In-vehicle device, information processing method, and program

Abstract

The control unit turns on the first upstream-side semiconductor switch and the second downstream-side semiconductor switch, and turns off the second upstream-side semiconductor switch and the first downstream-side semiconductor switch in the case where the current flows forward through the vehicle load, turns off the first upstream-side semiconductor switch and the second downstream-side semiconductor switch, and turns on the second upstream-side semiconductor switch and the first downstream-side semiconductor switch in the case where the current flows reverse through the vehicle load, performs PWM control on one of the upstream-side semiconductor switch and the downstream-side semiconductor switch to be turned on, and turns on the other semiconductor switch in the case where the vehicle load is subjected to PWM control, and switches the semiconductor switch subjected to PWM control and the semiconductor switch turned on according to the lapse of a prescribed period, thereby alternately performing PWM control on the upstream-side semiconductor switch and the downstream-side semiconductor switch.

Description

Technical Field

[0001] This technology relates to vehicle-mounted devices, information processing methods, and procedures.

[0002] This application claims priority based on Japanese Application No. 2024-050136, filed on March 26, 2024, and incorporates all the contents of the aforementioned Japanese application. Background Technology

[0003] The vehicle is equipped with a power supply control device that controls the power supply from the battery to the load (for example, see Patent Document 1). In the power supply control device described in Patent Document 1, a downstream semiconductor fuse is provided in the current path of the current flowing from the battery to the load, and the power supply from the battery to the load is controlled by switching the downstream semiconductor fuse on or off.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2013-143905 Summary of the Invention

[0007] One embodiment of the present disclosure provides an on-board device that drives and controls an on-board load connected to a full-bridge structure composed of multiple semiconductor switches. The on-board device includes a control unit that performs PWM control on the on-board load. The semiconductor switches of the full-bridge structure include: an upstream semiconductor switch, composed of a first upstream semiconductor switch and a second upstream semiconductor switch; and a downstream semiconductor switch, composed of a first downstream semiconductor switch and a second downstream semiconductor switch. When current flows forward through the on-board load, the control unit turns on the first upstream semiconductor switch and the second downstream semiconductor switch, and turns off the second upstream semiconductor switch and the first downstream semiconductor switch. When the current flows through the vehicle load in the reverse direction, the control unit turns off the first upstream semiconductor switch and the second downstream semiconductor switch, and turns on the second upstream semiconductor switch and the first downstream semiconductor switch. When performing PWM control on the vehicle load, the control unit performs PWM control on one of the upstream and downstream semiconductor switches to be turned on, and turns on the other semiconductor switch. The control unit switches between the semiconductor switch being PWM controlled and the turned-on semiconductor switch according to the elapsed time of a predetermined period, thereby alternately performing PWM control on the upstream and downstream semiconductor switches. Attached Figure Description

[0008] Figure 1 This is a schematic diagram illustrating the structure of a vehicle system including the vehicle-mounted device of Embodiment 1.

[0009] Figure 2 This is a block diagram illustrating the internal structure of an onboard device.

[0010] Figure 3 This is a flowchart illustrating the processing (discontinuous control during disconnection) of the control unit of the vehicle-mounted device.

[0011] Figure 4 This is an illustrative diagram illustrating how PWM control is performed alternately on the upstream and downstream semiconductor switches.

[0012] Figure 5 This is a flowchart illustrating the processing (start of PWM control) of the control unit of the vehicle-mounted device in Embodiment 2. Detailed Implementation

[0013] [The problem this disclosure aims to solve]

[0014] In the power supply control device described in Patent Document 1, the alternating PWM control of the upstream semiconductor switch and the downstream semiconductor switch is not considered in the full bridge connecting the vehicle load.

[0015] This disclosure was made in view of the following circumstances, and its object is to provide an on-board device, etc., capable of alternately performing PWM control on the upstream semiconductor switch and the downstream semiconductor switch in a full bridge connected to an on-board load.

[0016] [The Effects of This Disclosure]

[0017] According to one aspect of this disclosure, an on-board device, etc., can be provided that alternately performs PWM control on upstream and downstream semiconductor switches in a full bridge connected to an on-board load.

[0018] [Description of embodiments of this disclosure]

[0019] The embodiments described herein will be listed first. Furthermore, at least some of the embodiments described below may be combined arbitrarily.

