Vehicle power supply device

Abstract

A device capable of setting a target voltage value suitable for a voltage applied to a load with good responsiveness is realized. A vehicle-mounted power supply device (1) comprises a voltage conversion unit (20), a first voltage detection unit (40) for detecting the value of a first voltage applied to a second conductive circuit (12), and a second voltage detection unit (42) for detecting the value of a second voltage applied to a load-side conductive circuit (14). Furthermore, the vehicle-mounted power supply device (1) comprises a target voltage setting unit (50) for setting the target voltage value based on the value of the second voltage detected by the second voltage detection unit (42), and a control unit (5). The control unit (5) repeatedly performs the following feedback operation: based on the value of the first voltage detected by the first voltage detection unit (40), the duty ratio of the control signal is updated in such a manner that the value of the first voltage applied to the second conductive circuit (12) approaches the target voltage value.

Description

Technical Field

[0001] The present disclosure relates to a vehicle-mounted power supply device. Background Art

[0002] In conventional vehicle-mounted power supply devices, there is known a structure for performing constant voltage output by performing feedback control based on the deviation between the output voltage value and the target voltage value so as to make the output voltage close to the target voltage value. Patent document 1 discloses an example of such a vehicle-mounted power supply device, in which a setting method is adopted in which a low target voltage value is initially set for the final target voltage value and the target voltage value is gradually brought close to the final target voltage value as the output voltage rises.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-139339 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In a device that adopts a setting method that gradually brings the target voltage value closer to the final target voltage value, such as the device disclosed in Patent Document 1, in a transitional state in which the target voltage value is gradually increased, the physical characteristics are likely to be greatly different between the output voltage value detected for feedback control and the terminal voltage value of the target load. In such a device, if a setting method that sets the target voltage value based on the output voltage value is adopted, it is difficult to set the target voltage value suitable for the actual load voltage (terminal voltage of the load) with good responsiveness.

[0008] Therefore, in order to solve at least one of the above-mentioned problems, a technology is realized that can apply the output voltage to the conductive circuit on the output side while repeatedly performing feedback operation so that the output voltage approaches the target voltage value and can responsively set the target voltage value suitable for the voltage applied to the load.

[0009] Solutions to Solve Problems

[0010] As an example of the present disclosure, a vehicle-mounted power supply device includes: a voltage conversion unit having a switch element, the switch element performs an on-off operation according to a control signal to which an on signal and an off signal are alternately and repeatedly provided, the voltage conversion unit steps up or steps down a voltage applied to a first conductive circuit by the on-off operation of the switch element, and applies a voltage to a second conductive circuit; a first voltage detection unit detects a value of a first voltage applied to the second conductive circuit; a second voltage detection unit detects a value of a second voltage applied to a load-side conductive circuit, the load-side conductive circuit being interposed between the second conductive circuit and a load; a target voltage setting unit sets a target voltage value based on the value of the second voltage detected by the second voltage detection unit; and a control unit repeatedly performs the following feedback operation: based on the value of the first voltage detected by the first voltage detection unit, a duty ratio of the control signal is updated in such a manner that the value of the first voltage applied to the second conductive circuit approaches the target voltage value, and each time the duty ratio is updated, the control signal of the updated duty ratio is output to the switch element.

[0011] Effects of the Invention

[0012] According to the present disclosure, the output voltage can be applied to the conduction circuit on the output side while repeatedly performing feedback calculation so that the output voltage approaches the target voltage value, and the target voltage value suitable for the voltage applied to the load can be set with good responsiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 1 is a circuit diagram schematically showing an in-vehicle power supply system including the in-vehicle power supply device of the first embodiment.

[0014] Figure 2 is exemplified in Figure 1 Flowchart of the process of voltage conversion control performed in the vehicle-mounted power supply device.

[0015] Figure 3 is exemplified in Figure 1 Flowchart of the process of target voltage value setting processing performed in the vehicle-mounted power supply device.

[0016] Figure 4 This is a graph for explaining changes in the target voltage value in a transient state immediately after the operation of the voltage conversion unit is started.

[0017] Figure 5 1 is a circuit diagram schematically showing a target voltage setting unit in the second embodiment.

[0018] Figure 6 1 is a circuit diagram schematically showing a target voltage setting unit in the third embodiment. DETAILED DESCRIPTION

[0019] As an example of the present disclosure, a vehicle-mounted power supply device may also be configured to include: a voltage conversion unit that steps up or steps down the voltage applied to the first conductive circuit and applies the voltage to the second conductive circuit; and a first voltage detection unit that detects the value of the first voltage applied to the second conductive circuit. In addition, the vehicle-mounted power supply device may also be configured to include: a second voltage detection unit that detects the value of the second voltage applied to the load-side conductive circuit, which is between the second conductive circuit and the load; and a target voltage setting unit that sets the target voltage value based on the value of the second voltage detected by the second voltage detection unit. In addition, it may also be configured to include a control unit that outputs a control signal to the switching element, and it may also be configured such that the control unit repeatedly performs the following feedback operation: based on the value of the first voltage detected by the first voltage detection unit, the duty cycle of the control signal is updated in such a way that the value of the first voltage applied to the second conductive circuit is close to the target voltage value.

[0020] According to the above configuration, the target voltage setting unit can set the target voltage value based on the voltage value of the path (load-side conductive path) closer to the load side than the second conductive path to which the output voltage from the voltage conversion unit is applied. Therefore, even if the second conductive path and the load-side conductive path have different physical properties, the target voltage value suitable for the voltage applied to the load can be set with good responsiveness.

