Vehicle-internal power supply unit

Abstract

Vehicle-internal power supply device (1) configured to decrease a voltage applied to a first conductive path (10) electrically connected to a capacitive component (46) and apply the resulting voltage to a second conductive path (12), or to increase a voltage applied to the second conductive path (12) and apply the resulting voltage to the first conductive path (10), wherein the vehicle-internal power supply device (1) comprises: a first voltage conversion unit (21) comprising a first driver switching element (40), a second driver switching element (42) and a first inductor (44), which performs a first voltage conversion operation in accordance with a first control signal, in which switching alternately between an ON signal and an OFF signal is applied to the first driver switching element (40), whereby a voltage applied to the first conductive path (10) is decreased and an output voltage is applied to the second conductive path (12), and which performs a third voltage conversion operation in accordance with a third control signal, in which switching alternately between an ON signal and an OFF signal is applied to the second driver switching element (42), whereby a voltage applied to the second conductive path (12) is increased.and an output voltage is applied to the first conductive path (10); , a switching element (24) for preventing backflow, which is provided on the second conductive path (12) and which prevents a current flow on the second conductive path (12) in the direction of the first voltage conversion unit (21) when it is switched off; a second inductance (26) which is provided between the first voltage conversion unit (21) and the switching element (24) for backflow prevention on the second conductive path (12) and in series with the switching element (24) for backflow prevention; a semiconductor element part (28) formed by a diode or a switching element, one end of which is electrically connected between the second inductor (26) and the switching element (24) for reverse flow prevention on the second conductive path (12), and the other end of which is electrically connected to a conductive reference path; and a control unit (88) which outputs the first control signal to at least the first driver switching element (40) and outputs the third control signal to the second driver switching element (42), wherein several first voltage conversion units (21) are connected in parallel to each other between the first conductive path (10) and the second conductive path (12), a second voltage conversion unit (22) is provided by the switching element (24) for reverse flow prevention, the second inductor (26) and the semiconductor element part (28), and, if the part of the second conductive path (12) that is on the side of the first voltage conversion unit (21) as seen from the second voltage conversion unit (22) is considered an output-side conductive path (12B), and the part of the second conductive path (12) that is on the side opposite to the side of the first voltage conversion unit (21) is considered an input-side conductive path (12A), the second voltage conversion unit (22) performs the second voltage conversion operation, reducing the voltage applied to the input-side conductive path (12A) and applying an output voltage to the output-side conductive path (12B) is created the control unit (88) is configured to cause the second voltage conversion unit (22) to perform the second voltage conversion process when a certain pre-charge condition is met by applying a second control signal, in which an ON signal and an OFF signal are alternately switched, to the switching element (24) for backflow prevention, and After the start of the second voltage conversion process, the control unit (88) supplies the third control signal to only some of the first voltage conversion units (21) when a certain switching condition is met, causing some of the first voltage conversion units (21) to perform the third voltage conversion process.

Description

TECHNICAL AREA

[0001] The present invention relates to an in-vehicle power supply device. TECHNICAL BACKGROUND

[0002] In vehicles equipped with a rechargeable battery, when, for example, the ignition is switched off, the battery is disconnected from any load connected to it and, in some cases, put into standby mode to limit its current draw. In this standby mode, charges accumulated in the capacitive components of the load are discharged, increasing the voltage difference between the battery terminals and the load. If the rechargeable battery is connected to the load when this voltage difference is large, a significant inrush current will be drawn between the battery and the load.

[0003] A technical teaching, as disclosed in JP 2017-22805 A, has been proposed as a solution to this type of problem. According to the technical teaching disclosed in JP 2017-22805 A, the generation of a large inrush current between the rechargeable battery and the load is mitigated by pre-charging a capacitive component in the load using a DC-DC boost converter before the battery and load are connected.

[0004] DE 11 2016 003 991 T5 discloses a DC-DC converter comprising: a voltage converter unit containing a first switching element located between a first conductor path connected to a high-potential terminal of a primary-side power supply unit and a second conductor path connected to a high-potential terminal of a secondary-side power supply unit, converting a voltage applied to the first conductor path by switching the first switching element between an ON state and an OFF state and outputting the resulting voltage to the second conductor path; an abnormal state detection unit that detects a specific abnormal state; a first protection circuit unit containing a second switching element located in a high-voltage-side conductor path, with respect to the first conductor path and the second conductor path, and switching between an OFF state,in which the second switching element blocks at least one current flowing in one direction towards the voltage converter unit, and switches to an ON state in which the second switching element releases the blocking, wherein the first protection circuit unit switches the second switching element to an OFF state if the abnormal condition detection unit detects the abnormal condition; and a second protection circuit unit comprising a third switching element provided in a third conductor path located between the voltage converter unit and a reference conductor path maintained at a specific reference potential lower than the potential of the first conductor path and lower than the potential of the second conductor path, and between an OFF state in which the third switching element blocks at least one current flowing from the reference conductor path, and an ON state in which the third switching element releases the blocking.switching, wherein the second protection circuit unit switches the third switching element to an ON state when a terminal of at least one low-voltage power supply unit, with respect to the primary-side power supply unit and the secondary-side power supply unit, is in a normal connection state, and the third switching element switches to an OFF state when the terminal of at least one low-voltage power supply unit is in a reverse polarity state.