[0020] (1) An on-board device of the present disclosure drives and controls an on-board load connected to a full bridge composed of multiple semiconductor switches. The on-board device includes a control unit that performs PWM control on the on-board load. The semiconductor switches of the full bridge include: an upstream semiconductor switch, composed of a first upstream semiconductor switch and a second upstream semiconductor switch; and a downstream semiconductor switch, composed of a first downstream semiconductor switch and a second downstream semiconductor switch. When the current flows positively through the on-board load, the control unit turns on the first upstream semiconductor switch and the second downstream semiconductor switch, and turns off the second upstream semiconductor switch and the first downstream semiconductor switch. When the current flows through the vehicle load in the reverse direction, the control unit turns off the first upstream semiconductor switch and the second downstream semiconductor switch, and turns on the second upstream semiconductor switch and the first downstream semiconductor switch. When performing PWM control on the vehicle load, the control unit performs PWM control on one of the upstream and downstream semiconductor switches to be turned on, and turns on the other semiconductor switch. The control unit switches between the PWM-controlled semiconductor switch and the turned-on semiconductor switch according to the elapsed time of a predetermined period, thereby alternately performing PWM control on the upstream and downstream semiconductor switches.

[0021] In this method, the vehicle-mounted device has a full-bridge (H-bridge circuit). Drive control of the vehicle-mounted device connected to the full-bridge is achieved by controlling the on / off state of the four semiconductor switches constituting the full-bridge (first upstream semiconductor switch, second upstream semiconductor switch, first downstream semiconductor switch, and downstream semiconductor switch). The full-bridge is not limited to being housed in the same frame as the vehicle-mounted device; it can also be separately constructed from the vehicle-mounted device's frame and communicatively connected to the vehicle-mounted device via signal lines. The full-bridge includes an upstream semiconductor switch composed of the first upstream semiconductor switch and the second upstream semiconductor switch, and a downstream semiconductor switch composed of the first downstream semiconductor switch and the second downstream semiconductor switch. For example, for a power supply device such as a lead-acid battery (+B power supply), the first upstream semiconductor switch and the first downstream semiconductor switch are connected in series, and the second upstream semiconductor switch and the second downstream semiconductor switch are also connected in series. In the connection between the vehicle-mounted device, including the motor, and the full bridge, one end of the vehicle-mounted device is connected to a wire (first connecting wire) that connects a first upstream semiconductor switch and a first downstream semiconductor switch connected in series. The other end of the vehicle-mounted device is connected to a wire (second connecting wire) that connects a second upstream semiconductor switch and a second downstream semiconductor switch connected in series. The control unit of the vehicle-mounted device is configured, for example, a microcomputer, and is connected to each semiconductor switch (first upstream semiconductor switch, second upstream semiconductor switch, first downstream semiconductor switch, and downstream semiconductor switch) constituting the full bridge via signal lines through the input / output (I / F) terminals of the microcomputer. When current flows forward through the vehicle-mounted load, the control unit of the vehicle-mounted device turns on (ON) the paired first upstream semiconductor switch and the second downstream semiconductor switch, and turns off (OFF) the paired second upstream semiconductor switch and the first downstream semiconductor switch, thereby causing the motor included in the vehicle-mounted load to rotate forward. When the vehicle-mounted device's control unit reverses the current flow through the vehicle-mounted load, it turns off (opens) a pair of first upstream semiconductor switches and second downstream semiconductor switches, and turns on (closes) a pair of second upstream semiconductor switches and first downstream semiconductor switches, thereby reversing the motor included in the vehicle-mounted load. Furthermore, when adjusting the power supply to the vehicle-mounted load by increasing or decreasing it through PWM control, the control unit performs PWM (Pulse Width Modulation) control on one of the upstream and downstream semiconductor switches to be turned on (closed), turning on the other semiconductor switch. This PWM control determines the duty cycle based on the driving mode of the vehicle-mounted load.That is, when the motor included in the vehicle load rotates forward, the control unit of the vehicle device performs PWM control on the first upstream semiconductor switch and keeps the second downstream semiconductor switch in a conducting (closed) state, or keeps the first upstream semiconductor switch in a conducting (closed) state and performs PWM control on the second downstream semiconductor switch. Similarly, when the motor included in the vehicle load rotates in reverse, the control unit of the vehicle device performs PWM control on the second upstream semiconductor switch and keeps the first downstream semiconductor switch in a conducting (closed) state, or keeps the second upstream semiconductor switch in a conducting (closed) state and performs PWM control on the first downstream semiconductor switch. Furthermore, while continuously executing this PWM control, the control unit of the vehicle device switches between the semiconductor switch performing PWM control and the conducting (closed) semiconductor switch according to the elapsed period of a predetermined period (switching cycle), thereby alternately performing PWM control on the upstream and downstream semiconductor switches. This switching cycle can also be stored in the storage unit of the vehicle device. At this point, the switching cycle can be determined based on the rated current value (rated load current value) flowing through the vehicle load. In this case, it can also be set such that the larger the rated current value flowing through the vehicle load, the shorter the switching cycle. Alternatively, it can be set such that, during PWM control, the switching cycle becomes shorter as the number of switching operations (on / off cycles) increases within a specified processing unit time. For example, semiconductor switches composed of FETs (Field-Effect Transistors) are periodically switched on and off by PWM control, which tends to generate heat due to switching losses. Therefore, for example, compared to a DC drive that maintains the on state without periodic switching, it is necessary to select components with low on-resistance. In this case, there is a concern that the component cost or size may increase or become excessive. In contrast, when the control unit of the vehicle device continuously executes PWM control, after a predetermined period has elapsed, i.e., based on a specified switching cycle, it switches between the PWM-controlled semiconductor switch and the semiconductor switch that remains in the on (on) state. For example, when the motor included in the vehicle load is rotated forward, the control unit of the vehicle device switches to a state where it maintains the second downstream semiconductor switch in a conducting (closed) state (upstream PWM control state) after a predetermined period of time, and then maintains the second upstream semiconductor switch in a conducting (closed) state (downstream PWM control state). Even when the motor included in the vehicle load is rotated in reverse, the control unit of the vehicle device switches between the upstream PWM control state and the downstream PWM control state according to the elapsed time of a predetermined period (switching cycle).By switching the PWM-controlled semiconductor switches according to the switching cycle using upstream semiconductor switches (upstream PWM control state) and downstream semiconductor switches (downstream PWM control state), the heat generation of the upstream and downstream semiconductor switches can be balanced, and excessive heating of any one of the upstream or downstream semiconductor switches can be suppressed. Therefore, in the upstream and downstream semiconductor switches constituting the full bridge, the heat generated by the switching losses accompanying PWM control can be distributed, and the heat generation caused by each individual semiconductor switch can be reduced. As a result, lower-cost or smaller-sized semiconductor switches can be used, enabling cost reduction or miniaturization of products in automotive devices.

