JP2017127104A - Power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress promotion of deterioration near the elements of two step-up converters.SOLUTION: When the number Nch of switching both side drive mode for driving both first and second step-up converters, and one side drive mode for driving only one of the first and second step-up converters is equal to a threshold Nchref or more (S160), execution mode is held in both side drive mode (S200). Consequently, occurrence of such an event that the temperature of the elements of the first and second step-up converters changes relatively greatly by switching of both side drive mode and one side drive mode can be suppressed. As a result, promotion of deterioration near the elements of the first and second step-up converters can be suppressed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power supply device, and more particularly to a power supply device including a battery and two boost converters.

  Conventionally, as this type of power supply device, a battery, a first power line to which a motor is connected, and a second power line to which a battery is connected are connected in parallel to each other and the power of the second power line is supplied with a voltage. In a configuration including two boost converters that can supply the first power line with boost, both the two boost converters are driven at high output, and only one of the two boost converters is driven at low output. Have been proposed (see, for example, Patent Document 1). In this power supply device, this suppresses a decrease in efficiency at the time of low output.

JP 2012-210138 A

  In such a power supply device, the current flowing through the elements of the two boost converters changes relatively greatly when switching between the mode for driving both of the two boost converters and the mode for driving only one of the two boost converters. There is a possibility that the temperature of the element changes relatively greatly, and deterioration in the vicinity of the element (soldered portion, grease portion, etc.) is promoted.

  The main object of the power supply device of the present invention is to suppress the promotion of deterioration near the elements of the two boost converters.

  The power supply apparatus of the present invention employs the following means in order to achieve the main object described above.

The power supply device of the present invention is
Battery,
A first power line to which a motor is connected and a second power line to which the battery is connected are connected in parallel to each other, and the power of the second power line can be supplied to the first power line with a voltage boost. First and second boost converters,
When the required output of the motor is greater than or equal to a predetermined output, the first and second boost converters are controlled in a double-sided drive mode that drives both the first and second boost converters, and the required output of the motor is the predetermined output A control means for controlling the first and second boost converters in a one-side drive mode for driving only one of the first and second boost converters;
In a power supply device comprising:
The control means prohibits switching between the both-side drive mode and the one-side drive mode when the switching frequency between the both-side drive mode and the one-side drive mode is equal to or higher than a predetermined frequency.
This is the gist.

  In the power supply device of the present invention, when the switching frequency between the both-side drive mode for driving both the first and second boost converters and the one-side drive mode for driving only one of the first and second boost converters is a predetermined frequency or more. The switching between the both-side drive mode and the one-side drive mode is prohibited. Thereby, when the switching frequency is equal to or higher than the predetermined frequency, the occurrence of an event that the temperature of the elements of the first and second boost converters changes relatively greatly due to switching between the both-side drive mode and the one-side drive mode is suppressed. be able to. As a result, it is possible to suppress the deterioration in the vicinity of the elements of the first and second boost converters (soldered portion, grease portion, etc.).

  In such a power supply device of the present invention, the switching frequency may be the number of times of switching between the both-side drive mode and the one-side drive mode per unit time, or between the both-side drive mode and the one-side drive mode. It may be an integrated value of the number of times of switching (for example, an integrated value from when the ignition is turned on).

  Further, in the power supply device of the present invention, the control means may hold in the both-side drive mode when the switching frequency is equal to or higher than the predetermined frequency.

  Furthermore, in the power supply device of the present invention, when the control unit prohibits switching between the both-side drive mode and the one-side drive mode, when the predetermined time has elapsed, the control unit switches between the both-side drive mode and the one-side drive mode. It is good also as what re-permits switching.

It is a block diagram which shows the outline of a structure of the electric vehicle 20 carrying the power supply device 40 as one Example of this invention. It is a flowchart which shows an example of the execution mode setting routine performed by the electronic control unit 70 of an Example.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of the configuration of an electric vehicle 20 equipped with a power supply device 40 as an embodiment of the present invention. As shown in FIG. 1, the electric vehicle 20 of the embodiment includes a motor 32, an inverter 34, a battery 50, first and second boost converters 54 and 55, and an electronic control unit 70. Here, as the power supply device 40 of the embodiment, a battery 50, first and second boost converters 54 and 55, and an electronic control unit 70 correspond.

