KR20160140299A - A charger with battery diagnosis function and control method thereof - Google Patents

Abstract

Disclosed are a charger having a battery diagnosis function and a driving method thereof. The charger having the battery diagnosis function, which is connected between an input power source for supplying an input voltage and a battery for charging the battery with the input voltage, includes: a full bridge circuit connected to the input power source and including first to fourth switches; a transformer including a primary side winding and a secondary side winding, in which the primary side winding is connected to the full bridge circuit for converting the input voltage received through the full bridge circuit and transmitting the converted input voltage to the secondary side winding; and a rectifier circuit including a fifth switch and a sixth switch, and connected between the secondary side winding and the battery for rectifying the voltage transmitted through the transformer to charge the battery, or transmitting power in both directions to diagnose a lifespan of the battery.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a charger having a battery diagnosis function,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charger having a battery diagnostic function and a control method thereof, and more particularly to a charger capable of diagnosing the life and abnormal state of a battery and a control method thereof.

Generally, a battery goes through a cycle of discharging electricity, which changes the chemical energy electrically, and charging, which converts the electrical energy into chemical energy. The most common battery is a lead-acid battery, which is an application of galvanic cells. It consists of lead (Pb) and lead dioxide (PbO2) electrodes in a concentrated sulfuric acid aqueous solution. During long charging and discharging cycles, And various types of aging phenomena, including battery life, are shortened.

On the other hand, the above-described battery charges the electric power periodically through the charger. Such a charger generally does not have a function of diagnosing the condition of the battery in addition to the charging function of the battery. Accordingly, when the user uses the battery, the lifetime of the battery can not be known. Therefore, the reliability of the system can not be deteriorated because the life of the battery suddenly reaches the end of the life of the battery.

Accordingly, studies on a charger that diagnoses the life of the battery and informs the user when the battery is charged are being actively researched.

Typically, there is a method of calculating the maximum permissible capacity of the battery using the coulomb coefficient of the battery, a method of diagnosing battery life, and a method of diagnosing battery life based on a parameter change of the battery model.

However, these methods have a drawback in that the battery life diagnosis algorithm is complicated and the accuracy thereof is also lowered.

One aspect of the present invention provides a charger having a simple battery diagnosis algorithm for applying a perturbation voltage to a battery using a charger capable of bi-directional power transfer and diagnosing battery life based on a response current according to a perturbation voltage, and a driving method thereof do.

According to an aspect of the present invention, there is provided a charger having a battery diagnosis function connected between an input power source for supplying an input voltage and a battery, and charging the input voltage to the battery, the charger being connected to the input power source, A full bridge circuit including four switches; A primary side winding and a secondary side winding, the primary side winding being connected to the full bridge circuit to convert the input voltage received through the full bridge circuit and transfer the converted input voltage to the secondary side winding; And a fifth switch and a sixth switch connected between the secondary side winding and the battery so as to rectify the voltage transferred through the transformer to charge the battery or to diagnose the life of the battery And a rectifying circuit for transmitting electric power in both directions.

The first switch and the sixth switch may be controlled to charge the battery with the input voltage or to apply a perturbation voltage to diagnose the life of the battery, And a controller for diagnosing the lifetime of the battery based on the response current.

Further, the full bridge circuit may include a first leg and a second leg connected in parallel, the first switch and the second switch are provided on the first leg, and the third switch and the second switch are provided on the second leg, And the fourth switch may be provided.

The first switch and the fourth switch may be connected in parallel with a parasitic capacitor and a body diode, respectively.

In addition, the transformer may be provided with a tab on the secondary side winding.

The secondary winding may further include a smoothing circuit connected to the tab of the secondary side winding.

The rectifier circuit may include the sixth switch connected to one end of the secondary side winding and the fifth switch connected to the other end of the primary side winding.

The fifth switch and the sixth switch may be connected in parallel with a parasitic capacitor and a body diode, respectively.

In addition, the first switch to the fourth switch may be turned on by zero voltage switching (ZVS).

