminal; The second resonant converter may include a 2-1 switching element, an operation mode of which is controlled by inputting the second control signal to a gate node, having a drain node connected to one end of the input terminal and a source node connected to the other end of the phase-shift full bridge converter, a 2-2 switching element, an operation mode of which is controlled by inputting the second control signal to a gate node, having a drain node connected to a source node of the 2-1 switching element and a source node connected to a ground node, a 2-1 resonant inductor, one end of which is connected to the drain node of the 2-2 switching element, a 2-2 resonant inductor, one end of which is connected to the other end of the 2-1 resonant inductor and connected in parallel to an input end of the second transformer, a second resonant capacitor, one end of which is connected to the other end of the 2-2 resonant inductor and the other end of which is connected to the source node of the 2-2 switching element, and a second transformer, an input end of which is connected in parallel to the 2-2 resonant inductor and an output end of which is connected to the second output terminal.

[0013] The phase-shift full-bridge converter further includes a first diode, a second diode, a third diode, a third inductor, and a third capacitor. The third transformer has an input end connected to a source node of the first-1 switching element, the other end of the input end connected to a source node of the second-1 switching element, and an output end having two coils magnetically connected to the coils of the input end, one end of a first coil of the two coils connected to one end of the first diode, and the first coil the other end of the first coil is connected to one end of the second coil of the two coils, the other end of the second coil is connected to one end of the second diode, the other end of the first diode and the other end of the second diode are connected to one end of a third diode, one end of the third diode is connected to one end of the third inductor, the other end of the third inductor is connected to one end of the third capacitor, the other end of the third capacitor is connected to the other end of the third diode, and the third output terminal may be configured across both ends of the third capacitor.

[0014] In addition, the first control signal may have a first switching frequency and a first duty ratio determined based on a constant voltage control that tracks a predetermined ratio of a minimum output voltage value of the on-board charging device, and the second control signal may have a second switching frequency and a second duty ratio determined based on a constant voltage control that tracks a predetermined ratio of a minimum output voltage value of the on-board charging device.

[0015] In addition, the magnitude of a phase pulse of the second control signal that has a phase difference with the pulse of the first control signal can be determined based on the difference between the set output voltage value of the on-board charging device and the minimum output voltage value.

[0016] The technical solutions obtained from the present disclosure are not limited to the solutions described above, and other solutions not described will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the following description. Effect of the Invention

[0017] According to some embodiments of the present disclosure, it is possible to provide a converting circuit to improve the performance of an on-board charging device.

[0018] The effects obtained from the present disclosure are not limited to those described above, and other effects not described will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the following description.

[0019] Various aspects are described below with reference to several drawings, in which similar reference numerals are generally used to refer to similar components. In the following examples, for purposes of explanation, numerous specific details are presented to provide a comprehensive understanding of one or more aspects. However, it is clear that such aspect(s) can be implemented without such specific details. In other examples, well-known structures and devices are shown in block diagram form to facilitate the description of one or more aspects. [Brief description of the drawings]

[0020] [Figure 1a] FIG. 1a is a block diagram showing the structure of a battery charger for use in electric vehicles and the like. [Figure 1b] FIG. 1b is a graph of current and voltage versus charging time for a battery pack according to one embodiment. [Figure 2a] FIG. 2a is a circuit diagram illustrating a conventional LLC resonant converter. [Figure 2b] FIG. 2b is an illustration of a voltage gain graph with changing switching frequency of a conventional LLC converter. [Figure 3a] FIG. 3a is a circuit illustrating a conventional Phase Shift Full Bridge Converter. [Figure 3b]FIG. 3b is a graph of exemplary main waveforms for controlling a conventional phase-shifted full-bridge converter. [Figure 4a] FIG. 4a is a block diagram illustrating a converting circuit according to one embodiment. [Figure 4b] FIG. 4b is a power handling profile graph according to the battery operation section of the converting circuit of FIG. 4a. [Figure 5a] FIG. 5a is a diagram of a converting circuit for an on-board charging device according to one embodiment. [Figure 5b] FIG. 5b is a circuit diagram showing a control section of a converting circuit according to one embodiment of the present disclosure. [Figure 5c] FIG. 5c is a graph showing main waveforms during the battery operation period of the converting circuit of FIG. 5a. [Figure 5d] FIG. 5d is a graph showing main waveforms during the battery operation period of the converting circuit of FIG. 5a. [Figure 5e] FIG. 5e shows an example graph for a section in which the battery is fully charged and then discharged. [Figure 6a] FIG. 6a is a diagram of a converting circuit for an on-board charging device according to another embodiment. [Figure 6b] FIG. 6b is a diagram of a converting circuit for an on-board charging device according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Since the present invention can be modified in various ways and has various embodiments, a specific embodiment will be illustrated in the drawings and described in detail. However, this does not limit the present invention to the specific embodiment, and should be interpreted as including all modifications, equivalents, or alternatives within the spirit and technical scope of the present invention. In describing each drawing, similar reference numerals are used for similar components.