[0022] (2) In an on-board device according to one aspect of the present disclosure, when the control unit switches the semiconductor switch under PWM control between the upstream semiconductor switch and the downstream semiconductor switch, it performs discontinuous control during the disconnection period, such that the current does not flow through the upstream semiconductor switch and the downstream semiconductor switch during the disconnection period before and after the switch.

[0023] In this method, the control unit of the vehicle-mounted device performs the following control (discontinuous control during disconnection): It avoids discontinuous disconnection during the disconnection period, where current does not flow through the upstream and downstream semiconductor switches before and after switching the PWM-controlled semiconductor switch. Specifically, the control unit of the vehicle-mounted device performs discontinuous disconnection control by disconnecting the PWM-controlled semiconductor switch before switching to end PWM control, and then disconnecting the PWM-controlled semiconductor switch after switching to start PWM control, thus ensuring that the disconnection period is not continuous between the upstream and downstream semiconductor switches before and after switching. When switching a PWM-controlled semiconductor switch that periodically turns on and off according to the duty cycle using the upstream and downstream semiconductor switches, if the disconnection periods of the semiconductor switches before and after switching are continuous, the disconnection period becomes essentially twice the duty cycle, and the speed of the motor included in the vehicle load may slow down during this switching. In contrast, the control unit of the vehicle-mounted device performs discontinuous disconnection control during the disconnection period, which is characterized by no current flowing through the upstream and downstream semiconductor switches before and after the switching. This prevents the disconnection period from becoming longer relative to the duty cycle and maintains the duty cycle of the pulse width in PWM control. Consequently, motor swaying caused by interruption of load current relative to the vehicle load can be suppressed, and the vehicle load can be driven and controlled appropriately.

[0024] (3) In the vehicle-mounted device according to one aspect of the present disclosure, the control unit performs discontinuous control during the disconnection period by synchronizing the on-off cycle in the PWM control of the upstream semiconductor switch and the downstream semiconductor switch before and after the switching.