According to another aspect of the present invention, there is provided a full bridge circuit comprising: a full bridge circuit that is supplied with input power and includes first to fourth switches; a primary winding and a secondary winding; And a fifth switch and a sixth switch connected to the secondary side winding, for converting the input voltage received through the full bridge circuit and transmitting the converted input voltage to the secondary side winding, and connected to the secondary side winding, And a rectifying circuit for rectifying the received voltage to charge the battery. The method of claim 1, further comprising the steps of: And rectifying the input voltage according to a turn-on or a turn-off operation of the fifth switch and the sixth switch, And when the charging of the battery is completed, a perturbation voltage is applied to the battery, and the service life of the battery is diagnosed based on a response current output from the battery.

Meanwhile, the transmission of the input power to the transformer in accordance with the turn-on or turn-off operation of the first switch to the fourth switch may include switching the ZVS: zero voltage switching to transmit the input power to the transformer.

Also, charging the battery by rectifying the input voltage according to a turn-on or a turn-off operation of the fifth switch and the sixth switch includes the first and second legs connected in parallel And the fifth switch is connected to the other end of the secondary side winding, the sixth switch is connected to one end of the secondary side winding, and the first switch or the second leg provided on the upper side of the first leg, When the fourth switch provided on the lower side of the first switch is turned on, the fifth switch also turns on, and when the first switch and the fourth switch are all turned off, the fifth switch also turns off, When the second switch provided on the lower side of the first leg or the third switch provided on the upper side of the second leg is turned on, the sixth switch also turns on, When the third switch group are both turned off, may be by the turn-off operation is also the sixth switch for charging the battery by rectifying the input voltage.

The first switch to the sixth switch may be connected in parallel with a parasitic capacitor and a body diode, respectively.

In addition, power may be transmitted in both directions in accordance with the turn-on or turn-off operation of the fifth switch and the sixth switch.

According to one aspect of the present invention described above, an algorithm for diagnosing battery life based on a response current according to a perturbation voltage by applying a perturbation voltage to a battery by using a charger capable of bi-directional power transfer, Can be diagnosed.

Further, by operating a plurality of switches included in the charger by zero voltage switching (ZVS), it is possible to reduce the total loss of the charger due to the reduction of the switch loss.

In addition, conduction loss can be reduced by performing synchronous rectification in the rectifier circuit included in the charger.

1 is a schematic circuit diagram of a charger having a battery diagnostic function according to an embodiment of the present invention.
FIG. 2 is a graph showing currents flowing through the respective devices or voltages applied to the devices in the first to seventh modes of operation of the charger having the battery diagnosis function according to the embodiment of the present invention.
3 to 9 are schematic circuit diagrams for explaining the first to seventh modes of operation of the battery charger according to the embodiment of the present invention.
10 is a control block diagram for constant current / constant voltage (CC / CV) charging of a charger according to an embodiment of the present invention.
11 is a view showing an equivalent circuit of a battery according to an embodiment of the present invention.

The following detailed description of the invention refers to the accompanying drawings, which illustrate, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different, but need not be mutually exclusive. For example, certain features, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in connection with an embodiment. It is also to be understood that the position or arrangement of the individual components within each disclosed embodiment may be varied without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is to be limited only by the appended claims, along with the full scope of equivalents to which such claims are entitled, if properly explained. In the drawings, like reference numerals refer to the same or similar functions throughout the several views.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the drawings.

1 is a schematic circuit diagram of a charger having a battery diagnostic function according to an embodiment of the present invention.

Referring to FIG. 1, a charger 200 having a battery diagnostic function according to an embodiment of the present invention is connected between an input power source 100 and a battery 300, and includes a full bridge circuit 210, A transformer 220, a rectifier circuit 230, and a smoothing circuit 240. [

The charger 200 according to an embodiment of the present invention can charge the battery 300 using a constant current / constant voltage (CC / CV) charging method and can charge the battery 300 through an impedance spectroscopy (EIS: Electrochemical Impedance Spectroscopy) ) Can be diagnosed.

In particular, the charger 200 according to an embodiment of the present invention is capable of charging a large capacity battery 300, for example, a 3 kW lead / acid type battery 300 cell. The battery 300 has an internal resistance R _b and an internal capacitor C _b . In addition to the above-described battery type, all types of batteries can be applied to the embodiment of the present invention.