[0022] Terms such as first, second, A, B, etc. may be used to describe various components, but the components are not limited by these terms. The terms are used only to distinguish one component from another. For example, a first component may be named a second component, and similarly, the second component may be named the first component, without departing from the scope of the present invention. The term "and / or" includes a combination of the associated listed items or any of the associated listed items.

[0023] When a component is described as being "connected," "coupled," or "connected" to another component, it should be understood that the component may be directly connected, coupled, or connected to the other component, but that there may be other components between them. On the other hand, when a component is described as being "directly connected," "directly coupled," or "directly connected" to another component, it should be understood that there are no other components between them.

[0024] The terms used in this application are merely used to describe certain embodiments and are not intended to limit the present invention. A singular expression includes a plural expression unless the context clearly indicates otherwise. In this application, the terms "include" or "have" and the like specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should not be interpreted as precluding the presence or further possibility of one or more different features, numbers, steps, operations, components, parts, or combinations thereof.

[0025] 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 to which the present invention belongs. Terms similar to those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense unless expressly defined in this application.

[0026] FIG. 1a is a block diagram showing the structure of a battery charger for use in electric vehicles and the like.

[0027] Referring to Figure 1a, the battery charger generates a DC (Direct Current) link voltage V through a PFC (power factor correction) AC / DC converter in the AC system. dc The generated DC (Direct Current) link voltage V dc The DC / DC converter 110 generates a DC voltage or current required for charging according to the charging mode of the battery pack. This will be described in detail with reference to the graph of current and voltage according to charging time of the battery pack in FIG. 1b.

[0028] FIG. 1b is a graph of current and voltage versus charging time for a battery pack according to one embodiment.

[0029] Referring to FIG. 1b, a battery has a maximum voltage V batt.max When fully discharged, the minimum voltage V batt.min According to the operation mode, the battery discharged in the charging section (120) is charged with a certain DC current I batt The battery charging voltage is a minimum voltage V batt.min In the charging section (120) as described above, the DC / DC converter (110) generates a DC (Direct Current) link voltage V DCA constant DC current I batt It is necessary to control the constant current so that the output is constant.

[0030] In the discharge section (130) where the battery charging is completed and discharging starts, the DC / DC converter (110) outputs a voltage equal to the battery maximum voltage V batt.max As described above, the method of controlling the DC / DC converter (110) to output a constant DC current during battery charging according to the operating sections (120, 130) and to output a constant DC voltage when charging is completed is called the CCCV (constant current constant voltage) control method of the DC / DC converter, which is a common control method used when charging a battery.

[0031] As an example, the target battery specifications are: batt.min =250V, V batt.max = 400V, charging current I batt = 16.5A, the battery voltage increases linearly over time from 250V, and the charging current remains constant at 16.5A until the battery voltage reaches 400V. Incidentally, the charging section under constant current control may vary depending on the battery capacity and initial battery voltage conditions, but it usually takes about 2 to 12 hours. When the battery voltage reaches 400V, the DC / DC converter outputs the preset voltage of 400V, and the battery charging current decreases over time until it reaches 0A. As mentioned above, the discharging section under constant voltage control may also vary depending on the battery specifications, but it usually takes about 1 to 30 minutes. In the charging section (120) described in FIG. 1b, the DC / DC converter (110) is constant current controlled, and the output voltage V O Based on the above embodiment, the output current of the DC / DC converter (110) is maintained at a constant level of 16.5A, and the output voltage V OAs the current and voltage increase, the power throughput also varies between 4.125kW and 6.6kW. However, as shown in the current and voltage graphs in Figure 1b, even a DC / DC converter with a maximum capacity of 6.6kW operates under light load conditions in most of the charging section (120).

[0032] FIG. 2a is a circuit diagram illustrating a conventional LLC resonant converter.

[0033] Since each component of a conventional LLC resonant converter is easy for ordinary engineers to understand, the explanation of the configuration and operating principle will be omitted. The turn-on and turn-off operation of the switch included in the LLC resonant converter is repeated at a preset switching period TS, but the duty cycle (duty cycle = conduction time / period, duty ratio) is usually fixed at 0.5, and the switching frequency f for controlling the output voltage and current is sw The PFM (pulse frequency modulation) control method, which adjusts (=1 / TS), is widely used.

[0034] FIG. 2b is an illustration of a voltage gain graph with changing switching frequency of a conventional LLC converter.