[0025] Before and after switching the PWM-controlled semiconductor switches, the control unit of the vehicle-mounted device synchronizes the on / off cycles of the PWM control for the paired upstream and downstream semiconductor switches. This is achieved by using the same pulse width duty cycle, thus enabling discontinuous control during the off-period. Specifically, before and after switching, if the off-period (when no current flows through the upstream and downstream semiconductor switches) is continuous, the phase of the control signals (Hi / Lo signals) for the PWM control of these switches is reversed. Conversely, by synchronizing the on / off cycles of the PWM control for these semiconductor switches, i.e., making the control signals identical, continuous off-periods can be prevented. Alternatively, during such discontinuous off-period control, the control unit can output control signals (on signal (Hi signal), off signal (Lo signal)) to both the upstream and downstream semiconductor switches with the same on / off cycle (synchronizing the pulse width duty cycle). Furthermore, for a particular semiconductor switch that is being controlled to conduct (maintained in the on state), the control signal is masked, forcing the output to be on. In this way, by synchronizing the on / off cycles (duty cycle of the pulse width) in PWM control, discontinuous control during the off period can be performed with relatively simple processing.

[0026] (4) In the vehicle-mounted device according to one aspect of this disclosure, when the control unit switches the semiconductor switch under PWM control between the upstream semiconductor switch and the downstream semiconductor switch, the discontinuous control during the disconnection period is performed in the following manner: The system determines whether the vehicle load is powered on before the switch is about to begin. If the vehicle load is powered on, PWM control is initiated from the point of disconnection for the semiconductor switch that will be subject to PWM control after the switch. If the vehicle load is not powered on, PWM control is initiated from the point of connection for the semiconductor switch that will be subject to PWM control after the switch.

[0027] When the control unit of the vehicle-mounted device switches between upstream and downstream semiconductor switches using PWM control, it obtains information about whether the vehicle load was energized before the switch. Alternatively, the vehicle load or the wires connected to the vehicle load may be equipped with a current detection unit, such as a shunt resistor or a Hall element, and the control unit determines whether the vehicle load is energized based on the signal from this current detection unit. If the vehicle load is energized before the switch, the control unit determines that the PWM-controlled semiconductor switch was turned on before the switch, and starts PWM control from the point of deactivation for the semiconductor switch immediately after the switch. If the vehicle load is not energized before the switch, the control unit determines that the PWM-controlled semiconductor switch was deactivated before the switch, and starts PWM control from the point of activation for the semiconductor switch immediately after the switch. In other words, the control unit of the vehicle-mounted device outputs different signal levels (H / L) to the upstream and downstream semiconductor switches before and after the switch, thereby performing discontinuous control during the deactivation period. In this way, based on whether the vehicle load is powered before the switch, the semiconductor switch that becomes the object of PWM control after the switch is divided into a control mode starting from the turn-on and a control mode starting from the turn-off, thereby enabling efficient discontinuous control during the turn-off period.

[0028] (5) In the vehicle device according to one aspect of the present disclosure, when the control unit switches the semiconductor switch that is being PWM controlled between the upstream semiconductor switch and the downstream semiconductor switch, the discontinuous control during the disconnection period is performed in the following manner: for the semiconductor switch that is being PWM controlled immediately after the switch, PWM control starts from the time it is turned on.

[0029] When the control unit of the vehicle-mounted device switches between upstream and downstream semiconductor switches for PWM control, it always starts PWM control on the newly switched semiconductor switch from the on state. By starting PWM control on the switched semiconductor switch from the on state during this switching process, continuous current flow during the off-state of the upstream and downstream semiconductor switches before and after the switch can be reliably prevented, allowing for discontinuous control during the off-state with relatively simple control.

[0030] (6) In an on-board device according to one aspect of the present disclosure, the control unit starts PWM control while suppressing the flow of surge current to the on-board load.

[0031] In this approach, the control unit of the vehicle-mounted device initiates PWM control, for example, to suppress inrush current flowing through the vehicle-mounted load when the drive of the vehicle-mounted load is started, i.e., when the rotation of a motor included in the vehicle-mounted load is initiated. The control unit of the vehicle-mounted device, for example, starts the drive of the vehicle-mounted load based on received signals from various switches or messages from the vehicle-mounted ECU via the vehicle network. However, if the vehicle-mounted load includes a motor, there is concern about inrush current flowing through the motor. Therefore, the control unit of the vehicle-mounted device initiates PWM control upon receiving a signal or message instructing or requesting the start of the drive of the vehicle-mounted load, or upon detecting a predetermined event that would cause inrush current to the vehicle-mounted load. At this time, the control unit of the vehicle-mounted device can also determine whether an event related to the drive control of the vehicle-mounted load is one that would cause inrush current. By initiating PWM control upon detecting an event that would cause inrush current, the control unit of the vehicle-mounted device can suppress inrush current flowing through the vehicle-mounted load. Furthermore, while continuing PWM control, the control unit of the vehicle-mounted device switches the upstream semiconductor switch and the downstream semiconductor switch alternately to perform PWM control, thus enabling the heat generation of these upstream and downstream semiconductor switches to tend to be balanced.

