JP2008005662A - Power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device that makes high reliability compatible with miniaturization. <P>SOLUTION: The power supply device includes a capacitor unit 4 composed of a plurality of capacitors 41-47, a bypass switch 5 connected to at least one of the capacitors 41-47 so as to short-circuit both ends of the capacitor, and a temperature sensor 6 that measures a temperature near the capacitor unit 4. When executing charging to the capacitor unit 4 and if output of the temperature sensor 6 is below a fixed temperature, a control part 8 controls so as not to execute charging to the capacitor 47, connected with the bypass switch 5, by turning on the bypass switch 5, and also, if the output of the temperature sensor 6 exceeds the fixed temperature, the control part controls so as to execute charging also including the capacitor 47, connected with the bypass switch 5, by turning off the bypass switch 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an emergency power supply apparatus that continuously supplies power to a load in response to an abnormality in a main power supply.

  In recent years, the development of hybrid cars and electric cars has been rapidly progressing, and accordingly, various proposals from conventional mechanical hydraulic control to electrical hydraulic control have also been made for vehicle braking. However, if the battery used as the main power supply cannot supply electric power for some reason, electric hydraulic control cannot be performed, and the vehicle may not be braked. Therefore, a power supply device has been developed that enables vehicle braking in an emergency by mounting a large-capacity capacitor or the like as an auxiliary power supply in addition to the battery.

  As such a power supply device, for example, a power supply device as shown in Patent Document 1 has been proposed. FIG. 10 shows a basic configuration block circuit diagram of the power supply apparatus. A power source device 103 as an auxiliary power source for the battery 101 is connected between the battery 101 as a main power source and a load 102 that is a vehicle braking device that performs electrical hydraulic control.

  The power supply device 103 has a built-in capacitor unit 104 composed of a plurality of capacitors connected in series in order to store auxiliary power. Note that the capacitor may be connected in series-parallel according to the power specifications required by the load 102.

  Further, a changeover switch 105 that switches a power supply source to the load 102 is provided between the battery 101 and the power supply device 103. Note that the changeover switch 105 is constituted by a diode, for example.

  Next, the operation of the power supply apparatus 103 will be briefly described. Since the capacitor unit 104 is in a discharged state due to self-discharge or the like when the vehicle is started, the power of the battery 101 is supplied to the load 102 and the capacitor unit 104 via the changeover switch 105 when an ignition switch (not shown) is turned on. Eventually, when the capacitor unit 104 is fully charged, the charging of the capacitor unit 104 automatically stops and power is supplied only to the load 102.

  In this state, if an abnormality occurs in the battery 101 and the output voltage decreases to, for example, 9.5 V or less, which is the operation lower limit voltage of the load 102, the anode side voltage of the diode constituting the changeover switch 105 becomes higher than the cathode side voltage. Therefore, the changeover switch 105 is turned off. As a result, since electric power is continuously supplied from the capacitor unit 104 to the load 102, vehicle braking can be performed and safety can be ensured.

  The power supply device 103 is simply configured and operated as described above, and can be applied not only to a vehicle but also to other auxiliary power uses such as consumer use. However, in the case of a vehicle, high reliability is required. A corresponding actual detailed block circuit diagram is shown in FIG. 11, the same components as those in FIG. 10 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The power supply device 103 includes a power system circuit including a changeover switch 105, a charging circuit 106 that charges the capacitor unit 104, a discharging circuit 107 that discharges the power of the capacitor unit 104, and a voltage detection circuit 108 that measures the voltage of the battery 101. It is configured. In addition, in order to control the charging circuit 106, the discharging circuit 107, the voltage detection circuit 108, and the changeover switch 105, a control unit 109 electrically connected thereto is provided. In FIG. 11, the power system wiring is indicated by a thick line, and the control system wiring is indicated by a thin line. The control unit 109 is configured by a microcomputer, and the changeover switch 105 is configured by a three-terminal switch that can be controlled by the control unit 109.

  Next, the operation of the power supply device 103 will be described. The stored power of the capacitor unit 104 is charged when the vehicle is started to extend the life of the capacitor, and is quickly discharged when the use of the vehicle is finished. Thereby, high reliability is obtained. Therefore, the operation at the time of starting the vehicle will be described first.

  When an ignition switch (not shown) is turned on to start the vehicle, the control unit 109 switches the changeover switch 105 in the direction shown in FIG. 11 and selects the battery 101. Thereby, the power of the battery 101 is supplied to the load 102. At the same time, the control unit 109 instructs the charging circuit 106 to charge the capacitor unit 104 with the power of the battery 101. As a result, the capacitor unit 104 is charged with electric power. The charging circuit 106 stops charging from the battery 101 when the capacitor unit 104 is fully charged.

  Thereafter, the control unit 109 monitors the voltage of the battery 101 by the voltage detection circuit 108. When the use of the vehicle is completed while the voltage of battery 101 is normal, control unit 109 instructs discharge circuit 107 to discharge the power of capacitor unit 104. Thereby, the electric power charged in the capacitor unit 104 is quickly discharged.

On the other hand, if the battery 101 becomes abnormal voltage (9.5 V or less as described above) when the vehicle is used, the control unit 109 immediately switches the changeover switch 105 to the capacitor unit 104 side. Thereby, since the electric power stored in the capacitor unit 104 is supplied to the load 102, even if the electric power supply from the battery 101 is cut off for some reason, the load 102 continues to operate. Therefore, vehicle braking is possible and safety can be ensured.
JP 2005-28908 A

  As described above, since the conventional power supply device 103 can continue to supply power to the load 102 even when the battery 101 is abnormal, the vehicle can be braked and high reliability can be obtained. However, in order to ensure that the operation of the capacitor unit 104, particularly with respect to temperature changes, is ensured, both the configurations of FIGS. 10 and 11 have a considerable margin in the capacitance of the entire capacitor. A specific design example will be described below.