[0035] The LLC converter described above has the advantage of low switching loss and high power conversion efficiency because it supports zero voltage switching. However, when operating over a wide output voltage range, the primary resonant frequency f r1 and the secondary resonant frequency f r2 The switching frequency range is wide depending on the operating period defined by, and there is a disadvantage in realizing control for optimal operation. In summary, conventional LLC converters have the problem of low power conversion efficiency under light load conditions such as the battery charging period and under wide output voltage fluctuation conditions.

[0036] FIG. 3a is a circuit illustrating a conventional phase shift full bridge converter.

[0037] Since each component of the conventional phase-shift full-bridge converter is easy for ordinary engineers to understand, the description of the configuration and operation principle will be omitted. In the phase-shift full-bridge converter, a switching period T S The duty cycle is fixed, but the switch leg (e.g., S 1 , S 2 and S 3 , S 4 The control will use a PWM (pulse width modulation) method that adjusts the phase difference between the two.

[0038] FIG. 3b is a graph of exemplary main waveforms for controlling a conventional phase-shifted full-bridge converter.

[0039] Referring to FIG. 3b, a first transistor S1 and a second transistor S 2 are alternately turned on and off by a switching signal, and the third transistor S3 and the fourth transistor S4 are alternately turned on and off by a switching signal. 2 a first switch leg including a third transistor S 3 and the fourth transistor S 4The switching signals transmitted to the second switch leg including the first switch leg are controlled to have a preset phase shift. The phase-shift full-bridge converter has high power conversion efficiency due to low switching loss caused by zero-voltage operation, and can be expected to have the effect of easily achieving optimal control by fixing the switching frequency even when operating over a wide output voltage range. However, there is a limitation in that under light load conditions, which are mainly used in battery chargers, the zero-voltage operation condition of one of the switch legs cannot be satisfied, causing hard switching and resulting in switching loss. As with the LLC converter mentioned above, there is a problem of low power conversion efficiency due to light load conditions and wide output voltage fluctuations when applied to battery charging.

[0040] FIG. 4a is a block diagram illustrating a converting circuit according to one embodiment.

[0041] Referring to FIG. 4a, the converting circuit 400 may include a first resonant converter 410, a second resonant converter 420, a phase-shifted full-bridge converter 430, and a control unit 440. The first resonant converter 410 may include at least two first switching elements. The first resonant converter 410 may be constant-voltage controlled to track a predetermined ratio of the minimum voltage of a battery connected to an output terminal based on a first control signal input to the at least two first switching elements, and may output a first output voltage. Specifically, when the minimum output voltage of a target battery is 250V, the first output voltage may be set to 125V, which is 50% of the minimum output voltage. In this case, since the output voltage of the first resonant converter 410 is controlled to track 125V, the switching frequency for turning on or off the at least two first switching elements may be fixed, and the effect of solving the difficulty of optimal control due to the change in switching frequency may be expected.

[0042] The second resonant converter (420) may include at least two second switching elements. Like the first resonant converter (410), the second resonant converter (420) may be constant-voltage controlled to follow a predetermined ratio of the minimum voltage of a battery connected to an output terminal based on a second control signal input to the at least two second switching elements, and may output a second output voltage. Exemplarily, the predetermined ratio may be set in the same manner for the first resonant converter (410) and the second resonant converter (420), but is not limited thereto. For example, if the minimum output voltage of the target battery is 250V, the first output voltage may be set to 125V, which is 50% of the minimum output voltage. In this case, the output voltage of the second resonant converter (420) is controlled to follow 125V, so that the switching frequency for turning on or off the at least two second switching elements is fixed, and the difficulty of optimal control due to the change in switching frequency can be expected to be solved.

[0043] The phase-shift full-bridge converter (430) can transmit at least a portion of the DC voltage transmitted from the input terminal to the output terminal according to a phase difference between the first control signal and the second control signal, which are generated based on the operation mode of the battery. A specific operation of the phase-shift full-bridge converter (430) will be described in more detail with reference to additional drawings.

[0044] The control unit (440) can generate a first control signal and a second control signal, each of which has a switching frequency determined to follow a predetermined ratio of the minimum voltage of the battery, and transmit them to the switching elements included in the first resonant converter (410) and the second resonant converter (420). In addition, the control unit (440) can generate a pulse that creates a phase difference between the first control signal and the second control signal for constant current control that follows a reference current value set corresponding to a charging or discharging section of the battery, or constant voltage control that follows a difference value between the maximum and minimum voltages of the battery, and transmit the first control signal and the second control signal, each of which has a phase difference created by the pulse, to the switching elements included in the first resonant converter (410) and the second resonant converter (420).

[0045] FIG. 4b is a graph of the power handling profile through the battery operation section of the converting circuit according to FIG. 4a.