The full bridge circuit 210 includes a plurality of switches S ₁ , S ₂ , S ₃ and S ₄ and is connected to the input power supply 100 to supply the input voltage V _s To the transformer 220.

In particular, the full bridge circuit 210 may include a first leg 210-1 and a second leg 210-2 connected in parallel. A first switch S ₁ is provided on the high side of the first leg 210-1 and a second switch S ₂ is provided on the low side of the first leg 210-1 . The third switch S ₃ is provided on the high side of the second leg 210-2 and the fourth switch S ₄ is provided on the low side of the second leg 210-2. May be provided.

At this time, the plurality of switches _{(S 1, S 2, S} 3, S 4) is a BJT, JFET, may be provided with a MOSFET or the like, in the following description, a plurality of switches _{(S 1, S 2, S} 3, S 4 ) Is provided as a MOSFET switch. Further, the plurality of switches _{(S 1, S 2, S} 3, S 4) are respectively a first body diode (D _S1) to a fourth body diode (D _S4) of the first parasitic capacitor (C _S1) to a fourth parasitic And the capacitor C _S4 may be connected in parallel. For example, the drain terminal of the first switch S ₁ is connected to the cathode of the first body diode D _S1 and one end of the first parasitic capacitor C _S1 , and the source terminal of the first switch S ₂ May be connected to the anode of the first body diode (D _S1 ) and the other end of the first parasitic capacitor (C _S1 ). In this manner, the second switch (S ₂₎ to the fourth switch (S ₄₎ In addition, the second body diode (D _S2) to the fourth body diode (D _S4) and a second parasitic capacitor (C _S2) to the fourth The parasitic capacitor C _S4 may be connected in parallel.

The transformer 220 includes a primary side winding N _p and a secondary side winding N _s and is connected between the full bridge circuit 210 and the rectification circuit 230 and connected to the transformer turn ratio n 1: Can be performed. At this time, the transformer 220 is an insulated transformer, and can isolate the full bridge circuit 210 and the rectifier circuit 230 from each other.

Specifically, the primary winding N _p is magnetically coupled to the secondary winding N _s , and the first contact (1) between the first switch (S ₁ ) and the second switch (S ₂ ) May be provided on the input voltage line 215 connecting the second contact (2) between the switch S ₃ and the fourth switch S ₄ .

The secondary winding N _s may be magnetically coupled to the primary winding N _p and may be provided on the output voltage line 235 connected to the rectifying circuit 230. In this case, the secondary-side winding (N _s) is provided with tab 222 to split the output of the transformer 220, the secondary-side winding (N _s), the first secondary side winding (N _S1) and the second secondary And the side winding N _S2 .

The rectifier circuit 230 includes a fifth switch S ₅ and a sixth switch S ₆ and can rectify the output of the transformer 220 and transmit the rectified output to the smoothing circuit 240.

Specifically, rectifying circuit 230 is provided a sixth switch (S ₆₎ on the first output voltage line (235-1) which is connected to one end of the secondary side winding of the transformer (220) (N _s), the secondary side winding (N _s), there may be provided a fifth switch (s ₅₎ of the other on the second output voltage line (235-2) connected to end. That is, one end of the sixth switch S _{6 is} connected to one end of the secondary side winding N _s , one end of the fifth switch S ₅ is connected to the other end of the secondary side winding N _s , switch (S ₆₎ and the other terminal of the fifth switch (S ₅₎ may be connected to the third contact (③).

In this case, the fifth switch S ₅ and the sixth switch S ₆ may be formed of a BJT, a JFET, a MOSFET, and the like. In the following description, the fifth switch S ₅ and the sixth switch S ₆ MOSFET switch is provided as an example. The fifth switch S ₅ and the sixth switch S ₆ are respectively connected to the fifth body diode D _S5 and the sixth body diode D _S6 and the fifth parasitic capacitor C _S5 and the sixth parasitic capacitor C _S5 , (C _S6 ) may be connected in parallel.