[0032] (7) In one aspect of the vehicle-mounted device of the present disclosure, the control unit starts PWM control when the rotational speed of the motor included in the vehicle load is variable.

[0033] In this approach, the control unit of the vehicle-mounted device, upon receiving signals from various switches or messages from the vehicle-mounted ECU via the vehicle network, etc., changes the driving mode of the vehicle-mounted load based on the received messages, thereby changing the rotational speed of the motor included in the vehicle-mounted load. By initiating PWM control when the rotational speed of the motor included in the vehicle-mounted load becomes variable, the control unit of the vehicle-mounted device can change the average current value per unit time, thereby adjusting the rotational speed of the motor. Furthermore, while continuing PWM control, the control unit of the vehicle-mounted device switches upstream and downstream semiconductor switches, alternately performing PWM control, thus achieving a trend towards equalization of the heat generation of these upstream and downstream semiconductor switches.

[0034] (8) In an on-board device according to one aspect of the present disclosure, the control unit obtains the current value flowing through the full bridge, and based on the obtained current value, derives the temperature of the wires or the semiconductor switches included in the full bridge, and starts PWM control if the derived temperature exceeds a predetermined temperature threshold.

[0035] In this method, the control unit of the vehicle-mounted device uses the current detection function of the current detection unit provided in the full bridge or the IPD (Intelligent Power Device) constituting the semiconductor switch to obtain the current value flowing through the full bridge, such as the current flowing through the wires or the energized semiconductor switch between the full bridge and the vehicle-mounted load. Based on multiple current values ​​periodically obtained from the current detection unit of the full bridge, the control unit of the vehicle-mounted device derives the wire temperature of the wires included in the full bridge or the component temperature of the semiconductor switch. Alternatively, a temperature gauge can be stored in the storage unit of the vehicle-mounted device, which defines the temperature of the wires or semiconductor switch included in the full bridge for multiple periodically obtained current values. The control unit of the vehicle-mounted device derives the temperature corresponding to the current value by referring to this temperature gauge. Alternatively, the control unit may use, for example, the units disclosed in International Publication No. WO 2017 / 122781, Japanese Patent Application Publication No. 2009-130944, or Japanese Patent Application Publication No. 2009-226984, to derive the temperature of the wires or semiconductor switches included in the full bridge based on the acquired current value. When the derived temperature exceeds a predetermined temperature threshold, the control unit of the vehicle-mounted device initiates PWM control. This temperature threshold is stored in the storage unit of the vehicle-mounted device and is set to a temperature lower than the cutting temperature of the fuses (mechanical fuses or semiconductor fuses) set in the full bridge. Since the control unit of the vehicle-mounted device initiates PWM control when the temperature of the wires or semiconductor switches included in the full bridge exceeds the predetermined temperature threshold, the average current flowing through the full bridge can be reduced, thereby lowering the temperature. Furthermore, while continuing PWM control, the control unit of the vehicle-mounted device switches the upstream and downstream semiconductor switches alternately, thus promoting a more balanced distribution of heat generation from these upstream and downstream semiconductor switches.

[0036] (9) In an on-board device according to one aspect of the present disclosure, the semiconductor switch or the control unit included in the full bridge has a temperature warning function that outputs temperature warning information when the temperature in the full bridge exceeds a predetermined temperature threshold, and the control unit starts PWM control when it receives the temperature warning information.

