JP2010088150A - Charger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small charger capable of charging a secondary battery with high power factor and in a short time while putting much stress on environmental resistance. <P>SOLUTION: A time ratio in switching driving for a switching element SW1 is controlled on the basis of an AC input voltage Vacin, an AC input current Iacin and a maximum output voltage Vmax. In this way, it is possible to execute charging by an output voltage Vout including ripples of proper magnitude, and a smoothing capacitor 15C having a small capacity can be used compared to the case that charging is performed using a constant voltage and a constant current. Further, since a harmonic current included in the AC input current Iacin is also reduced, a power factor is improved. Still further, in thus controlling the time ratio, the waveform of the AC input current Iacin includes a fundamental component and its harmonic component. Thus, the degree of distribution along the time axis of the maximum current in the AC input current Iacin can be adjusted in accordance with the value of a target power factor. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a charging device that includes a switching element and charges a secondary battery.

  Conventionally, various switching power supply devices including switching elements have been proposed (for example, Patent Document 1). Among these, in a switching power supply device (charging device) for charging a secondary battery, for example, after rectifying an AC voltage (commercial voltage) input from a commercial power source, the rectified voltage is switched by a switching element. The voltage obtained by this switching is smoothed by a smoothing capacitor or the like, and the secondary battery is charged with a constant voltage and a constant current based on the DC voltage obtained thereby. At this time, in order to obtain power from the commercial power source, it is necessary to reduce the harmonic current on the input side to some extent according to the standard.

JP 2004-304961 A

  Therefore, various power factor improvement type charging devices have been proposed. In these charging devices, it is essential to convert the AC power into DC using a large-capacity smoothing capacitor or the like. If a smoothing capacitor or the like having a sufficient capacity is not used, the output voltage from the charging device includes a pulsating current, and it becomes difficult to charge a constant voltage and a constant current using the DC voltage as described above. Because it will end up. For this reason, in a conventional power factor correction type charging device, a large-capacity smoothing capacitor such as an electrolytic capacitor is used in order to reduce a change in output voltage. An electrolytic capacitor is an optimal device for a smoothing capacitor from the viewpoint of capacity, cost, and volume.

  However, it has been found that this electrolytic capacitor has a problem in environmental resistance. In a charging application for an in-vehicle secondary battery that has been attracting attention in recent years, it is necessary to mount the above-described power factor improvement type charging device in a car. At this time, the charging device is required to withstand an in-vehicle environment. In response to such demands, a charging device using an electrolytic capacitor cannot satisfy characteristic stability and life characteristics. Therefore, a charging device using a film capacitor having a large capacity and a high withstand voltage is currently used, but there is a problem that the charging device itself is increased in size.

  Here, in the switching power supply device of Patent Document 1, the average value of the output current and the output voltage value are used as the input signal of the correction feedback loop, thereby controlling the time ratio (duty ratio) when driving the switching element. It is supposed to be. Therefore, it is conceivable to apply such a time ratio control operation also to the switching element in the charging device. However, in Patent Document 1, since the duty ratio is controlled by using the average value of the output current, it is necessary to use a large-capacity smoothing capacitor as described above in order to obtain a high power factor. Therefore, it is considered difficult to reduce the size of the device.

  As described above, in the conventional technology, it is difficult to charge the secondary battery with a high power factor without increasing the size of the apparatus configuration that places importance on environmental resistance, and there is room for improvement.

  Therefore, it is conceivable to charge the secondary battery with an output voltage including an appropriate magnitude of pulsating current by controlling the duty ratio at the time of switching driving. In such a configuration, since the harmonic current included in the AC input current can be reduced, the power factor can be improved as compared with the conventional case, and charging is performed with a constant voltage and a constant current as in the past. This is because it is considered that a smoothing capacitor having a smaller capacity can be used as compared with the case where it is performed.

  However, when such a method is used, the maximum value of the charging current gradually decreases as the charging of the secondary battery proceeds due to the IV characteristics (current-voltage characteristics) of the secondary battery. turn into. Accordingly, it takes a long time to charge, and there is still room for improvement in this method.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a small-sized charging apparatus capable of charging a secondary battery in a short time with high power factor while placing importance on environmental resistance. There is to do.

  A first charging device of the present invention is for charging a secondary battery, and rectifies an AC input voltage to generate a rectified voltage, and switches the rectified voltage to generate a pulse. A switching element for generating a voltage, a smoothing capacitor for generating an output voltage to be supplied to the secondary battery by smoothing the pulse voltage, and a control for performing switching driving by pulse width modulation on the switching element Part. Here, the control unit determines the AC input current based on the AC input voltage, the AC input current flowing into the rectifier circuit, and the maximum output voltage that is the maximum value within a predetermined period of the output voltage. The time ratio at the time of the switching drive is controlled so that the waveform includes a fundamental wave component composed of a sine wave corresponding to the AC input voltage and its harmonic component. The “AC input voltage” includes a voltage used as a power supply voltage for electrical equipment, and is preferably used for a so-called commercial power supply.

  In the first charging device of the present invention, the AC input voltage is rectified in the rectifier circuit to generate a rectified voltage, and the rectified voltage is switched by the switching element to generate a pulse voltage. The output voltage is generated by being smoothed by the smoothing capacitor, and the output voltage is supplied to the secondary battery, whereby the secondary battery is charged. Further, by controlling the time ratio at the time of switching driving by pulse width modulation for the switching element based on the AC input voltage, the AC input current, and the maximum output voltage, an appropriate magnitude can be obtained for the secondary battery. It becomes possible to perform charging with the output voltage including the pulsating current. Thereby, the harmonic current contained in the AC input current can be reduced. Furthermore, when controlling such a time ratio, the waveform of the AC input current is made to include a fundamental wave component consisting of a sine wave corresponding to the AC input voltage and its harmonic component, The peak current in the AC input current is dispersed along the time axis, and the degree of dispersion can be adjusted according to the target power factor value at the time of charging.

  In the first charging device of the present invention, the control unit detects the maximum output voltage from the output voltage for each predetermined period and controls the time ratio using the detected maximum output voltage. Is possible. In this case, the control unit determines the peak value of the fundamental wave component and the peak value of the harmonic component based on the maximum output voltage and the target power factor at the time of charging. It is possible. In addition, the control unit can detect the maximum output voltage every period corresponding to at least a half cycle of the cycle of the AC input voltage.

  In the first charging device of the present invention, the control unit sets a target input current that is a target value within a predetermined period of the AC input current and takes a harmonic component into account, based on the maximum output voltage, It is preferable to control the duty ratio using the set target input current. When configured in this way, the target value of the AC input current within the predetermined period is set according to the maximum output voltage that is the maximum value of the output voltage within the predetermined period, whereby the maximum output voltage is increased. The input current value can be adjusted in accordance with the voltage, and the secondary battery can be charged with the output voltage including a pulsating flow of an appropriate magnitude. Thereby, the harmonic current contained in the AC input current can be suppressed. In addition, since the harmonic component is taken into account when setting the target input current, the target input current can be set according to the target power factor value at the time of charging.

