JP6076747B2 - Switching power supply - Google Patents

Description

  The present invention relates to a switching power supply device that can charge a storage battery that requires preliminary charging.

  Conventionally, for example, Patent Document 1 described below describes a switching power supply device that is effective in reducing the size and performance of an electronic device. Patent Document 2 below describes a resonance type charging device that can charge a secondary battery with high efficiency. In this resonance type charging device, a constant current circuit is configured using a series resonance converter (hereinafter referred to as “LLC”) in order to satisfy constant current characteristics.

  On the other hand, when charging a storage battery having a low cell voltage, such as a lithium ion battery, in general, in order to avoid deterioration of the storage battery, preliminary charging is performed in which charging is performed at a low voltage and a low current.

JP 2007-97303 A JP 2012-85378 A

  However, in the conventional switching power supply device, when the constant current circuit is configured using the LLC, the condition for satisfying the constant current characteristic is determined by the external LC resonance constant, and is set to the LC resonance constant satisfying normal charging. In this case, a constant current characteristic at a low voltage and a low current for precharging cannot be realized.

The switching power supply device of the present invention receives direct current (hereinafter referred to as “DC”) power, detects an LLC to which a storage battery is connected on the output side, a voltage value between terminals of the storage battery, and detects the storage battery from the detection result. A preliminary charge determination circuit for outputting a main circuit disconnection signal when the determination result indicates that a preliminary charge is required, and the main circuit disconnection signal from the preliminary charge determination circuit is input. A switching circuit that disconnects an output side of the main circuit of the LLC, wherein the LLC includes a primary winding having a first winding number and a secondary winding having a second winding number. The main circuit having a transformer with a winding; and a third winding number of auxiliary windings electromagnetically coupled to the primary winding and provided on the secondary side of the transformer; Windings connected in parallel to the output side of the main circuit It has a, and a circuit. When the separation circuit is in an on state, a charging current during normal charging is supplied from the output side of the main circuit to the storage battery. When the separation circuit is in an off state, from the output side of the winding circuit. A charging current at the time of preliminary charging is supplied to the storage battery.

According to the switching power supply apparatus of the present invention, the LLC, the storage battery is connected to the output side, a pre備充conductive judging circuit includes a disconnect circuit, a, a pre-charging judgment circuit, it is necessary to pre-charging of the battery When the determination is made, the disconnection circuit disconnects the output side of the LLC main circuit. As a result, when precharging the storage battery is necessary, low voltage and low current precharging can be realized by the winding circuit even if the LC resonance constant in the LLC is set to an LC resonance constant that satisfies normal charging. .

FIG. 1 is a block diagram showing an outline of the configuration of a switching power supply device 20 in Embodiment 1 of the present invention. FIG. 2 is a circuit diagram showing an example of the precharge determination circuit 60 in FIG. FIG. 3 is a block diagram showing an outline of the configuration of the switching power supply device 20A of the comparative example. FIG. 4 is a characteristic diagram showing the relationship of the output voltage Vo with respect to the switching frequency fsw of the LLC 40A in FIG. FIGS. 5A and 5B are circuit diagrams showing examples of the precharge circuit 80 in FIG. FIG. 6 is a diagram showing temporal transition of the charging voltage Vbatt and the charging current Ibatt of the switching power supply device 20 in FIG. FIG. 7 is a flowchart showing the charging control process according to the first embodiment of the present invention. FIG. 8 is a block diagram showing an outline of the configuration of the switching power supply device 20B according to the second embodiment of the present invention. FIG. 9 is a block diagram showing an outline of the configuration of the switching power supply 20C according to the third embodiment of the present invention. FIG. 10 is a block diagram showing an example of the voltage detection circuit 60A in FIG. FIG. 11 is a diagram showing an example of the charging table 65 in FIG. FIG. 12 is a flowchart showing the charging control process according to the third embodiment of the present invention.

  Modes for carrying out the present invention will become apparent from the following description of the preferred embodiments when read in light of the accompanying drawings. However, the drawings are only for explanation and do not limit the scope of the present invention.