  It is assumed that the electrostatic energy Q required by the load 102 to brake the vehicle is 32C (Coulomb). Accordingly, if the capacitor unit 104 is installed in the vicinity of the passenger compartment, for example, the entire temperature range at that location (from the lowest temperature at the start of the vehicle of −30 ° C. to the highest temperature in the passenger compartment at the time of vehicle travel is 30 ° C. Must have a capacity of 32C or more.

  Here, it is assumed that an electric double layer capacitor having a capacitance of 70 F (Farad) is used as a capacitor used in the capacitor unit 104. The withstand voltage (charge voltage at which deterioration does not proceed) of the electric double layer capacitor decreases as the temperature increases, and is about 1.9 V at the maximum temperature of 30 ° C. in the electric double layer capacitor used this time. Therefore, the voltage across the capacitor was 1.9 V over the entire temperature range. Therefore, since the initial output voltage of the capacitor unit 104 must be in the vicinity of 14V, which is the normal output voltage of the battery 101, the number of required capacitors is an integer close to 14V / 1.9V = 7.36. Individual. As a result, the initial output voltage of the capacitor unit 104 is 1.9 V × 7 = 13.3 V, and almost 14 V is obtained, so that the load 102 can be driven sufficiently.

  On the other hand, since seven capacitors must be connected in series in order to obtain the voltage, the combined capacitance Ca of the capacitor unit 104 is 1/7/70 = 10F.

  Now, when the capacitor unit 104 is at 30 ° C., the battery 101 becomes abnormal, the electric power of the capacitor unit 104 is discharged to drive the load 102, and the vehicle braking is performed. As a result, the output voltage of the capacitor unit 104 is Assume that the voltage drops to the lower limit voltage of 9.5V. As a result, the voltage drop ΔV of the capacitor unit 104 becomes 3.8V (= 13.3V−9.5V).

  Note that the voltage drop ΔV also occurs due to the internal resistance of the capacitor, and it is necessary to consider it. Therefore, the temperature characteristic of the internal resistance R of the electric double layer capacitor used this time is shown by the solid line in FIG. In FIG. 12, the horizontal axis represents the temperature T, the left vertical axis represents the internal resistance R, and the right vertical axis represents the value (= dR / dT) when the temperature characteristic (solid line) of the internal resistance R is differentiated by the temperature T. The dotted line in FIG. 12 represents the differential characteristic of the internal resistance R with respect to the temperature T.

  From the solid line in FIG. 12, it can be seen that the internal resistance R is a characteristic that is inversely proportional to the temperature T, and is almost negligible at about several mΩ at 30 ° C. Therefore, in the case of 30 ° C., the voltage drop due to the internal resistance R of the capacitor is not considered.

  From the above, the electrostatic energy usage amount ΔQ due to vehicle braking is ΔQ = ΔV × Ca = 3.8V × 10F = 38C. Since the electrostatic energy Q consumed by the load 102 until the vehicle actually stops is 32 C as described above, ΔQ at 30 ° C. is 38 C. This means that the driver brakes even when the vehicle stops. This is because the load 102 continued to move as a result of continuing the operation. Therefore, since the electrostatic energy Q of 32 C can be obtained before the output voltage of the capacitor unit 104 decreases to 9.5 V, which is the lower limit operating voltage of the load 102 at 30 ° C., the design has a margin of 6 C for subtraction. You can see that

  On the other hand, consider a case where the temperature of the vehicle interior is −30 ° C. which is the lowest temperature when the vehicle is started, and the battery 101 becomes abnormal before the vehicle interior is warmed. Since the worst condition at this time is when the passenger compartment is at -30 ° C, it is assumed that the temperature of the capacitor unit 104 is -30 ° C.

  Since the change in the temperature characteristic of the electric double layer capacitor is smaller than the temperature characteristic of the internal resistance R, the capacitance per capacitor at −30 ° C. remains 70 F. Accordingly, the combined capacitance Ca of the seven capacitor units 104 connected in series is 10 F as in the case of 30 ° C. Further, since the charging voltage of one capacitor is fixed at 1.9 V (at 30 ° C.) which is the worst condition of withstand voltage, the initial output voltage of the capacitor unit 104 at −30 ° C. is also 30 ° C. Like 1.9V × 7 pieces = 13.3V.

  Now, the battery 101 becomes abnormal at −30 ° C., the vehicle 102 is braked by driving the load 102 with the electric power of the capacitor unit 104, and the output voltage of the capacitor unit 104 has dropped to 9.5 V, which is the operation lower limit voltage of the load 102. To do. At this time, as shown by the solid line in FIG. 12, the internal resistance R of the capacitor becomes large and cannot be ignored, so a voltage drop corresponding to the internal resistance of the capacitor must also be considered.

  The internal resistance R per capacitor at −30 ° C. was about 72 mΩ according to the characteristics of the solid line in FIG. Therefore, the combined internal resistance Ra of the capacitor unit 104 in which seven capacitors are connected in series is 72 mΩ × 7 pieces = 504 mΩ≈0.5Ω. Since the consumption current of the load 102 due to vehicle braking is 1 A, when power is supplied from the capacitor unit 104 to the load 102, a voltage drop corresponding to the combined internal resistance Ra of the capacitor unit 104 occurs immediately. Since the value ΔVr is 1A × 0.5Ω = 0.5V, the output voltage of the capacitor unit 104 drops rapidly to 13.3V−0.5V = 12.7V.

  Accordingly, if the output voltage of the capacitor unit 104 drops from 12.7V to 9.5V, which is the operation lower limit voltage of the load 102, due to vehicle braking at -30 ° C, the voltage drop ΔV is 12.7V-9.5V = 3. 2V. Therefore, the electrostatic energy usage amount ΔQ is ΔQ = ΔV × Ca = 3.2V × 10F = 32C, and it is possible to obtain the electrostatic energy Q that enables vehicle braking at −30 ° C.

  From the above, it can be seen that the design is made so that the electrostatic energy Q that can sufficiently brake the vehicle is obtained in the entire temperature range (-30 to 30 ° C.) to which the capacitor unit 104 is exposed. Thereby, the power supply apparatus 103 which can obtain high reliability for vehicles has been realized.