In this case, the control unit can set the target input current based on a comparison result between the maximum output voltage and a predetermined first threshold voltage. Specifically, for example, when the maximum output voltage (Vmax) is larger than the first threshold voltage (Vt1), the control unit uses the following equation (1) to calculate the target input current (I0). When the maximum output voltage (Vmax) is equal to or lower than the first threshold voltage (Vt1), the current target input current (I0 (n)) is calculated using the following equation (2). It is possible to reset the target input current to a new target input current (I0 (n + 1)). Note that “Gain” in the equation (2) represents a gain corresponding to an increase in the AC input current by adding the harmonic component. When configured in this manner, the target input current is set to the target maximum current value according to the magnitude of the maximum output voltage, thereby including a pulsating flow of an appropriate magnitude for the secondary battery. Charging with the output voltage can be made. Thereby, the harmonic current contained in the AC input current can be suppressed. Further, in the formula (2), by multiplying Gain, a harmonic component is added to the fundamental wave component, and an AC input current can be increased.
I0 = Imax (predetermined target maximum current value) (1)
I0 (n + 1) = I0 (n) × (Vt1 / Vmax) × Gain (2)

  Further, it is preferable that the control unit sets the target input current based on a comparison result between the maximum output voltage and a second threshold voltage that is lower than the first threshold voltage. When configured in this way, for example, the first threshold voltage is set to the maximum output voltage value at which the secondary battery can be normally charged, and the second threshold voltage is reduced to the harmonic current included in the AC input current. By setting the maximum output voltage value for the above, deterioration of the secondary battery due to excessive charging can be avoided while reducing the harmonic current on the input side.

  In addition, the control unit can set the target input current every half period of the cycle of the AC input voltage. In this case, it is preferable that the control unit sets the target input current at a timing near the zero cross point in the AC input voltage. When comprised in this way, the harmonic current contained in alternating current input current is reduced more effectively. In this case, the control unit detects the zero cross point in the AC input voltage, obtains the AC input voltage by calculation in synchronization with the zero cross point detected by the zero cross point detection unit, and determines the obtained AC input voltage. More preferably, the target input current is set by using the same. When configured in this way, even if the AC input current is distorted from a sine waveform due to noise or the like, the harmonic current on the input side is reliably reduced regardless of the waveform of the AC input voltage. Is done.

  In the first charging device of the present invention, the harmonic component may be configured by mixing a plurality of types of harmonic components with respect to the fundamental wave component. Further, the waveform of the harmonic component may be arbitrarily switched between a plurality of types of waveforms in accordance with, for example, a change in the target power factor.

  In the first charging device of the present invention, an AC input voltage detection unit that detects the AC input voltage is provided, and the control unit uses the AC input voltage detected by the AC input voltage detection unit to adjust the time ratio. It is possible to perform control. Moreover, while providing the alternating current input detection part which detects the said alternating current input current, the said control part may control a time ratio using the alternating current input current detected by this alternating current input current detection part. Is possible. In addition, an output voltage detection unit that detects the output voltage can be provided, and the control unit can control the duty ratio by using the output voltage detected by the output voltage detection unit.

  In the first charging device of the present invention, the switching element may be provided in a booster circuit for boosting a rectified voltage to generate the pulse voltage.

  In the 1st charging device of this invention, it is preferable that the said smoothing capacitor is comprised using the film capacitor. When configured in this manner, the smoothing capacitor and the entire device can be easily miniaturized and the environment can be further improved, and the reliability of the device is improved as compared with the case where a conventional electrolytic capacitor is used.

  In the 1st charging device of this invention, it is preferable that the said secondary battery is comprised using a lithium ion battery. In such a configuration, charging by an output voltage including a pulsating current is allowed, and therefore, it is more suitable by such a charging method.

  The second charging device of the present invention outputs an output voltage from the other input / output terminal pair based on an input voltage input from one input / output terminal pair of the first and second input / output terminal pairs. The AC / DC is for charging using this output voltage and is arranged on the first input / output terminal side, and includes a switching circuit having a first switching element and a smoothing capacitor. Switching unit, DC / DC conversion unit arranged on the second input / output terminal side and including the second switching element, and switching driving by pulse width modulation for the first and second switching elements The control part which performs is provided. Here, the control unit generates a DC output voltage that is a basis for charging the secondary battery based on the AC input voltage input from the first input / output terminal pair in the AC / DC conversion unit. When generating, the waveform of the AC input current is based on the AC input voltage, the AC input current flowing into the switching circuit, and the maximum output voltage that is the maximum value within a predetermined period of the DC output voltage. The time ratio at the time of switching driving for the first switching element is controlled so as to include a fundamental wave component consisting of a sine wave corresponding to the AC input voltage and its harmonic component. .

  In the second charging device of the present invention, during forward operation, an AC input voltage is input from the first input / output terminal pair, and in the AC / DC converter, a switching circuit that functions as a rectifier circuit and an inverter circuit, and a smoothing circuit A capacitor generates a DC output voltage based on the AC input voltage. In the DC / DC converter, voltage conversion is performed based on the DC output voltage, whereby a DC voltage for charging the secondary battery is generated and output from the second input / output terminal pair. Is done. On the other hand, during reverse operation, a DC input voltage is input from the second input / output terminal pair, and the DC / DC converter performs voltage conversion based on the DC input voltage to generate a transformed DC voltage. The In the AC / DC converter, an AC output voltage is generated based on the transformed DC voltage, and is output from the first input / output terminal pair. Further, during such forward operation and reverse operation, switching driving is performed by pulse width modulation on the first and second switching elements. Here, in the AC / DC converter, when the DC output voltage is generated based on the AC input voltage (during forward operation), the AC / DC converter is based on the AC input voltage, the AC input current, and the maximum output voltage. Thus, by controlling the time ratio at the time of switching driving for the first switching element, the secondary battery can be charged with the output voltage including a pulsating flow of an appropriate magnitude. Thereby, the harmonic current contained in the AC input current can be reduced. Further, when controlling the duty ratio for such a first switching element, the waveform of the AC input current includes a fundamental wave component consisting of a sine wave corresponding to the AC input voltage and its harmonic component. As a result, the peak current in the AC input current is distributed along the time axis, and the degree of dispersion can be adjusted according to the target power factor value during charging.

  According to the charging device of the present invention, based on the AC input voltage, the AC input current, and the maximum output voltage, the time ratio at the time of switching driving by pulse width modulation for the switching element (first switching element) is controlled. As a result, the secondary battery can be charged with an output voltage including a pulsating flow of an appropriate magnitude, and smoother with a smaller capacity than when charging with a constant voltage and a constant current as in the past. Capacitors can be used. Further, by such control, harmonic currents included in the AC input current can be reduced, and the power factor can be improved. Furthermore, when controlling the duty ratio, the waveform of the AC input current includes the fundamental wave component and its harmonic component, so that the target power factor for charging can be reduced. Depending on the value, the degree of dispersion along the time axis of the peak current in the AC input current can be adjusted, and the active power can be increased by increasing the pulsating current while improving the power factor than before. Can do. Therefore, it is possible to realize a small charging device that charges the secondary battery in a short time with high power factor while placing importance on environmental resistance.

  Hereinafter, the best mode for carrying out the present invention (hereinafter simply referred to as an embodiment) will be described in detail with reference to the drawings.

  FIG. 1 shows a circuit configuration of a charging device (charging device 1) according to an embodiment of the present invention. The charging device 1 is applied to, for example, an automobile and charges a lithium ion battery 20 that is a secondary battery based on an AC input voltage Vacin (so-called commercial voltage) supplied from a commercial power supply 10. The input voltage detection circuit 11, the rectifier circuit 12, the capacitor C1, the input current detection circuit 13, the booster circuit 14 including the switching element SW1, the smoothing circuit 15 including the smoothing capacitor 15C, and the output voltage detection circuit 16 and a control unit 17 for switching and driving the switching element SW1.