[0021] In a vehicle-mounted power supply device as an example of the present disclosure, the target voltage setting unit may repeatedly perform the following processing: based on the deviation between the value of the second voltage detected by the second voltage detection unit and a predetermined target voltage reference value, the target voltage value is updated in such a manner that the target voltage value approaches the target voltage reference value.

[0022] If constructed in the above manner, even if the value of the second voltage applied to the load-side conductive circuit deviates from the target voltage reference value, by repeatedly updating the target voltage value based on the voltage value of the load-side conductive circuit, it is possible to responsively set a target voltage value suitable for the voltage applied to the load, and the target voltage value can be gradually brought close to the target voltage reference value.

[0023] In the vehicle-mounted power supply device as an example of the present disclosure, a period at which the target voltage setting unit updates the target voltage value may be greater than a period at which the control unit updates the duty ratio.

[0024] With the above configuration, the duty cycle can be set shorter to increase the update frequency. On the other hand, the target voltage value can be updated at a cycle greater than the duty cycle, so the processing load required to update the target voltage value can be reduced.

[0025] The vehicle-mounted power supply device as an example of the present disclosure may include an electronic component disposed between the second conductive path and the load-side conductive path. Furthermore, the electronic component may include at least one of a resistor and an inductor.

[0026] According to the above configuration, the target voltage can be set according to the voltage of the load-side conduction circuit even when the voltage of the second conduction circuit deviates from the voltage of the load-side conduction circuit due to the electronic component while the electronic component functions.

[0027] <Example 1>

[0028] Figure 1 The illustrated vehicle-mounted power supply system 100 includes a power supply unit 90 and a vehicle-mounted power supply device 1 (hereinafter, also simply referred to as a power supply device 1 ), and is configured as a system capable of supplying electric power to a load 92 mounted on a vehicle.

[0029] In addition, in this specification, unless otherwise explicitly stated, "voltage" means a potential difference with respect to the ground.

[0030] The power supply unit 90 is configured as a known vehicle-mounted storage battery such as a lead-acid battery, for example. The power supply unit 90 electrically connects the terminal on the high potential side to the first wiring unit 81, and applies a predetermined output voltage to the first wiring unit 81. The power supply unit 90 is electrically connected to the input side terminal 60 of the vehicle-mounted power supply device 1 via the first wiring unit 81. The output voltage of the power supply unit 90 when fully charged is set to a value greater than 0 V and a value greater than a target voltage reference value Vft described later.

[0031] The load 92 is a known vehicle-mounted electrical component and is electrically connected to the output terminal 62 of the power supply device 1 via the second wiring section 82. The power supply unit 90 supplies power to the load 92 via the first wiring section 81, the power supply device 1, and the second wiring section 82.

[0032] The power supply device 1 has a first conductive circuit 11, a second conductive circuit 12, a voltage conversion unit 20, an intermediate conductive circuit 13, a load-side conductive circuit 14, a second inductance unit 30 (hereinafter, also referred to as the inductance unit 30), a resistor unit 32, a capacitor unit 34, a capacitor unit 36, an input side terminal 60, an output side terminal 62, a first voltage detection unit 40, a second voltage detection unit 42, and a voltage conversion control device 3.

[0033] The first conductive path 11 functions as a conductive path on the input side of the voltage conversion unit 20, and one end is electrically connected to the input side terminal 60, and the other end is electrically connected to the voltage conversion unit 20. That is, the voltage conversion unit 20 is electrically connected to the power supply unit 90 via the first conductive path 11, and can receive power supply from the power supply unit 90.

[0034] The second conductive path 12 functions as a conductive path on the output side of the voltage conversion unit 20 , and has one end electrically connected to the voltage conversion unit 20 and the other end electrically connected to one end of the second inductance unit 30 .

[0035] The intermediate conductive path 13 is a conductive path between the second conductive path 12 and the output terminal 62 and is arranged closer to the load 92 than the second conductive path 12. One end of the intermediate conductive path 13 is electrically connected to the other end of the second inductor 30, and the other end is electrically connected to one end of the resistor 32.

[0036] The load-side conductive path 14 is a conductive path between the second conductive path 12 and the output-side terminal 62, and is arranged as a path closer to the load 92 side than the second conductive path 12 (more specifically, a path closer to the load 92 side than the intermediate conductive path 13). One end of the load-side conductive path 14 is electrically connected to the other end of the resistor section 32, and the other end is electrically connected to the output-side terminal 62.

[0037] The second inductor 30 corresponds to an example of an electronic component or an inductor, and is configured as a known inductor, for example, and is interposed between the second conductive path 12 and the load-side conductive path 14. One end of the second inductor 30 is electrically connected to the second conductive path 12, and the other end is electrically connected to the intermediate conductive path 13. In other words, the second inductor 30 is arranged on the load 92 side relative to the second conductive path 12, and the load-side conductive path 14 is arranged on the load 92 side relative to the second inductor 30. The second inductor 30 may function as a filter, or may have other functions.

[0038] The resistor section 32 is configured as, for example, a known resistor, and is interposed between the second conductive path 12 and the load-side conductive path 14. One end of the resistor section 32 is electrically connected to the intermediate conductive path 13, and the other end is electrically connected to the load-side conductive path 14. In other words, the resistor section 32 is arranged on the load 92 side relative to the second conductive path 12, and the load-side conductive path 14 is arranged on the load 92 side relative to the resistor section 32. The resistor section 32 may function as a shunt resistor for current detection, or may have other functions.

[0039] The capacitor unit 34 is configured as, for example, a known non-polar capacitor, one end of which is electrically connected to the second conductive path 12 , and the other end of which is electrically connected to a reference conductive path (ground).