  However, since it is designed according to the most severe conditions (−30 ° C.) so as to be able to cope with the entire temperature range, the capacity per capacitor must be increased, and the capacitor becomes larger. As a result, the capacitor unit 104 also becomes large, and there is a problem that the installation location of the power supply device 103 in the passenger compartment is restricted.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a power supply apparatus that can simultaneously achieve downsizing of a capacitor unit while ensuring high reliability for a vehicle.

  In order to solve the conventional problems, a power supply device of the present invention includes a capacitor unit composed of a plurality of capacitors, a bypass switch connected to at least one of the capacitors and short-circuiting both ends of the capacitor, and the vicinity of the capacitor unit A temperature sensor that measures the temperature of the capacitor, and when the controller charges the capacitor unit, if the output of the temperature sensor is equal to or lower than a predetermined temperature, the bypass switch is turned on by turning on the bypass switch. The connected capacitor is controlled so as not to be charged, and when the output of the temperature sensor exceeds the predetermined temperature, the bypass switch is turned off to turn off the capacitor to which the bypass switch is connected. It controls to perform charging including.

  With this configuration, a small number of small capacitors can be charged with high voltage by using the increase in withstand voltage of the capacitor at low temperature, so that electrostatic energy that can drive the load at low temperature is obtained, and withstand voltage of the capacitor at high temperature The load can be driven by controlling to increase the number of the small-capacitance capacitors by the amount of decrease. As a result, the object can be achieved.

  According to the power supply device of the present invention, a small-capacitance capacitor is used for charging by changing the quantity according to the temperature. As a result, it becomes possible to satisfy high reliability and miniaturization at the same time.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block circuit diagram when the temperature exceeds a predetermined temperature of the power supply device according to Embodiment 1 of the present invention. FIG. 2 is a block circuit diagram in the case where the temperature is lower than the predetermined temperature of the power supply device according to the first embodiment of the present invention. In the wirings of FIGS. 1 and 2, the meanings of the thick and thin lines are the same as those in the conventional FIG. In the first embodiment, a case of a simple auxiliary power source corresponding to the conventional FIG. 10 will be described.

  In FIG. 1, a power supply device 3 as an auxiliary power source for the battery 1 is connected between a battery 1 as a main power source and a load 2.

  The power supply device 3 includes a capacitor unit 4 that stores auxiliary power supplied to the load 2. The capacitor unit 4 is composed of a plurality (seven in the first embodiment) of capacitors 41 to 47 connected in series. The capacitors 41 to 47 were electric double layer capacitors. Further, the capacitors 43 to 46 are omitted in FIG.

  The bypass switch 5 that short-circuits both ends of the capacitor 47 is connected to at least one of the capacitors 41 to 47 (capacitor 47 in the first embodiment). The capacitor 47 to which the bypass switch 5 is connected is assumed to have one end connected to the ground from FIG. The reason for this will be described later.

  The capacitor unit 4 is provided with a temperature sensor 6 for measuring the temperature in the vicinity thereof. Since the temperature sensor 6 uses, for example, an element such as a thermistor whose resistance value changes with temperature, a temperature sensor resistor 7 for converting the resistance value change into a voltage change is connected in series. Therefore, by applying a constant voltage Vcc to the temperature sensor 6 and the temperature sensor resistor 7, the voltage at the connection point between the temperature sensor 6 and the temperature sensor resistor 7 changes according to the temperature.

  The bypass switch 5 and the connection point between the temperature sensor 6 and the temperature sensor resistor 7 are electrically connected to the control unit 8. Thereby, the control unit 8 can acquire the temperature information and can control the bypass switch 5 on and off.

  Further, a changeover switch 9 for switching a power supply source to the load 2 is provided between the battery 1 and the power supply device 3. This is composed of a diode as in the conventional case. Therefore, the operation when the battery 1 is abnormal is the same as that of the conventional FIG.

  Next, the charging / discharging operation at the normal time in the above-described power supply device 3 will be described first from the case of −30 ° C. where the temperature conditions are the strictest.

  If the output of the temperature sensor 6 is −30 ° C. at the time of starting the vehicle, the control unit 8 turns on the bypass switch 5 connected to the capacitor 47 because it is below a predetermined temperature described later. A block circuit diagram at this time is shown in FIG. From FIG. 2, since both ends of the capacitor 47 are short-circuited, the capacitor unit 4 is equivalent to a circuit configuration in which six capacitors 41 to 46 are connected in series.

  Here, it is assumed that capacitors having the same capacity of 70 F as the conventional capacitors 41 to 47 are used. In this case, the combined capacitance Ca of the capacitor unit 4 is 1/6/70 = 11.7F. The combined internal resistance Ra of the capacitor unit 4 is 72 mΩ × 6 = 432 mΩ≈0.4Ω because the internal resistance R per capacitor is 72 mΩ at −30 ° C. from FIG.

  In this state, it is assumed that charging of the capacitor unit 4 is started by starting the vehicle, and the voltage of the capacitor unit 4 is charged to 13.3 V as in the conventional case. The voltage of the capacitor unit 4 is 13.3 V, which is obtained by subtracting the voltage drop (≈0.7 V) due to the changeover switch 9 from the normal voltage 14 V of the battery 1.

  In this case, since the bypass switch 5 is on, the charging current does not reach the capacitor 47 but flows to the ground as it is. Therefore, the capacitors 41 to 46 are charged. Therefore, since the number of capacitors is 6, the voltage across each of the capacitors 41 to 46 is 13.3V / 6 pieces≈2.2V. Here, as described in the conventional power supply device, the withstand voltage of the capacitor increases as the temperature decreases, and the capacitors 41 to 47 used in the first embodiment have about 2.5 V at −30 ° C. It was. Therefore, the withstand voltage is not reached even when the voltage across the capacitors 41 to 46 reaches 2.2 V due to the above charging, and the deterioration of the capacitors 41 to 46 is not promoted. Therefore, reliability can be ensured even with the above configuration.