[0005] JP 2017-085810A discloses a vehicle power supply system comprising: a high-voltage circuit including a main battery and a load, and a relay that switches between a connected and disconnected state of the connection between the main battery and the load, further comprising a capacitor between the relay and the load; and an auxiliary DC / DC converter whose primary side is connected to an auxiliary battery and whose secondary side is connected to the capacitor, and which, before the relay switches from the disconnected to the connected state, boosts the voltage of the auxiliary battery and charges the capacitor, wherein, if a voltage sensor for detecting the voltage of the main battery has failed, the auxiliary DC / DC converter boosts the output voltage to an intermediate voltage value and charges the capacitor.where the intermediate voltage value lies between a maximum open-circuit voltage (OCV) and a minimum open-circuit voltage (OCV), which correspond to a maximum state of charge (SOC) and a minimum state of charge (SOC) respectively within a predetermined SOC usage range of the main battery. OVERVIEW OF THE INVENTION TASKS TO BE SOLVED BY THE INVENTION

[0006] Furthermore, to perform precharging using a DC-DC converter, a switching element, which serves as the main component carrying out the voltage conversion process, must be driven by a driver, and for this purpose, energy must be supplied to the driver. In recent years, however, to obtain the power required for DC-DC converters, a design has been used in which several switching elements are arranged in parallel, and the converters are connected in parallel, thus increasing the number of phases. Due to this increased parallelization, the current (driver current) supplied to the switching element and the like via the driver tends to increase.As a result, a more significant voltage drop tends to occur in resistive components, diode components, and the like, which are located in a path between the driver and a power supply that provides energy to the driver. Accordingly, if the power supply voltage (the voltage from the power supply that provides energy to the driver) drops, the voltage (threshold voltage) required for the driver to operate cannot be reached.

[0007] The present invention was made to solve at least one of the problems described above and aims to realize an in-vehicle power supply device in which, even if the power supply voltage drops, a state can be avoided in which a control unit receiving energy supplied by a power supply cannot perform the control of a pre-charging process. MEANS OF SOLVING THE TASK

[0008] A first aspect of the present invention is a vehicle-internal power supply device which is configured to decrease a voltage applied to a first conductive path which is electrically connected to a capacitive component and to apply the resulting voltage to a second conductive path, or to increase a voltage applied to the second conductive path and to apply the resulting voltage to the first conductive path, wherein The vehicle's internal power supply system includes: a first voltage conversion unit comprising a first driver switching element, a second driver switching element and a first inductor, which performs a first voltage conversion operation in accordance with a first control signal, in which switching alternately between an ON signal and an OFF signal is applied, and which is supplied to the first driver switching element, whereby a voltage applied to the first conductive path is decreased, and an output voltage is applied to the second conductive path, and which performs a third voltage conversion operation in accordance with a third control signal, in which switching alternately between an ON signal and an OFF signal is applied, and which is supplied to the second driver switching element, wherein a voltage applied to the second conductive path is increased, and an output voltage is applied to the first conductive path; a switching element for preventing backflow, which is provided on the second conductive path and which prevents a current from flowing on the second conductive path towards the first voltage conversion unit when it is switched off; a second inductance provided between the first voltage conversion unit and the backflow prevention switching element on the second conductive path and in series with the backflow prevention switching element; a semiconductor element part formed by a diode or switching element, one end of which is electrically connected between the second inductor and the switching element for backflow prevention on the second conductive path, and the other end of which is electrically connected to a conductive reference path; and a control unit that outputs the first control signal to at least the first driver switching element, and outputs the third control signal to the second driver switching element, in which several first voltage conversion units are connected in parallel to each other between the first conductive path and the second conductive path, a second voltage conversion unit is set up by the backflow prevention switching element, the second inductor, and the semiconductor element part, and, if the part of the second conductive path that, as seen from the second voltage conversion unit, lies on the side of the first voltage conversion unit is considered an output-side conductive path, and the part of the second conductive path that is on the side opposite to the side of the first voltage conversion unit is considered an input-side conductive path, the second voltage conversion unit performs the second voltage conversion operation, reducing the voltage applied to the input-side conductive path and applying an output voltage to the output-side conductive path, the control unit is configured to cause the second voltage conversion unit to perform the second voltage conversion process when a certain pre-charge condition is met, by applying a second control signal, in which an ON signal and an OFF signal are alternately switched, to the switching element for backflow prevention, and After the second voltage conversion process has started, the control unit only supplies the third control signal to some of the first voltage conversion units when a certain switching condition is met, causing some of the first voltage conversion units to perform the third voltage conversion process. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0009] Since, according to the first aspect, a vehicle's internal power supply unit can cause the second voltage conversion unit to perform the second voltage conversion process upon fulfillment of a specific pre-charge condition, if the switching unit is switched from the OFF state to the ON state at least after the second voltage conversion process has been carried out accordingly, the switching unit will be switched from the OFF state to the ON state in a state where the charging of the capacitive component has progressed to a certain extent. Accordingly, it is possible to prevent an inrush current flowing into the capacitive component from the first power supply unit immediately after switching.

[0010] If a certain condition is met in the second voltage conversion process, it is additionally possible to perform the third voltage conversion process in such a way that the voltage applied to the second conductive path is increased and the resulting voltage is applied to the first conductive path, and thus the charging of the capacitive component connected to the side of the first conductive path can proceed further.