(Configuration of Example 1)
FIG. 1 is a block diagram showing an outline of a configuration of a switching power supply device 20 according to the first embodiment of the present invention.

  The switching power supply device 20 includes an LLC 40, a precharge determination circuit 60, and a disconnection circuit 70.

The LLC 40 switches the input DC voltage Vin and DC current Iin, converts the switched DC voltage Vin and DC current Iin by series resonance, and then rectifies the second DC voltage Vo and the second DC voltage Vin. Is a circuit that outputs a DC current Io. This LLC40 the two switches 42a, 42b, a capacitor 43 for the series resonant inductor 44, winding number n2 as the primary winding 45a and a number of second winding of the winding number n1 of the first winding number A secondary transformer 45b, a conversion transformer (hereinafter referred to as "conversion transformer") 45, a rectifying diode 46, a smoothing capacitor 47, a current detection circuit 48 for measuring an output current, and two switches 42a, It is composed of an LLC control circuit 41 etc. for controlling on / off of 42b. The storage battery 21 is connected to the first and second output terminals OUT1, OUT2 of the LLC 40. When the storage battery 21 is connected to the output terminals OUT1 and OUT2 of the LLC 40, the current detection circuit 48 measures the charging current supplied from the switching power supply 20 to the storage battery 21.

A winding circuit 50 is further connected in parallel to the first and second output terminals OUT1 and OUT2. The winding circuit 50 is a circuit that outputs a low voltage and a low current between the first output terminal OUT1 and the second output terminal OUT2 at the time of precharging, and the primary circuit of the conversion transformer 45 in the LLC 40. An inductor 51 having a spare winding as an auxiliary winding of the third winding number (n3) electromagnetically coupled to the winding , a rectifying diode 52, and a smoothing capacitor 53 are configured.

When the voltages of the secondary winding 45b and the auxiliary winding 51 of the conversion transformer 45 are Vb and Vc, respectively,
Vb / n2 = Vc / n3 (1)
Vc = (n3 / n2) · Vb (2)
It becomes. Here, for example, if n3 / n2 = 1/3, a voltage Vc that is 1/3 of the voltage Vb of the secondary winding 45b of the conversion transformer 45 can be extracted from the output terminal of the winding circuit 50.

The preliminary charging determination circuit 60 detects the inter-terminal voltage value Vbatt of the storage battery 21 and determines whether or not the preliminary charging of the storage battery 21 is necessary from the detection result. If the determination result indicates that the preliminary charging is necessary, the main circuit It is a circuit that outputs a separation signal S60. Further, the disconnect circuit 70 is a circuit that disconnects the output of the main circuit of the LLC 40 when the main circuit disconnect signal S60 from the precharge determination circuit 60 is input.

FIG. 2 is a circuit diagram showing an example of the precharge determination circuit 60 in FIG.
The precharge determination circuit 60 measures the inter-terminal voltage value Vbatt of the storage battery 21, compares the inter-terminal voltage value signal S61 and the precharge determination voltage V1 with the voltmeter 61 that outputs the inter-terminal voltage value signal S61. The preliminary charging determination unit 62 outputs a main circuit disconnection signal S60 when preliminary charging is required. The precharge determination unit 62 includes, for example, a comparator 62a that is a comparator, a DC power supply 62b that generates a precharge determination voltage V1 and supplies the precharge determination voltage V1 to one input terminal of the comparator 62a, and an output terminal of the comparator 62a that is connected to the DC voltage Vcc. And a resistor 62c that is pulled up at the same time.

(Operation of Example 1)
The operation of the switching power supply device 20 according to the first embodiment is divided into (I) the operation of the conventional comparative example, (II) the operation of the first embodiment, and (III) the charge control process in the first embodiment. To do.

(I) Operation of Comparative Example FIG. 3 is a block diagram showing an outline of the configuration of the switching power supply device 20A of the comparative example. Elements common to FIG. 1 showing the first embodiment are denoted by common reference numerals. .

  The switching power supply device 20A of the comparative example has a configuration in which a preliminary charging circuit 80 is added to the LLC 40A similar to the first embodiment except that the winding circuit 50 is not connected to the output side.