[0040] The capacitor section 36 is configured as, for example, a known polar capacitor, one end of which is electrically connected to the intermediate conductive path 13 (the other end of the second inductor section 30 and one end of the resistor section 32 ) and the other end of which is electrically connected to the reference conductive path (ground).

[0041] The voltage conversion unit 20 is configured as, for example, a known DCDC converter, and can operate in a manner of stepping down the voltage (voltage of the same magnitude as the output voltage of the power supply unit 90) applied to the first conductive path 11 and applying a predetermined output voltage to the second conductive path 12. The voltage conversion unit 20 includes a first switching element 22, a second switching element 24, and a first inductor unit 26.

[0042] The first switching element 22 and the second switching element 24 are each an element that performs an on-off operation according to a control signal (PWM signal) that is provided with an on signal and an off signal alternately and repeatedly, and is configured as a well-known MOSFET, for example. In addition, the first switching element 22 is equivalent to an example of a switching element. The first inductor 26 is configured as a well-known inductor coil, for example.

[0043] In the first switch element 22, the drain is electrically connected to the first conductive circuit 11, and the source is electrically connected to the drain of the second switch element 24 and one end of the first inductor 26. In the second switch element 24, the drain is electrically connected to the source of the first switch element 22 and one end of the first inductor 26, and the source is electrically connected to the reference conductive circuit (ground). One end of the first inductor 26 is electrically connected to the source of the first switch element 22 and the drain of the second switch element 24, and the other end is electrically connected to the second conductive circuit 12.

[0044] The voltage conversion unit 20 can perform the following step-up or step-down operation (step-down operation in this embodiment): the voltage applied to the first conductive path 11 is stepped up or stepped down (step-down operation in this embodiment) by the on-off operation of the first switch element 22, and the output voltage is applied to the second conductive path 12. The voltage conversion unit 20 performs the step-up or step-down operation (step-down operation in this embodiment) according to the control signal provided to the first switch element 22 by the control circuit 44 described later. More specifically, in the voltage conversion control in which the control circuit 44 causes the voltage conversion unit 20 to perform the voltage conversion operation, the control circuit 44 inputs the on-off signals (PWM signals) complementary to each other to each switch element of the first switch element 22 and the second switch element 24. In such voltage conversion control, the second switch element 24 is in the off-operation when the first switch element 22 is in the on-operation, and the second switch element 24 is in the on-operation when the first switch element 22 is in the off-operation, and the dead time in which the two elements are in the off state is set when the switches of the two elements are switched.

[0045] The first voltage detection unit 40 is configured as a known voltage detection circuit, for example. The first voltage detection unit 40 is electrically connected to the second conductive circuit 12, and is capable of detecting the voltage value V1 of the second conductive circuit 12. Specifically, a voltage detection position P1 of the first voltage detection unit 40 is set between the voltage conversion unit 20 and the second inductance unit 30, and the first voltage detection unit 40 inputs the value representing the voltage at the position P1 to the first deviation calculation unit 46. In addition, the value input by the first voltage detection unit 40 to the first deviation calculation unit 46 can be a value that can specify the voltage value V1 of the second conductive circuit 12, which can be as follows: Figure 1 The voltage value V1 of the second conductive path 12 shown in the figure may not be itself. For example, the first voltage detection unit 40 may include a voltage dividing circuit and input a voltage obtained by dividing the voltage value V1 at a predetermined voltage dividing ratio to the first deviation calculation unit 46 .

[0046] The second voltage detection unit 42 is configured as, for example, a well-known voltage detection circuit. The second voltage detection unit 42 is electrically connected to the load-side conductive circuit 14, and can detect the voltage value V2 of the load-side conductive circuit 14. Specifically, a voltage detection position P2 of the second voltage detection unit 42 is set between the second inductance unit 30 and the output-side terminal 62, and the voltage detection position P2 is set to be closer to the load 92 side than the voltage detection position P1 of the first voltage detection unit 40. The second voltage detection unit 42 inputs the value representing the voltage at the position P2 to the target voltage setting unit 50. In addition, the value input by the second voltage detection unit 42 to the target voltage setting unit 50 can be a value that can specify the voltage value V2 of the load-side conductive circuit 14, and can be such as Figure 1 The voltage value V2 of the load-side conductive path 14 shown above may not be itself. For example, the second voltage detection unit 42 may include a voltage dividing circuit and input a voltage obtained by dividing the voltage value V2 at a predetermined voltage dividing ratio to the target voltage setting unit 50 .

[0047] The voltage conversion control device 3 includes a control unit 5 and a target voltage setting unit 50. The control unit 5 includes a first deviation calculation unit 46 and a control circuit 44. The target voltage setting unit 50 includes a second deviation calculation unit 52 and a PI control unit 54.

[0048] The control circuit 44 constituting a part of the control unit 5 is constituted by, for example, a well-known microcomputer and a drive circuit, and has a processor such as a CPU, a memory such as a ROM and a RAM, etc. The control circuit 44 repeatedly performs feedback control for updating the duty ratio of the control signal based on the voltage value V1 input from the first voltage detection unit 40 so that the value of the output voltage applied to the second conductive circuit 12 approaches the target voltage value Vt, and each time the duty ratio is updated, the control signal (first PWM signal) of the updated duty ratio can be output to the first switching element 22. In addition, the control signal (second PWM signal) that reverses the on-off of the control signal (first PWM signal) output to the first switching element 22 in a form in which a dead time is set can be output to the second switching element 24.

[0049] The first deviation calculation unit 46 can be configured as a well-known subtraction circuit, for example, or can be implemented by a microcomputer. The first deviation calculation unit 46 uses the voltage value V1 of the second conductive path 12 detected by the first voltage detection unit 40 and the target voltage value Vt set by the target voltage setting unit 50 as input values. The first deviation calculation unit 46 calculates the deviation between the voltage value V1 of the second conductive path 12 set as the input value and the target voltage value Vt as the first deviation Et1, and sets the calculated first deviation Et1 as the output value for the control circuit 44.