  The motor 32 is configured as, for example, a synchronous generator motor, and a rotor is connected to a drive shaft 26 that is connected to drive wheels 22a and 22b via a differential gear 24. The inverter 34 is connected to the motor 32 and is connected to the first and second boost converters 54 and 55 via the high voltage system power line 60 as the first power line. The motor 32 is rotationally driven by switching control of a plurality of switching elements (not shown) of the inverter 34 by the electronic control unit 70.

  The battery 50 is configured as, for example, a lithium ion secondary battery or a nickel hydride secondary battery, and is connected to the first and second boost converters 54 and 55 via a low voltage system power line 62 as a second power line. ing.

  The first boost converter 54 is connected to a high voltage system power line 60 to which the inverter 34 is connected and a low voltage system power line 62 to which the battery 50 is connected. The first boost converter 54 includes two transistors T31 and T32, two diodes D31 and D32, and a reactor L1. The transistor T31 is connected to the positive electrode line 60a of the high voltage system power line 60. The transistor T32 is connected to the transistor T31 and the negative electrode lines 60b and 62b of the high voltage system power line 60 and the low voltage system power line 62. The two diodes D31 and D32 are respectively connected in parallel to the transistors T31 and T32 in the reverse direction. Reactor L1 is connected to intermediate point Cn1 of transistors T31 and T32 and to positive line 62a of low voltage system power line 62. The first boost converter 54 adjusts the on-time ratio of the transistors T31 and T32 by the electronic control unit 70, so that the power of the low voltage system power line 62 is increased with the voltage boost. Or the power of the high voltage system power line 60 is supplied to the low voltage system power line 62 with a voltage step-down.

  The second boost converter 55 is connected to the high voltage system power line 60 and the low voltage system power line 62 in parallel with the first boost converter 54. Similar to the first boost converter 54, the second boost converter 55 includes two transistors T41 and T42, two diodes D41 and D42, and a reactor L2. The transistor T41 is connected to the positive line 60a of the high voltage system power line 60. The transistor T42 is connected to the transistor T41 and the negative electrode lines 60b and 62b of the high voltage system power line 60 and the low voltage system power line 62. The two diodes D41 and D42 are respectively connected in parallel to the transistors T41 and T42 in the reverse direction. Reactor L1 is connected to intermediate point Cn2 of transistors T41 and T42 and to positive line 62a of low voltage system power line 62. The second boost converter 55 adjusts the on-time ratio of the transistors T41 and T42 by the electronic control unit 70, whereby the power of the low voltage system power line 62 is increased with the voltage boost. Or the power of the high voltage system power line 60 is supplied to the low voltage system power line 62 with a voltage step-down.

  A smoothing capacitor 61 is attached to the positive electrode line 60 a and the negative electrode line 60 b of the high voltage system power line 60. A smoothing capacitor 63 is attached to the positive electrode line 62 a and the negative electrode line 62 b of the low voltage system power line 62.

  Although not shown, the electronic control unit 70 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, and an input / output port in addition to the CPU.

Signals from various sensors are input to the electronic control unit 70 via input ports. Examples of signals input to the electronic control unit 70 include the following.
A rotational position θm from a rotational position detection sensor that detects the rotational position of the rotor of the motor 32
A phase current from a current sensor that detects a current flowing in each phase of the motor 32. A voltage Vb of the battery 50 from a voltage sensor 50a installed between terminals of the battery 50.
The current Ib of the battery 50 from the current sensor 50b attached to the output terminal of the battery 50
The voltage VH of the capacitor 61 (high voltage system power line 60) from the voltage sensor 61a attached between the terminals of the capacitor 61.
The voltage VL of the capacitor 63 (low voltage system power line 62) from the voltage sensor 63a attached between the terminals of the capacitor 63.
The current IL1 of the reactor L1 from the current sensor 54a that detects the current flowing through the reactor L1
The current IL2 of the reactor L2 from the current sensor 55a that detects the current flowing through the reactor L2.
-Ignition signal from the ignition switch 80-Shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81
Accelerator opening degree Acc from the accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal 83
-Brake pedal position BP from the brake pedal position sensor 86 that detects the amount of depression of the brake pedal 85
・ Vehicle speed V from vehicle speed sensor 88

Various control signals are output from the electronic control unit 70 via an output port. Examples of signals output from the electronic control unit 70 include the following.
Switching control signals to a plurality of switching elements (not shown) of the inverter 34 Switching control signals to the transistors T31, T32, T41, T42 of the first and second boost converters 54, 55

The electronic control unit 70 performs the following calculations.
The rotational speed Nm of the motor 32 based on the rotational position θm of the rotor of the motor 32 from the rotational position detection sensor
Battery storage ratio SOC of battery 50 based on the integrated value of current Ib of battery 50 from current sensor 50b

  The storage ratio SOC of the battery 50 is the ratio of the capacity of power that can be discharged from the battery 50 to the total capacity of the battery 50.