[0046] The output voltage corresponding to the first power section (451) may be provided to the battery by the output voltages of the first resonant converter (410) and the second resonant converter (420). batt,min By performing constant voltage control at a fixed switching frequency so as to output a predetermined ratio of the above, it is possible to compensate for zero voltage control and eliminate inefficiencies such as current stress caused by control over a wide voltage range.

[0047] Furthermore, the output voltage and output current corresponding to the second power section 452 according to the operating section of the battery can be provided at the output of the phase shift full bridge converter 430. In the discharge section of the battery, the phase shift full bridge converter 430 outputs a maximum voltage V batt,max and the minimum battery voltage V batt,minBy performing constant voltage control to track the difference between the maximum allowable current I o,max This is expected to have the effect of ensuring zero voltage switching conditions even under light load conditions with the magnetizing current of the resonant converter.

[0048] FIG. 5a is a diagram of a converting circuit for an on-board charging device according to one embodiment.

[0049] 5a, the converting circuit 500 may include a first resonant converter 510, a second resonant converter 520, a phase-shifted full bridge converter 530, and at least one output terminal. However, the components described above are not required to implement the converting circuit 500, and the converting circuit 500 may have more or less components than those described above.

[0050] The first resonant converter (510) includes at least two first switching elements S 1 and S 2 and the first transformer T A Here, the resonant converter can be a device that uses a change in frequency to control the output voltage. The first resonant converter (510) has a first output terminal V O1 It is possible to perform constant voltage control so that the output voltage outputted from the battery pack follows a predetermined ratio of the minimum voltage corresponding to the specifications of the battery pack. A first control signal, which will be described later, indicates a control signal whose switching frequency is determined so as to follow the predetermined ratio of the minimum voltage.

[0051] Exemplarily, the first resonant converter (510) may be embodied in the form of a resonant half-bridge converter.

[0052] The first resonant converter (510) receives an input voltage V in The first resonant converter (510) may be coupled to at least two first switching elements S 1 and S 2 The input voltage V in At least a portion of the DC voltage transmitted from the first transformer T A Through the first output terminal V O1 It is possible to communicate this to

[0053] At least two first switching elements S 1 and S 2 can control the operation mode of the first resonant converter (510) through the on-off switching of an electrical signal. 1 and S 2 Each of may be a transistor including a gate node, a drain node, and a source node.

[0054] Transformer 1 T A The first transformer T can play the role of insulation between the input and output and voltage conversion. A At least two first switching elements S 1 and S 2 At least a part of the DC voltage transmitted from the input terminal based on the first control signal input at O1 It is possible to communicate this to

[0055] The second resonant converter (520) includes at least two second switching elements S 3 and S 4 and the second transformer T B The second resonant converter (520) may include a second output terminal V O2 The output voltage output through the battery pack 1 can be controlled to be constant voltage so as to follow a predetermined ratio of the minimum voltage corresponding to the specifications of the battery pack. A second control signal, which will be described later, also indicates a control signal whose switching frequency is determined so as to follow the predetermined ratio of the minimum voltage.

[0056] According to one embodiment, the second resonant converter 520 may be implemented in the form of a resonant half-bridge converter.

[0057] The second resonant converter (520) receives the input voltage V in , the first resonant converter 510 may be connected in parallel to the second resonant converter 520. This is merely an exemplary embodiment to facilitate understanding, and an embodiment in which the first resonant converter 510 and the second resonant converter 520 are connected in series with respect to the input terminal is also within the scope of the concept of the present technology.

[0058] The second resonant converter (520) includes at least two second switching elements S 3 and the input voltage V in At least a part of the second transformer T B Through the second output terminal V O2 It is possible to communicate this to

[0059] At least two second switching elements S 3 and S 4 can control the operation mode of the second resonant converter (520) through the on-off switching of the electrical signal. 3 and S 4 Each of the may be a transistor including a gate node, a drain node, and a source node.

[0060] 2nd transformer T B The second transformer T can play the role of insulation between the input and output and voltage conversion. B At least two second switching elements S 3 and S 4 at least a part of the DC voltage transmitted from the input terminal based on a second control signal input to the second output terminal V O2 It is possible to communicate this to

[0061] The phase-shifted full-bridge converter (530) includes a third transformer T X The phase shift full-bridge converter (530) can perform conversion through a phase shift control method. The phase shift full-bridge converter (530) converts at least a portion of the input voltage Vin to a third output terminal V through a third transformer TX based on a phase difference between the first and second control signals and a winding ratio of an input terminal and an output terminal of the third transformer TX. O3 The phase-shifted full-bridge converter (530) can transmit the first-1 switching element S of the first resonant converter (510) to the 1 The source terminal of the first and second switching elements S 2 A node A to which the drain terminals of the first resonant converter 520 and the second switching element S1 of the second resonant converter 520 are connected may be connected to one end of the input terminal. 3 and the source terminal of the second-2 switching element S 4 A node B to which the drain terminal of the first transistor is connected may be connected to the other end of the input terminal.