The smoothing circuit 240 may include an output inductor 241 and an output capacitor 242. The smoothing circuit 240 may smooth the output voltage rectified by the rectifying circuit 230 and output the smoothed output voltage to the battery 300. [

More specifically, one end of the output inductor 241 may be connected to the tab 222 of the secondary side winding N _s , the other end may be connected to one end of the output capacitor 242, and the other end of the output capacitor 242 may be connected to And may be connected to the third contact point (3). The output capacitor 242 may be connected to the battery 300 in parallel.

The charger 200 according to an embodiment of the present invention can charge the battery 300 by converting the input voltage V _s supplied from the input power source 100 through the transformer 220.

Here, the primary side of the transformer 220 is connected to the full bridge circuit 210 and is connected to the full bridge circuit 210 in accordance with the switching operation of the plurality of switches S ₁ , S ₂ , S ₃ , and S ₄ included in the full bridge circuit 210 And receives the input voltage V _s from the input power supply 100. The plurality of switches S ₁ , S ₂ , S ₃ and S ₄ may be PWM-controlled by a separate control unit (not shown) such as a digital signal processor and the leakage inductance L _1k of the transformer 220, And a first parasitic capacitor C _S1 to a fourth parasitic capacitor C _S4 added to each of the plurality of switches S ₁ , S ₂ , S ₃ and S ₄ to form a resonant loop, And can be turned on by a zero voltage switching (ZVS) method.

The secondary side of the transformer 220 is connected to the rectifying circuit 230 and the smoothing circuit 240 so that the voltage received from the primary side of the transformer 220 is rectified by the full- have. At this time, the rectifying circuit 230 is provided with a plurality of switches S ₅ and S ₆ to enable bidirectional power transmission. Thus, the lifetime of the battery 300 can be diagnosed through an impedance spectroscopy (EIS: Electrochemical Impedance Spectroscopy) . At this time, the plurality of switches S ₅ and S ₆ of the rectifying circuit 230 may also be PWM-controlled by a separate control unit (not shown) such as a digital signal processor.

A separate control unit such as a digital signal processor is provided inside or outside the charger 200 and is electrically connected to the respective elements in the charger 200 circuit so as to be controlled by software (or application) _{S 1, S 2, S 3} , S 4, S 5, it is possible to control the turn-on or turn-off operations of S _6).

That is, the control unit controls the first to sixth switches S ₁ to S 6 so as to charge the battery 300 with the input voltage V _s or to apply a perturbation voltage to diagnose the life of the battery 300 ₆ ) and diagnose the life of the battery 300 based on the response current output from the battery 300 according to the perturbation voltage. A detailed description thereof will be given later.

Hereinafter, a specific driving method of the charger 200 according to an embodiment of the present invention can be described with reference to FIGS. 2 to 6. FIG.

FIG. 2 is a graph of a current flowing through each element or a voltage applied to each element in the first to seventh modes of operation of the charger according to an embodiment of the present invention, and FIGS. And is a schematic circuit diagram for explaining the first to seventh modes of operation of the switch according to the example.

First, referring to FIG. 2, the first to sixth switches S ₁ to S ₆ may be phase-shift PWM controlled. At this time, the first switch S ₁ to the sixth switch S ₆ may be controlled by a separate control unit (not shown) such as a digital signal processor.

The fifth switch S ₅ is turned on when the first switch S ₁ or the fourth switch S ₄ is turned on and the first switch S ₁ and the fourth switch S ₄ are turned on Off can be controlled at turn-off time.

In addition, a sixth switch (S ₆₎ is a second switch (S ₂₎ or 3 is turned on when the control is always turn-on of the switch (S _3), the second switch (S ₂₎ and the third switch (S ₃₎ Off can be controlled at turn-off time.

2 and 3, in the first operation mode [t ₁ to t ₂ ], the first switch S ₁ and the fourth switch S ₄ are turned on and the second switch S ₂ and The third switch S ₃ is in the turned off state and therefore the fifth switch S ₅ may be turned on and the sixth switch S ₆ may be turned off.