  FIG. 4 is a characteristic diagram showing the relationship of the output voltage Vo with respect to the switching frequency fsw of the LLC 40A in FIG.

  The characteristic of the voltage Vo before the precharge circuit 80 with respect to the switching frequency fsw of the LLC 40A shown in FIG. 3 is shown by a curve Q in FIG. Looking at the curve Q, even if the switching frequency fsw is increased, the output voltage Vo cannot be lowered to the precharge determination voltage V1.

The preliminary charging circuit 80 is a circuit for reducing the output voltage Vo to the preliminary charging determination voltage V1.
5A and 5B are circuit diagrams showing examples of the precharge circuit 80 in FIG.

  FIG. 5A shows a dropper type preliminary charging circuit 80. When the output voltage Vo of the LLC 40A in FIG. 3 is lowered to the precharge determination voltage V1 by the dropper type precharge circuit 80, the heat loss increases and the efficiency of the switching power supply 20A decreases.

  FIG. 5B shows a step-down converter type precharge circuit 80. When the output voltage Vo of the LLC 40A in FIG. 3 is lowered to the precharge determination voltage V1 by the step-down converter type precharge circuit 80, the loss is smaller than the dropper type precharge circuit 80, and the efficiency of the switching power supply 20A is improved. Although the decrease is small, the number of parts increases.

  Thus, in the first embodiment, the configuration of the switching power supply device 20 as shown in FIGS. 1 and 2 is adopted, and the output voltage Vo is increased to the precharge determination voltage V1 without adding the precharge circuit 80. I try to lower it.

(II) Operation of Embodiment 1 The operation of the switching power supply device 20 of Embodiment 1 will be described based on FIGS. 1 and 2.
During normal charging, the inter-terminal voltage signal S61 supplied from the voltmeter 61 to the preliminary charging determination unit 62 in FIG. 2 is equal to or higher than the preliminary charging determination voltage V1, and thus is the output of the comparator 62a in the preliminary charging determination unit 62. The main circuit separation signal S60 is at a high level (hereinafter referred to as “H level”), and the separation circuit 70 is turned on.

In FIG. 1, when the separation circuit 70 is in the on state, the charging current Ibatt during normal charging is supplied to the storage battery 21 from the main circuit of the LLC 40 including the conversion transformer 45, the rectifying diode 46, the smoothing capacitor 47, and the like. Is done.

  On the other hand, at the time of preliminary charging, since the inter-terminal voltage signal S61 given from the voltmeter 61 to the preliminary charging determination unit 62 in FIG. 2 is less than the preliminary charging determination voltage V1, the output of the comparator 62a in the preliminary charging determination unit 62 is output. The main circuit disconnection signal S60 is at a low level (hereinafter referred to as “L level”), and the disconnection circuit 70 is turned off.

In FIG. 1, when the separation circuit 70 is in the off state, the main circuit of the LLC 40 is separated from the storage battery 21 and is composed of an inductor 51, a rectifier diode 52, a smoothing capacitor 53, and the like, which are spare windings having a winding number n3. The charging current Ibatt at the time of preliminary charging is supplied to the storage battery 21 from the winding circuit 50 that is provided.

The voltage Vc supplied to the storage battery 21 from the winding circuit 50 of the auxiliary winding 51 having the number of windings n3 indicates the number of turns of the primary winding 45a and the secondary winding 45b of the conversion transformer 45 in the LLC 40 by n1. , N2 and the charging voltage during normal charging is Vb,
Vc = (n3 / n2) · Vb
It becomes.

Therefore, the number of turns n3 of the auxiliary winding 51 in the winding circuit 50 is
n3 = (Vc / Vb) · n2 (3)
That is, if the number of windings obtained by multiplying the number n2 of secondary windings of the conversion transformer 45 by (preliminary charging voltage / normal charging voltage) is preliminarily charged from the winding circuit 50 to the storage battery 21 at the time of preliminary charging. The voltage Vc can be supplied.