[0062] According to one embodiment, the third output terminal V O3 The voltage value at can be determined based on the following formula:

number

[0063] Here, V o3 is the voltage value at the third output terminal, and V in can be the voltage value of the DC voltage transmitted from the input terminal. TIFF2025044101000003.tif15122 can be the phase difference between the first and second control signals. n3 is the third transformer T X The turns ratio can be as follows:

[0064] The phase shift full bridge converter 530 can be turned on according to the phase difference between the first resonant converter 510 and the second resonant converter 520. The phase shift full bridge converter 530 can output a voltage of 0 to 150V according to the set output. As a result, the overall range of the voltage output by the converting circuit 500 is 250 to 400V, and it is possible to satisfy the minimum and maximum conditions of the voltage specification. In addition, since the phase shift full bridge converter 530 is turned on or off according to the phase difference between the first resonant converter 510 and the second resonant converter 520, it can be controlled regardless of the boundary conditions of the transistors. In other words, even if the phase shift full bridge converter 530 is present, the converting circuit 500 can be prevented from suffering from LOSS under the boundary conditions.

[0065] Meanwhile, according to some embodiments of the present disclosure, the first control signal may have a first duty ratio determined based on constant voltage control to follow a predetermined ratio of the minimum output voltage value of the on-board charging device. Furthermore, the second control signal may have a second duty ratio determined based on constant voltage control to follow a predetermined ratio of the minimum output voltage value of the on-board charging device. Hereinafter, the first control signal and the second control signal will be described with reference to Figures 5c to 5d.

[0066] Hereinafter, the control section of the converting circuit (500) according to the present disclosure will be described with reference to FIG. 5b.

[0067] FIG. 5b is a circuit diagram showing a control section of a converting circuit according to one embodiment of the present disclosure.

[0068] Referring to FIG. 5b, the control unit of the converting circuit 500 is a phase difference generating A series of control scenarios can be executed through the Phase Shift Generation (PSFB) block, the Phase Shift Full Bridge (PSFB) CCCV control block, and the Voltage Controlled Oscillator (VCO) block.

[0069] According to one embodiment, the first resonant converter (510) of the converting circuit (500) includes at least two first switching elements S 1 and S 2 The control signal is input to the first control signal input terminal.

[0070] The first control signal may have a first duty ratio determined based on constant voltage control that tracks a predetermined ratio of the minimum output voltage value of the on-board charging device. The minimum output voltage value may be, for example, 250V. The duty ratio is a percentage value that indicates the ratio of the time that the signal is turned on in one period of the turn-on and turn-off signal. Furthermore, a switching frequency corresponding to the time interval of the pulses that turn on and off the first resonant converter 510 in the first control signal may be embodied as a fixed value by constant voltage control.

[0071] The second resonant converter (520) of the converting circuit (500) also includes at least two second switching elements S 3 and S 4 The control signal is operable based on a second control signal input to the

[0072] The second control signal may have a second duty ratio determined based on constant voltage control that tracks a predetermined ratio of the minimum output voltage value of the on-board charging device. Similarly, when PFM is used, the second resonant converter (520) is subjected to constant voltage control, so that the switching frequency corresponding to the time interval of the pulses that turn on and off the second resonant converter (520) in the second control signal may be embodied as a fixed value through constant voltage control.

[0073] According to an embodiment, the first control signal can determine a first duty ratio based on constant voltage control so that the first output terminal outputs 125V, which is 50% of the minimum output voltage value. The second control signal can determine a second duty ratio based on constant voltage control so that the second output terminal outputs 125V, which is 50% of the minimum output voltage value.

[0074] The magnitude of the pulse of the second control signal can be determined to have a phase difference with the pulse of the first control signal.

[0075] Specifically, the magnitude of the phase pulse of the second control signal can be determined so as to have a phase difference with the pulse of the first control signal based on the difference between the set output voltage value and the minimum output voltage value of the on-board charging device.

[0076] According to the above, the first resonant converter 510 and the second resonant converter 520 can be constant-voltage controlled so that the output voltage follows a fixed value. As a result, wide-range operation of the first resonant converter 510 and the second resonant converter 520 may be unnecessary. In addition, the first resonant converter 510 and the second resonant converter 520 can operate in such a way that ZVS (Zero Voltage Switch) and ZCS (Zero Current Switch) operations are guaranteed and current stress is minimized. Therefore, the charging efficiency of the converting circuit 500 can be maximized.