  Now, the battery 1 becomes abnormal under −30 ° C., the load 2 is driven by the electric power of the capacitor unit 4 to perform vehicle braking, and the output voltage of the capacitor unit 4 drops to 9.5 V, which is the operation lower limit voltage of the load 2. Suppose. Also at this time, a voltage drop due to the internal resistance R of the capacitors 41 to 46 occurs as in the conventional case, and the value ΔVr is 1 A of current consumption of the load 2, so ΔVr = 1A × 0.4Ω = 0.4V. Become. Therefore, when electric power is supplied from the capacitor unit 4 to the load 2 by vehicle braking, the output voltage rapidly drops to 13.3V-0.4V = 12.9V.

  This value becomes larger as the number of capacitors 47 is smaller than in the prior art. Accordingly, if the output voltage of the capacitor unit 4 drops from 12.9V to 9.5V which is the lower limit operation voltage of the load 2 due to vehicle braking at -30 ° C., the voltage drop ΔV is 12.9V−9.5V = 3. 4V. Therefore, the electrostatic energy usage amount ΔQ is ΔQ = ΔV × Ca = 3.4V × 11.7F = 39.78C, and the electrostatic energy Q = 32C necessary for vehicle braking can be sufficiently supplied at −30 ° C. Become.

  As described in the conventional power supply device, since the electrostatic energy is the smallest at −30 ° C., the fact that the electrostatic capacity has a margin here means that even if the small-capacitance capacitors 41 to 47 are used. It will be good. Therefore, first, the combined capacitance Ca of the capacitor unit 4 required for setting Q = 32C at −30 ° C. is obtained. When the number of capacitors is 6, ΔV = 3.4V as described above, and therefore Ca≈9.41F from Q (= 32) = ΔV × Ca = 3.4 × Ca. Therefore, since the capacitor Cb of each of the capacitors 41 to 47 is equivalent to the capacitor unit 4 in which six capacitors 41 to 46 are connected in series, 1/6 / Cb = 9.41, Cb≈56 .5F. Therefore, the conventional 70F capacitor can be reduced to, for example, a 60F capacitor having a slightly larger capacity than the above calculation result. The electrostatic energy ΔQ that can be supplied to the load 2 in this case is ΔQ = ΔV × 1/6 / 60F = 3.4V × 10F = 34C, which exceeds 32C necessary for vehicle braking.

  From the above, at −30 ° C., the vehicle braking can be sufficiently performed by the configuration in which six 60 F capacitors 41 to 46 that are smaller than the conventional ones are used in series.

  On the other hand, when the output of the temperature sensor 6 is 30 ° C. which is the maximum temperature with the above configuration, as described in the conventional power supply device, the withstand voltage of the capacitors 41 to 46 is 1.9V. Therefore, the charging voltage of the capacitor unit 4 must be 1.9V × 6 pieces = 11.4V. However, since this voltage is lower than the normal voltage 13.3 V supplied from the battery 1 via the change-over switch 9, this configuration exceeds the withstand voltage of the capacitors 41 to 46, and the reliability deteriorates.

  Therefore, in the first embodiment, if the output of the temperature sensor 6 is higher than a predetermined temperature described later, control is performed so that the capacitor 47 is charged. That is, as shown in FIG. 1, by turning off the bypass switch 5, the capacitor 47 to which the bypass switch 5 is connected is also charged.

  In this case, since seven capacitors 41 to 47 are charged as in the conventional case, the charging voltage of the capacitor unit 4 is 1.9V × 7 = 13.3V. Similar to the charging voltage at −30 ° C., this voltage is a value obtained by subtracting 0.7 V of the voltage drop of the changeover switch 9 from the voltage (14 V) of the battery 1 at the normal time. Therefore, since the withstand voltage is applied to each of the capacitors 41 to 47 by charging the seven capacitors 41 to 47, their lifetime is not shortened, and the reliability of the power supply device 3 is improved. It can be secured.

  As a result of the above charging, the voltage drop ΔV of the capacitor unit 4 when power is supplied to the load 2 is 3.8V (= 13.3V−9.5V) ignoring the internal resistance. The combined capacitance Ca of the capacitor unit 4 is Ca = 1/7 / 60≈8.6F because the capacitance of each of the capacitors 41 to 47 is 60F.

  Therefore, the electrostatic energy use amount ΔQ due to vehicle braking is ΔQ = ΔV × Ca = 3.8V × 8.6F = 32.68C, and the capacitor unit 4 in which seven capacitors 41 to 47 having a capacity 60F are connected in series. By adopting the configuration, the electrostatic energy Q (= 32C) necessary for vehicle braking can be sufficiently supplied at 30 ° C.

  Summarizing the above configuration and operation, if the temperature exceeds a predetermined temperature, which will be described later, by controlling the bypass switch 5 to be turned off and charging all the capacitors 41 to 47, the load 2 is maintained even at the maximum temperature (30 ° C.). High power can be obtained. Furthermore, although the total number of capacitors is not different from the conventional one, the capacitance Cb of each of the capacitors 41 to 47 can be reduced from the conventional 70F to 60F, so that the capacitor unit 4 can be downsized.

  Here, the predetermined temperature will be described. The temperature conditions described above are only for the minimum temperature (−30 ° C.) and the maximum temperature (30 ° C.), but the capacitor 47 is controlled not to be charged when the temperature is low, and all capacitors are controlled when the temperature is high. Since control is performed so as to charge to 41 to 47, it is determined whether or not to charge the capacitor 47 at a certain temperature. The temperature is obtained from the characteristic that the electrostatic energy ΔQ that can be supplied to the load 2 varies depending on whether or not the internal resistance of the capacitors 41 to 47 can be ignored as described above.