(III) Processing of Charging Control in Embodiment 1 FIGS. 6A and 6B are diagrams showing temporal transitions of the charging voltage Vbatt and the charging current Ibatt of the switching power supply device 20 in FIG. (A) is a figure which shows the time transition of the voltage value Vbatt between terminals with respect to the charging time of the storage battery 21, FIG.6 (b) is a figure which shows the time transition of the charging current value Ibatt with respect to the charging time of the storage battery 21. It is.

  In the preliminary charging period Ty in which the inter-terminal voltage value Vbatt of the storage battery 21 is less than the preliminary charging determination voltage V1, the charging current value Ibatt indicates the preliminary charging current Iy. V0 to V1 in the preliminary charging period Ty are preliminary charging voltages.

  When the preliminary charging continues and the inter-terminal voltage value Vbatt of the storage battery 21 becomes equal to or higher than the preliminary charging determination voltage V1, the charging current value Ibatt changes from the preliminary charging current Iy to the normal charging current Is, and shifts to the normal charging period Ts. .

  In the normal charging period Ts, the inter-terminal voltage value Vbatt of the storage battery 21 increases from the preliminary charging determination voltage V1 to V2. When the inter-terminal voltage value Vbatt of the storage battery 21 reaches V2, the charging current value Ibatt gradually decreases.

FIG. 7 is a flowchart illustrating the charging control process according to the first embodiment of the present invention.
With reference to FIGS. 1, 2, and 6, the charge control process in the switching power supply device 20 of the first embodiment will be described based on the flowchart shown in FIG.

  1 and 2, when the storage battery 21 is connected to the output terminals OUT1 and OUT2 of the LLC 40, the charging control process in the preliminary charging control circuit 60 is started, and the process proceeds to step ST1. In step ST1, the voltmeter 61 measures the inter-terminal voltage Vbatt of the storage battery 21, gives the inter-terminal voltage value signal S61 to the precharge determination unit 62 in the precharge control circuit 60, and proceeds to step ST2.

  In step ST2, the comparator 62a in the precharge determination unit 62 in FIG. 2 determines whether the inter-terminal voltage value signal S61 is less than the precharge determination voltage V1, and the inter-terminal voltage value signal S61 is the precharge determination voltage. If less than V1 (Y), the process proceeds to step ST3, and if the inter-terminal voltage value signal S61 is equal to or higher than the precharge determination voltage V1 (N), the process proceeds to step ST7.

  In step ST3, when the precharge determination circuit 60 in FIG. 1 outputs the main circuit disconnection signal S60, the disconnection circuit 70 is turned off. Thereafter, the LLC 40 is activated, the LLC control unit 41 controls the switching frequency fsw of the LLC 40, and the DC voltage V <b> 1 is supplied to the storage battery 21 as the output voltage Vc of the winding circuit 50. At this time, as shown in FIG. 6, the preliminary charging current Iy is supplied to the storage battery 21, and the process proceeds to step ST4.

  In step ST4, the voltmeter 61 in FIG. 2 measures the inter-terminal voltage Vbatt of the storage battery 21, and provides the inter-terminal voltage value signal S61 to the precharge determination unit 62 in the precharge determination circuit 60, and then proceeds to step ST5. move on. In step ST5, the comparator 62a in the precharge determination unit 62 in FIG. 2 determines whether or not the inter-terminal voltage value signal S61 is equal to or higher than the precharge determination voltage V1, and the inter-terminal voltage value signal S61 is the precharge determination voltage. Steps ST4 and ST5 are repeated until V1 is equal to or higher than (Y). If the inter-terminal voltage value signal S61 is equal to or higher than the precharge determination voltage V1 (Y), the process proceeds to step ST6.

  In step ST6, when the precharge determination circuit 60 in FIG. 1 changes the logic level of the main circuit disconnection signal S60 from the L level to the H level, the disconnection circuit 70 is turned on. Thereafter, DC voltages V1 to V2 are supplied to the storage battery 21 as the output voltage Vo of the main circuit of the LLC 40, and the normal charging current Is is supplied to the storage battery 21 as shown in FIG. To do.