  The input voltage detection circuit 11 is disposed on the connection lines H1 and L1 between the input terminals T1 and T2 and a rectifier circuit 12 described later, and is supplied from the commercial power supply 10 via the input terminals T1 and T2. The AC input voltage Vacin is detected, and a detection signal S (Vacin) corresponding to the detected AC input voltage Vacin is output to the control unit 17. As a specific circuit configuration of the input voltage detection circuit 11, for example, the AC input voltage Vacin is detected by a voltage dividing resistor (not shown) disposed between the connection lines H1 and L1, and the input voltage detection circuit 11 is in accordance with this. Examples are those that generate voltage.

  The rectifier circuit 12 is a bridge type rectifier circuit having four rectifier diodes 12D1 to 12D4. Specifically, the anode of the diode 12D1 and the cathode of the diode 12D2 are connected to the input terminal T1 via the connection line H1, and the anode of the diode 12D3 and the cathode of the diode 12D4 are connected to the input terminal T2 via the connection line L1. It is connected. The cathode of the diode 12D1 and the cathode of the diode 12D3 are connected to the connection line H2, and the anode of the diode 12D2 and the anode of the diode 12D4 are connected to the connection line L2. With such a configuration, in the rectifier circuit 12, the input AC input voltage Vacin is rectified, and the rectified voltage V1 is generated between the connection lines H2 and L2.

  The capacitor C1 is disposed between the connection lines H2 and L2 between the rectifier circuit 12, the input current detection circuit 13 and the booster circuit 14 described later, and functions as a smoothing capacitor. Specifically, it is for smoothing and reducing noise or the like during a switching operation by the switching element SW1 described later.

  The input current detection circuit 13 is arranged on the connection line L2 between one end of the capacitor C1 and a booster circuit 14 to be described later, and receives the AC input current Iacin flowing into the rectifier circuit 12 as shown in FIG. In addition to detection, a detection signal S (Iacin) corresponding to the detected AC input current Iacin is output to the control unit 17. A specific circuit configuration of the input current detection circuit 13 includes, for example, a circuit including a current transformer.

  The booster circuit 14 includes a switching element SW1, an inductor 14L, and a diode 14D. Specifically, the inductor 14L is inserted and arranged on the connection line H2, one end is connected to the other end of the capacitor C1, and the other end is connected to one end (drain) of the switching element SW. The switching element SW1 is a switching element for switching the rectified voltage V1 to generate the pulse voltage V2. For example, a field effect transistor (MOS-FET), a bipolar transistor, It is comprised by IGBT (Insulated Gate Bipolar Transistor) etc. Here, the switching element SW1 is composed of an N-channel MOS-FET, the gate is connected to the signal line of the SW control signal S1 supplied from the control unit 17, the source is connected to the connection line L2, and the drain is connected. It is connected to the connection line H2. The anode of the diode 14D is connected to the other end of the inductor 14L and the drain of the switching element SW1, and the cathode of the diode 14D is connected to one end of a smoothing capacitor 15C described later. With this configuration, the booster circuit 14 generates a pulse voltage V2 boosted based on the rectified voltage V1, as will be described in detail later.

  The smoothing circuit 15 includes a smoothing capacitor 15C configured using, for example, a film capacitor. Specifically, one end of the smoothing capacitor 15C is connected to the cathode of the diode 14D, and the other end of the smoothing capacitor 15C is connected to the connection line L2. With such a configuration, the smoothing circuit 15 generates the output voltage Vout to be supplied to the lithium ion battery 20 by smoothing the pulse voltage V2.

  The output voltage detection circuit 16 is disposed on the connection lines H2 and L2 between the smoothing circuit 15 and the output terminals T3 and T4, and is supplied to the lithium ion battery 20 via the output terminals T3 and T4. The voltage Vout is detected, and a detection signal S (Vout) corresponding to the detected output voltage Vout is output to the control unit 17. As a specific circuit configuration of the output voltage detection circuit 16, as in the input voltage detection circuit 11, for example, the output voltage Vout is generated by a voltage dividing resistor (not shown) disposed between the connection lines H2 and L2. And generating a voltage corresponding to this.

  The controller 17 receives the AC input voltage Vacin (specifically, the detection signal S (Vacin)) supplied from the input voltage detection circuit 11 and the AC input current Iacin (specifically, the input current detection circuit 13). Generates the SW control signal S1 and switches based on the detection signal S (Iacin)) and the output voltage Vout (specifically, the detection signal S (Vout)) supplied from the output voltage detection circuit 16. By supplying to the gate of the element SW1, switching driving is performed on the switching element SW1 by pulse width modulation (PWM). Specifically, the control unit 17 includes the AC input voltage Vacin, the AC input current Iacin, and a maximum output voltage (maximum output voltage Vmax described later) that is a maximum value within a predetermined period of the output voltage Vout. Based on the above, the time ratio (duty ratio) at the time of switching driving of the switching element SW1 is controlled. As a result, as will be described in detail later, unlike the conventional charging device using a constant voltage and constant current, the lithium ion battery 20 is charged with a pulsating flow in the output voltage Vout. . In addition, when the control unit 17 controls the time ratio, the waveform of the AC input current Iacin is a sine wave corresponding to the AC input voltage Vacin (specifically, in phase and in phase with the AC input voltage Vacin). The duty ratio is controlled so as to include a fundamental wave component having a periodic sine wave) and a harmonic component thereof. Thereby, although the details will be described later, the maximum current in the AC input current Iacin is distributed along the time axis.

  Here, with reference to FIG. 2, the detailed structure of the control part 17 is demonstrated. FIG. 2 shows a detailed block configuration of the control unit 17.

  The control unit 17 includes a calculation unit 171, a maximum value detection unit 172, a target current determination unit 173, and a duty ratio correction unit 174.

  The calculation unit 171 includes an AC input voltage Vacin (specifically, a detection signal S (Vacin)) supplied from the input voltage detection circuit 11 and a target input current (a target described later) supplied from a target current determination unit described later. The input current I0) is subjected to a predetermined calculation process, and includes a phase calculation unit 171A, a harmonic addition unit 171B, and a multiplication unit 171C.

  The phase calculation unit 171A calculates a phase in the detection signal S (Vacin). At this time, the phase calculation unit 171A detects a zero cross point (specifically, a detection signal S (zp) not shown) in the AC input voltage Vacin.

  The harmonic addition unit 171B adds the harmonics (for example, third harmonics) to the AC input voltage Vacin (fundamental wave) made of a sine wave, so that the AC after adding such harmonics. The input voltage Vacin 'is generated. Such harmonic waveform signals are stored in, for example, a memory (not shown) in the control unit 17. However, the harmonic adding unit 171B may calculate such a harmonic by performing a predetermined calculation (for example, Taylor expansion). At this time, the AC input voltage Vacin ′ after the addition of the harmonic is subjected to a predetermined calculation (for example, for example, in synchronization with the zero cross point (specifically, the detection signal S (zp)) detected by the phase calculation unit 171A. It is preferable to obtain by Taylor development. As a result, even when the AC input current Iacin is distorted from a sine waveform due to noise or the like, the harmonic current can be reliably reduced regardless of the waveform of the AC input voltage Vacin. Because it becomes.

  The multiplier 171C multiplies the harmonic input AC voltage Vacin ′ supplied from the harmonic adder 171B by the target input current I0, and the multiplication result (Vacin ′ × I0) will be described later. Is output to the time ratio correction unit 174.