[0011] Due to a design in which only some of the first voltage conversion units are caused to perform the third voltage conversion process by supplying the third control signal to only some of the first voltage conversion units among the several of the first voltage conversion units, it is possible, in a case where the control unit causes the first voltage conversion unit to perform the third voltage conversion process when a certain switching condition is met, to reduce the energy required by the control unit to activate the first voltage conversion unit during the third voltage conversion process.Even if the voltage of the power supply that provides energy to the control unit drops accordingly, a situation is unlikely to occur in which the control unit cannot perform the control of the pre-charging process (control of the third voltage conversion process). BRIEF DESCRIPTION OF THE FIGURES Fig. Figure 1 is a block diagram which schematically shows an embodiment of a vehicle-internal energy supply system, which shows a vehicle-internal energy supply device according to a first embodiment. Fig. Figure 2 is a block diagram, which in particular shows an embodiment of a voltage conversion device that is included in the vehicle's internal power supply unit. Fig. Figure 3 is a flowchart showing the operational sequence of a pre-charging process carried out by a control unit contained in the vehicle's internal power supply unit. DESCRIPTION OF THE EXECUTION FORMS

[0012] The vehicle-internal power supply device according to the present invention can also have several third conductive paths, which serve as a power supply path from the second conductive path to the control unit. The third conductive paths can furthermore be connected in parallel to each other between the second conductive path and the control unit, and a voltage generation unit, which amplifies a voltage applied to the conductive path on the side of the second conductive path and applies the output voltage to the conductive path on the side of the control unit, can also be provided on one of the third conductive paths.

[0013] Even if the voltage applied to the second conductive path is small, according to this design, the voltage generation unit can increase the voltage applied to the conductive path on the second conductive path side and apply the output voltage to the conductive path on the control unit side. Therefore, even if the voltage applied to the second conductive path is small, the drive voltage required for the operation of the control unit is easily ensured.

[0014] In the vehicle-internal power supply unit according to the present invention, the control unit can also output the control signal to only one of the several voltage conversion units in the third voltage conversion process.

[0015] Since the number of switching elements that are controlled can be minimized with this design, the energy consumed by the control unit that generates the control signal to control the driver switching elements can also be minimized.

[0016] After starting the second voltage conversion process, the control unit can also supply the third control signal to only one of the several first voltage conversion units if a certain switching condition is met, thereby causing the first voltage conversion unit to perform the third voltage conversion process.

[0017] This design further reduces the energy required by the control unit to drive the first voltage conversion unit during the third voltage conversion process. Even if the voltage of the power supply to the control unit drops accordingly, a situation is less likely to occur in which the control unit cannot perform the pre-charging process (control of the third voltage conversion process). FIRST VERSION

[0018] A first embodiment, which is a specific example of the present invention, is described below.

[0019] A vehicle-internal power supply unit 1 (hereinafter also referred to as "power supply unit 1") of the first embodiment is part of a vehicle-internal power supply system 100 (hereinafter also referred to as "power supply system 100") that is located in Fig. Figure 1 shows the following. The power supply system 100, for example, has a first power supply unit 90, a second power supply unit 92, a first load 94, a second load 96, and a power supply device 1. The power supply system 100 is configured as a system that can supply energy to the first load 94 using the first power supply unit 90 as the power supply source, and that can charge (pre-charge) a capacitive component of the first load 94 that has discharged when an ignition switch or the like has been turned off, using the second power supply unit 92 as the power supply source via the power supply device 1.

[0020] The first power supply unit 90 is a component capable of supplying energy to the first load 94 or the second load 96 and is configured as a known vehicle-integrated battery, such as a lithium-ion battery. Within the first power supply unit 90, a high-potential terminal is electrically connected to the first conductive path 10, and a low-potential terminal is electrically connected to a conductive reference path (ground, not shown). A specific output voltage is applied to the first conductive path 10. When the switching unit 98 provided on the first conductive path 10 is switched from an OFF state to an ON state, the first power supply unit 90 is electrically connected to the first load 94 and the first power supply device 1 via the first conductive path 10.

[0021] The second power supply unit 92 is a component that can supply energy to the first load 94 or the second load 96 and is designed as a conventional vehicle battery, such as a lead-acid battery. In the second power supply unit 92, a high-potential terminal is electrically connected to the second conductive path 12, and a low-potential terminal is electrically connected to the ground (not shown). A specific output voltage is applied to the second conductive path 12. The second power supply unit 92 is electrically connected to the second load 96 and the first power supply unit 1 via the second conductive path 12.

[0022] The first load 94 has a capacitive component, and this capacitive component corresponds to an example of the capacitive component of the present invention. The first load 94 is electrically connected to the first conductive path 10 and is connected to the power supply device 1 via the first conductive path 10. The capacitive component can be a capacitor or the like, or another capacitive component.

[0023] The second load 96 has a capacitive component. The second load 96 is electrically connected to the second conductive path 12, and is connected to the power supply unit 1 via the second conductive path 12.

[0024] The power supply device 1 is configured as a device that can decrease a voltage applied to the first conductive path 10 and apply the resulting voltage to the second conductive path 12, and which can also increase or decrease a voltage applied to the second conductive path 12 and apply the resulting voltage to the first conductive path 10. The power supply device 1 includes, for example, a first voltage detection unit 80, a first current detection unit 84, a second voltage detection unit 82, a second current detection unit 86, a voltage conversion device 20, and a control unit 88.

[0025] The first voltage detection unit 80, for example, is configured as a known voltage detector and detects and outputs the voltage of the first conductive path 10. In particular, the first voltage detection unit 80 detects the voltage output by the power supply unit 1 to the first load 94 and outputs a value that reflects the detected (output) voltage (for example, the exact value or a voltage-divided value of the voltage of the first conductive path 10) as the detected value.

[0026] The first current detection unit 84, for example, is configured as a known current detector and detects and outputs the current supplied by the power supply device 1 to the first load 94. Specifically, the first current detection unit 84 comprises a resistor arranged on the first conductive path 10 and a differential amplifier. The voltage between the two ends of the resistor is input to the differential amplifier; the voltage drop generated across the resistor due to the current flowing through the first conductive path 10 is amplified by the differential amplifier, and the resulting value is output as the detected value.