[0050] The target voltage setting unit 50 is constituted by, for example, a well-known microcomputer, and has a processor such as a CPU, a memory such as a ROM and a RAM, etc. The target voltage setting unit 50 is a part that sets the target voltage value Vt based on the voltage value of the load-side conductive path 14 (the conductive path closer to the load 92 side than the voltage detection position P1 of the first voltage detection unit 40). Figure 1 In the example, a value indicating the voltage value V2 of the load-side conductive path 14 is input from the second voltage detection unit 42 to the target voltage setting unit 50 , and the target voltage setting unit 50 sets the target voltage value Vt based on the voltage value V2 of the load-side conductive path 14 .

[0051] Specifically, the target voltage setting unit 50 sets the target voltage value Vt based on the deviation between the voltage value V2 of the load-side conductive circuit 14 and the target voltage reference value (final target voltage value) Vft. Here, the target voltage reference value (final target voltage value) Vft refers to the final target value of the target voltage value Vt repeatedly set based on the voltage value V2 of the load-side conductive circuit 14, and can be set based on a signal from the outside or stored in advance. The target voltage setting unit 50 performs a known feedback operation based on the current target voltage value Vt and the target voltage reference value (final target voltage value) Vft so that the target voltage value is close to the target voltage reference value (final target voltage value) Vft, and sets a new target voltage value. In addition, when the period for setting the target voltage value Vt by the target voltage setting unit 50 (that is, the period for updating the target voltage value Vt by feedback operation) is set to the second period, it is preferred that the second period is greater than the period (first period) for updating the duty ratio by the control circuit 44 by feedback operation, but it can also be smaller than the first period, or it can be the same period as the first period.

[0052] The second deviation calculation unit 52 constituting the target voltage setting unit 50 uses the voltage value V2 of the load side conduction path 14 detected by the second voltage detection unit 42 and the target voltage reference value Vft as input values. The second deviation calculation unit 52 continuously performs an operation of calculating a deviation Et2 (hereinafter also referred to as a second deviation Et2) between the voltage value V2 of the load side conduction path 14 set as the input value and the target voltage reference value (final target voltage value) Vft.

[0053] The PI control unit 54 has a function of performing feedback operation in a known PI operation method, for example. The PI control unit 54 sets the second deviation Et2 calculated by the second deviation calculation unit 52 as an input value, and performs feedback operation to determine the target voltage value Vt based on the second deviation Et2 by a known PI operation, so that the voltage value V2 is close to the target voltage reference value (final target voltage value) Vft, and periodically performs such feedback operation (PI operation) in a second cycle.

[0054] Next, the operation of the power supply device 1 will be described.

[0055] The voltage conversion control device 3 repeatedly performs the following steps when a predetermined start condition is satisfied. Figure 2The voltage conversion control shown in the figure causes the voltage conversion unit 20 to perform a voltage conversion operation. In addition, in the power supply device 1, for example, a "signal indicating that a start switch (specifically, an ignition switch) for starting a power source of the vehicle is in an on state" and a "signal indicating that the start switch is in an off state" are input to the voltage conversion control device 3 from an external device not shown in the figure. In a device with such a structure, switching the start switch from an off state to an on state can be set as "start condition is satisfied". This example is described below.

[0056] When the above-mentioned starting condition is satisfied, the control device 3 repeatedly performs the following steps in a predetermined first cycle: Figure 2 The control device 3 starts Figure 2 In the case of control, the target voltage value Vt is first determined in step S1. The process of step S1 is a process in which the control unit 5 obtains the target voltage value Vt currently set by the target voltage setting unit 50 (at the time of execution of step S1).

[0057] Here, the target voltage value setting process performed by the target voltage setting unit 50 will be described.

[0058] The target voltage setting unit 50 repeats the operation with a predetermined second cycle (for example, a cycle larger than the first cycle). Figure 3 The target voltage setting unit 50 performs the target voltage value setting process. Figure 3 After the processing starts, the voltage value V2 of the load-side conductive circuit 14 is first obtained (S11). Then, the target voltage setting unit 50 obtains the target voltage reference value (final target voltage value) Vft (S12) after step S11. The processing of steps S11 and S12 can be performed simultaneously or reversely. Specifically, the second deviation calculation unit 52 performs the processing of steps S11 and S12 to calculate the deviation Et2 (hereinafter also referred to as the second deviation Et2) between the voltage value V2 of the load-side conductive circuit 14 input at the time point of step S11 and the target voltage reference value (final target voltage value) Vft input at the time point of step S12.

[0059] The target voltage setting unit 50 performs feedback operation (S13) for calculating a new target voltage value Vt after steps S11 and S12. The PI control unit 54 performs the process of step S13, and the second deviation calculation unit 52 obtains the second deviation Et2 calculated through steps S11 and S12, and sets the target voltage value Vt based on the second deviation Et2. Specifically, the PI control unit 54 performs feedback operation in a well-known PI operation method, and is the following operation: based on the deviation (second deviation Et2) between the voltage value V2 obtained at the operation time point (the execution time point of steps S11 to S13) and the target voltage reference value (final target voltage value) Vft and the predetermined proportional gain and integral gain, the new target voltage value Vt is calculated in such a way that the voltage value V2 is close to the target voltage reference value (final target voltage value) Vft. The proportional gain, integral gain, and differential gain used in the PI operation method or the PID operation method are each preset to an appropriate fixed value.