  Details of the operation of the arithmetic unit 171 having such a configuration will be described later.

  The maximum value detector 172 detects the maximum output voltage Vmax for each predetermined period from the output voltage Vout (specifically, the detection signal S (Vout)) supplied from the output voltage detection circuit 16. Specifically, such detection of the maximum output voltage Vmax is performed every period (at least 0.5 × T period) of at least a half period of the period T in the AC input voltage Vacin.

  Based on the maximum output voltage Vmax supplied from the maximum value detection unit 172, the target current determination unit 173 is a target input that is a target value within a predetermined period of the AC input current Iacin and that takes into account the harmonic components described above. The current I0 is set. Specifically, the target input current I0 is set based on the comparison result between the maximum output voltage Vmax and a predetermined threshold voltage Vt1 set in advance. Further, such setting of the target input current I0 is performed every period (at least 0.5 × T period) of the period T in the AC input voltage Vacin (at least half period of the period T). It is updated every period). Details of the operation of the target current determination unit 173 will be described later.

  The time ratio correction unit 174 includes an AC input current Iacin (specifically, a detection signal S (Iacin)) supplied from the input current detection circuit 13 and a calculation result (multiplication result (Vacin ′) supplied from the calculation unit 171. Based on × I0)), the time ratio of the switching element SW1 is feedback-corrected to generate and output the SW control signal S1 of the switching element SW1. The subtraction unit 174A and the PI compensation calculation unit 174B And have. The subtraction unit 174A takes a difference between the multiplication result (Vacin ′ × I0) and the detection signal S (Iacin) (subtracts the value of the detection signal S (Iacin) from the multiplication result (Vacin ′ × I0)). Thus, an error value e (= (Vacin ′ × I0) −Iacin) as a subtraction result is output. The PI compensation calculation unit 174B generates a SW control signal S1 that has been subjected to the time ratio correction by performing a predetermined PI compensation calculation on the input error value e. Details of the operation of the PI compensation calculation unit 174B will be described later.

  Note that the function of the control unit 17 of the present embodiment is configured by software, and all processing by the control unit 17 is performed by a digital signal processing device. Therefore, an A / D (analog / digital) converter (not shown) is provided in each of the input voltage detection circuit 11, the input current detection circuit 13, and the output voltage detection circuit 16 described above. Such a digital signal processing device is preferably composed of, for example, a logic circuit group or a microcomputer, and is preferably composed of a DSP (Digital Signal Processor).

  Next, the operation and effect of the charging device 1 of the present embodiment will be described.

  Initially, with reference to FIGS. 1-4, the basic operation | movement (charging operation to the lithium ion battery 20) of the charging device 1 is demonstrated. FIG. 3 is a timing waveform diagram showing the overall operation of the charging apparatus 1, (A) shows the AC input voltage Vacin, (B) shows the rectified voltage V1, and (C) shows the output voltage Vout, respectively. Represents. For the AC input voltage Vacin, the rectified voltage V1 and the output voltage Vout, the direction of the arrow shown in FIG. 1 represents the positive direction.

  In this charging device 1, for example, as shown in FIG. 3A, when an AC input voltage Vacin (commercial voltage) composed of a sine wave with a period T is supplied between the input terminals T1 and T2, the rectifier circuit 12 By rectification, for example, as shown in FIG. 3B, a rectified voltage V1 composed of a positive half wave is generated.

Next, the booster circuit 14 generates a boosted pulse voltage V2 by performing a boosting operation as shown in FIGS. 4A and 4B, for example, based on the rectified voltage V1. Specifically, the pulse voltage V2 is generated by switching the rectified voltage V1 by the switching element SW1. More specifically, first, when the switching element SW1 is turned on in response to the SW control signal S1 (on period Ton), for example, as shown in FIG. A current I1 flows to SW1, and thereby magnetic energy is stored in the inductor 14L. When the switching element SW1 is turned off in accordance with the SW control signal S1 (off period Toff), for example, as shown in FIG. 4B, the current I2 in the order of the inductor 14L, the diode 14D, and the capacitor 15C. As a result, the magnetic energy stored in the inductor 14L is stored in the capacitor 15C, and a boosting operation is performed. It should be noted that the relationship between the rectified voltage V1 and the pulse voltage V2 during such a boosting operation is expressed as shown in the following equation (10).
V2 = {(Ton + Toff) / Toff} × V1 (10)

  Next, in the smoothing circuit 15, the input pulse voltage V <b> 2 is smoothed, and an output voltage Vout to be supplied to the lithium ion battery 20 is generated. In the present embodiment, the output voltage Vout includes a pulsating flow having a cycle of 0.5 × T as shown in FIG. 3C, for example. Thereby, the lithium ion battery 20 is charged by the output voltage Vout including such a pulsating current and the output current Iout shown in FIG.

  Next, referring to FIGS. 5 to 10 in addition to FIGS. 1 to 4, the control operation of the switching element SW by the control unit 17, which is one of the characteristic parts of the present invention, is compared with the comparative example. The details will be described. Here, FIG. 5 is a characteristic diagram (characteristic diagram showing a relationship between the charging voltage and the charging current) of the charging operation in the charging device according to the comparative example.

  In the charging device according to this comparative example, the control unit uses the AC input voltage Vacin, the AC input current Iacin, and the maximum output voltage Vmax to determine the time ratio (duty ratio in the SW control signal S1) when switching the switching element SW1. Is controlled. As a result, charging with the output voltage Vout including a pulsating flow of an appropriate magnitude is possible, and the AC input current Iacin can have the same phase and waveform as the AC input voltage Vacin. The harmonic current contained in the current Iacin is reduced.

  At this time, as described above, the AC input current Iacin has the same phase and waveform as the AC input voltage Vacin. Therefore, the output voltage Vout generated in this comparative example is, for example, the code P101 in FIG. As shown by (3), it becomes a sine wave (the waveform of the broken line in FIG. 3C). However, when the lithium ion battery 20 is charged using the output voltage Vout composed of such a sine wave, the following improvements will occur.

  FIG. 5 schematically shows an example of the IV characteristic (charging current-charging voltage) characteristic in the lithium ion battery during the charging operation in the charging device according to the comparative example. In this figure, a characteristic line P201 represents a characteristic line when the state of charge of the lithium ion battery is empty (state of not being charged at all). In addition, characteristic lines P202 and P203 represent characteristic lines when charging in the lithium ion battery proceeds as indicated by an arrow P200 in the drawing.

  Here, in the charging device according to this comparative example, at the start of charging, first, charging is performed along the characteristic line P201. At this time, charging is performed with a pulsating current (target current I01 in the figure) that is equal to or less than the maximum value of the charging current (corresponding to a target maximum current value Imax described later). Next, as charging progresses, charging is performed along the characteristic line P202. Here, the charging is performed by a charging current corresponding to a charging voltage equal to or lower than the maximum value of the charging voltage (corresponding to the maximum output voltage Vmax described above). It will be done by current. As charging further proceeds, charging is performed along the characteristic line P203. The charging at this time is performed by the pulsating current by the target current I03 in the figure for the above reason. Thus, in this comparative example, the maximum value of the charging current gradually decreases as the charging proceeds due to the IV characteristics of the lithium ion battery (target current I01 in the figure). → Refer to I02 → I03), it takes a long time to charge.