  In the electric vehicle 20 of the embodiment configured as described above, the electronic control unit 70 first requires the required torque Tp * required for traveling (required for the drive shaft 26) based on the accelerator opening Acc and the vehicle speed V. And the set required torque Tp * is set as the torque command Tm * of the motor 32. Then, the switching of the plurality of switching elements of the inverter 34 is controlled so that the motor 32 is driven by the torque command Tm *. Also, the two-sided drive mode for driving both the first and second boost converters 54 and 55 or the one-side drive mode for driving only one of the first and second boost converters 54 and 55 is set as the execution mode, and the execution mode is set. Thus, the first and second boost converters 54 and 55 are controlled. In the embodiment, when the execution mode is the one-side drive mode, only the first boost converter 54 is driven.

  When the execution mode is the double-side drive mode, the target voltage VH * of the high voltage system power line 60 is set based on the target drive point (torque command Tm *, rotation speed Nm) of the motor 32. Further, the target power Pm * of the motor 32 is calculated as the product of the torque command Tm * of the motor 32 and the rotation speed Nm. Subsequently, based on the voltage VH and target voltage VH * of the high voltage system power line 60 and the target power Pm * of the motor 32, the target of the total current flowing from the low voltage system power line 62 to the high voltage system power line 60 is determined. The target current IL * is set as a value. Then, target current IL * is multiplied by distribution ratios D1 and D2 of first and second boost converters 54 and 55 (reactors L1 and L2) to set target currents IL1 * and IL2 * of reactors L1 and L2. Here, the distribution ratios D1 and D2 are changed from the low voltage system power line 62 to the high voltage system power line 60 via the first and second boost converters 54 and 55 (reactors L1 and L2) in the target current IL *, respectively. The ratio of the flowing current, and the sum of the distribution ratio D1 and the distribution ratio D2 is a value of 1. The distribution ratio D1 can be set to 0.5, for example. The transistors T31, T32, and T32 of the first and second boost converters 54 and 55 are set so that the currents IL1 and IL2 of the reactors L1 and L2 of the first and second boost converters 54 and 55 become the target currents IL1 * and IL2 *. Switching control is performed on T41 and T42.

  When the execution mode is the one-side drive mode, the target voltage VH * of the high voltage system power line 60, the target power Pm * of the motor 32, and the target current IL * are set as in the case where the execution mode is the double-side drive mode. Then, the transistors T31 and T32 of the first boost converter 54 are subjected to switching control so that the current IL of the reactor L1 of the first boost converter 54 becomes the target current IL *.

  Next, the operation of the electric vehicle 20 of the embodiment configured as described above, particularly the operation when setting the execution mode (both sides drive mode, one side drive mode) of the first and second boost converters 54 and 55 will be described. FIG. 2 is a flowchart illustrating an example of an execution mode setting routine executed by the electronic control unit 70 of the embodiment. This routine is executed repeatedly.

  When the execution mode setting routine is executed, the electronic control unit 70 first inputs the target power Pm * of the motor 32 and the elapsed time tc from the previous switching of the execution mode (step S100). Here, as the target power Pm * of the motor 32, a value calculated as the product of the torque command Tm * of the motor 32 and the rotation speed Nm is input. As the elapsed time tc, a value measured by a timer (not shown) is input. The timer resets the elapsed time tc to a value of 0 and starts measuring the elapsed time tc when the ignition is turned on and when the execution mode is switched (when switching between the both-side drive mode and the one-side drive mode).

  When the data is thus input, the elapsed time tc is compared with the predetermined time tc1 (step S110). Here, for example, 5 minutes, 10 minutes, 15 minutes, or the like can be used as the predetermined time tc1.

  When the elapsed time tc is less than the predetermined time tc1 in step S110, it is determined whether or not the execution mode has been switched (step S120). This determination is based on the execution mode set in the processing of steps S180 and S200, which will be described later when the routine is executed two times before, and the execution mode set in the processing of steps S180, S200, which will be described later when the routine is executed last time. And can be done by comparing.