[0077] In addition, the phase shift full bridge converter (530) can perform CCCV (constant current, constant voltage) control. The operation performed through the phase shift full bridge converter (530) has a low output voltage, so the stress on the secondary voltage can be reduced. Specifically, the PSFB CCCV control block adjusts the output current of the converting circuit (500) to I corresponding to the battery specifications based on the charging or discharging mode of the battery.o,max It is possible to perform constant current control to make the output voltage of the phase shift full bridge converter (530) follow the difference between the maximum and minimum voltages of the battery, or constant voltage control to make the output voltage of the phase shift full bridge converter (530) follow the difference between the maximum and minimum voltages of the battery. Specifically, the PSFB CCCV control block controls V using the minimum value of the output of the PSFB current controller and the output of the PSFB voltage controller. e The reason for selecting the minimum value of the two outputs is to select the control mode based on the dominant control factor, either constant current control or constant voltage control. More specifically, V e Sawtooth Wave VS AW The magnitude of the reference voltage for performing PWM (pulse width modulation) is compared with that of the first control signal. Based on the calculation result for PWM control, the phase difference generation block can generate a pulse for generating a phase difference between the first control signal and the second control signal. Also, the phase difference generation block outputs the first control signal to which the pulse for the phase difference is added to the first switching element S. 1 and the second switching element S 2 The second control signal, which has a pulse for phase difference added, is input to the gate terminal of the third switching element S 3 and the fourth switching element S 4 It is possible to input the signal to the gate terminal of the

[0078] 5c to 5d are graphs showing main waveforms of wind speed according to the battery operation section of the converting circuit of Fig. 5a. As an example, a case will be described in which the minimum voltage of the battery connected to the converting circuit 500 is 250V, the maximum voltage is 400V, and the rated current IDC is 16.5A.

[0079] First, Figure 5c shows the initial charging period of the battery, with the battery voltage V batt The first switching element S 1 and the second switching element S 2receives a first control signal having a duty ratio and a switching frequency determined in accordance with a preset voltage (e.g., 130V) and receives a first control signal having a turn-on period and a turn-off period alternately repeated. Similarly, the third switching element S 3 and the fourth switching element S 4 Also, the first control signal receives an input of a second control signal having a duty ratio (e.g., 50%) and a switching frequency (e.g., 50 kHz) determined in accordance with a preset voltage (e.g., 130 V) and an input of a second control signal in which a turn-on period and a turn-off period are alternately repeated. However, in this case, since there is no further output voltage or output current provided by the phase shift full bridge converter, the phase difference between the first control signal and the second control signal is set to 0 degrees and the phase shift full bridge converter is maintained in a turned-off state.

[0080] FIG. 5d shows an example graph for a section in which the battery charging is completed. Compared to FIG. 5c, the phase difference between the first and second control signals is set to 90 degrees, and the phase-shifted full-bridge converter provides an output voltage of about 145V. However, the voltage V batt Even if I increases, the switching frequency of the two resonant converters remains fixed, and I Lr1 and I Lr2 is fixed, which is expected to have the effect of reducing current stress.

[0081] 5e shows an example graph for a section in which the battery is fully charged and then discharged. Compared to FIG. 5c, the phase difference between the first and second control signals is set to 180 degrees, and the phase-shifted full-bridge converter provides an output voltage of about 145V.

[0082] FIG. 6a is a diagram of a converting circuit for an on-board charging device according to another embodiment.

[0083] Referring to FIG. 6a, a converting circuit for an on-board charging device according to another embodiment may include a first resonant converter, a second resonant converter, a phase-shifted full-bridge converter, and at least one output terminal.

[0084] The first resonant converter may include at least two first switching elements and a first transformer. The first resonant converter has a first output terminal V O1 The first resonant converter can be controlled to have a constant voltage so that the output voltage from the first resonant converter follows a predetermined ratio of the minimum voltage corresponding to the specifications of the battery pack. in The first resonant converter may be coupled to an input voltage V based on a first control signal input to at least two first switching elements. in At least a portion of the DC voltage transmitted from the first output terminal V O1 The first control signal indicates a control signal whose switching frequency is determined so as to track a predetermined ratio of the minimum voltage.

[0085] The second resonant converter may include at least two second switching elements and a second transformer. The second resonant converter has a second output terminal V O2 The second resonant converter can be controlled to have a constant voltage so that the output voltage outputted through the second resonant converter follows a predetermined ratio of the minimum voltage corresponding to the specifications of the battery pack. 、 The input voltage V is determined based on a second control signal input to at least two second switching elements. in At least a portion of the voltage is supplied to the second output terminal V through the second transformer. O2 The second control signal indicates a control signal whose switching frequency is determined so as to track a predetermined ratio of the minimum voltage.