  Further, in the charging device according to this comparative example, by using the output voltage Vout composed of a sine wave synchronized with the commercial power supply 10, a very high power factor of, for example, 99% or more can be realized during charging. However, in actual use, a high power factor is rarely required. For example, when JIS-S-61000-3-2, which is a harmonic regulation, is applied to a charging system of 100 V and 200 A, the power factor required by this standard is 93.7% or more.

  Therefore, in charging device 1 of the present embodiment, in control unit 17, the waveform of AC input current Iacin includes a fundamental component composed of a sine wave corresponding to AC input voltage Vacin and its harmonic component. As described above, the duty ratio at the time of switching driving of the switching element SW1 is controlled. Thus, for example, as indicated by reference sign P1 in FIG. 3C, the output voltage Vout generated in the charging device 1 is, for example, sine as indicated by reference sign P1 and an arrow in FIG. The waveform includes a fundamental wave component composed of a wave and its harmonic component (solid line waveform in FIG. 3C).

  Specifically, first, the target current determination unit 173 in the control unit 17 performs, for example, as shown in FIG. 6, a target power factor at the time of charging and Gain (an alternating current by adding a harmonic component). The gain value used in the case of a target current I0 to be described later is held according to the relationship with the gain corresponding to the increase in the input current Iacin. In addition, FIG. 6 is a thing at the time of using the 3rd harmonic as a harmonic component. As can be seen from FIG. 6, when the third harmonic is used, the Gain becomes the maximum value (about 1.15 times) near the target power factor = 98.6%. This value of power factor = 98.6% is a value that sufficiently satisfies the harmonic regulation standard. When a higher power factor is required than this, the value of Gain determined by the characteristic curve shown in FIG. 6 may be used as appropriate.

  The harmonic adding unit 171B in the control unit 17 adds a harmonic waveform signal corresponding to the target power factor value to be added to the AC input voltage Vacin (fundamental wave) composed of a sine wave. keeping. Thus, for example, as shown in FIG. 7, the waveform of the AC input current Iacin corresponding to the target power factor value (a fundamental wave component consisting of a sine wave corresponding to the AC input voltage Vacin, and its harmonic component) Will be obtained).

  In FIGS. 6 and 7, the third harmonic is used as the added harmonic. However, any other harmonic such as the second harmonic, the fourth harmonic, and the fifth harmonic can be used. It is possible to use. Further, not only one harmonic but also a plurality of types of harmonics may be added simultaneously (for example, the third harmonic and the fifth harmonic are added simultaneously to the fundamental wave). It may be) That is, the harmonic component may be configured by mixing a plurality of types of harmonic components with respect to the fundamental wave component. However, for example, in JIS-S-61000-3-2, which is a harmonic regulation, a larger value than the other harmonic current is allowed for the third harmonic current. Therefore, it can be said that it is desirable to add the third harmonic as the main component (include the third harmonic) as the added harmonic.

  In addition, the harmonic adding unit 171B holds a plurality of types of harmonics in advance, and can arbitrarily switch the added harmonics according to, for example, a target power factor change. May be. In this case, the target current determination unit 173 also holds a plurality of types of Gain values respectively corresponding to a plurality of types of harmonics. Further, as described above, when the harmonic component is configured by mixing a plurality of types of harmonic components with respect to the fundamental component, the mixing ratio between the plurality of types of harmonic components is set to the target. It may be possible to switch arbitrarily according to a change in the power factor.

  At this time, when the target input current I0 is set, the harmonic component is taken into account, so that the target input current I0 can be set according to the target power factor value at the time of charging. It becomes. Specifically, although details will be described later, the peak value of the fundamental component and the peak value of the harmonic component are determined based on the maximum output voltage Vmax and the target power factor at the time of charging. Become.

  Thus, in the present embodiment, for example, as indicated by arrows P21 to P23 in FIG. 7, the peak current in the AC input current Iacin is distributed along the time axis. Specifically, as indicated by an arrow P21 in the figure, a current peak is generated as the target power factor decreases as compared with a fundamental wave (power factor = 100%) consisting of a single sine wave. While the value of decreases, as indicated by arrows P22 and P23 in the figure, the value of the current peak in the dispersed portion increases. Therefore, it is possible to adjust the degree of dispersion along the time axis of the peak current in the AC input current Iacin according to the target power factor value at the time of charging, while improving the power factor than before. The effective power can be increased by increasing the pulsating current.

  In this case, more specifically, the control operation shown in FIG. FIG. 8 is a flowchart showing an example of the control operation by the control unit 17 (processing for determining the target input current I0 by the target current determination unit 173).

  First, during the charging operation, the AC input voltage Vacin is detected by the input voltage detection circuit 11, the AC input current Iacin is detected by the input current detection circuit 13, and the output voltage Vout is detected by the output voltage detection circuit 16. The Then, the detection signal S (Vacin) from the input voltage detection circuit 11, the detection signal S (Iacin) from the input current detection circuit 13, and the detection signal S (Vout) from the output voltage detection circuit 16 are supplied to the control unit 17, respectively. Is done.

  Then, the control unit 17 performs a control operation as described below based on the detection signal S (Vacin), the detection signal S (Iacin), and the detection signal S (Vout), thereby performing the time ratio correction SW. A control signal S1 is generated.

  First, as shown in FIG. 2, the phase of the AC input voltage Vacin is calculated from the detection signal S (Vacin) in the phase calculator 171A in the calculator 171. At this time, the phase calculator 171A detects a zero cross point in the AC input voltage Vacin.

  On the other hand, in the maximum value detection unit 172, for example, the detection signal S (Vout) is like the maximum output voltages Vmax (n−1), Vmax (n), Vmax (n + 1),... Shown in FIG. Thus, for each period of a half period of the period T in the AC input voltage Vacin (0.5 × T period), the maximum output voltage Vmax that is the maximum value of the output voltage Vout within that period is detected.

  Next, in the target current determination unit 173, based on the input maximum output voltage Vmax, for example, as shown in FIG. 8, within a predetermined period in the AC input current Iacin (here, the period T in the AC input voltage Vacin). A target input current I0 that is a target value for a period of half a cycle (within a period of 0.5 × T) and in which a harmonic component is added is set as needed for each period of 0.5 × T ( Updated from time to time). In the present embodiment, for example, as shown in FIG. 3C, such setting of the target input current I0 is performed at a timing near the zero cross point in the AC input voltage Vacin.

More specifically, the target current determination unit 173 first compares the maximum output voltage Vmax and the threshold voltage Vt1 (step S11 in FIG. 8). Here, when the maximum output voltage Vmax is equal to or lower than the threshold voltage Vt1 (step S11: N), the target input current I0 is set using the following equation (11) (step S12). On the other hand, when the maximum output voltage Vmax is larger than the threshold voltage Vt1 (step S11: Y), a new target input current is calculated from the current target input current (I0 (n)) using the following equation (12). The target input current I0 is reset to (I0 (n + 1)) (step S13). After that, it is determined whether or not the entire process for determining the target input current I0 is to be ended (step S14). If not to be ended (step S14: N), the process returns to step S11 and ends. In this case (step S14: Y), the entire process for determining the target input current I0 is completed.
I0 = Imax (predetermined target maximum current value) (11)
I0 (n + 1) = I0 (n) × (Vt1 / Vmax) × Gain (12)
(Gain: Gain corresponding to an increase in AC input current Iacin by adding harmonic components)

The duty ratio in the SW control signal S1 is such that the AC input current Iacin varies in proportion to the absolute value of the AC input voltage Vacin, and the absolute value of the AC input voltage Vacin is maximum. The AC input current Iacin at the time corresponds to the target input current I0. Imax is a value corresponding to the maximum rated input current value of the secondary battery to be charged, and Vt1 is a value corresponding to the maximum rated input voltage value of the secondary battery to be charged. Further, the following expression (13) may be used instead of the above expression (12).
I0 (n + 1) = Imax × Gain (13)

  Next, in the multiplication unit 171C in the calculation unit 171, the AC input voltage Vacin ′ after the harmonic addition supplied from the harmonic addition unit 171B and the target input current I0 supplied from the target current determination unit 173 are mutually connected. The multiplication result (Vacin ′ × I0) is output to the duty ratio correction unit 174.

