JP6601912B2 - Parallel-type charging device and calibration method for the charging device - Google Patents

Description

  The present invention relates to a charging device including a plurality of power supply units connected in parallel to each other, and a calibration method for calibrating each power supply unit of the charging device.

  With the recent increase in capacity of secondary batteries, demand for charging devices capable of outputting a large current has increased. In order to meet this demand, various types of charging devices including a plurality of power supply units connected in parallel with each other have been studied. According to this type of charging device, a large current can be easily output simply by increasing the number of power supply units. That is, according to this type of charging device, it is possible to satisfy the demand for a large current without redesigning the power supply unit.

  The charging device may have a calibration function for calibrating the current output by itself. The calibration usually includes a voltage drop value and a reference voltage value when a predetermined current is passed through a shunt resistor built in the power supply unit (or each power supply unit when a plurality of power supply units are provided). This is done by comparing When the voltage drop value is lower than the reference voltage value, the current is shifted slightly. On the other hand, when the voltage drop value exceeds the reference voltage value, the current is shifted higher.

  By the way, the shunt resistance varies slightly depending on the temperature. In addition, when current is passed, the temperature of the shunt resistor increases. For this reason, in order to increase the accuracy of calibration, it is necessary to allow the same amount of current to flow through the shunt resistor before detecting the voltage drop value, and to raise the temperature of the shunt resistor to the saturation point. There is. To stabilize the temperature by passing a current in advance is referred to as “warming up” in this specification.

  Calibration is performed according to the timing charts shown in FIGS. 3 and 4, for example. In these figures, Ira, Irb, Irc, and Ird are currents that flow through the shunt resistors Ra, Rb, Rc, and Rd provided in the first to fourth power supply units connected in parallel to each other. Further, t1, t3, t5, and t7 are warm-up periods, and t2, t4, t6, and t8 are detection periods. The warm-up periods t1, t3, t5, and t7 have the same length. The detection periods t2, t4, t6, and t8 have the same length.

  In the example shown in FIG. 3, the warm-up periods t1, t3, t5, and t7 and the detection periods t2, t4, t6, and t8 are arranged so as not to overlap in time. On the other hand, in the example shown in FIG. 4, in order to shorten the calibration time, the warm-up periods t1, t3, t5, t7 and the detection periods t2, t4, t6, t8 are arranged so as to overlap in time. However, also in FIG. 4, the detection periods t2, t4, t6, and t8 do not overlap.

  Such a timing chart is disclosed in, for example, Patent Document 1. However, Patent Document 1 is not a document related to the charging device.

JP 2014-196931 A

  However, the calibration according to the timing chart of FIG. 4 has a slight problem in accuracy because the environment in the detection periods t2, t4, t6, and t8 is different from the environment in actual use. That is, in actual use, all the power supply units operate simultaneously and affect each other thermally. In the timing chart of FIG. 4, the other power supply units stop operating particularly in the detection period t8 of the fourth power supply unit. Since the influence of the other power supply section on the shunt resistance Rd is reduced, there is a problem that the calibration of the current Ird is not accurate. The timing chart of FIG. 3 has the same problem.

  This invention is made | formed in view of such a situation, The place made into the subject is providing the charging device which can be calibrated more correctly than before, and the calibration method in this charging device.

  In order to solve the above-described problems, a charging device according to the present invention includes N current detection units that generate voltage signals corresponding to an output current and are connected in parallel to each other (where N is an integer equal to or greater than 2). ) And a control unit that sends a command signal to the power supply unit and controls the current output from the power supply unit, and the control unit includes (1) a first time In addition, a command signal is sent to N power supply units to start output of current, and (2) one power supply unit is excluded at a second time when a predetermined warm-up period has elapsed from the first time. A command signal is sent to the N-1 power supply units to stop the output of current, and (3) between the second time and the third time when a predetermined detection period has elapsed from the second time, Read the voltage signal of the one power supply unit and (4) send a command signal to the N-1 power supply units at the third time (5) At the fourth time when a predetermined re-warming-up period has elapsed from the third time, N− except for one power supply unit other than the one power supply unit. A command signal is sent to one power supply unit to stop the output of current. (6) Between the fourth time and the fifth time when the detection period has elapsed from the fourth time, It is configured to calibrate the current by reading the voltage signal of the power supply unit and (7) sending out a command signal to the N-1 power supply units and restarting the output of the current at the fifth time. In addition, the rewarming period is shorter than the warming period.