[0060] In the second cycle repeated Figure 3 In the process, the PI control unit 54 sets (updates) the target voltage value Vt calculated in step S13 to the current target voltage value Vt (S14) every time a feedback operation (e.g., PI operation) is performed in step S13 (i.e., every second cycle). The PI control unit 54, for example, sets the current target voltage value Vt set in step S14 as the output value for the first deviation calculation unit 46, and maintains the target voltage value Vt (output value) set in step S14 of each cycle until a new target voltage value Vt is set in step S14 of the next cycle.

[0061] The target voltage value Vt is set by such processing. The control unit 5 performs the above-mentioned process repeatedly. Figure 2 When the process of step S1 is performed in the control, the latest target voltage value Vt set at the time of executing the process of step S1 is obtained.

[0062] exist Figure 2 After step S1 shown in , the control unit 5 performs feedback operation to determine the duty cycle based on the current (execution time point of step S2) output voltage value V1 of the second conductive circuit 12 and the target voltage value Vt obtained in the most recent step S1 by using a well-known PI operation method or a PID operation method, so that the output voltage value V1 is close to the target voltage value Vt (S2).

[0063] Specifically, the control unit 5 repeatedly performs Figure 2During the voltage conversion control period shown in FIG. 1 (i.e., during the voltage conversion operation performed by the voltage conversion unit 20), the deviation Et1 (first deviation Et1) between the voltage value V1 of the second conductive path 12 detected by the first voltage detection unit 40 and the target voltage value Vt set by the target voltage setting unit 50 is continuously provided from the first deviation calculation unit 46 to the control circuit 44. Furthermore, the control circuit 44 acquires the first deviation Et1 in the process of step S2 and performs feedback operation for calculating a new duty ratio by reflecting the acquired first deviation Et1.

[0064] In the process of step S2, the control unit 5 (specifically, the control circuit 44) performs feedback operation to determine the duty ratio by a known PI operation method or PID operation method based on the first deviation Et1 input from the first deviation calculation unit 46, so that the output voltage value V1 of the second conductive circuit 12 is close to the target voltage value Vt. In addition, the feedback operation of "calculating a new duty ratio by a PI operation method or a PID operation method based on the current output voltage value and the target voltage value so that the output voltage value is close to the target voltage value" is well known in the control of the DCDC converter, so the details are omitted. The proportional gain, integral gain, and differential gain used in the PI operation method or the PID operation method are each preset to an appropriate fixed value, for example.

[0065] Thus, the control unit 5 performs Figure 2 The duty ratio is updated in step S2 during control (ie, every first cycle), and after the update, the duty ratio set in step S2 is maintained until the duty ratio is updated in the next step S2.

[0066] After the processing of step S2, the control unit 5 outputs a PWM signal (S3) using the new duty ratio calculated in the most recent step S2. When the control unit 5 outputs the PWM signal of the duty ratio calculated in the most recent step S2 in step S3, the PWM signal of the duty ratio is maintained until the next step S3 (step S3 of the next cycle), and when the duty ratio is updated in the next step S3, the output of the PWM signal is continued, so that the output of the PWM signal using the updated duty ratio is maintained until the next step S3.

[0067] In this way, the control unit 5 repeatedly performs Figure 2 During the control period, the PWM signal of the latest duty ratio is continuously output to the first switching element 22, and a complementary signal is output to the second switching element 24. The voltage conversion unit 20 receives such a control signal and performs a voltage conversion operation (specifically, a step-down operation) so that the voltage of the second conductive circuit 12 is close to the target voltage value Vt.

[0068] Here, a transition state when the voltage conversion operation of the voltage conversion unit 20 is started while the voltage conversion unit 20 is stopped will be described.

[0069] When the voltage conversion unit 20 is stopped, the voltage value V1 of the second conductive path 12 and the voltage value V2 of the load-side conductive path 14 are set to 0 V, for example. Figure 4 As an example, in the initial stage after the voltage conversion unit 20 just starts the voltage conversion operation (immediately after time 0), the voltage value V2 of the load-side conductive circuit 14 is close to 0V, so the PI control unit 54 performs feedback operation (PI operation) based on the voltage value V2 of about 0V and the target voltage reference value Vft, and updates the target voltage value Vt to a value slightly higher than the voltage value V2 (about 0V) at this time point. When such setting (updating) is performed, the control unit 5 controls the voltage conversion unit 20 so that the output voltage value V1 becomes the newly set target voltage value Vt (a value slightly higher than 0V), so that the voltage value V2 of the load-side conductive circuit 14 is slightly increased by this control. Then, when the voltage value V2 increases in this way, in the next cycle, the PI control unit 54 performs feedback operation (PI operation) based on the increased voltage value V2 and the target voltage reference value Vft, and updates the target voltage value Vt to a value higher than the increased voltage value V2. When performing such an update, the control unit 55 controls the voltage conversion unit 20 so that the output voltage value (voltage value V1) becomes the newly set target voltage value Vt, so that the voltage value V2 of the load-side conductive circuit 14 further increases. In the next cycle, the PI control unit 54 updates the target voltage value Vt to a value higher than the voltage value V2.

[0070] Due to such control, during the period from the target voltage value Vt to the target voltage reference value Vft, the PI control unit 54 repeatedly performs feedback operation (PI operation) to gradually increase the target voltage value Vt. According to the increase in the target voltage value Vt, the output voltage value V1 of the voltage conversion unit 20 and the voltage value V2 of the load-side conductive circuit 14 gradually increase. In this way, the output voltage of the voltage conversion unit 20 can be gradually increased within a predetermined period after the start of the voltage conversion operation, so that soft start control can be achieved. Then, the final target voltage value Vt converges to the vicinity of the target voltage reference value Vft. After the target voltage value Vt reaches the target voltage reference value Vft, the voltage conversion unit 20 performs the voltage conversion operation in a manner of outputting the target voltage reference value Vft to the second conductive circuit 12.