  Next, the duty ratio correction unit 174 switches the switching element SW1 based on the detection signal S (Iacin) supplied from the input current detection circuit 13 and the multiplication result (Vacin ′ × I0) supplied from the calculation unit 171. As a result, the SW control signal S1 is generated. Specifically, first, the subtraction unit 174A obtains a difference between the multiplication result (Vacin ′ × I0) and the detection signal S (Iacin) (from the multiplication result (Vacin ′ × I0), the detection signal S (Iacin) By subtracting the value, an error value e (= (Vacin ′ × I0) −Iacin) as a subtraction result is output. Then, the PI compensation unit 174B performs a predetermined PI compensation operation on the input error value e by using the following equations (14) and (15) in synchronization with the switching frequency, thereby correcting the time ratio. The SW control signal S1 subjected to is generated.

  The switching element SW1 in the booster circuit 14 performs a switching operation in accordance with the SW control signal S1 thus corrected for the time ratio, thereby performing the above-described generation operation and boosting operation of the pulse voltage V2. The Rukoto.

  Thus, in charging device 1 of the present embodiment, AC input voltage Vacin is rectified in rectifier circuit 12 to generate rectified voltage V1, and this rectified voltage V1 is switched by switching element SW1 to generate a pulse. The voltage V2 is generated, and the pulse voltage V2 is smoothed by the smoothing capacitor C1 to generate the output voltage Vout. The output voltage Vout is supplied to the lithium ion battery 20, whereby the lithium ion battery 20 is Charging is done. Thereby, the lithium ion battery 20 is charged with the output voltage Vout including the pulsating flow.

  At this time, the control unit 17 controls the time ratio (duty ratio in the SW control signal S1) at the time of switching driving for the switching element SW1 based on the AC input voltage Vacin, the AC input current Iacin, and the maximum output voltage Vmax. Thus, charging with the output voltage Vout including a pulsating flow of an appropriate magnitude is possible, so that the harmonic current included in the AC input current Iacin is reduced.

  In such a time ratio control, the waveform of the AC input current Iacin is a sine wave corresponding to the AC input voltage Vacin (specifically, a sine wave having the same phase and the same period as the AC input voltage Vacin). Therefore, the peak current in the AC input current Iacin is dispersed along the time axis, and the target power factor for charging is obtained. The degree of dispersion can be adjusted according to the value of. In addition, in the above-described equation (2), by multiplying Gain, a harmonic component is added to the fundamental wave component, and the AC input current Iacin can be increased.

At this time, the peak value of the fundamental wave component and the peak value of the harmonic component are determined based on the maximum output voltage Vmax and the target power factor at the time of charging. Thus, for example, FIG. 9 (a third harmonic component added to the fundamental wave component) and FIG. 10 (a third harmonic component and a fifth harmonic component added to the fundamental wave component). The AC input current Iacin as shown in FIG. Specifically, for example, when adding a third harmonic component as shown in FIG. 9, if the target power factor is 98.6%, the target current I0 of the fundamental component and the third harmonic component are set. Each of I0 ′ is obtained as follows. First, {I0 / √ (I0 ² + I0 ′ ² )} = 0.986, so that I0 ′ = (0.169 × I0). Next, since it has changed to (Vt1 / Vmax) = 0.8, if the third harmonic is taken into account, I0 (n + 1) = I (n) × 0.8 × 1 .15, and I0 ′ = {0.169 × I (n + 1)}. Therefore, for example, when I0 (n) = 15A, I0 (n + 1) = 13.8A and I0 ′ = 2.62A, and the combined peak current is 12A. That is, Vmax shown in FIG. At this time, when the AC input voltage Vacin = 100 V, the effective power is 1.38 kW, which is 1.15 times larger than the effective power (1.20 kW) in the case of only a sine wave. Thereby, it turns out that charge in a shorter time is attained compared with the charging device which concerns on the above-mentioned comparative example.

  As described above, in the present embodiment, the time ratio (duty ratio in the SW control signal S1) at the time of switching driving for the switching element SW1 is controlled based on the AC input voltage Vacin, the AC input current Iacin, and the maximum output voltage Vmax. As a result, it is possible to charge the lithium ion battery 20 with the output voltage Vout including a pulsating flow of an appropriate magnitude. Compared to the case where charging is performed with a constant voltage and a constant current as in the conventional case, the capacity is reduced. A small smoothing capacitor 15C can be used. In addition, by such control, the harmonic current included in the AC input current Iacin can be reduced, and the power factor can be improved. Further, when controlling the duty ratio, the waveform of the AC input current Iacin includes a fundamental wave component consisting of a sine wave corresponding to the AC input voltage Vacin and its harmonic component. The degree of dispersion along the time axis of the peak current in the AC input current Iacin can be adjusted according to the target power factor value at the time of charging, while improving the power factor than before, The effective power can be increased by increasing the pulsating current. Therefore, it is possible to realize a small charging device that charges the secondary battery in a short time with high power factor while placing importance on environmental resistance.

  Further, a target input current I0 that is a target value within a predetermined period in the AC input current Iacin based on the maximum output voltage Vmax and that takes the harmonic component into account is set, and the target input current I0 that is set is used to set the time. Since the ratio is controlled, the target value of the AC input current Iacin within the predetermined period can be set according to the maximum output voltage Vmax, which is the maximum value of the output voltage Vout within the predetermined period. Therefore, the input current value can be adjusted according to the magnitude of the maximum output voltage Vmax, and the lithium ion battery 20 can be charged with the output voltage Vout including a pulsating flow of an appropriate magnitude. Thereby, the harmonic current contained in the AC input current Iacin can be suppressed. Further, since the harmonic component is taken into account when setting the target input current I0, the target input current I0 can be set according to the target power factor value at the time of charging. It becomes possible.

  When the maximum output voltage Vmax is less than or equal to the threshold voltage Vt1, the target input current I0 is set using the above equation (11), and when the maximum output voltage Vmax is greater than the threshold voltage Vt1, Since the target input current is reset from the current target input current I0 (n) to the new target input current I0 (n + 1) using the equation (12), the maximum input voltage Vmax is set according to the maximum output voltage Vmax. Thus, the target input current I0 can be set to the target maximum current value Imax, and the lithium ion battery 20 can be charged with the output voltage Vout including an appropriately pulsating current. . Thereby, the harmonic current contained in the AC input current Iacin can be suppressed. Further, in the above equation (12), since the gain (gain corresponding to the increase in the AC input current Iacin by adding the harmonic component) is multiplied, the harmonic component is added to the fundamental wave component, and the AC The input current Iacin can be increased.

  In addition, since the target input current I0 is set at a timing near the zero cross point in the AC input voltage Iacin, the harmonic current included in the AC input current Iacin can be more effectively reduced. .