  In step ST7, when the precharge determination circuit 60 in FIG. 1 changes the logic level of the main circuit disconnection signal S60 from the L level to the H level, the disconnection circuit 70 is turned on, and then the LLC 40 is activated and the LLC 40 As the output voltage Vo of the main circuit, DC voltages V1 to V2 are supplied to the storage battery 21, and as shown in FIG. 6, the normal charging current Is is supplied to the storage battery 21, and the charging control process ends.

  6A and 6B show time transitions of the charging voltage Vbatt and the charging current Ibatt according to the charging control process of the flowchart shown in FIG.

(Effect of Example 1)
According to the switching power supply device 20 of the first embodiment, the preliminary charging determination circuit 60 determines whether or not preliminary charging is necessary based on the inter-terminal voltage value Vbatt of the rechargeable battery 21, and the preliminary charging determination circuit 60 If necessary, the main circuit disconnect signal S60 is output to disconnect the main circuit of the LLC 40. Thereby, the switching power supply device 20 can realize a constant current characteristic at a low voltage and a low current for precharging without adding a precharging circuit 80 like the switching power supply device 20A of the comparative example.

(Configuration and operation of embodiment 2)
FIG. 8 is a block diagram showing an outline of the configuration of the switching power supply device 20B according to the second embodiment of the present invention. Elements common to FIG. 1 showing the first embodiment are denoted by common reference numerals.

  The switching power supply device 20B includes the same LLC 40, precharge determination circuit 60, and disconnection circuit 70 as in the first embodiment, an AC (hereinafter referred to as “AC”) power supply 10, an input unit 11, and a power factor correction circuit (hereinafter “ 30) is added.

The input unit 11 includes an unwanted radiation countermeasure (EMI) filter (not shown), a diode bridge, and the like, and switches the input voltage AC and the voltage Vin and Ii obtained by full-wave rectification to the same switching source device as in FIG. 20 is input.

  The PFC 30 receives the AC power, improves the power factor by switching the current and the voltage in the AC power so that the phase of the current and the voltage in the AC power matches, and determines a predetermined first DC voltage Vpfc, and This is a circuit that outputs the first DC current Ipfc to the LLC 40.

  The PFC 30 includes an inductor 32, a switch 33, a rectifying diode 34, a smoothing capacitor 35, and a PFC control circuit 31 that controls on / off of the switch 33.

  The PFC control circuit 31 includes an error amplifier (not shown) and a reference voltage source that is input to one input terminal of the error amplifier, and a voltage obtained by dividing the first DC voltage Vpfc at a certain ratio is an error amplifier (not shown). In this circuit, the switch 33 is turned on / off so that the voltage difference between the input terminals of an error amplifier (not shown) is zero and is input to the other input terminal. Other configurations and operations of the second embodiment are the same as those of the first embodiment.

(Effect of Example 2)
According to the switching power supply device 20B of the second embodiment, the PFC 30 is provided on the input side of the switching power supply device 20 of the first embodiment, and AC power supplied from the PFC 30 is efficiently converted into a DC voltage Vpfc and a DC current Ipfc. To LLC40. Thereby, it is possible to efficiently perform a low voltage and low current precharge from the input of the commercial power supply.

(Configuration of Example 3)
FIG. 9 is a block diagram showing an outline of the configuration of the switching power supply device 20C according to the third embodiment of the present invention. Elements common to FIG. 8 showing the second embodiment are denoted by common reference numerals.

  The switching power supply device 20B according to the third embodiment of the present invention includes a PFC 30, the LLC 40, and the disconnect circuit 70 similar to those in the second embodiment, and a precharge determination circuit 60A having a different configuration and function from the precharge determination circuit 60 according to the second embodiment. And is constituted by.

FIG. 10 is a block diagram illustrating an example of the precharge determination circuit 60A in FIG.
The precharge control circuit 60A stores a precharge determination unit 62A having a function different from that of the first embodiment, a newly added type detection unit 64, and charge control information in a voltmeter 61 similar to that of the first embodiment. And a charging table 65.