  That is, as shown by the solid line in FIG. 12, the internal resistance R of each of the capacitors 41 to 47 has an inversely proportional relationship with respect to the temperature T, and at the same time has a characteristic that the internal resistance R increases abruptly when the temperature decreases from a certain temperature. Have. Accordingly, the inflection of the differential characteristic (dotted line in FIG. 12) at the temperature T in the correlation between the temperature T and the internal resistance R of the capacitors 41 to 47 (solid line in FIG. 12). The temperature near the point is the default temperature. Here, the inflection point is mathematically defined as the point at which the slope of the differential characteristic (dotted line) in FIG. 12 takes the maximum or minimum, that is, the point that becomes 0 when the differential characteristic in FIG. Therefore, the inflection points in the differential characteristics of FIG. 12 are the points shown in the figure. In the first embodiment, −10 ° C. slightly higher than the inflection point in FIG.

  For these reasons, the internal resistance R of the capacitors 41 to 47 cannot be ignored at a predetermined temperature (−10 ° C.) or less, and accordingly, the voltage drop occurs at the same time as the power supply to the load 2 is started. Therefore, even if a voltage drop due to the internal resistance R occurs, the combined capacitance Ca of the capacitor unit 4 must be increased in order to supply sufficient power to the load 2. Therefore, the combined capacitance Ca is increased by reducing the number of capacitors in series from 7 to 6 without charging any capacitor when the temperature is lower than the predetermined temperature. This makes it possible to supply power to the load 2 even at a predetermined temperature or lower.

  On the other hand, when the temperature is higher than the predetermined temperature, the internal resistance R can be ignored, but the withstand voltage of each of the capacitors 41 to 47 is lowered. Therefore, in the configuration with six capacitors, the charging voltage of the capacitor unit 4 is set to prevent deterioration. It must be lowered. In order to increase the charging voltage, one capacitor is added and seven capacitor units 4 are connected in series. However, although the combined capacitance Ca is decreased, the charging voltage is increased and the internal resistance R can be ignored. It is possible to supply power to the load 2 even when the load is on.

  As described above, when the capacitor unit 4 is below the predetermined temperature, the bypass switch 5 connected to the capacitor 47 is controlled to be turned on so that the capacitor 47 is not charged. Then, by controlling the bypass switch 5 to be turned off so as to charge the capacitor 47 as well, power can be supplied to the load 2 in the entire temperature range, and high reliability can be obtained, and the total number of capacitors is not different from the conventional one. However, since the capacitance of each of the capacitors 41 to 47 can be reduced, a power supply device that can reduce the size of the capacitor unit 4 can be realized.

  Although the case where the bypass switch 5 is connected to the capacitor 47 has been described in the first embodiment, any capacitor may be used. However, for the following reason, the capacitor connected to the bypass switch 5 is preferably a capacitor 47 having one end connected to the ground.

  That is, the voltage applied to the bypass switch 5 is less than or equal to the withstand voltage of the capacitor 47 (maximum about 2.5V). Therefore, when an FET is used for the bypass switch 5, the signal voltage for turning on and off is also less than or equal to the withstand voltage. It will be good. Accordingly, since the signal voltage may be equal to or lower than the drive voltage (5 V) of the control unit 8, the bypass switch 5 can be directly on / off controlled by the control unit 8. In this case, an N-channel FET having a small internal resistance can be used as the bypass switch 5, so even if the bypass switch 5 is turned on at a predetermined temperature or lower, the resistance loss when a charging current flows through the FET becomes small and heat is generated. Is suppressed. Therefore, high reliability of the FET can be obtained. Therefore, the capacitor connected to the bypass switch 5 is preferably a capacitor 47 having one end connected to the ground.

  When the bypass switch 5 is connected to another capacitor, it is necessary to use a P-channel FET in order to directly control the on / off of the FET by the control unit 8, but the P-channel FET has a large internal resistance when turned on. Resistance loss is large and heat is generated. Accordingly, although it is possible to connect the bypass switch 5 to another capacitor, it is not desirable.

(Embodiment 2)
FIG. 3 is a block circuit diagram in the case where the temperature is lower than the predetermined temperature of the power supply device according to the second embodiment of the present invention. FIG. 4 is a block circuit diagram when the temperature of the power supply device in Embodiment 2 of the present invention exceeds a predetermined temperature or lower. FIG. 5 is a block circuit diagram when the temperature exceeds a predetermined temperature of the power supply device according to the second embodiment of the present invention. In addition, in the wiring of FIGS. 3-5, the meaning of a thick line and a thin line is the same as the conventional FIG.

  In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. That is, in FIGS. 3 to 5, the structural features of the second embodiment are as follows.

  1) Switches 11 to 16 (switches 13 to 16 are omitted in the figure) are connected to one ends of capacitors 41 to 46 to which the bypass switch 5 is not connected, and the other ends of the switches 11 to 16 are connected. And resistors 21 to 26 (resistors 23 to 26 are omitted in the drawing) between the other ends of the capacitors 41 to 46, respectively.

  2) A signal wiring for performing on / off control of each of the switches 11 to 16 was connected to the control unit 8.

  3) A voltage monitoring circuit 30 for transmitting the voltage values of the capacitors 41 to 47 to the control unit 8 is provided. The voltage monitoring circuit 30 has a configuration in which the voltage values of the capacitors 41 to 47 are sequentially switched and measured and transmitted to the control unit 8.

  Next, since the operation when the battery 1 is abnormal in the above-described power supply device 3 is the same as that of the conventional FIG. 10, the charge / discharge operation at the normal time will be described.

  The operational feature of the second embodiment is that the load 2 can continue to be driven even if the temperature of the power supply device 3 is lower than the predetermined temperature (−10 ° C.) at the time of startup and exceeds the predetermined temperature during use. It is a point which controls so that energy Q can be stored.

  On the other hand, the operation of the first embodiment is based on the assumption that the temperature of the capacitor unit 4 does not change during subsequent use only by selecting whether the bypass switch 5 is turned on or off depending on the temperature at the time of startup. It was control of. Such premise could be used sufficiently under conditions with little temperature change (for example, areas and seasons where the temperature does not change for vehicles, or consumer applications where the temperature change was originally low), but the temperature changes with use, and the default If it exceeded the temperature, it could not be used. Therefore, in the second embodiment, an operation corresponding to a temperature change over a predetermined temperature is performed.