  In addition, since the smoothing capacitor 15C is configured using a film capacitor, the smoothing capacitor 15C and the charging device 1 as a whole can be easily miniaturized and have a higher resistance compared to the case where a conventional electrolytic capacitor is used. Since the environment can be improved, the reliability of the apparatus can be improved.

  Furthermore, since the secondary battery to be charged is configured using a lithium ion battery, charging by the output voltage Vout including the pulsating current can be allowed, and it is adapted by such a charging method. It becomes possible to set it as the structure which carried out.

  While the present invention has been described with reference to the embodiment, the present invention is not limited to this embodiment, and various modifications can be made.

  For example, in the above embodiment, the case where the target input current I0 is set by comparing the maximum output voltage Vmax and the threshold voltage Vt1 is described. For example, as shown in FIG. 11, the maximum output voltage The target input current I0 may be set based on a comparison result between Vmax and a threshold voltage Vt2 that is lower than the threshold voltage Vt1. When configured in this way, for example, the threshold voltage Vt1 is set to the maximum output voltage value at which the lithium ion battery 20 can be normally charged, and the threshold voltage Vt2 is reduced to a harmonic current included in the AC input current Iacin. Therefore, it is possible to avoid deterioration of the lithium ion battery 20 due to excessive charging while reducing the harmonic current.

  In the above embodiment, the PI compensation unit 174B generates the SW control signal S1 with the time ratio corrected by performing the PI compensation calculation using the above equations (13) and (14). As described above, for example, the SW control signal S1 subjected to the time ratio correction may be generated by performing the P compensation calculation or the PID compensation calculation using the following expression (16) or (17). .

  In the above-described embodiment, the target input current I0 is set at a timing near the zero cross point in the AC input voltage Iacin. However, such a target input current I0 is set to other values. You may make it carry out at timing.

  Further, the configurations of the rectifier circuit, the booster circuit, the smoothing circuit, and the control unit described in the above embodiment are not limited to these, and may be other configurations.

  For example, in the above embodiment, the case where the rectifier circuit and the booster circuit are separately provided and the switching element is provided in the booster circuit has been described. However, for example, as in the charging device 1A shown in FIG. As an alternative, the synchronous rectifier circuit 19 may be used as a part of the booster circuit, and the switching elements SW11 to SW14 in the synchronous rectifier circuit 19 may also serve as switching elements of the booster circuit. Specifically, the synchronous rectifier circuit 19 includes two inductors 14L1 and 14L2, four switching elements SW11 to SW14, and a diode 14D. The inductor 14L1 is inserted and disposed on the connection line H1, and the inductor L2 is inserted and disposed on the connection line L1. The gate of the switching element SW11 is connected to the signal line of the SW control signal S11 supplied from the control unit 17B, the source is connected to the connection line H1, and the drain is connected to the connection line H2. The gate of the switching element SW12 is connected to the signal line of the SW control signal S12 supplied from the control unit 17B, the source is connected to the connection line L2, and the drain is connected to the connection line H1. The gate of the switching element SW13 is connected to the signal line of the SW control signal S13 supplied from the control unit 17B, the source is connected to the connection line L1, and the drain is connected to the connection line H2. The gate of the switching element SW14 is connected to the signal line of the SW control signal S14 supplied from the control unit 17B, the source is connected to the connection line L2, and the drain is connected to the connection line L1. The anode of the diode 14D is connected to the drains of the switching elements SW11 and SW13, and the cathode of the diode 14D is connected to one end of the smoothing capacitor 15C. With this configuration, in the synchronous rectifier circuit 19, when the AC input voltage Vacin is positive, the switching elements SW11 and SW14 are turned on, the switching element SW13 is turned off, and the switching element SW12 is turned on / off (the time ratio is Controlled state). On the other hand, when the AC input voltage Vacin is negative, the switching elements SW12 and SW13 are turned on, the switching element SW11 is turned off, and the switching element SW14 is turned on / off (time ratio is controlled).

  Further, for example, like the AC / DC converter 5A shown in FIGS. 13 to 16, the charging device 1A described above is provided as an AC / DC conversion unit, and a DC / DC conversion unit 3A is provided in the subsequent stage, and the AC / DC converter is provided. The entire converter 5A may be configured as a charging device capable of bidirectional operation. 13 to 16, the control unit 17 in the charging device 1A is provided in the control unit 4 for controlling switching operations in the AC / DC conversion unit 1A and the DC / DC conversion unit 3A for convenience. It is illustrated as being provided. Here, in the AC / DC converter 1A, the switching elements SW21 to SW24 are each composed of a MOS-FET. Further, in the DC / DC converter 3A, the full bridge type switching elements SW31 to SW34 are each configured by a MOS-FET, and the full bridge type switching elements SW41 to SW44 each configured by a MOS-FET are provided. It has been. The DC / DC converter 3A is provided with a transformer 32 having windings 321 and 322 and a smoothing capacitor 34C. In this case, each of the switching elements SW21 to SW24, SW31 to SW34, and SW41 to SW44 can be regarded as including a switching element and a rectifier diode (parasitic diode of the switching element) connected in parallel to them. In such a configuration, the DC output voltage Vout is generated based on the AC input voltage Vacin input from the input terminals T1 and T2 and output from the output terminals T3 and T4 as described in the above embodiment. In addition to the direction operation (refer to the current path of the arrow shown in FIGS. 13 and 14), the AC output voltage Vacout is generated based on the DC input voltage Vdcin input from the output terminals T3 and T4, and the input terminals T1, It is also possible to perform the reverse operation (see the current path indicated by the arrows shown in FIGS. 15 and 16) output from T2 (bidirectional operation is possible).

  In this case, the AC / DC converter 5A corresponds to a specific example of “charging device” in the present invention. The input terminals T1 and T2 correspond to a specific example of “first input / output terminal” in the present invention, and the output terminals T3 and T4 correspond to a specific example of “second input / output terminal” in the present invention. To do. Further, the switching elements SW21 to SW24 correspond to a specific example of “first switching element” in the present invention, and the switching elements SW31 to SW34 and SW41 to SW44 correspond to a specific example of “second switching element” in the present invention. Corresponding to The full bridge circuit composed of the switching elements SW21 to SW24 corresponds to a specific example of “switching circuit” in the present invention, and the smoothing capacitor 15C corresponds to a specific example of “smoothing capacitor” in the present invention.

  In the above embodiment, the function of the control unit 17 is configured by software. However, the function of the control unit 17 may be configured by hardware. However, when configured by hardware, the circuit scale increases, and it is difficult to correct variations in each element. Therefore, it is preferable to configure by software as in the above embodiment.

  Furthermore, although the case where the secondary battery to be charged is configured using a lithium ion battery has been described in the above embodiment, the charging device of the present invention is used for secondary batteries other than lithium ion batteries. Can also be applied.