In the first mode of operation, the primary side current I _pri of the transformer 220 may increase in accordance with the total inductance value of the primary side of the transformer 220.

Further, on the secondary side of the transformer 220, the voltage converted from the primary side winding N _p to the second secondary side winding N _s2 may be induced as the fifth switch S ₅ is turned on.

2 and 4, in the second operation mode [t ₂ to t ₃ ], the first switch S ₁ maintains the turn-on state and the fourth switch S ₄ turns on at t ₂ The fifth switch S ₅ is turned on and the sixth switch S ₆ is turned off so that the second switch S ₂ and the third switch S ₃ are turned off, Lt; / RTI >

In the second operation mode, the primary side of the transformer 220 forms a resonance loop with the third switch S ₃ and the fourth switch S ₄ , respectively, so that the leakage inductance L _lk is applied to the fourth switch S ₄ The fourth parasitic capacitor C _S4 connected in parallel can be charged and the third parasitic capacitor C _S3 connected in parallel to the third switch S ₃ can be discharged.

2 and 5, in the third operation mode [t ₃ to t ₄ ], the first switch S ₁ maintains the turn-on state and the second switch S ₂ , the third switch S ₃ and the fourth switch S ₄ are also kept in the turned off state so that the fifth switch S ₅ can be turned on and the sixth switch S ₆ can be kept turned off.

In the third operation mode, when the third parasitic capacitor C _S3 connected in parallel to the third switch S ₃ is completely discharged, the third body diode D _S3 connected in parallel to the third switch S ₃ is turned on Accordingly, the primary-side current I _pri of the transformer 220 can flow back along the first switch S ₁ and the third body diode D _S3 .

At this time, the conduction time of the third body diode (D _S3 ) must be minimized in order to reduce the additional loss.

2 and 6, in the fourth operation mode [t ₄ to t ₅ ], the first switch S ₁ maintains the turn-on state and the second switch S ₂ and the fourth switch S ₄ ) also maintains the turn-off state, and the third switch S ₃ can be turned on at t ₄ . Therefore, the fifth switch S ₅ can be kept turned on, and the sixth switch S ₆ can also be turned on.

In the fourth operation mode, since the voltage of the third switch S ₃ is "0", the third switch S ₃ operates at zero voltage switching (ZVS) at t ₄ and can be turned on. Accordingly, the primary current I _pri of the transformer 220 can flow back along the third switch S ₃ and the first switch S ₁ .

At this time, the primary side current (I _pri ) of the transformer 220 can be gradually decreased according to the voltage loss depending on the parasitic resistance value on the return path and the decrease in the load current reflected on the primary winding N _p .

Since the output inductance L on the secondary side of the transformer 220 is larger than the leakage inductance L _lk on the primary side of the transformer 220, the secondary side current I _L of the transformer 220 is connected to the transformer 220 ) &_Lt; / RTI > primary side current I _pri .

Therefore, to balance the transformer 220, the magnetic flux, and the sixth can has to flow a current corresponding to the equation (1) below the switch (S _6).

In Equation 1, I _L denotes a current flowing to the output inductor 241, I _DS5 denotes a current flowing to the fifth switch S ₅ , and I _DS6 denotes a current flowing to the sixth switch S ₆ .

2 and 7, in the fifth operation mode [t ₅ to t ₆ ], the first switch S ₁ is turned off at t ₅ , and the second switch S ₂ and the fourth switch S ₄₎ maintains a turn-off state, and the third switch (S ₃₎ maintains a turn-on state, therefore, the fifth switch (S ₅₎ is turned off, the sixth switch (S ₆₎ are turned on State can be maintained.

In the fifth mode of operation, the primary side of the transformer 220 forms a resonant loop with the first switch S ₁ and the second switch _S2 , respectively, so that the first switch S _{1 is} connected in parallel to the first switch S ₁ by the leakage inductance L _1k . The connected first parasitic capacitor C _S1 may be charged and the second parasitic capacitor C _S2 connected in parallel to the second switch S ₂ may be discharged.

At this time, the primary current I _{pri of the} transformer 220 may be decreased according to the following equation (2).