  The type detection unit 64 determines the type of the storage battery 21 and whether or not the precharge is the required type based on the storage battery signal S21 given from the storage battery 21. Further, the type detection unit 64 refers to the charging table 65, acquires the charge control information corresponding to the type of the storage battery 21, and detects the type including information indicating whether or not preliminary charging is required and the charge control information. The signal S64 is given to the preliminary charge determination unit 62A. The preliminary charging determination unit 62A determines whether or not preliminary charging is necessary from the inter-terminal voltage signal S61 based on the type detection signal S64 given from the type detection unit 64 when the type requires preliminary charging. .

  For example, the shape of the battery pack is changed according to the type of the storage battery 21 and the number of cells, and the method of expressing the information of the type of the storage battery 21 and the number of cells according to the shape of the battery pack, or the identification terminal other than the positive electrode and the negative electrode The storage battery signal S21 can be obtained from the storage battery 21 by a known method such as a method of connecting different resistance values depending on the type and the number of cells of the storage battery 21 between the negative electrode and the identification terminal.

FIG. 11 is a diagram illustrating an example of the charging table 65 in FIG.
In the example of the charging table 65 shown in FIG. 11, the values of the preliminary charging determination voltage V1, the preliminary charging current Iy, and the normal charging current Is corresponding to the types A, B, and C of the storage battery 21 are stored.

  In FIG. 11, types A, B, and C are batteries that need to be precharged, and the precharge determination voltages V1 of types A, B, and C are 2.0V, 4.0V, and 6.0V, respectively. The pre-charging currents Iy for types A, B, and C are 50 mA, 70 mA, and 130 mA, respectively. Furthermore, the normal charging currents Is of types A, B, and C are 2.0 A, 2.5 A, and 3.0 A, respectively. In FIG. 11, type D is a battery that does not require preliminary charging, and the normal charging current Is of type D is 3.0A.

  The values of the precharge determination voltage V1, the precharge current Iy, and the normal charge current Is shown in FIG. 11 are provisional values for explaining the configuration of the third embodiment. The actual values of the precharge determination voltage V1, the precharge current Iy, and the normal charge current Is are individually designed according to the type of the storage battery 21 and the number of cells, or are determined by experiments.

(Operation of Example 3)
FIG. 12 is a flowchart illustrating the charging control process according to the second embodiment of the present invention.
The charging control process of the second embodiment will be described with reference to FIGS. 9 to 11 and based on FIG.

  In FIG. 9, when the storage battery 21 is connected to the output of the LLC 40, the charging control process in the preliminary charging determination circuit 60A is started, and the process proceeds to step ST21. In step ST21, the type detection unit 64 in FIG. 10 detects the type of the storage battery 21 based on the storage battery signal S21 input from the storage battery 21, and proceeds to step ST22.

  In step ST22, the type detection unit 64 reads the charge control information corresponding to the type of the storage battery 21 with reference to the charging table 65, and proceeds to step ST23. In step ST23, the type detecting unit 64 determines whether or not the storage battery needs to be precharged. If necessary (Y), the process proceeds to step ST1, and if not necessary (N), the process proceeds to step ST6. In FIG. 11, if the battery type is A, preliminary charging is necessary, so the process proceeds to step ST1, and if the battery type is D, preliminary charging is not necessary, so the process proceeds to step ST7.

  When the process proceeds to step ST1, in steps ST1 to ST5, the same process as in the first embodiment is performed, and the process proceeds to step ST6. However, in steps ST2 and ST5 in FIG. 12, the inter-terminal voltage signal S61 is compared with the precharge determination voltage V1 changed in accordance with the type of storage battery shown in FIG.

  In step ST7, the disconnection circuit 70 is turned on, the LLC 40 is activated, and the charge control process in the preliminary charge determination circuit 60A is terminated.

(Effect of Example 3)
According to the third embodiment of the present invention, in addition to the configurations of the first and second embodiments, the newly added type detection unit 64 and the charging table 65 determine whether or not the storage battery needs to be precharged. Only in this case, the separation circuit 70 is turned off to perform preliminary charging. Thereby, when the storage battery 21 is a storage battery that does not need to be precharged, the normal charging control voltage Vs is immediately set and the LLC 40 is started, so that the charging time can be shortened.