It is a circuit diagram showing the structure of the charging device which concerns on one embodiment of this invention. It is a block diagram showing the detailed structure of the control part shown in FIG. It is a timing waveform diagram for demonstrating operation | movement of the whole charging device. FIG. 2 is a circuit diagram for explaining the operation of the booster circuit shown in FIG. 1. It is a characteristic view for demonstrating the charging operation in the charging device which concerns on a comparative example. It is a characteristic view showing an example of the relationship between a power factor and a gain. It is a characteristic view showing an example of the relationship between a power factor and a current waveform. It is a flowchart showing an example of the control action by a control part. It is a characteristic view showing an example of the current waveform concerning an embodiment. It is a characteristic view showing the other example of the current waveform which concerns on embodiment. It is a schematic diagram for demonstrating the threshold voltage which concerns on the modification of this invention. It is a circuit diagram showing the structure of the charging device which concerns on the other modification of this invention. It is a circuit diagram for demonstrating the forward direction operation | movement of the whole AC / DC converter which concerns on the other modification of this invention. It is a circuit diagram for demonstrating the forward direction operation | movement of the whole AC / DC converter which concerns on the other modification of this invention. It is a circuit diagram for demonstrating the reverse direction operation | movement of the whole AC / DC converter which concerns on the other modification of this invention. It is a circuit diagram for demonstrating the reverse direction operation | movement of the whole AC / DC converter which concerns on the other modification of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,1A ... Charger (AC / DC conversion part), 10 ... Commercial power supply, 11 ... Input voltage detection circuit, 12 ... Rectifier circuit, 13 ... Input current detection circuit, 14 ... Booster circuit, 15 ... Smoothing circuit, 16 ... Output voltage detection circuit 17, 17B ... control unit, 171 ... calculation unit, 171A ... phase calculation unit, 171B ... harmonic addition unit, 171C ... multiplication unit, 172 ... maximum value detection unit, 173 ... target current determination unit, 174 ... time ratio correction unit, 174A ... subtraction unit, 174B ... PI compensation calculation unit, 19 ... synchronous rectification circuit, 20 ... lithium ion battery, 3A ... DC / DC conversion unit, 32 ... transformer, 321, 322 ... winding, 4 ... Control unit, 5A ... AC / DC converter, 60 ... Load, T1, T2 ... Input terminal, T3, T4 ... Output terminal, H1, L1, H2, L2 ... Connection line, Vacin, Vacin '... AC input voltage, V1 ... Current voltage, V2 ... pulse voltage, Vout ... output voltage, Vmax ... maximum output voltage, Vt1, Vt2 ... threshold voltage, Vdcout ... DC output voltage, Iacin ... AC input current, I0 ... target input current, Imax ... target maximum current value , Iout ... output current, I1, I2 ... current, Gain ... gain, S (Vacin), S (Iacin), S (Vout) ... detection signal, S1, S11 to S14 ... SW control signal, 12D1 to 12D4 ... diode, C1... Capacitor, SW1, SW11 to SW14, SW21 to SW24, SW31 to SW34, SW41 to SW44 ... Transistor (switching element), 14L, 14L1, 14L2 ... Inductor, 14D ... Diode, 15C, 34C ... Smoothing capacitor, T ... AC Input current cycle, t0 to t4... Timing.

Claims (19)

A charging device for charging a secondary battery,
A rectifier circuit that rectifies an AC input voltage to generate a rectified voltage;
A switching element for switching the rectified voltage to generate a pulse voltage;
A smoothing capacitor that generates an output voltage to be supplied to the secondary battery by smoothing the pulse voltage;
A controller that performs switching driving by pulse width modulation on the switching element, and
The control unit, based on the AC input voltage, the AC input current flowing into the rectifier circuit, and the maximum output voltage that is the maximum value within a predetermined period in the output voltage, the waveform of the AC input current, A charging device, wherein a time ratio at the time of the switching drive is controlled so as to include a fundamental wave component composed of a sine wave corresponding to the AC input voltage and a harmonic component thereof. The said control part detects the said maximum output voltage from the said output voltage for every said predetermined period, and controls the said time ratio using this detected maximum output voltage. Charging device. The control unit determines a peak value of the fundamental component and a peak value of the harmonic component based on the maximum output voltage and a target power factor at the time of charging. Item 3. The charging device according to Item 2. 4. The charging device according to claim 2, wherein the control unit detects the maximum output voltage every period corresponding to at least a half cycle of the cycle of the AC input voltage. 5. The control unit sets a target input current that is a target value within a predetermined period of the AC input current based on the maximum output voltage and takes the harmonic component into account, and sets the set target input current. The charging device according to claim 1, wherein the duty ratio is controlled by using the charging device. The charging device according to claim 5, wherein the control unit sets the target input current based on a comparison result between the maximum output voltage and a predetermined first threshold voltage. When the maximum output voltage (Vmax) is less than or equal to the first threshold voltage (Vt1), the controller sets the target input current (I0) using the following equation (1), and When the maximum output voltage (Vmax) is larger than the first threshold voltage (Vt1), a new target input current (I0 (n)) is calculated from the current target input current (I0 (n)) using the following equation (2). The charging apparatus according to claim 6, wherein the target input current is reset to I0 (n + 1)).
I0 = Imax (predetermined target maximum current value) (1)
I0 (n + 1) = I0 (n) × (Vt1 / Vmax) × Gain (2)
(Gain: Gain corresponding to an increase in the AC input current by adding the harmonic component) The control unit sets the target input current based on a comparison result between the maximum output voltage and a second threshold voltage that is lower than a predetermined first threshold voltage. 5. The charging device according to 5. The said control part performs the setting of the said target input current for every period for the half period of the period in the said alternating current input voltage. The charging device of Claim 5 characterized by the above-mentioned. The charging device according to claim 9, wherein the control unit sets the target input current at a timing near a zero cross point in the AC input voltage. The charging device according to any one of claims 1 to 10, wherein the harmonic component is configured by mixing a plurality of types of harmonic components with respect to the fundamental wave component. The charging device according to any one of claims 1 to 11, wherein a waveform of the harmonic component can be arbitrarily switched between a plurality of types of waveforms. An AC input voltage detection unit for detecting the AC input voltage;
The charging according to any one of claims 1 to 12, wherein the control unit controls the duty ratio using the AC input voltage detected by the AC input voltage detection unit. apparatus. An AC input current detection unit for detecting the AC input current;
The charging according to any one of claims 1 to 13, wherein the control unit controls the duty ratio using an AC input current detected by the AC input current detection unit. apparatus. An output voltage detector for detecting the output voltage;
The charging device according to any one of claims 1 to 14, wherein the control unit controls the duty ratio by using the output voltage detected by the output voltage detection unit. The charging device according to any one of claims 1 to 15, wherein the switching element is provided in a booster circuit that boosts the rectified voltage to generate the pulse voltage. . The said smoothing capacitor is comprised using the film capacitor. The charging device of any one of the Claims 1 thru | or 16 characterized by the above-mentioned. The charging device according to any one of claims 1 to 17, wherein the secondary battery is configured using a lithium ion battery. An output voltage is output from the other input / output terminal pair based on an input voltage input from one input / output terminal pair of the first and second input / output terminal pairs, and charging is performed using this output voltage. A charging device for
An AC / DC converter configured to include a switching circuit disposed on the first input / output terminal side and having a first switching element, and a smoothing capacitor;
A DC / DC converter disposed on the second input / output terminal side and configured to include a second switching element;
A controller that performs switching driving by pulse width modulation on the first and second switching elements, and
The control unit generates a DC output voltage that is a basis for charging the secondary battery based on the AC input voltage input from the first input / output terminal pair in the AC / DC conversion unit. In doing so, based on the AC input voltage, the AC input current flowing into the switching circuit, and the maximum output voltage that is the maximum value within a predetermined period of the DC output voltage, the waveform of the AC input current is: The time ratio at the time of switching driving for the first switching element is controlled so as to include a fundamental wave component composed of a sine wave corresponding to the AC input voltage and a harmonic component thereof. Charging device.

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