  In order to solve the above-described problem, the calibration method according to the present invention includes N current detectors connected in parallel, each having a current detection unit that generates a voltage signal corresponding to an output current (where N is 2 or more). (1) a calibration method for calibrating current in a parallel-type charging device including power supply units, and (1) starting N current power supply units to output current at a first time; 2) at a second time when a predetermined warm-up period has elapsed from the first time, the N−1 power supply units excluding one power supply unit stop outputting current, and (3) a second A step of reading a voltage signal of the one power supply unit between the time and a third time when a predetermined detection period has elapsed from the second time, and (4) at the third time, the N-1 Resuming output of current to each power supply unit, and (5) predetermined from the third time. At a fourth time when the re-warming period has elapsed, N−1 power supply units other than the one power supply unit other than the one power supply unit are suspended from outputting current (6 ) Reading a voltage signal of the other power supply unit between the fourth time and the fifth time when the detection period has elapsed from the fourth time; and (7) at the fifth time, the N− Resuming the output of current to one power supply unit, and the rewarming period is shorter than the warming period.

  According to these configurations, since the power supply units other than the power supply unit to be calibrated continue to output current until immediately before the detection period, the environment in the detection period becomes more similar to the environment in actual use than before, and Accuracy is improved. It should be noted that the output of the current of the N-1 power supply units excluding one power supply unit to be calibrated is temporarily stopped at the location where the outputs of each power supply unit are aggregated (for example, the secondary battery to be charged). This is because there is a case where it may be desired to individually detect the current output from each power supply unit immediately before.

  In the charging device and the calibration method, the current detection unit can be configured with a shunt resistor, but the present invention is not limited to this.

  ADVANTAGE OF THE INVENTION According to this invention, the charging device which can be calibrated more correctly than before, and the calibration method in this charging device can be provided.

It is a block diagram of the charging device which concerns on the Example of this invention. It is a timing chart regarding the calibration of the charging device according to the embodiment of the present invention, (A) shows the current flowing through the current detection unit of each power supply unit, (B) is each corresponding to (A) Indicates the temperature of the current detection unit of the power supply unit. It is a timing chart regarding conventional calibration. It is another timing chart regarding the conventional calibration.

  Embodiments of a charging device and a calibration method according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows a charging device 1 according to an embodiment of the present invention. As shown in the figure, the charging device 1 includes an AC / DC converter 2 that converts the AC voltage output from the commercial AC power supply 10 into DC, and four identical power supply units 3a, 3b, 3c connected in parallel to each other. , 3d and a control unit 4. Each power supply unit 3a, 3b, 3c, 3d has an input side connected to the AC / DC converter 2 and an output side connected to a secondary battery 11 as a charging target.

  The four power supply units 3a, 3b, 3c and 3d have shunt resistors Ra, Rb, Rc and Rd as current detection units of the present invention. More specifically, the first power supply unit 3a has a shunt resistor Ra, the second power supply unit 3b has a shunt resistor Rb, the third power supply unit 3c has a shunt resistor Rc, and the fourth power supply unit 3d has a shunt resistor. It has a resistance Rd. A current output from the first power supply unit 3a toward the secondary battery 11 flows through the shunt resistor Ra. The same applies to the other shunt resistors Rb, Rc, Rd.

  The control part 4 controls the electric current which each power supply part 3a, 3b, 3c, 3d outputs by sending a command signal to each power supply part 3a, 3b, 3c, 3d. Specifically, the control unit 4 sends a command signal to all of the four power supply units 3a, 3b, 3c, 3d to start / stop current output all at once, or power supply units 3a, 3b, 3c. , 3d can be sent individually to start / stop only the output of the current of the power supply unit. Of course, the control unit 4 can also command the current value.