  If it is determined that the execution mode has not been switched, the switching frequency Nch is held (step S130). On the other hand, when it is determined that the execution mode has been switched, the previous switching count (previous Nch) is incremented by 1 and the switching count Nch is updated (step S140). Note that the number Nch of switching is set to a value of 0 as an initial value when the ignition is turned on, and is then reset to a value of 0 by a process in step S150 described later.

  Next, the switching frequency Nch is compared with a threshold value Nchref (step S160). Here, the threshold value Nchref can be, for example, 80 times, 100 times, 120 times, or the like.

  When the switching frequency Nch is less than the threshold value Nchref in step S160, it is determined that switching of the execution mode is permitted (step S170), and the execution mode is set according to the target power Pm * of the motor 32 (step S180). Exit. In this case, when the target power Pm * of the motor 32 is greater than or equal to the threshold value Pmref, the both-side drive mode is set to the execution mode, and when the target power Pm * of the motor 32 is less than the threshold value Pmref, the one-side drive mode is set to the execution mode. It was supposed to be. Here, the threshold value Pmref can be determined so that the total efficiency of the first and second boost converters 54 and 55 is good. By such control, the total efficiency of the first and second boost converters 54 and 55 can be improved.

  When the switching frequency Nch is greater than or equal to the threshold value Nchref in step S160, it is determined that execution mode switching is prohibited (step S190), and the both-side drive mode is set to the execution mode regardless of the target power Pm * of the motor 32 ( Step S200), this routine is finished. Therefore, when the execution mode is the one-side drive mode immediately after the switching number Nch reaches the threshold value Nchref or more, the execution mode is switched to the double-sided drive mode, and the execution mode is set immediately after the switching number Nch reaches the threshold value Nchref or more. In the double-side drive mode, the execution mode is held in the double-side drive mode as it is. When the execution mode is switched (when switching between the double-side drive mode and the single-side drive mode), the current flowing through the elements (transistors, diodes, reactors) of the first and second boost converters 54 and 55 changes relatively greatly. There is a possibility that the temperature of the element changes relatively greatly, and deterioration in the vicinity of the element (soldered portion, grease portion, etc.) is promoted. In the embodiment, the elements of the first and second boost converters 54 and 55 are switched by switching between the double-side drive mode and the single-side drive mode by holding the execution mode in the double-side drive mode when the switching frequency Nch is equal to or greater than the threshold Nchref. It is possible to suppress the occurrence of an event that the temperature of the liquid crystal changes relatively greatly. As a result, promotion of deterioration in the vicinity of the elements of the first and second boost converters 54 and 55 can be suppressed. In this case, by holding the execution mode not in the one-side drive mode but in the both-side drive mode, the respective elements of the first and second boost converters 54 and 55 are compared with those held in the one-side drive mode. The current flowing through can be reduced.

  When the elapsed time tc is equal to or longer than the predetermined time tc1 in step S110, the number of switching times Nch is reset to 0 (step S150). Here, when the elapsed time tc reaches the predetermined time tc1 or more, it is executed when the target power Pm * of the motor 32 does not cross the threshold value Pmref over the predetermined time tc1 and by the processing of steps S160, S190, and S200. When the mode is held in the double-sided drive mode. When the switching frequency Nch is reset in this way, it is determined in step S160 that the switching frequency Nch is less than the threshold value Nchref, and the processing from step S170 is executed. Therefore, when the switching number Nch reaches the threshold value Nchref or more and the execution mode is held in the double-side drive mode, the switching of the execution mode is permitted (re-permission) when the state continues for the predetermined time tc1. become.

  In the power supply device 40 included in the electric vehicle 20 of the embodiment described above, only the one-sided drive mode for driving both the first and second boost converters 54 and 55 and the first and second boost converters 54 and 55 are driven. When the switching frequency Nch to the one-side drive mode is equal to or greater than the threshold value Nchref, the execution mode is held in the both-side drive mode. Thereby, it is possible to suppress the occurrence of an event that the temperature of the elements of the first and second boost converters 54 and 55 changes relatively greatly due to switching between the both-side drive mode and the one-side drive mode. As a result, promotion of deterioration in the vicinity of the elements of the first and second boost converters 54 and 55 can be suppressed.