[0027] The second voltage detection unit 82 is, for example, configured as a known voltage detector and detects and outputs the voltage of the second conductive path 12. In particular, the first voltage detection unit 82 detects a voltage output from the power supply unit 1 to the second load 96 and outputs the value that reflects the detected (output) voltage (for example, the exact value or a voltage-divided value of the voltage of the second conductive path 12) as the detected value.

[0028] The second current detection unit 86, for example, is configured as a known current detector and detects and outputs the current flowing through the second conductive path 12. Specifically, the second current detection unit 86 includes a resistor arranged on the second conductive path 12 and a differential amplifier. The voltage between the two ends of the resistor is input to the differential amplifier. The voltage drop generated across the resistor due to the current flowing through the second conductive path 12 is amplified by the differential amplifier, and the resulting value is output as the detected value.

[0029] The voltage conversion device 20 has several first voltage conversion units 21 arranged in parallel and is designed as a multiphase DC-DC converter which can be operated by means of synchronous rectification. One end of the voltage conversion device 20 is electrically connected to the first conductive path 10 and the other end is electrically connected to the second conductive path 12. The voltage conversion device 20 can decrease the voltage applied to the first conductive path 10 and apply the resulting voltage to the second conductive path 12, and increase the voltage applied to the second conductive path 12 and apply the resulting voltage to the first conductive path 10.

[0030] The control unit 88 is a component that controls the operation of the voltage conversion circuit 20 and is essentially configured as comprising a control circuit, first driver units 50, and a second driver unit 32. In the control unit 88, the control circuit is configured, for example, as a microcomputer and includes a processing unit such as a CPU, memory such as ROM or RAM, an A / D converter, and the like. Power is supplied to the control unit 88 by the first power supply unit 90 or the second power supply unit 92.

[0031] The control unit 88 is electrically connected to the first voltage detection unit 80, the second voltage detection unit 82, the first current detection unit 84, and the second current detection unit 86, and can receive the detected values ​​from these detection units. The control unit 88 has the function of determining or setting a duty cycle based on the received detected value and generating and outputting a PWM signal with the determined duty cycle. The control unit 88 can individually control the multiple first voltage conversion units 21 by generating a PWM signal SG1 and outputting the PWM signal SG1 to the first driver units 50 provided in each of the first voltage conversion circuits 21. Accordingly, the control unit 88 can perform the control such that the first voltage conversion units 21 (voltage conversion unit 20) increase or decrease the voltage.

[0032] As in Fig. As shown in Figure 2, the power supply unit 1 includes, for example, the first voltage conversion units 21, several switching elements 24 for backflow prevention, a second inductor 26, a switching element 28, a capacitor, the second driver unit 32 and a signal generation circuit 34.

[0033] The first voltage conversion units 21 are arranged in parallel to each other. Each voltage conversion unit 21 is configured as a DC-DC boost / drag converter with synchronous rectification and can perform a first voltage conversion operation, reducing the voltage applied to the first conductive path 10 and applying the resulting voltage to the second conductive path 12. Furthermore, one end of each first voltage conversion unit 21 is electrically connected to the first conductive path 10, and the other end is electrically connected to the second conductive path 12.

[0034] The first voltage conversion units 21 are each connected to a high-side switching element 40, a low-side switching element 42, and a first inductor 44. The switching element 40 is configured as an N-channel MOSFET, and the first conductive path 10 is electrically connected to the drain of the switching element 40. The drain of the switching element 42 and one end of the first inductor 44 are connected to a source of the same. The drain of the switching element 42 is electrically connected to the junction of the switching element 40 and the first inductor 44. The source of the switching element 42 is electrically connected to the conductive reference path. It should be noted that the switching element 40 corresponds to one example of the first driver switching element. The switching element 42 corresponds to a second example of the second driver switching element.

[0035] The first voltage conversion units 21 each have a high-side capacitor 46 and a low-side capacitor 48. One end of capacitor 46 is connected to the first conductive path 10, and the other end is electrically connected to the conductive reference path. One end of capacitor 48 is connected to the second conductive path 12, and to the other end of the first inductor 44, and to one end of the second inductor 26 via the second conductive path 12. The other end of capacitor 48 is electrically connected to the conductive reference path.

[0036] The first driver units 50 are each provided for the first voltage conversion units 21. The first driver units 50 correspond to an example of a driver unit and apply an ON signal (PWM signal) to the gate of the switching elements 40 and 42 to alternately switch on the switching elements 40 and 42, based on the PWM signal SG1, which is generated by the control unit 88. It should be noted that the PWM signal output to the switching elements 40 by the first driver unit 50 when a voltage reduction process is carried out corresponds to an example of a first control signal. Hereinafter, the PWM signal output to the switching elements 40 and 42 by the first driver unit 50 will also be referred to as the "control signal".

[0037] The (all) backflow prevention switching elements 24 are arranged such that several semiconductor switching elements 24A, 24B, 24C, and so on are connected in parallel to each other. The backflow prevention switching elements 24 have the function of interrupting a current flowing into the first voltage conversion circuits 21 on the second conductive path 12 when all the semiconductor switching elements 24A, 24B, 24C, and so on are switched off. In particular, the backflow prevention switching elements 24A, 24B, 24C, and so on are each configured as an N-channel MOSFET, and the drains thereof are electrically connected to the conductive path of the second conductive path 12 on the side of the second power supply unit 92, and the sources thereof are connected to the conductive path of the second conductive path 12 on the side of the first voltage conversion unit 21.