  A specific operation will be described below.

  First, it is assumed that the power supply device 3 is activated when the temperature condition is -30 ° C., that is, when the temperature is not more than a predetermined temperature. If the output of the temperature sensor 6 is equal to or lower than the predetermined temperature, the control unit 8 turns on the bypass switch 5 and turns off the switches 11 to 16 as shown in FIG. As a result, the capacitor unit 4 is equivalent to the configuration of FIG. 2 in which the six capacitors 41 to 46 are connected in series, so that charging is performed in addition to the capacitor 47 to which the bypass switch 5 is connected. Since the characteristic specifications of the capacitors 41 to 47 at this time are the same as those of the first embodiment, the stored electrostatic energy Q is large enough to drive the load 2.

  In this state, for example, it is assumed that the temperature in the vicinity of the capacitor unit 4 increases during use of the vehicle and exceeds a predetermined temperature. In this case, the switch 11 discharges electric charges (electrostatic energy stored in the capacitors 41 to 46) by the resistors 21 to 26 so that the capacitors 41 to 46 do not exceed the withstand voltage through the voltage monitoring circuit 30. And the capacitor 47 connected to the bypass switch 5 is controlled to be charged so as not to exceed the withstand voltage.

  Specifically, as shown in FIG. 4, the control unit 8 first turns on the switches 11 to 16 and simultaneously turns off the bypass switch 5 as shown in FIG. As a result, the charges of the capacitors 41 to 46 are discharged through the resistors 21 to 26, and the voltage decreases. On the other hand, since the bypass switch 5 is off in the capacitor 47, the power from the battery 1 is charged through the switches 11 to 16 and the resistors 21 to 26. At this time, the control unit 8 monitors the voltage across the capacitors 41 to 46 with the voltage monitoring circuit 30. Among these, when the voltage across the discharged capacitors 41 to 46 reaches the withstand voltage (lowest 1.9 V) at the maximum temperature of 30 ° C., the switches 11 to 16 connected to the capacitors 41 to 46 are turned off. To do. However, since the capacitors 41 to 46 have characteristic variations, they are turned off from the switch 11 connected to the capacitor (for example, the capacitor 41) that has reached the withstand voltage at an early stage. At this time, since electric power is continuously supplied from the battery 1 to the capacitor unit 4 to charge the capacitor 47, the capacitor 41 whose switch 11 is off is charged again, and the voltage rises. As a result, when the voltage of the capacitor 41 exceeds the withstand voltage, the voltage monitoring circuit 30 repeats the operation of turning on the switch 11 again to lower the voltage.

  In this way, the control unit 8 performs on / off control of the switches 11 to 16 so that the voltage of the capacitors 41 to 46 does not exceed the withstand voltage. As a result, the switches 11 to 16 are finally turned off, and the voltages across the capacitors 41 to 46 are discharged so as not to exceed the withstand voltage. At this time, the constant voltage 13.3V from the battery 1 is applied to the capacitor unit 4, and the voltage across the other capacitors 41 to 46 is 1.9V as described above, so the bypass switch 5 is connected. The voltage across the capacitor 47 is inevitably 13.3V-1.9V × 6 = 1.9V. Therefore, the capacitor 47 can also be charged so as not to exceed the withstand voltage.

  FIG. 5 shows a block circuit diagram when this charge / discharge operation is completed. Since all the switches 11 to 16 and the bypass switch 5 are off, the circuit of the capacitor unit 4 is equivalent to FIG. Therefore, the electrostatic energy Q stored in the capacitor unit 4 is large enough to continue to drive the load 2 even at the highest temperature (30 ° C.), which is the most severe condition, as in the first embodiment. Note that if the temperature exceeds the predetermined temperature when the power supply device 3 is activated, the capacitor unit 4 is charged with the circuit configuration of FIG. 5 from the beginning.

  Here, when the temperature of the capacitor unit 4 rises and falls near the predetermined temperature (−10 ° C.), the charging / discharging operation for the capacitor 47 is repeated each time, so that the control of the control unit 8 becomes complicated. In order to avoid this, it is sufficient to perform the above operation only once when the power supply device 3 is used. Therefore, in the power supply device 3, at least the capacitor unit 4 is configured to have a predetermined temperature or higher. Specifically, the capacitor unit 4 is configured to be installed in a place where the temperature is equal to or higher than a predetermined temperature in a steady state (when a normal vehicle is used). As such a place, for example, the vicinity of a heat source such as an engine or a heating device can be mentioned even in a vehicle interior. However, if the temperature is too high, the withstand voltage of the capacitors 41 to 47 is further lowered. It is necessary to select a place that does not exceed. Even if the temperature of these places increases during use of the vehicle, the temperature does not fall below a predetermined temperature (−10 ° C.), so that the charge / discharge operation is performed only once. As a result, the control of the control unit 8 is simplified and high reliability is obtained.

  In the above description, the example in which the capacitor unit 4 is installed at a place where the temperature is equal to or higher than the predetermined temperature in a steady state is shown. Moreover, it is good also as a structure heated with a heater etc. so that the capacitor unit 4 may become predetermined temperature or more.

  With the above configuration and operation, even if a temperature change that crosses the predetermined temperature during use occurs, power can be supplied to the load 2 in the entire temperature range, and high reliability can be obtained. By using the capacitors 41 to 47, the capacitance Cb of each of the capacitors 41 to 47 can be reduced, so that the capacitor unit 4 can be reduced in size.

  In the second embodiment, any capacitor can be connected to the bypass switch 5, but for the reason described in the first embodiment, it is desirable that the capacitor 47 has one end connected to the ground.