[0037] In this approach, the semiconductor switches included in the full bridge, namely the upstream and downstream semiconductor switches, are composed of an IPD (Intelligent Power Device) with a temperature warning function. When the element temperature of the semiconductor switch exceeds a predetermined temperature threshold, the IPD containing the semiconductor switches outputs a temperature warning message to the control unit, indicating that the temperature in the full bridge exceeds the predetermined temperature threshold. The entity that outputs this temperature warning message to the control unit is not limited to the IPD; it can also be a drive circuit (driver IC) that generates and outputs drive signals such as gate signals to the semiconductor switches included in the full bridge. In this case, the drive circuit (driver IC) is communicatively connected to the control unit, generates and outputs drive signals based on control signals from the control unit, and the drive circuit (driver IC) can also be included in the control unit or constitute a part of the control unit. Alternatively, the microcomputer constituting the control unit can also have a temperature warning function that outputs temperature warning information. The upstream semiconductor switch included in the full bridge is equivalent to a high-side switch, and the downstream semiconductor switch is equivalent to a low-side switch. The drive circuit (driver IC) can also boost the voltage applied from a power source such as a lead-acid battery (+B power supply) to the upstream semiconductor switch, which acts as a high-side switch, and generate and output drive signals such as gate signals. When the control unit of the vehicle-mounted device receives temperature warning information from the IPD or drive circuit, it starts PWM control, thereby reducing the average current flowing through the full bridge and lowering the temperature within the full bridge. Furthermore, while continuing PWM control, the control unit of the vehicle-mounted device switches the upstream and downstream semiconductor switches alternately, thus achieving a trend towards equalizing the heat generation of these upstream and downstream semiconductor switches.

[0038] (10) An information processing method according to one aspect of this disclosure causes a computer that drives and controls an on-board load connected to a full bridge consisting of an upstream semiconductor switch consisting of a first upstream semiconductor switch and a second upstream semiconductor switch, and a downstream semiconductor switch consisting of a first downstream semiconductor switch and a second downstream semiconductor switch, to perform the following processing: when current flows forward through the on-board load, turning on the first upstream semiconductor switch and the second downstream semiconductor switch, turning off the second upstream semiconductor switch and the first downstream semiconductor switch, and turning off the current flow reverse through the on-board load. In the case of vehicle-mounted load, the first upstream semiconductor switch and the second downstream semiconductor switch are turned off, and the second upstream semiconductor switch and the first downstream semiconductor switch are turned on. When performing PWM control on the vehicle-mounted load, PWM control is performed on one of the upstream and downstream semiconductor switches to be turned on, while the other semiconductor switch is turned on. The semiconductor switch being PWM controlled and the turned-on semiconductor switch are switched according to the elapsed period of a specified period, thereby alternately performing PWM control on the upstream and downstream semiconductor switches.

[0039] In this approach, an information processing method is provided that enables a computer to function as an on-board device in a full-bridge connected to an on-board load, performing PWM control on the upstream and downstream semiconductor switches alternately.

[0040] (11) A procedure according to one aspect of this disclosure causes a computer that drives and controls an on-board load connected to a full bridge consisting of an upstream semiconductor switch consisting of a first upstream semiconductor switch and a second upstream semiconductor switch, and a downstream semiconductor switch consisting of a first downstream semiconductor switch and a second downstream semiconductor switch, to perform the following processing: when current flows forward through the on-board load, turning on the first upstream semiconductor switch and the second downstream semiconductor switch, turning off the second upstream semiconductor switch and the first downstream semiconductor switch, and when current flows backward through the on-board load... Under load, the first upstream semiconductor switch and the second downstream semiconductor switch are turned off, and the second upstream semiconductor switch and the first downstream semiconductor switch are turned on. When performing PWM control on the vehicle load, PWM control is performed on one of the upstream and downstream semiconductor switches to be turned on, while the other semiconductor switch is turned on. The semiconductor switch being PWM controlled and the turned-on semiconductor switch are switched according to the elapsed period, thereby alternately performing PWM control on the upstream and downstream semiconductor switches.

[0041] In this approach, a program can be provided that enables a computer to function as an on-board device that alternately performs PWM control on upstream and downstream semiconductor switches in a full-bridge connected to an on-board load.

[0042] [Details of the embodiments of this disclosure]

[0043] This disclosure will be specifically described based on the accompanying drawings illustrating embodiments thereof. Hereinafter, a vehicle-mounted device 1 according to an embodiment of this disclosure will be described with reference to the accompanying drawings. It should be noted that this disclosure is not limited to these examples, and as indicated by the claims, it is intended to include all modifications within the meaning and scope equivalent to the claims.