[0038] The second inductor 26 is provided between the first voltage conversion unit 21 and the backflow prevention switching elements 24 on the second conductive path 12, and is connected in series with the backflow prevention switching elements 24. Specifically, one end of the second inductor 26 is electrically connected to the connection points of the first inductors 44 and the capacitors 48 of the first voltage conversion units 21, and the other end is electrically connected to the sources of the backflow prevention switching elements 24 and the drain of the switching element 28.

[0039] The switching element 28 corresponds to an example of a semiconductor switching component and is, for example, designed as a MOSFET. The drain (one end) of the switching element 28 is electrically connected between the second inductor 26 and the switching elements 24 for backflow prevention on the second conductive path 12, and the source (the other end) of this is electrically connected to the conductive reference path.

[0040] One end of the capacitor 30 is connected to the second conductive path 12 on the side of the second power supply unit 92 of the switching elements 24 for backflow prevention, and the other end is electrically connected to the conductive reference path.

[0041] In this embodiment, the second voltage conversion unit 22 is formed by the switching elements 24 for reverse current prevention, the second inductor 26, and the switching element 28 (semiconductor element part). This second voltage conversion unit 22 forms a DC-DC boost / drag converter with synchronous rectification. The second conductive path 12 has an output conductive path 12B on the side of the first voltage conversion unit 21 of the second voltage conversion unit 22, and an input conductive path 12A on the opposite side of the first voltage conversion unit 21. The second voltage conversion unit 22 can perform a second voltage conversion operation, whereby the voltage applied to the input conductive path 12A is reduced, and the output voltage is applied to the output conductive path 12B.

[0042] The second driver unit 32 applies an ON signal (PWM signal) to the gates of the backflow preventer 24 and the backflow preventer 28 to alternately switch on the backflow preventer 24 and the backflow preventer 28, based on the PWM signal SG2 generated by the control unit 88. It should be noted that the PWM signal output by the second driver unit 32 to the backflow preventer 24 is an example of a second control signal. Hereinafter, the PWM signal output by the second driver unit 32 to the backflow preventer 24 will be referred to as a "control signal".

[0043] Furthermore, of the several switching elements 24 for backflow prevention, the control signal from the second driver unit 32 is supplied directly to the gate of some (one in the first embodiment) of the switching elements 24 for backflow prevention, and the control signal from the second driver unit 32 is supplied to another switching element 24B for backflow prevention via the signal generation circuit 34.

[0044] The signal generation circuit 34 is located between the second driver unit 32 and the gate of the backflow preventer 24B. Based on an interruption instruction signal SG3, which is output by the control unit 88, the signal generation circuit 34 interrupts the control signal that is output from the second driver unit 32 to the backflow preventer 24B.

[0045] Three conductive paths 60 are provided, one between the second conductive path 12 and the first driver unit 50, and the other between the second conductive path 12 and the second driver unit 32. The three conductive paths 60 are arranged such that portions thereof are connected in parallel, with one parallel conductive path being provided with a diode 62 and the other conductive path being provided with a diode 64 and a voltage generation unit 66. The anode of the diode 62 is connected to the second conductive path 12, and the cathode is connected to the first driver unit 50 and the second driver unit 32. The voltage generation unit 66 is connected in series with the diode 64 and is connected on the side of the second power supply unit 92 of the diode 64. The anode of the diode 64 is connected to the voltage generation unit 66, and the cathode is connected to the first driver unit 50 and the second driver unit 32.The voltage generation unit 66, for example, is designed as a booster circuit and can boost the voltage input from the side of the second conductive path 12 and output the resulting voltage to the side of the first driver unit 50 and the second driver unit 32 based on a boost instruction signal SG4 from the control unit 88.

[0046] Next, the operation of energy supply facility 1 will be explained.

[0047] When the switching unit 98 is switched from the OFF state to the ON state, so that energy is supplied from the first power supply unit 90 to the first load 94, the power supply unit 1 can perform a pre-charging operation of the capacitive component of the first load 94 using energy from the second power supply unit 92, thus preventing a large current from flowing rapidly into the capacitive component present in the first load 94.

[0048] The control unit 88 is designed to control the pre-loading control, which is in Fig. 3 is shown, to execute repeatedly, and to determine whether a certain preload condition is met, in accordance with the start of the preload control in Fig.3 is fulfilled. The pre-load condition can be, for example, that "the switching unit 98 (for example, an ignition switch) is switched from the OFF state to the ON state", whereby another specific pre-load condition is also possible.

[0049] After determining that the pre-charge condition is satisfied in step S1, the control unit 88, in step S2, causes the second voltage conversion unit 22 to start the second voltage conversion process. The second voltage conversion process is a process in which the second voltage conversion unit 22 reduces the voltage applied to the input-side conductive path 12A of the second conductive path 12 and applies the resulting voltage to the output-side conductive path 12B in accordance with the control signal supplied externally. In particular, the second voltage conversion process is implemented as follows.

[0050] After the second voltage conversion process is started in step S2, the control unit 88 determines in step S3, based on the detected value from the first voltage detection unit 80, whether the switching condition has been met. Specifically, the control unit 88 determines in step S3 whether the voltage of the first conductive path 10 is greater than or equal to a certain threshold. If the voltage of the first conductive path 10 is less than or equal to the specified threshold, the processing proceeds to "No" in step S3. If the voltage of the first conductive path 10 is greater than or equal to the specified threshold, the processing proceeds to "Yes" in step S3 and, in step S4, shifts from the second voltage conversion process to a third voltage conversion process.