(Modification)
This invention is not limited to the said Examples 1-3, A various utilization form and a modification are possible. For example, there are the following (1) and (2) as usage forms and modifications.

  (1) In the first to third embodiments, the precharge determination unit 62 determines whether or not precharge is necessary by comparing the inter-terminal voltage value signal S61 output from the voltmeter 61 with the precharge determination voltage V1. Although an example of an analog circuit using the comparator 62a has been described, the precharge determination unit 62 is not limited to an analog circuit. For example, the same function may be configured by a digital circuit, or the same function may be executed by software.

  (2) In the first embodiment, the example in which the preliminary charging determination unit 62 determines whether or not preliminary charging is necessary based only on the inter-terminal voltage value signal S61 has been described, but the current detection result of the current detection circuit 48 Also, it may be determined whether or not preliminary charging is necessary. If it is determined whether or not preliminary charging is necessary in consideration of the current detection result, deterioration of the storage battery 21 that needs preliminary charging can be avoided more reliably.

20, 20A, 20B Switching power supply 21 Storage battery 30, 30A PFC
31 PFC control circuit 31d Error amplifier 31e Switching control unit 40, 40A LLC
41 LLC control circuit 48 Current detection circuit 49 Voltage detection circuit 50 Winding circuit 60, 60A Precharge determination circuit 62, 62A Precharge determination unit 64 Type detection unit 65 Charging table

Claims (6)

A series resonant converter that receives DC power and has a storage battery connected to the output side;
Preliminary charge determination that detects a voltage value between terminals of the storage battery, determines whether or not a preliminary charge for the storage battery is necessary from the detection result, and outputs a main circuit disconnection signal when the determination result requires the preliminary charge Circuit,
When the main circuit disconnection signal from the precharge determination circuit is input, a disconnect circuit that disconnects the output side of the main circuit of the series resonant converter;
A switching power supply device comprising:
The series resonant converter is:
The main circuit having a transformer having a primary winding of a first winding number and a secondary winding of a second winding number;
A winding circuit electromagnetically coupled to the primary winding and having a third winding number of auxiliary windings provided on the secondary side of the transformer and connected in parallel to the output side of the main circuit When,
With
When the disconnecting circuit is in an on state, a charging current during normal charging is supplied from the output side of the main circuit to the storage battery, and when the disconnecting circuit is in an off state, preliminary charging is performed from the output side of the winding circuit. A switching power supply device characterized in that a charging current at the time is supplied to the storage battery . The preliminary charge determination circuit is
A voltmeter that measures the voltage value between the terminals and outputs a voltage value signal between the terminals;
Comparing the voltage value signal between the terminals and the precharge determination voltage value, and when the voltage value signal between the terminals is less than the precharge determination voltage value, a precharge determination unit that outputs the main circuit disconnection signal;
The switching power supply device according to claim 1, comprising: The third winding number of the auxiliary winding is:
3. The switching power supply device according to claim 1 , wherein the number of the secondary windings is less than the number of the second windings . The disconnect circuit is
2. A circuit that is on / off controlled in accordance with the presence or absence of the main circuit disconnection signal input from the precharge determination circuit, wherein a resistance value in an on state is smaller than a resistance value in an off state. 4. The switching power supply device according to any one of 3 above. The switching power supply device according to any one of claims 1 to 4,
A power factor that inputs AC power, improves the power factor by switching control so that the phase of current and voltage in the AC power matches, outputs a predetermined DC voltage, and applies the DC voltage to the series resonant converter Improvement circuit ,
Switching power supply unit, characterized in that it comprises a. The precharge determination circuit further includes:
A type detection unit for detecting the type of the storage battery;
A charging table storing charging control information corresponding to the type of the storage battery;
Have
The charging control information corresponding to the type of the storage battery detected by the type detection unit is read from the charging table, and the preliminary charging determination voltage value and a preliminary charging current that is a charging current at the time of preliminary charging are read from the charging table. 3. The switching power supply device according to claim 2 , wherein the value and a normal charging current value that is a charging current during normal charging are changed.

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