[0071] Next, the effects of the power supply device 1 will be described.

[0072] The power supply device 1 includes: a first voltage detection unit 40 for detecting the value of the first voltage (voltage value V1) applied to the second conductive circuit 12; a second voltage detection unit 42 for detecting the value of the second voltage (voltage value V2) applied to the load-side conductive circuit 14, which is interposed between the second conductive circuit 12 and the load 92; a target voltage setting unit 50 for setting the target voltage value Vt based on the value of the second voltage (voltage value V2) detected by the second voltage detection unit 42; and a control unit 5. The control unit 5 repeatedly performs the following feedback operation: based on the value V1 of the first voltage detected by the first voltage detection unit 40, the duty ratio of the control signal is updated so that the value V1 of the first voltage applied to the second conductive circuit 12 is close to the target voltage value Vt.

[0073] According to the above configuration, the target voltage setting unit 50 can set the target voltage value Vt based on the voltage value V2 of the path (load-side conductive path 14) on the load 92 side of the second conductive path 12 to which the output voltage from the voltage conversion unit 20 is applied. Therefore, even if the second conductive path 12 and the load-side conductive path 14 have different physical characteristics, the target voltage value Vt suitable for the voltage applied to the load 92 can be set with good responsiveness. In particular, compared with the configuration in which the target voltage value Vt is set based on the voltage value V1 of the second conductive path 12, the target voltage value Vt can be set based on the voltage value V2 at a position closer to the load 92. Therefore, even if the voltage value V1 of the second conductive path 12 and the voltage value V2 of the load-side conductive path 14 deviate from each other, the target voltage value Vt can be set in a form that is suitable for the load voltage.

[0074] The target voltage setting unit 50 operates in the following manner: the target voltage value Vt is repeatedly updated to approach the target voltage reference value Vft based on the deviation (second deviation Et2) between the value of the second voltage (voltage value V2) detected by the second voltage detection unit 42 and the predetermined target voltage reference value Vft. If configured as described above, even if the value V2 of the second voltage applied to the load-side conductive path 14 deviates from the target voltage reference value Vft, the target voltage value Vt suitable for the voltage applied to the load 92 can be set with good responsiveness by repeatedly performing the process of updating the target voltage value Vt based on the voltage value V2 of the load-side conductive path 14, and the target voltage value Vt can be gradually approached to the target voltage reference value Vft.

[0075] The period (second period) at which the target voltage setting unit 50 updates the target voltage value Vt is greater than the period (first period) at which the control unit 5 updates the duty cycle. If configured as described above, the period can be set shorter for the duty cycle of the PWM signal to increase the update frequency. On the other hand, the target voltage value Vt can be updated at a period greater than the update period of the duty cycle, so the processing load required for updating the target voltage value Vt can be suppressed.

[0076] The power supply device 1 has an electronic component arranged between the second conductive path 12 and the load-side conductive path 14. The electronic component includes a resistor 32 and an inductor 30. If it is configured in the above manner, it is possible to set the target voltage according to the voltage of the load-side conductive path even when the voltage of the second conductive path and the voltage of the load-side conductive path diverge due to the electronic component while exerting the function of the electronic component. In particular, when the resistor 32 and the inductor 30 are interposed, it is possible to add current detection, a filter or other functions to the path from the voltage conversion unit 20 to the load 92, which can produce advantages, but on the other hand, there is also a problem that the voltage of the second conductive path 12 and the voltage of the load-side conductive path 14 are easy to diverge. In contrast, if the above structure is adopted, the target voltage value Vt can be set based on the voltage of the load-side conductive path 14, so it is easy to eliminate the problem of setting an inappropriate target voltage value due to the above-mentioned divergence.

[0077] <Example 2>

[0078] The vehicle power supply device 1 of the second embodiment replaces the target voltage setting unit 50 of the vehicle power supply device 1 of the first embodiment with a target voltage setting unit 250, and the other structures are the same as the vehicle power supply device 1 of the first embodiment. The same reference numerals are used for the same structures as the first embodiment, and the description thereof is omitted.

[0079] Similar to the target voltage setting unit 50 of the first embodiment, the target voltage setting unit 250 is configured to calculate and output the target voltage value Vt based on the target voltage reference value Vft input to itself and the voltage value V2 of the load-side conductive circuit 14, and is configured to calculate the current target voltage value Vt taking into account the target voltage value Vt outputted previously. The target voltage setting unit 250 is configured as a digital filter (FIR (Finite Impulse Response) filter), for example, an IC (Integrated Circuit) capable of software processing or logic processing, a microcomputer, etc.

[0080] like Figure 5 As shown, the target voltage setting section 250 includes a second deviation calculation section 52 , a multiplication section 254 , an addition section 256 , and a delay section 258 .

[0081] The second deviation calculation unit 52 has a function of performing calculations by taking the target voltage reference value Vft and the voltage value V2 of the load-side conductive path 14 as input values. The second deviation calculation unit 52 has a function of calculating the deviation (second deviation Et2) between the target voltage reference value Vft and the voltage value V2 of the load-side conductive path 14 as input values ​​and setting the calculated second deviation Et2 as an output value (calculated value).

[0082] The multiplication unit 254 has a function of multiplying the input second deviation Et2 by a preset coefficient Gss and setting the multiplication value as an output value (calculated value). The coefficient Gss is a value of 1 or less.