[0044] (Implementation Method 1)

[0045] The embodiments will now be described with reference to the accompanying drawings. Figure 1 This is a schematic diagram illustrating the structure of a vehicle system S, including the vehicle-mounted device 1 of embodiment 1. Figure 2 This is a block diagram illustrating the internal structure of the vehicle-mounted device 1. The vehicle-mounted system S consists of the vehicle-mounted device 1 mounted on the vehicle C and the vehicle-mounted load 4 connected to the vehicle-mounted device 1 via power lines 51. The vehicle-mounted device 1 is communicatively connected to multiple vehicle-mounted ECUs 2 via a vehicle network 3, and drives (starts power supply) or stops (cuts off power supply) the vehicle-mounted load 4 connected to the vehicle-mounted device 1 based on messages sent from these vehicle-mounted ECUs 2 or output signals from various sensors, etc.

[0046] When driving the vehicle load 4, the vehicle-mounted device 1 controls the speed of the motor 41 contained in the vehicle load 4 through PWM control. The motor 41 of the vehicle load 4 is connected to the full bridge 6 (H-bridge circuit) of the vehicle-mounted device 1 and is controlled to rotate in either forward or reverse direction according to the control signal from the microcomputer 10 of the vehicle-mounted device 1.

[0047] Vehicle C is equipped with a power supply unit 5 consisting of a lead-acid battery, an alternator, or a secondary battery. The power supply unit 5 and the on-board device 1 are connected via a power line 51. The connection between the power supply unit 5 and the on-board device 1 is not limited to a direct connection via the power line 51; they can also be indirectly connected by an electrical box (junction box) such as a relay box or fuse box sandwiched between them.

[0048] The vehicle-mounted device 1 and one or more vehicle-mounted loads 4 are connected via power lines 51, and the vehicle-mounted device 1 distributes power to these multiple vehicle-mounted loads 4. That is, the vehicle-mounted device 1 functions as a power distribution device that distributes power supplied from the power supply device 5 via the power lines 51 to multiple vehicle-mounted loads 4 arranged downstream in the direction of current flow.

[0049] The vehicle load 4 is an actuator such as a door rearview mirror opening and closing device or a seat moving device, including a motor 41 with rotation directions corresponding to both forward and reverse rotation. The vehicle load 4 is connected based on a full axle 6.

[0050] The on-board unit 1 functions as a power control device that controls the drive or stop of the on-board load 4. For example, it can be a device with relay function, such as a CAN gateway. Alternatively, the on-board unit 1 can be a comprehensive ECU (on-board computer) that controls the entire vehicle C and has relay function. Alternatively, the on-board unit 1 can be an independent ECU connected to the lower level of the comprehensive ECU and configured in various areas of the vehicle C. Alternatively, the on-board unit 1 can be configured as a body ECU that controls the body system actuators of the vehicle C. Alternatively, the on-board unit 1 can be a PLB (Power LAN Box), which, in addition to relaying communication-related functions, also functions as a power distribution device that distributes and relays power output from power supply devices 5, such as secondary batteries, and supplies power to on-board equipment such as actuators.

[0051] The vehicle-mounted device 1 includes a control unit 11, a storage unit 12, a communication unit 13, and an input / output (I / O) unit 14, which may be packaged as, for example, a microcomputer 10. Furthermore, the vehicle-mounted device 1 includes one or more full bridges 6, to which a vehicle-mounted load 4 is connected. In the illustrations of this embodiment, the vehicle-mounted device 1 includes only one full bridge 6, but it is not limited to this; two or more full bridges 6 may also be mounted on the vehicle-mounted device 1.

[0052] The control unit 11 is composed of a CPU (Central Processing Unit) or MPU (Microprocessing Unit), etc., and performs various control and calculation processes by reading and executing the control program P (program product) and data pre-stored in the storage unit 12. The control unit 11 outputs control signals such as duty cycle via the input / output I / F 14 and signal line 140, thereby controlling the on / off state of the upstream semiconductor switches 7 (first upstream semiconductor switch 71, second upstream semiconductor switch 72) and the downstream semiconductor switches 8 (first downstream semiconductor switch 81, second downstream semiconductor switch 82) included in the full bridge 6.

[0053] The storage unit 12 is composed of volatile memory elements such as RAM (Random Access Memory), non-volatile memory elements such as ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable ROM), or flash memory, or a combination of these storage devices, and pre-stores a control program P (program product) and data referenced during processing. The control program P (program product) stored in the storage unit 12 may also be a program that stores a control program P (program product) that can be read from a recording medium M that can be read from the vehicle-mounted device 1. Alternatively, the control program P (program product) may be downloaded from an external computer (not shown) connected to a communication network (not shown) and stored in the storage unit 12.