  Further, the control unit 4 generates voltage drop values (in other words, shunt resistors Ra, Rb, Rc, Rd) at the shunt resistors Ra, Rb, Rc, Rd of the power supply units 3a, 3b, 3c, 3d at an arbitrary timing. It is also possible to store the result of comparing the read value with the reference voltage value in the storage unit 5. For example, if the voltage drop value of the shunt resistor Ra indicates a value corresponding to 9.8 [A] when outputting the current of 10 [A] to the first power supply unit 3a, the control unit 4 -0.2 [A] or 98 [%] is stored in the storage unit 5. The control unit 4 sends a command signal corrected based on the information stored in the storage unit 5 to each power supply unit 3a, 3b, 3c, 3d during actual use.

  In FIG. 2, the timing chart regarding the calibration of the charging device 1 is shown. FIG. 5A shows currents Ira, Irb, Irc, and Ird that flow through the shunt resistors Ra, Rb, Rc, and Rd of the power supply units 3a, 3b, 3c, and 3d, and FIG. The temperatures Tra, Trb, Trc, Trd of the shunt resistors Ra, Rb, Rc, Rd corresponding to A) are shown.

  First, at time ta, the control unit 4 sends a command signal to each of the power supply units 3a, 3b, 3c, 3d, and outputs the currents Ira, Irb, Irc, Ird to the power supply units 3a, 3b, 3c, 3d. Let it begin. Thereby, the temperature Tra, Trb, Trc, Trd of the shunt resistors Ra, Rb, Rc, Rd starts to rise toward the saturation point.

  At time tb when a predetermined warm-up period t1 has elapsed from time ta, the control unit 4 sends a command signal to the three power supply units 3b, 3c, 3d except for the first power supply unit 3a to send currents Irb, The output of Irc and Ird is paused. As a result, the temperatures Trb, Trc, Trd of the shunt resistors Rb, Rc, Rd begin to gradually fall. As described above, when the current Ira of the first power supply unit 3a is calibrated, the outputs of the currents Irb, Irc, and Ird of the other power supply units 3b, 3c, and 3d are paused in parallel with the main calibration. The current (current Ira) of the power source unit (first power source unit 3a) being calibrated at the location where the outputs of the units 3a, 3b, 3c, 3d are collected, in other words, the location where the currents Ira, Irb, Irc, Ird merge. This is because there is a case where it is desired to detect them individually.

  In the detection period t2 starting from time tb, the control unit 4 reads the voltage drop value of the shunt resistor Ra, and stores the result of comparing this with the reference voltage value in the storage unit 5. At this time, the temperatures Trb, Trc, and Trd hardly decrease from the temperature at the time tb. For this reason, the voltage drop value of the shunt resistor Ra is read in an environment equivalent to the case where the power supply units 3b, 3c, and 3d continue to output current.

  At the time tc when the detection period t2 has elapsed, the control unit 4 sends command signals to the three power supply units 3b, 3c, and 3d to restart the output of the currents Irb, Irc, and Ird. As a result, the temperatures Trb, Trc, Trd return to the saturation point before the time td. The reason why the current Ira is output even after the calibration of the first power supply unit 3a (detection of the current Ira) is completed is to bring the environment for detecting the current Irb (Irc, Ird) closer to the environment during actual use. It is. In actual use, all the power supply units 3a, 3b, 3c, 3d often output current under the same conditions. According to this configuration, immediately before calibration of a certain power supply unit (for example, the second power supply unit 3b). Since the warm-up is continued in other power supply units (for example, the power supply units 3a, 3c, and 3d) except the power supply unit, a temperature environment close to actual use is maintained and the accuracy of calibration is improved.

  As described above, the temperatures Trb, Trc, and Trd decrease only slightly during the detection period t2. Therefore, the period t3 from time tc to time td (hereinafter referred to as “re-warming-up period”) may be much shorter than the warm-up period t1, and thereby, the conventional calibration shown in FIG. Calibration time is greatly reduced.

  At time td, the control unit 4 sends out command signals to the three power supply units 3a, 3c, and 3d excluding the second power supply unit 3b to stop the output of the currents Ira, Irc, and Ird. As a result, the temperatures Tra, Trc, Trd of the shunt resistors Ra, Rc, Rd begin to gradually fall.

  In the detection period t4 starting from time td, the control unit 4 reads the voltage drop value of the shunt resistor Rb and stores the result of comparing this with the reference voltage value in the storage unit 5. At this time, the temperatures Tra, Trc, Trd are hardly lowered from the temperature at time td. For this reason, the voltage drop value of the shunt resistor Rb is read in an environment equivalent to the case where the power supply units 3a, 3c, and 3d continue to output current.