[0051] Furthermore, the control unit 88 determines the duty cycle based on the detected value of the first voltage detection unit 80 or the first current detection unit 84 and generates the PWM signal SG2 with the determined duty cycle. The control unit 88 then outputs the PWM signal SG2 to the second driver unit 32. After receiving this PWM signal SG2, the second driver unit 32 outputs the control signal with the duty cycle of the PWM signal SG2 to a switching element 24A of the switching elements 24 for backflow prevention and outputs the PWM signal complementary to this control signal to the switching elements 28. In other words, a synchronous rectification control is executed in which switching element 28 is switched off when switching element 24A is switched on, and switching element 28 is switched on when switching element 24A is switched off, while a dead time is also set.The control signal from the second driver unit 32 is also input into the signal generation circuit 34. If signal SG3 is an interrupt instruction signal, the signal generation circuit 34 outputs the OFF signal to switching elements 24B and 24C, and at this time, switching elements 24B and 24C are switched to the OFF state. If signal SG3 is an enable signal, the signal generation unit 34 outputs a signal to switching elements 24B and 24C that is the same as the signal output to the gate of switching element 24A by the second driver unit 32.While the second voltage conversion unit 22 is performing the second voltage conversion operation (during the output of the control signal to the gate of switching element 24A), the control unit 88 sets the signal SG3, which is input to the signal generation unit 34, as the interrupt instruction signal. Thus, switching elements 24B and 24C are held in the OFF state while the second voltage conversion unit 22 performs the second voltage conversion operation. In other words, while the second voltage conversion unit 22 is performing the second voltage conversion operation, the control signal output by the second driver unit 32 is only output to switching element 24A, and switching elements 24B and 24C are held in an OFF state. Accordingly, only switching element 24A is turned on or off.

[0052] Based on the PWM signal (control signal) supplied to the switching elements 24A by the second driver unit 32, the second voltage conversion unit 22 accordingly performs the second voltage conversion process such that the voltage applied to the input-side conductive path 12A is reduced, and the resulting voltage is applied to the output-side conductive path 12B. During this second voltage conversion process, the control is carried out such that the feedback process for calculating the duty cycle is repeated, ensuring that the voltage applied to the first conductive path 10 is approximately the desired voltage, which is lower than the output voltage when the second power supply unit 92 is fully charged, and that the voltage applied to the first conductive path 10 is approximately the desired target voltage.It should be noted that the control unit 88 can also control the duty cycle of the PWM signal supplied to the switching element 24A, while the current flowing through the first conductive path 10 is monitored such that the current flowing through the first conductive path 10 remains constant during the second voltage conversion process. During the second voltage conversion process, the capacitive component of the first load 94 is charged. It should be noted that, although the switching elements 42 are held in the OFF state during the second voltage conversion process, the switching elements 40 can also be held in the ON state to prevent a loss, or the switching element 40 can also be held in the OFF state.

[0053] If it is determined that the specified switching condition in step S3 is met, in other words, if it is determined that the voltage of the first conductive path 10 is greater than or equal to the specified threshold, the control unit 88 terminates the second voltage conversion process by the second voltage conversion unit 22 in step S4 and starts the third voltage conversion process by the first voltage conversion unit 21. The third voltage conversion process is a process in which a synchronous rectification voltage boosting process is carried out in the voltage conversion unit 20, in which an ON signal based on the PWM signal SG1 is alternately supplied to the switching elements 40 and 42 by the first driver unit 50, and the voltage applied to the second conductive path 12 is boosted and applied to the first conductive path 10.

[0054] During this third voltage conversion process, the control unit 88 terminates the output of the interrupt instruction signal SG3 to the signal generation circuit 34 and outputs the OFF signal to the second driver unit 32. Upon receiving this ON signal, the second driver unit 32 outputs the ON signal to all switching elements 24A, 24B, 24C, etc., which constitute the backflow prevention switching element 24, and outputs the OFF signal to the switching element 28. Accordingly, during the third voltage conversion process, all switching elements 24A, 24B, 24C, etc., which constitute the backflow prevention switching element 24, are held in the ON state, and the switching element 28 is held in the OFF state.

[0055] The control unit 88 determines the duty cycle based on the value detected by the first voltage detection unit 80 or the first current detection unit 84 and generates a PWM signal SG1 with the determined duty cycle. Specifically, the control unit 88 performs a control operation such that the feedback process for calculating the duty cycle is repeated in such a way that the voltage applied to the first conductive path 10 is approximately the desired target voltage, which is higher than the output voltage when the second power supply unit 92 is fully charged, and the voltage applied to the first conductive path 10 is approximately the desired target voltage. The control unit 88 outputs the PWM signal SG1 thus generated only to the first driver unit 50, which corresponds to one of the first voltage conversion units 21 of the multiple first voltage conversion units 21.Upon receiving the input of this PWM signal SG1, the first driver unit 50 outputs a control signal (third control signal) with the duty cycle of the PWM signal SG1 to the switching element 42, and outputs a control signal to the switching element 40 that is complementary to this control signal (PWM signal SG1). In other words, synchronous rectification control is implemented such that the switching element 40 is switched off when the switching element 42 is switched on, and the switching element 40 is switched on when the switching element 42 is switched off, while a dead time is set. It should be noted that the control unit 88 outputs an OFF signal to the first driver units 50 of the other first voltage conversion units 21 (the first voltage conversion units 21 that do not receive the input of the PWM signal) of the multiple first voltage conversion units 21.After receiving the input of the OFF signal, the first driver units 50 keep the corresponding switching elements 40 and 42 in the OFF state.