[0083] The adding unit 256 has a function of calculating the target voltage value Vt and setting the target voltage value Vt as an output value (calculated value) for the first deviation calculating unit 46. The delay unit 258 has a function of setting the target voltage value Vt calculated by the adding unit 256 as an input value and providing an output value to the adding unit 256 when the adding unit 256 calculates the next target voltage value Vt. That is, when the adding unit 256 calculates the n-1 target voltage value Vt[n-1] generated by the delay unit 258, the adding unit 256 sets the input value. The adding unit 256 calculates the target voltage value Vt[n] by adding the output value of the multiplication unit 254, i.e., the multiplication value, to the output value of the delay unit 258, i.e., the target voltage value Vt[n-1], and sets the target voltage value Vt[n] as an output value (calculated value) for the first deviation calculating unit 46.

[0084] The vehicle-mounted power supply device 1 of the second embodiment can set the target voltage value Vt taking the previous target voltage value Vt into consideration by adopting such a calculation method.

[0085] <Example 3>

[0086] The vehicle power supply device 1 of the third embodiment replaces the target voltage setting unit 50 of the vehicle power supply device 1 of the first embodiment with a target voltage setting unit 350, and the other structures are the same as the vehicle power supply device 1 of the first embodiment. The same reference numerals are used for the same structures as the first embodiment, and the description thereof is omitted.

[0087] Similar to the target voltage setting unit 50 of the first embodiment, the target voltage setting unit 350 is configured to calculate and output the target voltage value Vt based on the second deviation Et2, and is configured to take into account the second deviation Et2 calculated previously when calculating the current target voltage value Vt. The target voltage setting unit 350 is configured as a digital filter (IIR (Infinite Impulse Response) filter), for example, composed of an IC, a microcomputer, etc. capable of software processing or logic processing.

[0088] like Figure 6 As shown, the target voltage setting unit 350 includes a second deviation calculation unit 52 , a multiplication unit 354 , an addition unit 356 , a delay unit 358 , a multiplication unit 360 , an upper and lower limit check unit 362 , a delay unit 364 , and a multiplication unit 366 .

[0089] The second deviation calculation unit 52 has a function of performing calculations using the target voltage reference value Vft and the voltage value V2 of the load-side conductive path 14 as input values. The second deviation calculation unit 52 calculates the deviation (second deviation Et2) between the target voltage reference value Vft and the voltage value V2 of the load-side conductive path 14 as input values, and sets the calculated second deviation Et2 as an output value (calculated value).

[0090] The multiplication unit 354 has a function of performing calculation using the second deviation Et2 calculated by the second deviation calculation unit 52 as an input value. The multiplication unit 354 functions to multiply the second deviation Et2 calculated by the second deviation calculation unit 52 by a preset coefficient b0 and to output the multiplication value (calculation value).

[0091] The delay unit 358 uses the second deviation Et2, which is the output value (calculated value) of the second deviation calculation unit 52, as an input value. The delay unit 358 delays the output of the second deviation Et2 calculated by the second deviation calculation unit 52, and when the second deviation calculation unit 52 calculates the second deviation Et2[n] for the nth time, the second deviation calculation unit 52 uses the second deviation Et2[n-1] calculated for the n-1th time as the output value for the multiplication unit 360.

[0092] The multiplier 360 uses the second deviation Et2[n-1] output from the delay unit 358 as an input value. The multiplier 360 multiplies the second deviation Et2[n-1] output from the delay unit 358 by a predetermined coefficient b1 and uses the multiplied value as an output value (calculated value) to the adder 356.

[0093] The adding unit 356 uses the output value (multiplication value) of the multiplication unit 354, the output value (multiplication value) of the multiplication unit 360, and the output value (multiplication value) of the multiplication unit 366 described later as input values. The adding unit 356 adds the multiplication value of the multiplication unit 354, the multiplication value of the multiplication unit 360, and the multiplication value of the multiplication unit 366 set as input values, and uses the added value as the output value for the upper and lower limit checking unit 362.

[0094] The upper and lower limit check unit 362 sets the output value (addition value) calculated by the adder 356 as an input value. The upper and lower limit check unit 362 sets the upper limit value as the output value when the output value (addition value) generated by the adder 356 exceeds the preset upper limit value, sets the lower limit value as the output value when the output value (addition value) generated by the adder 356 is lower than the preset lower limit value, and sets the output value (addition value) calculated by the adder 356 as the output value when the output value is within the preset range. The upper and lower limit check unit 362 sets the checked value as the target voltage value Vt as the output value for the first deviation calculation unit 46.

[0095] The delay unit 364 sets the target voltage value Vt output from the upper and lower limit check unit 362 as an input value. The delay unit 364 delays the target voltage value Vt set as the input value, and inputs it to the multiplication unit 366 when the addition unit 356 performs the next addition process. That is, when the target voltage setting unit 350 sets the n-th target voltage value Vt[n-1], the delay unit 364 sets the n-1th target voltage value Vt[n-1] as the output value for the multiplication unit 366.

[0096] The multiplication unit 366 uses the target voltage value Vt[n-1], which is the output value of the delay unit 364, as an input value. The multiplication unit 366 multiplies the target voltage value Vt[n-1], which is the output value of the delay unit 364, by a preset coefficient a1, and uses the multiplication value as an output value for the addition unit 356. In addition, b0, b1, and a1 may be set to arbitrary values ​​so as to realize the desired filter characteristics.

[0097] The vehicle-mounted power supply device 1 of the third embodiment can set the target voltage value Vt taking the previous second deviation Et2 into consideration by adopting such a calculation method.

[0098] <Other Examples>

[0099] The present disclosure is not limited to the embodiments described in the above description and drawings, and includes, for example, the following embodiments.