In Equation (2),? I /? T denotes a change amount of the primary side current I _pri of the transformer 220 with respect to time, V _s is the input voltage, V _c2 is the voltage of the second parasitic capacitor C _s2 , L _lk is the leakage inductance.

Further, on the secondary side of the transformer 220, the fifth body diode D _S5 connected in parallel with the fifth switch S ₅ is turned on according to the turn-off of the fifth switch S ₅ , The current I _DS5 flowing through the fifth switch S ₅ decreases and the current I _DS6 flowing through the sixth switch S ₆ can increase.

2 and 8, in the sixth operation mode [t ₆ to t ₇ ], the first switch S ₁ to the sixth switch S ₆ can maintain the same state as the fifth operation mode .

In the sixth operation mode, when the second parasitic capacitor C _S2 connected in parallel to the second switch S ₃ is completely discharged, the second body diode D _S2 connected in parallel to the second switch S ₂ is turned on Accordingly, the primary side current I _pri of the transformer 220 can flow back along the third switch S ₃ and the second body diode D _S2 .

At this time, the conduction time of the second body diode (D _S2 ) must also be minimized in order to alleviate additional losses.

2 and 9, in the seventh operation mode [t ₇ to t ₈ ], the first switch S ₁ and the fourth switch S ₄ are kept in the turned off state, and the third switch S ₃ ) maintains the turn-on state, and the second switch S ₂ can be turned on at t ₇ .

In the seventh operation mode, since the voltage of the second switch S ₂ is "0", the second switch S ₂ operates at zero voltage switching (ZVS) at t ₇ and can be turned on. Accordingly, the direction of the primary current I _pri of the transformer 220 can be changed.

Further, on the secondary side of the transformer 220, as the current I _DS5 flowing through the fifth switch S ₅ becomes "0", the fifth body diode D _S5 can be cut off.

The charger 200 according to an embodiment of the present invention operates in this manner to charge the battery 300 through a constant current / constant voltage (CC / CV) charging method. At this time, It is preferable to charge the battery 300 using the power source 100 and the charger 200, but the present invention is not limited thereto.

10 is a control block diagram for constant current / constant voltage (CC / CV) charging of a charger according to an embodiment of the present invention.

Referring to FIG. 10, the charger 200 according to an exemplary embodiment of the present invention can charge the battery 300 using a constant current / constant voltage (CC / CV) charging method through dual loop control.

The constant current / constant voltage (CC / CV) charging method is a charging method in which, when the voltage of the battery 300 reaches a predetermined value, the battery 300 is charged with a constant current and the charging current is gradually reduced while being charged to a constant voltage. .

Thus, the dual loop for constant current / constant voltage (CC / CV) charging can consist of a voltage loop 10 for CV mode control and a current loop 20 for CC mode control .

The transfer function of the current output to the battery 300 through the output inductor 241 is expressed by Equation (3) below.

In Equation 3, G _id denotes a control-to-output voltage transfer function, n denotes a transformer 220 turn ratio, V _s denotes an input voltage, L denotes an output inductor 241, C is the capacitance of the output capacitor 242, and s is the Laplace variable. In addition, R _d is Rd = 4n ² is a value satisfying L _lk f _s, is the value that satisfies the _{Z b = R b + 1 /} (sC b), where, n is the transformer 220 turns ratio, L _lk is The leakage inductance, f _s is the switching frequency, R _b is the resistance of the battery 300, and C _b is the capacitance of the battery 300.

The transfer function of the output voltage of the battery 300 is expressed by Equation (4) below.

In Equation (4), G _vd denotes a control-to-output voltage transfer function, n denotes a transformer 220 turn ratio, V _s denotes an input voltage, L denotes an output inductor 241, C is the capacitance of the output capacitor 242, and s is the Laplace variable. In addition, R _d is Rd = 4n ² is a value satisfying L _lk f _s, is the value that satisfies the _{Z b = R b + 1 /} (sC b), where, n is the transformer 220 turns ratio, L _lk is The leakage inductance, f _s is the switching frequency, R _b is the resistance of the battery 300, and C _b is the capacitance of the battery 300.