(Embodiment 3)
FIG. 6 is a block circuit diagram in the case where the temperature is lower than the predetermined temperature of the power supply device according to the third embodiment of the present invention. FIG. 7 is a block circuit diagram when the temperature of the power supply device in Embodiment 3 of the present invention exceeds a predetermined temperature or lower. FIG. 8 is a block circuit diagram in the case where the temperature exceeds a predetermined temperature of the power supply device according to Embodiment 3 of the present invention. FIG. 9 is a block circuit diagram when electric charges are discharged from the capacitor unit at the end of the operation of the power supply device according to the third embodiment of the present invention. 6-9, the meanings of the thick and thin lines are the same as those in the conventional FIG.

  The third embodiment will be described based on a configuration actually applied as a power supply device for a vehicle, corresponding to the conventional FIG. In the third embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted. That is, in FIGS. 6 to 9, the structural feature of the third embodiment is that the switch 17 and the resistor 27 connected in series are also connected to both ends of the capacitor 47 to which the bypass switch 5 is connected.

  Details of the configuration of the power supply device 3 different from that of the second embodiment will be described below.

  First, the switch 17 and the resistor 27 are connected in series in the same manner as the other capacitors 41 to 46 at both ends of the capacitor 47 to which the bypass switch 5 is connected. The on / off control of the switch 17 is performed by the control unit 8 in the same manner as the other switches 11 to 16.

  Charging from the battery 1 to the capacitor unit 4 is performed via the charging circuit 32. The charging circuit 32 has a function of controlling start and stop of charging at a specified charging voltage according to an instruction from the control unit 8.

  The changeover switch 9 has a three-terminal switch configuration instead of the diode used in the first and second embodiments. Since the changeover switch 9 is switched by the control unit 8, when the control unit 8 instructs the changeover operation at an arbitrary timing when the power supply device 3 is used, the operation of the changeover switch 9 can be confirmed and high reliability can be obtained. Accordingly, when the battery 1 is abnormal as in the first and second embodiments, the configuration in which the power is automatically supplied from the capacitor unit 4 to the load 2 is eliminated. A voltage detection circuit 34 that detects the voltage and transmits it to the control unit 8 is provided. As a result, when the battery 1 becomes abnormal and the voltage decreases, the abnormal voltage is transmitted from the voltage detection circuit 34 to the control unit 8, and the control unit 8 switches the changeover switch 9 to the capacitor unit 4 side in response thereto. As a result, it is possible to continue supplying power from the capacitor unit 4 to the load 2.

  Next, since the operation when the battery 1 is abnormal in the power supply device 3 according to the third embodiment is the same as that of the conventional FIG. 11, the charge / discharge operation in the normal state will be described.

  The operational feature of the third embodiment is that, when the operation of the power supply device 3 is finished, when the electric charge is quickly discharged from the capacitor unit 4, the control unit 8 turns off the bypass switch 5, and 47, the switches 11 to 17 connected to 47 are controlled to be turned on.

  On the other hand, in the conventional configuration of FIG. 11, a discharge circuit is used to discharge charges from the capacitor unit 4. In this Embodiment 3, since it can discharge quickly with each resistor 21-27 connected to each capacitor 41-47, it becomes the structure containing the function of a discharge circuit. Therefore, the power supply device 3 can be miniaturized as much as the discharge circuit becomes unnecessary.

  A specific operation will be described below.

  First, it is assumed that the power supply device 3 is activated when the temperature is equal to or lower than a predetermined temperature, for example, −30 ° C. If the output of the temperature sensor 6 is equal to or lower than the predetermined temperature, the controller 8 turns on the bypass switch 5 and turns off the switches 11 to 17 as shown in FIG. As a result, the capacitor unit 4 is equivalent to the configuration of FIG. 2 in which the six capacitors 41 to 46 are connected in series, so that charging is performed in addition to the capacitor 47 to which the bypass switch 5 is connected. Also in the third embodiment, since the characteristic specifications of the capacitors 41 to 47 are the same as those of the first and second embodiments, the stored electrostatic energy Q is large enough to drive the load 2. When the charging is completed, the charging circuit 32 stops outputting the charging voltage.

  In this state, for example, it is assumed that the temperature near the capacitor unit 4 increases during use of the vehicle and exceeds a predetermined temperature. In this case, as in the second embodiment, the switches 11-16 are controlled so that the capacitors 21-46 do not exceed the withstand voltage and the resistors 21-26 discharge the charges, and the bypass switch 5 is connected. The controlled capacitor 47 is also controlled to be charged so as not to exceed the withstand voltage.

  Specifically, as shown in FIG. 7, the control unit 8 turns on the switches 11 to 16 and turns off the bypass switch 5 at the same time. At this time, the switch 17 remains off. Further, the charging voltage is output from the charging circuit 32. As a result, the electric charges of the capacitors 41 to 46 are discharged through the resistors 21 to 26 and the voltage is lowered, and the capacitor 47 is charged in the same manner as in the second embodiment because the switch 17 and the bypass switch 5 are off. To go. At this time, the control unit 8 monitors the voltage across the capacitors 41 to 46 with the voltage monitoring circuit 30. Among these, the voltage across the discharged capacitors 41 to 46 reaches a value obtained by dividing the charging voltage set by the control unit 8 (set to a value considering the withstand voltage of the capacitors 41 to 47) into seven equal parts. For example, the switches 11 to 16 connected to the capacitors 41 to 46 are turned off. As in the second embodiment, the switches 11 to 16 may be turned on / off again due to the characteristic variation of the capacitors 41 to 46, but this operation causes the voltage across the capacitors 41 to 46 to exceed the withstand voltage. It can be discharged so as not to. Accordingly, the switches 11 to 16 are finally turned off. At this time, the charging voltage from the charging circuit 32 is applied to the capacitor unit 4, and the voltages across the other capacitors 41 to 46 have the charging voltage of 7. Since the values are equally divided, the voltage across the capacitor 47 to which the bypass switch 5 is connected is inevitably charged so that it does not exceed the withstand voltage, similarly to the charging voltages of the other capacitors 41 to 46.