[0100] In the above-mentioned embodiment, as the voltage conversion unit 20, a DCDC converter of a non-insulated synchronous rectification method is exemplified, but in any example of the present disclosure, a diode-type DCDC converter may be used. In addition, in the above-mentioned embodiment, a step-down DCDC converter is exemplified, but in any example of the present disclosure, a step-up type may be used, or a step-up / step-down type may be used. In addition, in the above-mentioned embodiment, a unidirectional DCDC converter with a first conductive circuit as an input side and a second conductive circuit as an output side is exemplified, but in any example of the present disclosure, a bidirectional type having the function of using the second conductive circuit as an input side and the first conductive circuit as an output side may be used. In addition, various known elements and structures may be used for the elements and specific structures constituting the voltage conversion unit 20.

[0101] In the above-mentioned embodiment, the power supply unit 90 uses a lead acid battery, but in any example of the present disclosure, the power supply unit 90 may use other power supply components (other known power storage components, power generation components, etc.) instead of or in addition to the lead acid battery.

[0102] In the first embodiment, the PI control unit 54 is exemplified as the feedback calculation unit included in the target voltage setting unit 50 . However, a PID control unit that performs a known PID calculation may be used as the feedback calculation unit included in the target voltage setting unit 50 .

[0103] In the first embodiment, the control circuit 44 and the first deviation calculation unit 46 are configured as separate circuits, but these parts can also be realized by a common circuit. For example, the microcomputer may have the functions of the control circuit 44 and the first deviation calculation unit 46. In addition, in the first embodiment, the PI control unit 54 and the second deviation calculation unit 52 are configured as separate circuits, but these parts can also be realized by a common circuit. For example, the microcomputer may have the functions of the PI control unit 54 and the second deviation calculation unit 52. In addition, in the first embodiment, the control unit 5 and the target voltage setting unit 50 are configured as separate circuits, but these parts can also be realized by a common circuit. For example, the microcomputer may have the functions of the control unit 5 and the target voltage setting unit 50.

[0104] In the second embodiment, the target voltage setting unit 250 takes the previous target voltage value Vt into consideration to calculate the current target voltage value Vt, but the target voltage values ​​Vt of two or more previous times may also be taken into consideration to calculate. In addition, the target voltage setting unit 250 only takes the previous target voltage value Vt into consideration to calculate the current target voltage value Vt, but the target voltage values ​​Vt of multiple previous times may also be taken into consideration to calculate.

[0105] In the third embodiment, the target voltage setting unit 350 takes the second deviation Et2 of the previous time into consideration to calculate the target voltage value Vt for this time, but the second deviations Et2 of two or more previous times may also be taken into consideration to calculate. In addition, the target voltage setting unit 350 only takes the second deviation Et2 of the previous time into consideration to calculate the target voltage value Vt for this time, but the second deviations Et2 of multiple previous times may also be taken into consideration to calculate.

[0106] In the first embodiment, a structure including a microcomputer is exemplified as the feedback operation unit of the target voltage setting unit 50, but it may also be composed of a hardware circuit. For example, the PI control unit may be a known PI control circuit including an amplifier, a resistor, a capacitor, etc., or a known PID control circuit including an amplifier, a resistor, a capacitor, etc.

[0107] Description of Reference Numerals

[0108] 1…In-vehicle power supply device

[0109] 5…Control Unit

[0110] 11…First conductive circuit

[0111] 12…Second conductive circuit

[0112] 14… Load side conduction circuit

[0113] 20…Voltage conversion unit

[0114] 22 ... first switching element (switching element)

[0115] 30…Second inductor unit (inductor unit)

[0116] 32…Resistor

[0117] 40 ... first voltage detection unit

[0118] 42 ... second voltage detection unit

[0119] 50, 250, 350...target voltage setting unit.

Claims

1. A vehicle-mounted power supply device, comprising: A voltage conversion unit, comprising a switch element, the switch element being switched on and off according to a control signal to which an on signal and an off signal are alternately and repeatedly provided, the voltage conversion unit stepping up or down the voltage applied to the first conductive circuit by the on and off action of the switch element, and applying a voltage to the second conductive circuit connected to the output end; a first voltage detection unit for detecting a value of a first voltage applied to the second conductive circuit; a second voltage detection unit for detecting a value of a second voltage applied to a load-side conductive circuit, the load-side conductive circuit being interposed between the second conductive circuit and a load, and at least one of a resistor and an inductor being arranged between the second conductive circuit and the load-side conductive circuit; a target voltage setting unit that sets a target voltage value based on a value of the second voltage detected by the second voltage detection unit; and a control unit that repeatedly performs the following feedback operation: based on the value of the first voltage detected by the first voltage detection unit, updates the duty ratio of the control signal in such a manner that the value of the first voltage applied to the second conductive circuit approaches the target voltage value, and outputs the control signal of the updated duty ratio to the switching element each time the duty ratio is updated, The target voltage setting unit repeatedly performs the following processing: calculating a deviation between the value of the second voltage detected by the second voltage detection unit and a predetermined target voltage reference value, performing feedback operation based on the calculated deviation so as to make the value of the second voltage detected by the second voltage detection unit close to the target voltage reference value to update the target voltage value, and outputting the updated target voltage value to the control unit, The control unit calculates a deviation between a currently detected first voltage value and a latest acquired target voltage value, and based on the calculated deviation updates the duty cycle of the control signal so that the value of the first voltage applied to the second conductive circuit approaches the latest target voltage value.

2. The vehicle-mounted power supply device according to claim 1, wherein: A period at which the target voltage setting unit updates the target voltage value is greater than a period at which the control unit updates the duty ratio.

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