From the viewpoint of Equation (3), for example, the bandwidth of the current loop 20 can be selected to be 3 kHz, which is 1/20 of the switching frequency in Table 1, and the bandwidth of the voltage loop 10, 20) can be selected.

Accordingly, the transfer function of the current loop 20 calculated using Equation (3) by the limitations shown in Table 1 can be set as shown in Equation (5) below, and the voltage loop 10) can be set as shown in Equation (6) below.

However, the following equations (5) and (6) are illustrative and do not limit the embodiments of the present invention.

In equation (5) and 6, G _ic (z) is the transfer function means (Discrete transfer function of current PI controller for CC / CV charge), and G _{vc _ CCCV} (z) of the current loop 20 includes a voltage loop ( 10) transfer function of the PI controller for CC / CV charge.

The charger 200 according to an embodiment of the present invention controls the charger 200 in a separate control unit (not shown) such as a digital signal processor according to the double loop control to perform a constant current / constant voltage (CC / CV) So that the battery 300 can be charged.

On the other hand, in the case of the input power source 100, the charger 200, and the battery 300 having the specifications as shown in Table 1, when the charging of the battery 300 is completed by the constant current / constant voltage (CC / Can be given. At this time, in order to perform impedance spectroscopy (EIS) in a separate control unit (not shown) such as a digital signal processor, a voltage of a sinusoidal waveform is applied to the open circuit voltage (V _oc ) of the charger 200 as shown in Equation (7) So that a perturbation voltage can be generated and applied to the battery 300.

In Equation 7, V denotes the perturbation voltage, V _oc denotes the open circuit voltage of the charger 200, _ΔV denotes the output voltage ripple, V _m denotes the peak value of the perturbation voltage (peak value of voltage perturbation.

In this way, the charger 200 can apply a perturbation voltage to the battery 300 under the control of a separate controller such as a digital processor to derive the current response output of the battery 300 as shown in Equation (8) below .

In Equation (8),? I denotes the response current,? Denotes the phase angle between the response current and the perturbation voltage, I _m denotes the peak value of the response current current response.

At this time, the impedance of the battery 300 can be calculated according to the following equation (9) according to the perturbation voltage and the response current.

In Equation 9, Z (ω) means the mean impedance of the battery (300), V _m is the peak value of the perturbation voltage (peak value of voltage perturbation). In addition, I _m denotes the peak value of the current response, and φ denotes the phase angle between the response current and the perturbation voltage.

According to Equation (9), it can be confirmed that the impedance of the battery 300 is a frequency-dependent parameter. That is, the impedance of the battery 300 may be characterized by a real part and an imaginary part, or a coefficient and a phase.

Therefore, in order to prevent the perturbation voltage from being distorted during the impedance measurement of the battery 300, the impedance of the battery 300 is preferably measured between 0.1 Hz and 1 kHz in the embodiment of the present invention. However, no.

Then, the charger 200 can use the impedance of the battery 300 to generate an equivalent circuit of the battery 300, thereby diagnosing the life of the battery 300 according to Equation (10).

In Equation (10), the SOH _arbitrary means the lifetime (State-Of-Health of an arbitrary battery) of the battery 300, and R _s ^selected indicates the ohmic resistance of the battery test, R _s ^aged is the ohmic resistance of the aged battery, and R _s ^fresh is the ohmic resistance of the fresh battery.

That is, the charger 200 can calculate the impedance spectrum according to the response current of the battery 300, and select the equivalent circuit model of the battery 300 according to the calculated impedance spectrum. Here, the equivalent circuit model can be modeled by a known LAN-equivalent circuit.

11 is a view showing an equivalent circuit of a battery according to an embodiment of the present invention.

Referring to FIG. 11, an equivalent circuit of the battery 300 may include two resistors R _s and R _ct and one capacitor C _dl .