[0056] Accordingly, the third voltage conversion process is carried out, whereby the voltage applied to the second conductive path 12 is increased and applied to the first conductive path 10. In this third voltage conversion process, it is possible to further accumulate electrical charge in the capacitive component of the first load 94, in which the electrical charge was accumulated by the second voltage conversion process, and to further increase the charging voltage of the capacitive component.

[0057] After the third voltage conversion process is started in step S4, the control unit 88 determines in step S5 whether a specific pre-charge end condition is met. This specific pre-charge end condition might be, for example, that "the voltage of the first conductive path 10 has reached a certain voltage" or something similar.

[0058] If it is determined that the pre-charge end condition in step S5 has not been met, the control unit 88 repeats step S5 until the pre-charge end condition is met. During this time, the charging of the capacitive component of the first load 94 continues. If it is determined that the pre-charge end condition in step S5 has been met, the control unit 88 terminates the third voltage conversion operation in step S6. In other words, the control unit 88 stops outputting the PWM signal SG1, the PWM signal SG2, the interrupt instruction signal SG3, and the increase instruction signal SG4. Accordingly, the pre-charging of the first load is complete.

[0059] After the third voltage conversion process in step S6 is completed, the control unit 88 switches the switching unit 98 from the OFF state to the ON state. This allows the switching unit 98 to be switched to the ON state when the capacitive component of the first load 94 has already been charged to some extent, thus reducing the likelihood of a large current flowing into the capacitive component of the first load 94. After switching the switching unit 98 to the ON state in accordance with step S6, the control unit 88 can then cause the voltage conversion device 20 to perform the voltage reduction process described above, thereby reducing the voltage applied to the first conductive path 10 and applying the output voltage to the second conductive path 12.

[0060] In this embodiment, it should be noted that the control unit 88 outputs the increased instruction signal SG4 to the voltage generation unit 66 during the first voltage conversion process, the second voltage conversion process, or the third voltage conversion process. During the time period in which this increased instruction signal SG4 is supplied to the voltage generation unit 66, the voltage generation unit 66 increases the input voltage (voltage applied to the second conductive path 12) and outputs the resulting voltage to the anode side of the diode 64. It should be noted that the control unit 88 can also output the increase instruction signal SG4 in one or all of the time periods, namely during the first voltage conversion process, the second voltage conversion process, and the third voltage conversion process.The control unit 88 can only output the increase instruction signal SG4 if the voltage output to the second conductive path 12 is less than or equal to a certain value.

[0061] Next, the effects of energy supply facility 1 will be described.

[0062] The power supply unit 1 described above can cause the second voltage conversion unit 22 to perform the second voltage conversion process when a certain pre-charging condition is met. Accordingly, if it is possible to switch the switching unit 98 from the OFF state to the ON state, at least after the second voltage conversion process has been carried out in this manner, the switching unit 98 will be switched from the OFF state to the ON state in a state where the charging of the capacitive component has progressed to a certain extent. As a result, it is possible to suppress the inrush current that flows into the capacitive component from the first power supply unit 90 immediately after switching.

[0063] Furthermore, if a certain switching condition is met in the second voltage conversion process, the third voltage conversion process can be carried out such that the voltage applied to the second conductive path 12 is increased, and the resulting voltage is applied to the first conductive path 10, making it possible to further charge the capacitive component connected to the side of the first conductive path.

[0064] If, with this configuration, the control unit 88 further causes the first voltage conversion unit 21 to perform the third voltage conversion process when a certain switching condition is met, the third control signal is supplied to only some of the semiconductor switching elements 21 of the multiple semiconductor switching elements 21, thereby causing only some of the first voltage conversion units 21 to perform the third voltage conversion process. Accordingly, it is possible to reduce the energy required by the control unit 88 to activate the first voltage conversion unit 21 during the third voltage conversion process.Even if the voltage of the power supply that provides energy to the control unit 88 drops accordingly, a situation is less likely to occur in which the control unit 88 cannot perform the control of the pre-charging process (control of the third voltage conversion process).

[0065] Furthermore, the power supply unit 1 is provided with several third conductive paths 60, which serve as the power supply path from the second conductive path 12 to the control unit 88. The third conductive paths 60 are connected in parallel to each other between the second conductive path 12 and the control unit 88, and one of the third conductive paths 60 is connected to the voltage generation unit 66, which increases the voltage applied to the conductive path on the side of the second conductive path 12 and applies the output voltage to the conductive path on the side of the control unit 88.Even if the voltage applied to the second conductive path 12 is small, the voltage generation unit 66, with this configuration, can increase the voltage applied to the conductive path on the side of the second conductive path 12 and apply the output voltage to the conductive path on the side of the control unit 88. Thus, even if the voltage applied to the second conductive path 12 is small, it is likely that the drive voltage required for the operation of the control unit 88 is ensured.

[0066] After the second voltage conversion process has started, the control unit 88 further supplies the third control signal to one of the first voltage conversion units 21 among several, so that only the first voltage conversion unit 21 is caused to carry out the third voltage conversion process. With this design, it is possible to further reduce the energy required by the control unit 88 to control the first voltage conversion unit 21 during the third voltage conversion process. Even if the voltage of the power supply that provides energy to the control unit 88 drops, a situation is less likely to occur in which the control unit 88 cannot control the pre-charging process (control of the third voltage conversion process). OTHER VERSIONS

[0067] The present invention is not limited to the embodiment shown on the basis of the above descriptions and figures, and the following embodiments are also included in the technical scope of the present invention.