  In the power supply device 40 included in the electric vehicle 20 according to the embodiment, it is determined whether the switching of the execution mode is permitted or prohibited by comparing the switching frequency Nch and the threshold value Nchref. However, instead of the switching frequency Nch, it may be determined whether to permit or prohibit the switching of the execution mode by comparing the switching rate Rch, which is the switching frequency per unit time, and the threshold value Rchref. Here, for example, 40 times / minute, 50 times / minute, 60 times / minute, or the like can be used as the threshold value Rchref.

  In the power supply device 40 provided in the electric vehicle 20 of the embodiment, when the switching frequency Nch is less than the threshold value Nchref, the both-side drive mode or the one-side drive mode is set to the execution mode according to the target power Pm * of the motor 32. However, when the switching frequency Nch is less than the threshold Nchref, the double-sided drive mode or the single-sided drive mode may be set to the execution mode according to the target current Im * of the motor 32 instead of the target power Pm * of the motor 32. . In this case, when the target current Im * of the motor 32 is greater than or equal to the threshold value Imref, the both-side drive mode is set to the execution mode, and when the target current Im * of the motor 32 is less than the threshold value Imref, the one-side drive mode is set to the execution mode. That's fine. Here, as the target current Im * of the motor 32, the above-described target current IL * can be used, or a value obtained by dividing the target power Pm * of the motor 32 by the voltage VH of the high voltage system power line 60 can be used. .

  In the power supply device 40 provided in the electric vehicle 20 of the embodiment, the execution mode is held in the both-side drive mode when the switching frequency Nch is greater than or equal to the threshold value Nchref. However, when the switching frequency Nch is equal to or greater than the threshold value Nchref, the execution mode may be held in the one-side drive mode, or the execution mode is maintained as the execution mode immediately after the switching frequency Nch reaches the threshold value Nchref or more. Also good.

  In the power supply device 40 included in the electric vehicle 20 according to the embodiment, when it is determined that the switching number Nch exceeds the threshold Nchref and the switching of the execution mode is prohibited (when the execution mode is held in the both-side drive mode), When the state continues for a predetermined time tc1, switching of the execution mode is permitted (re-permitted). However, execution mode switching may not be permitted (re-permitted) until the ignition is turned off.

  In the power supply device 40 provided in the electric vehicle 20 of the embodiment, when the target power Pm * of the motor 32 does not cross the threshold value Pmref for a predetermined time tc1 (switching of the execution mode is not prohibited, When the switching to the one-side drive mode has not been performed for a predetermined time), the switching frequency Nch is reset to the value 0, but may not be reset.

  In the embodiment, the power supply device 40 is mounted on the electric vehicle 20 that travels using only the power from the motor 32. However, a configuration of a power supply device mounted on a hybrid vehicle that travels using power from the motor and power from the engine may be employed.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the battery 50 corresponds to a “battery”, the first boost converter 54 corresponds to a “first boost converter”, the second boost converter 55 corresponds to a “second boost converter”, and the electronic control unit 70. Corresponds to “control means”.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the power supply device manufacturing industry.

  20 electric vehicle, 22a, 22b drive wheel, 24 differential gear, 26 drive shaft, 32 motor, 34 inverter, 40 power supply, 50 battery, 50a, 61a, 63a voltage sensor, 50b, 54a, 55a current sensor, 54 1st Boost converter, 55 Second boost converter, 60 High voltage system power line, 60a, 62a Positive line, 60b, 62b Negative line, 61, 63 capacitor, 62 Low voltage system power line, 70 Electronic control unit, 80 Ignition switch, 81 Shift lever, 82 Shift position sensor, 83 Accelerator pedal, 84 Accelerator pedal position sensor, 85 Brake pedal, 86 Brake pedal position sensor, 88 Vehicle speed sensor, Cn1, Cn2 Intermediate point, D31, D32 D41, D42 diodes, L1, L2 reactor, T31, T32, T41, T42 transistor.

Claims (1)

Battery,
A first power line to which a motor is connected and a second power line to which the battery is connected are connected in parallel to each other, and the power of the second power line can be supplied to the first power line with a voltage boost. First and second boost converters,
When the required output of the motor is greater than or equal to a predetermined output, the first and second boost converters are controlled in a double-sided drive mode that drives both the first and second boost converters, and the required output of the motor is the predetermined output A control means for controlling the first and second boost converters in a one-side drive mode for driving only one of the first and second boost converters;
In a power supply device comprising:
The control means prohibits switching between the both-side drive mode and the one-side drive mode when the switching frequency between the both-side drive mode and the one-side drive mode is equal to or higher than a predetermined frequency.
Power supply.

Images