Thereafter, the charger 200 calculates the impedance parameter from the equivalent circuit of the battery 300 using the known complex nonlinear least-squares fitting method, and applies the impedance parameter of the battery 300 to Equation (10) ) Can be diagnosed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

100: Input power
200: Charger
210: full bridge circuit
220: Transformer
230: rectifier circuit
240: Smoothing circuit
300: Battery

Claims (14)

A charger having a battery diagnostic function connected between an input power source for supplying an input voltage and a battery and charging the input voltage into the battery,
A full bridge circuit coupled to the input power supply and including first to fourth switches;
A primary side winding and a secondary side winding, the primary side winding being connected to the full bridge circuit to convert the input voltage received through the full bridge circuit and transfer the converted input voltage to the secondary side winding; And
And a sixth switch connected between the secondary side winding and the battery so as to rectify the voltage transferred through the transformer to charge the battery or to diagnose the life of the battery, And a rectifier circuit for transmitting power to the battery. The method according to claim 1,
Controls the first switch and the sixth switch so as to apply a perturbation voltage to charge the battery with the input voltage or to diagnose the life of the battery,
And a controller for diagnosing the lifetime of the battery based on a response current output from the battery according to the perturbation voltage. The method according to claim 1,
The full bridge circuit comprises:
A first leg and a second leg connected in parallel,
Wherein the first switch and the second switch are provided on the first leg,
And the third switch and the fourth switch are provided on the second leg. The method according to claim 1,
Wherein the first switch to the fourth switch comprises:
A charger having a battery diagnostic function in which a parasitic capacitor and a body diode are connected in parallel. The method according to claim 1,
Wherein the transformer comprises:
And a battery diagnostic function in which the secondary winding is provided with a tab. 6. The method of claim 5,
And a smoothing circuit connected to the tap provided on the secondary side winding. The method according to claim 1,
The rectifying circuit includes:
A sixth switch connected to one end of the secondary side winding, and the fifth switch connected to the other end of the primary side winding. The method according to claim 1,
Wherein the fifth switch and the sixth switch,
A charger having a battery diagnostic function in which a parasitic capacitor and a body diode are connected in parallel. The method according to claim 1,
Wherein the first switch to the fourth switch comprises:
Charger with battery diagnostic function that is turned on by zero voltage switching (ZVS). A full bridge circuit including first to fourth switches, and a primary side winding and a secondary side winding, the primary side winding being connected to the full bridge circuit to receive the full bridge circuit, And a transformer connected to the secondary side winding for rectifying the voltage received through the transformer to charge the battery. The secondary side winding is connected to the transformer, And a rectifying circuit for allowing the battery to be charged,
The input power is transmitted to the transformer according to a turn-on or a turn-off operation of the first switch to the fourth switch,
And rectifying the input voltage according to a turn-on or a turn-off operation of the fifth switch and the sixth switch to charge the battery,
And a battery diagnosis function of applying a perturbation voltage to the battery when the charging of the battery is completed and diagnosing the life of the battery based on a response current output from the battery. 11. The method of claim 10,
The transmission of the input power to the transformer in response to a turn-on or turn-off operation of the first switch to the fourth switch,
(ZVS) during the turn-on of the first switch to the fourth switch to transmit the input power to the transformer. 11. The method of claim 10,
And charging the battery by rectifying the input voltage according to a turn-on or a turn-off operation of the fifth switch and the sixth switch,
Wherein the full bridge circuit comprises a first leg and a second leg connected in parallel,
The fifth switch is connected to the other end of the secondary side winding, the sixth switch is connected to one end of the secondary side winding,
When the first switch provided on the upper side of the first leg or the fourth switch provided on the lower side of the second leg is turned on, the fifth switch also turns on,
When the first switch and the fourth switch are both turned off, the fifth switch is also turned off,
When the second switch provided on the lower side of the first leg or the third switch provided on the upper side of the second leg is turned on, the sixth switch also turns on,
Wherein when the second switch and the third switch are all turned off, the sixth switch also turns off to rectify the input voltage to charge the battery. 11. The method of claim 10,
Wherein the first switch to the sixth switch comprises:
Wherein a parasitic capacitor and a body diode are connected in parallel, respectively. 11. The method of claim 10,
Further comprising: bi-directionally transmitting power according to a turn-on or a turn-off operation of the fifth switch and the sixth switch.

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