[0068] In the first embodiment, the control signal is output to only one of the switching elements 24 for backflow prevention in the second voltage conversion process, but an embodiment is also possible in which the control signal is output to two or more switching elements 24 for backflow prevention, as long as it is only a part of the switching elements 24 for backflow prevention.

[0069] In the first embodiment, the voltage generation unit 66 is provided on the third conductive path 60, but the voltage generation unit 66 can also be omitted.

[0070] In the first embodiment, the switching element is switched on during the second voltage conversion process, but the switching element 40 can also be switched off. In this case, the current flows through the body diode of the switching element 40 in the direction of the first load 94.

[0071] In the third voltage conversion process in the first embodiment, the control signal is output to the switching element 40 and 42 of one of the several first voltage conversion units 21, but the control signal can also be output to the switching elements 40 and 42 of two or more of the first voltage conversion units 21, as long as it is only the switching elements 40 and 42 of a part of the first voltage conversion units 21.

[0072] Although the semiconductor element is the switching element in the first embodiment, the semiconductor element can also be a diode. If the semiconductor element is a diode, an embodiment is possible in which the anode is electrically connected to the conductive reference path, the cathode is electrically connected between the second inductor 26 and the switching element 24 for reverse flow prevention on the second conductive path 12, and the second voltage conversion unit 22 functions as a diode DC-DC converter. REFERENCE MARK LIST 1 vehicle-internal power supply unit 10 first conductive path 12 second conductive path 12A input conductive path 12B output conductive path 21 first voltage conversion unit 22 second voltage conversion unit 24 Switching element for backflow prevention 24A, 24B, 24C Semiconductor switching element 26 second inductance 28 Switching element (semiconductor element part) 40 Switching element (driver switching element) 42 Switching element (driver switching element) 44 first inductance 60 third conductive path 66 Voltage generation unit 88 Control unit 90 first energy supply unit 92 second power supply unit 94 first load 96 second load 98 Switching unit 100 vehicle-internal power supply system

Claims

[1] Vehicle-internal power supply device (1) configured to decrease a voltage applied to a first conductive path (10) electrically connected to a capacitive component (46) and apply the resulting voltage to a second conductive path (12), or to increase a voltage applied to the second conductive path (12) and apply the resulting voltage to the first conductive path (10), wherein the vehicle-internal power supply device (1) comprises: a first voltage conversion unit (21) comprising a first driver switching element (40), a second driver switching element (42) and a first inductor (44), which performs a first voltage conversion operation in accordance with a first control signal, in which switching alternately between an ON signal and an OFF signal is applied to the first driver switching element (40), whereby a voltage applied to the first conductive path (10) is decreased and an output voltage is applied to the second conductive path (12), and which performs a third voltage conversion operation in accordance with a third control signal, in which switching alternately between an ON signal and an OFF signal is applied to the second driver switching element (42), whereby a voltage applied to the second conductive path (12) is increased.and an output voltage is applied to the first conductive path (10); a switching element (24) for preventing backflow, which is provided on the second conductive path (12) and which prevents a current flow on the second conductive path (12) in the direction of the first voltage conversion unit (21) when it is switched off; a second inductance (26) which is provided between the first voltage conversion unit (21) and the switching element (24) for backflow prevention on the second conductive path (12) and in series with the switching element (24) for backflow prevention; a semiconductor element part (28) formed by a diode or a switching element, one end of which is electrically connected between the second inductor (26) and the switching element (24) for reverse flow prevention on the second conductive path (12), and the other end of which is electrically connected to a conductive reference path; and a control unit (88) which outputs the first control signal to at least the first driver switching element (40) and outputs the third control signal to the second driver switching element (42), wherein several first voltage conversion units (21) are connected in parallel to each other between the first conductive path (10) and the second conductive path (12), a second voltage conversion unit (22) is provided by the switching element (24) for reverse flow prevention, the second inductor (26) and the semiconductor element part (28), and, if the part of the second conductive path (12) that is on the side of the first voltage conversion unit (21) as seen from the second voltage conversion unit (22) is considered an output-side conductive path (12B), and the part of the second conductive path (12) that is on the side opposite to the side of the first voltage conversion unit (21) is considered an input-side conductive path (12A), the second voltage conversion unit (22) performs the second voltage conversion operation, reducing the voltage applied to the input-side conductive path (12A) and applying an output voltage to the output-side conductive path (12B) is created the control unit (88) is configured to cause the second voltage conversion unit (22) to perform the second voltage conversion process when a certain pre-charge condition is met by applying a second control signal, in which an ON signal and an OFF signal are alternately switched, to the switching element (24) for backflow prevention, and After the start of the second voltage conversion process, the control unit (88) supplies the third control signal to only some of the first voltage conversion units (21) when a certain switching condition is met, causing some of the first voltage conversion units (21) to perform the third voltage conversion process. [2] Vehicle-internal power supply device (1) according to claim 1, comprising: several third conductive paths (60) that serve as a power supply path from the second conductive path (12) to the control unit (88), wherein the third conductive paths (60) are connected in parallel to each other between the second conductive path (12) and the control unit (88), and a voltage generation unit (66) is provided on one of the third conductive paths (60) which increases a voltage applied to the conductive path on the side of the second conductive path (12) and which applies the output voltage to the conductive path on the side of the control unit (88). [3] Vehicle internal power supply device (1) according to claim 1 or 2, wherein after the start of the second voltage conversion process, the control unit (88) supplies the third control signal to only one first voltage conversion unit (21) of the several first voltage conversion units (21) when a certain switching condition is met, thereby causing the one first voltage conversion unit (21) to carry out the third voltage conversion process.

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