  At time te when the detection period t4 has elapsed, the control unit 4 sends command signals to the three power supply units 3a, 3c, and 3d to resume output of the currents Ira, Irc, and Ird. As a result, the temperatures Tra, Trc, and Trd return to the saturation point until time tf.

  Similarly, the voltage drop values of the shunt resistor Rc of the third power supply unit 3c and the shunt resistor Rd of the fourth power supply unit 3d are sequentially read, and the calibration ends.

  Note that the detection periods t2, t4, t6, and t8 have the same length. The lengths of the rewarming periods t3, t5, and t7 are also the same.

  As described above, in the charging device and the calibration method according to the present invention, the output of current from other power supply units (for example, the power supply units 3a, 3c, and 3d) is suspended in the detection period (for example, the detection period t4). Until that time, other power supply units continue to output current. Therefore, according to the present invention, the voltage drop value can be read in an environment equivalent to the case where the other power supply unit continues to output current, and the calibration accuracy can be improved.

  In addition, the structure of this invention is not limited to the structure of the said Example.

  For example, the shunt resistor is merely an example of a current detection unit that generates a voltage signal corresponding to a current that flows, and can be replaced with a circuit or an element having an equivalent function.

  Further, the number of power supply units connected in parallel to each other is not limited to four and may be an integer of 2 or more.

DESCRIPTION OF SYMBOLS 1 Charging apparatus 2 AC / DC converter 3a 1st power supply part 3b 2nd power supply part 3c 3rd power supply part 3d 4th power supply part 4 Control part 5 Memory | storage part 10 Commercial AC power supply 11 Secondary battery Ra, Rb, Rc, Rd Shunt Resistance (current detector)

Claims (4)

N power supply units connected in parallel to each other, each having a current detection unit that generates a voltage signal corresponding to an output current (where N is an integer of 2 or more), and a command signal is sent to the power supply unit A parallel type charging device including a control unit for controlling a current output from the power source unit,
The controller is
(1) At the first time, the command signal is sent to the N power supply units to start outputting the current,
(2) At a second time when a predetermined warm-up period has elapsed from the first time, the command signal is sent to N-1 power supply units excluding one power supply unit, and the current Pause the output,
(3) Read the voltage signal of the one power supply unit between the second time and a third time at which a predetermined detection period has elapsed from the second time,
(4) At the third time, the command signal is sent to the N-1 power supply units to restart the output of the current,
(5) N-1 power supply units excluding one power supply unit different from the one power supply unit at a fourth time when a predetermined rewarming period has elapsed from the third time. To send the command signal to stop the output of the current,
(6) Read the voltage signal of the another one power supply unit between the fourth time and the fifth time when the detection period has elapsed from the fourth time,
(7) At the fifth time, the command signal is sent to the N-1 power supply units to restart the output of the current.
Thus, the charging device is configured to calibrate the current, and the rewarming period is shorter than the warming period.   The charging device according to claim 1, wherein the current detection unit is a shunt resistor. In a parallel type charging device having N (where N is an integer of 2 or more) power supply units connected in parallel to each other, the current detection unit has a current detection unit that generates a voltage signal corresponding to an output current. A calibration method for calibrating
(1) causing the N power supply units to start outputting the current at a first time;
(2) suspending the output of the current to N-1 power supply units excluding one power supply unit at a second time when a predetermined warm-up period has elapsed from the first time;
(3) reading the voltage signal of the one power supply unit between the second time and a third time at which a predetermined detection period has elapsed from the second time;
(4) resuming output of the current to the N-1 power supply units at the third time;
(5) N-1 power supply units excluding one power supply unit different from the one power supply unit at a fourth time when a predetermined rewarming period has elapsed from the third time. Stopping the output of the current;
(6) reading the voltage signal of the another one power supply unit between the fourth time and a fifth time when the detection period has elapsed from the fourth time;
(7) resuming the output of the current to the N-1 power supply units at the fifth time;
The calibration method is characterized in that the rewarming period is shorter than the warming period.   The calibration method according to claim 3, wherein a shunt resistor is used as the current detection unit.

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