  FIG. 8 shows a block circuit diagram when this charge / discharge operation is completed. Since all the switches 11 to 17 and the bypass switch 5 are off, the circuit of the capacitor unit 4 is equivalent to FIG. Therefore, the electrostatic energy Q stored in the capacitor unit 4 is large enough to continue to drive the load 2 even at the highest temperature (30 ° C.), which is the most severe condition, as in the first embodiment. If the predetermined temperature is exceeded when the power supply device 3 is activated, the capacitor unit 4 is charged from the beginning with the circuit configuration of FIG.

  Next, the end of the operation of the power supply device 3 will be described with reference to FIG.

  In the third embodiment, at the end of the operation, the capacitors 41 to 47 are controlled to be discharged quickly from the capacitor unit 4 in order to extend the lifetime. Therefore, the control unit 8 turns off the bypass switch 5 and turns on the switches 11 to 17 connected to the capacitors 41 to 47 regardless of the output of the temperature sensor 6. At this time, the charging circuit 32 stops outputting. Thereby, the electric charges stored in the capacitors 41 to 47 are discharged simultaneously and quickly through the resistors 21 to 27. With such a configuration, an operation for balancing the voltages of the capacitors 41 to 46 when the temperature in the vicinity of the capacitor unit 4 changes over a predetermined temperature, and a quick discharge operation of the capacitors 41 to 47 at the end of the operation. Can be realized by the same resistors 21 to 27, so that a conventional discharge circuit can be dispensed with.

  With the configuration and operation described above, in addition to the effects of the second embodiment, the power supply device 3 can be further reduced in size since a discharge circuit is not required when discharging electric charge from the capacitor unit 4 at the end of the operation.

  In the third embodiment, any capacitor may be connected to the bypass switch 5, but for the reason described in the first embodiment, it is desirable that the capacitor 47 has one end connected to the ground.

  The capacitor unit 4 described in the first to third embodiments has a configuration in which seven 60 F capacitors 41 to 47 are connected in series. However, the present invention is not limited to this, and the power source required by the load 2 is not limited thereto. The capacity and quantity may be changed according to the power specifications of the device 3, the characteristics of the capacitor, etc., or a series-parallel connection may be used. Furthermore, the number of capacitors that are not charged when the temperature is lower than the predetermined temperature may be plural according to the specifications of the power supply device 3 and the like.

  Moreover, although the application example to the power supply device for vehicles was described in this Embodiment 1-3, even if this is applied to the power supply device of other uses, such as a consumer, an equivalent effect is acquired.

  According to the power supply device of the present invention, since the capacitor unit can be miniaturized and highly reliable, it is useful as various emergency power supplies from consumer use to vehicles.

Block circuit diagram in the case of exceeding the predetermined temperature of the power supply device in the first embodiment of the present invention Block circuit diagram when power supply device has a predetermined temperature or lower in Embodiment 1 of the present invention Block circuit diagram when power supply device has a predetermined temperature or lower in Embodiment 2 of the present invention Block circuit diagram when the temperature of the power supply device in Embodiment 2 of the present invention exceeds a predetermined temperature or lower Block circuit diagram in the case of exceeding the predetermined temperature of the power supply device in the second embodiment of the present invention Block circuit diagram in the case where the temperature is lower than the predetermined temperature of the power supply device in Embodiment 3 of the present invention Block circuit diagram when the temperature of the power supply device in Embodiment 3 of the present invention exceeds a predetermined temperature or lower Block circuit diagram in the case of exceeding the predetermined temperature of the power supply device in Embodiment 3 of the present invention Block circuit diagram when discharging electric charge from the capacitor unit at the end of the operation of the power supply device in Embodiment 3 of the present invention Basic configuration block circuit diagram of a conventional power supply device Detailed configuration block circuit diagram of a conventional power supply device Temperature-internal resistance correlation diagram of capacitor of conventional power supply device, and internal resistance differential characteristic diagram by temperature

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Power supply device 4 Capacitor unit 5 Bypass switch 6 Temperature sensor 8 Control part 11-17 Switch 21-27 Resistor 30 Voltage monitoring circuit 41-47 Capacitor

Claims (6)

A capacitor unit composed of a plurality of capacitors connected in series or in series and parallel;
A bypass switch connected to at least one of the capacitors and short-circuiting both ends of the capacitor;
A temperature sensor for measuring the temperature in the vicinity of the capacitor unit;
The bypass switch and the temperature sensor have a control unit electrically connected,
The controller, when charging the capacitor unit,
If the output of the temperature sensor is below a predetermined temperature, by turning on the bypass switch, the capacitor connected to the bypass switch is controlled not to be charged,
If the output of the temperature sensor is higher than the predetermined temperature, the power supply device that controls charging including the capacitor to which the bypass switch is connected by turning off the bypass switch. A switch connected to one end of each capacitor to which a bypass switch is not connected;
A resistor connected between the other end of each switch and the other end of each capacitor;
A voltage monitoring circuit for transmitting a voltage value of each capacitor to the control unit;
When the output of the temperature sensor is equal to or lower than a predetermined temperature, the control unit turns on the bypass switch and turns off each switch to charge other than the capacitor to which the bypass switch is connected. After
When the output of the temperature sensor exceeds a predetermined temperature, the switch is controlled so as to discharge the charge with the resistor so that the capacitors do not exceed the withstand voltage through the voltage monitoring circuit, and
The power supply device according to claim 1, wherein charging is performed such that the capacitor to which the bypass switch is connected does not exceed a withstand voltage. A switch and a resistor connected in series are connected to both ends of a capacitor to which a bypass switch is connected.
3. The power supply device according to claim 2, wherein the control unit controls to turn off the bypass switch and turn on each switch connected to each capacitor when discharging the electric charge from the capacitor unit at the end of the operation of the power supply device. . The power supply device according to claim 2, wherein at least the capacitor unit has a predetermined temperature or higher during use of the power supply device. The power supply device according to claim 1, wherein the capacitor to which the bypass switch is connected is a capacitor having one end connected to the ground. The power supply device according to claim 1, wherein the predetermined temperature is in the vicinity of an inflection point of the differential characteristic at the temperature in the correlation between the temperature and the internal resistance of the capacitor.

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