[0086] The phase-shift full-bridge converter may include a third transformer. The phase-shift full-bridge converter is configured to generate an input voltage V based on a phase difference between the first control signal and the second control signal and a winding ratio between the input terminal and the output terminal of the third transformer. in At least a part of the voltage is supplied to the third output terminal V through the third transformer. O3 It is possible to communicate this to

[0087] Compared to FIG. 5a, the first resonant converter and the second resonant converter can be connected in series with respect to the input terminal. Furthermore, the first resonant converter has an output terminal V O1 The second resonant converter is connected in series to the output terminal V O2 The overall output terminal of the converting circuit can be connected in series to the output terminal V of the first resonant converter. O1、 Output terminal V of the second resonant converter O2 and the third output terminal VO3 of the phase shift full bridge converter may be connected in series. As described above, the converting circuit according to the present disclosure may generate a pulse that creates a phase difference between the first control signal and the second control signal. Furthermore, the phase shift full bridge converter of the converting circuit may operate in a manner that transfers at least a portion of the DC voltage transferred from the input terminal to the output terminal according to the generated phase difference. Thus, the converting circuit according to the present disclosure may be embodied without being limited to the network structure as shown in FIG. 5a and FIG. 6a.

[0088] FIG. 6b is a diagram of a converting circuit for an on-board charging device according to another embodiment.

[0089] Referring to FIG. 6b, a converting circuit for an on-board charging device according to another embodiment may include a first resonant converter, a second resonant converter, a phase-shifted full-bridge converter, and at least one output terminal.

[0090] The first resonant converter may include at least two first switching elements and a first transformer. The first resonant converter has a first output terminal V O1 The first resonant converter can be controlled to have a constant voltage so that the output voltage from the first resonant converter follows a predetermined ratio of the minimum voltage corresponding to the specifications of the battery pack. in The first resonant converter may be coupled to an input voltage V based on a first control signal input to at least two first switching elements. in At least a portion of the DC voltage transmitted from the first output terminal V O1 The first control signal indicates a control signal whose switching frequency is determined so as to track a predetermined ratio of the minimum voltage.

[0091] The second resonant converter may include at least two second switching elements and a second transformer. The second resonant converter has a second output terminal V O2 The second resonant converter can be constant-voltage controlled so that the output voltage output from the second resonant converter tracks a predetermined ratio of a minimum voltage corresponding to the specifications of the battery pack. The second resonant converter controls the input voltage V based on a second control signal input to at least two second switching elements. in At least a portion of the voltage is supplied to the second output terminal V through the second transformer. O2 The second control signal indicates a control signal whose switching frequency is determined so as to track a predetermined ratio of the minimum voltage.

[0092] The phase-shift full-bridge converter may include a third transformer. The phase-shift full-bridge converter is configured to generate an input voltage V based on a phase difference between the first control signal and the second control signal and a winding ratio between the input terminal and the output terminal of the third transformer. in At least a part of the voltage is supplied to the third output terminal V through the third transformer. O3 It is possible to communicate this to

[0093] Compared to FIG. 5a, the first resonant converter and the second resonant converter can be connected in parallel with respect to the input terminal. Furthermore, the first resonant converter and the second resonant converter can be connected in parallel with respect to the output terminal (V O2 +V O2 ) can be connected in parallel. As described above, the converting circuit according to the present disclosure can generate a pulse that creates a phase difference between the first control signal and the second control signal. Furthermore, the phase-shift full-bridge converter of the converting circuit can operate in a manner that transfers at least a portion of the DC voltage transferred from the input terminal to the output terminal according to the generated phase difference. Thus, the converting circuit according to the present disclosure can be embodied in a network structure different from that of FIG. 5a and FIG. 6a.

[0094] According to another embodiment, the first resonant converter and the second resonant converter may be serially connected to the input terminal. Furthermore, the first resonant converter and the second resonant converter may be serially connected to the output terminal (V O2 +V O2 ) may also be connected in parallel.

[0095] The description of the embodiments presented is provided to enable any person of ordinary skill in the art to which the disclosure pertains to the present disclosure to utilize or practice the present disclosure. Various modifications to the embodiments will be apparent to those of ordinary skill in the art to which the disclosure pertains, and the general principles defined herein may be applied to other embodiments without departing from the scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the embodiments presented herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. 1. A converting circuit for an on-board charging device, comprising: a first resonant converter including at least two first switching elements, the first resonant converter being constant-voltage controlled to follow a predetermined ratio of a minimum voltage of a battery connected to an output terminal based on a first control signal input to the at least two first switching elements, and outputting a first output voltage; a second resonant converter including at least two second switching elements, the second resonant converter being constant-voltage controlled to track a predetermined ratio of a minimum voltage of the battery based on a second control signal input to the at least two second switching elements, and outputting a second output voltage; a phase-shift full-bridge converter that transmits at least a portion of a DC voltage transmitted from an input terminal to an output terminal according to a phase difference between the first control signal and the second control signal, the phase difference being generated based on an operation mode of the battery; and a control unit that generates a first control signal and a second control signal to determine a switching frequency to follow a predetermined ratio of a minimum voltage of the battery, and generates a pulse that generates a phase difference between the first control signal and the second control signal for constant current control to follow a reference current value set corresponding to a charge or discharge section of the battery, or constant voltage control to follow a difference value between a maximum voltage and a minimum voltage of the battery; A converting circuit for an on-board charging device including:

2. In claim 1, The first resonant converter comprises: transmit at least a portion of a DC voltage transmitted from the input terminal to a first output terminal through a first transformer based on a first control signal connected to the input terminal and input to the at least two first switching elements; The second resonant converter comprises: a second switching element connected to the input terminal, and transmitting at least a portion of a DC voltage transmitted from the input terminal to a second output terminal through a second transformer based on a second control signal input to the at least two second switching elements; The phase shift full bridge converter comprises: a third transformer, wherein at least a portion of a DC voltage transmitted from the input terminal is transmitted to a third output terminal through the third transformer based on a phase difference between the first control signal and the second control signal and a winding ratio of an input terminal and an output terminal of the third transformer. Converting circuit for on-board charging device.

3. In claim 2, The first resonant converter comprises: a first-1 switching element, an operation mode of which is controlled by inputting the first control signal to a gate node thereof, a drain node of which is connected to one end of the input terminal, and a source node of which is connected to one end of the phase shift full bridge converter; a first-2 switching element, an operation mode of which is controlled by inputting the first control signal to a gate node thereof, a drain node of which is connected to a source node of the first-1 switching element, and a source node of which is connected to a ground node; a 1-1 resonant inductor, one end of which is connected to a drain node of the 1-1 switching element; a first-second resonant inductor, one end of which is connected to the other end of the first-first resonant inductor and which is connected in parallel to an input end of the first transformer; a first resonant capacitor, one end of which is connected to the other end of the first-2 resonant inductor and the other end of which is connected to a source node of the first-1 switching element; and the first transformer, an input end of which is connected in parallel with the first and second resonant inductors and an output end of which is connected to the first output terminal; Including, The second resonant converter comprises: a second-1 switching element, an operation mode of which is controlled by inputting the second control signal to a gate node thereof, a drain node of which is connected to one end of the input terminal, and a source node of which is connected to the other end of the phase-shift full-bridge converter; a second-2 switching element, an operation mode of which is controlled by inputting the second control signal to a gate node thereof, a drain node of which is connected to a source node of the second-1 switching element, and a source node of which is connected to a ground node; a second-1 resonant inductor, one end of which is connected to a drain node of the second-2 switching element; a second-second resonant inductor, one end of which is connected to the other end of the second-first resonant inductor and which is connected in parallel to an input end of the second transformer; a second resonant capacitor, one end of which is connected to the other end of the 2-2 resonant inductor and the other end of which is connected to the source node of the 2-2 switching element; and A converting circuit for an on-board charging device includes a second transformer, the input terminal of which is connected in parallel with the second-second resonant inductor and the output terminal of which is connected to the second output terminal.

4. In claim 3, The phase shift full bridge converter comprises: a first diode, a second diode, and a third diode; a third inductor; and a third capacitor; The third transformer is one end of the input terminal is connected to a source node of the first-1 switching element, and the other end of the input terminal is connected to a source node of the second-1 switching element; At the output end, two coils are magnetically connected to the coils at the input end, one end of a first coil of the two coils is connected to one end of the first diode, the other end of the first coil is connected to one end of a second coil of the two coils, and the other end of the second coil is connected to one end of the second diode, the other end of the first diode and the other end of the second diode are connected to one end of a third diode; one end of the third diode is connected to one end of the third inductor, the other end of the third inductor is connected to one end of the third capacitor, and the other end of the third capacitor is connected to the other end of the third diode; The third output terminal is A converting circuit for the on-board charging device configured across the third capacitor.

5. In claim 1, The first control signal is a first switching frequency and a first duty ratio are determined based on a constant voltage control that tracks a predetermined ratio of a minimum output voltage value of the on-board charging device; The second control signal is A converting circuit for an on-board charging device, in which a second switching frequency and a second duty ratio are determined based on a constant voltage control for tracking a predetermined ratio of a minimum output voltage value of the on-board charging device.

6. In claim 5, The second control signal is A converting circuit for an on-board charging device, in which a magnitude of a phase pulse having a phase difference with a pulse of the first control signal is determined based on a difference between a set output voltage value of the on-board charging device and the minimum output voltage value.

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