[0054] The communication unit 13 uses an input / output interface that employs communication protocols such as CAN, CAN-FD, or Ethernet (registered trademark). The control unit 11 communicates with the vehicle ECU 2 connected to the vehicle network 3 via the communication unit 13. Multiple communication units 13 may be provided in the vehicle device 1.

[0055] The input / output I / F14 is, for example, a communication interface for serial communication. The input / output I / F14 includes multiple terminals (signal terminals). Signal lines 140 are respectively connected to the gate terminals of the upstream semiconductor switches 7 (first upstream semiconductor switch 71, second upstream semiconductor switch 72) and the downstream semiconductor switches 8 (first downstream semiconductor switch 81, second downstream semiconductor switch 82) included in the full bridge 6. The signal lines 140 are, for example, constructed from a serial cable, a wire harness, or a conductive cable (straight-through line) that transmits only one signal.

[0056] The vehicle-mounted device 1 may also include a drive circuit (driver IC) that generates and outputs drive signals such as gate signals. In this case, the drive circuit (driver IC) is positioned between the upstream semiconductor switch 7, which serves as a high-side switch, and the microcomputer 10, and is communicatively connected to the control unit 11 via the input / output I / F 14. At this time, the drive circuit (driver IC) or the IPD (Intelligent Power Device) containing the semiconductor switches of the full bridge 6 may also have a temperature warning function, outputting temperature warning information to the control unit 11 (microcomputer 10) when the temperature in the full bridge 6 exceeds a predetermined temperature threshold.

[0057] The full-bridge 6 (H-bridge circuit) includes a first upstream semiconductor switch 71 and a second upstream semiconductor switch 72 as upstream semiconductor switches 7, and a first downstream semiconductor switch 81 and a second downstream semiconductor switch 82 as downstream semiconductor switches 8. These upstream semiconductor switches 7 and downstream semiconductor switches 8 are constructed, for example, by NchFET (Field-effect transistor) or PchFET. Alternatively, the upstream semiconductor switches 7 and downstream semiconductor switches 8 may also be constructed by IPD (Intelligent Power Device) including semiconductor switching elements such as FETs. The full-bridge 6 includes a current detection unit 61 that detects or senses the current value flowing through the vehicle load 4 connected to the full-bridge 6 (load current).

[0058] Relative to power supply 5 (+B power supply), a first upstream semiconductor switch 71 and a first downstream semiconductor switch 81 are connected in series, and a second upstream semiconductor switch 72 and a second downstream semiconductor switch 82 are connected in series. The first downstream semiconductor switch 81 and the second upstream semiconductor switch 72 are connected (grounded) to a common ground wire (G) such as the chassis in vehicle C.

[0059] A series circuit (first series circuit) consisting of a first upstream semiconductor switch 71 and a first downstream semiconductor switch 81 is connected in parallel with a series circuit (second series circuit) consisting of a second upstream semiconductor switch 72 and a second downstream semiconductor switch 82. When the vehicle-mounted device 1 (motor 41) is connected to the full axle 6, one end of the vehicle-mounted device 1 is connected to a wire (first connecting wire) that connects the first upstream semiconductor switch 71 and the first downstream semiconductor switch 81 connected in series, and the other end of the vehicle-mounted device 1 is connected to a wire (second connecting wire) that connects the second upstream semiconductor switch 72 and the second downstream semiconductor switch 82 connected in series.

[0060] A current detection unit 61 (current sensor) is disposed on a wire connected to one end or the other end of the vehicle-mounted device 1, and is composed of, for example, a shunt resistor or a Hall element. The current detection unit 61 is connected to the control unit 11 (microcomputer 10) in a communicable manner via signal line 140 and input / output I / F 14, and periodically detects or identifies the load current value flowing through the vehicle-mounted device 1, and outputs the detected load current value to the control unit 11 (microcomputer 10).

[0061] Figure 3 This is a flowchart illustrating the processing (discontinuous control during disconnection) of the control unit 11 of the vehicle-mounted device 1. When the vehicle C stops or starts, the control unit 11 of the vehicle-mounted device 1 performs the following processing, for example, based on signals from various switches or messages from the vehicle-mounted ECU 2.

[0062] The control unit 11 of the vehicle-mounted device 1 acquires a message related to the start of driving of the vehicle-mounted load 4 (S101). The control unit 11 of the vehicle-mounted device 1 acquires the message related to the start of driving of the vehicle-mounted load 4, for example, by continuously receiving signals from various switches or messages from the vehicle-mounted ECU 2.

[0063] The control unit 11 of the vehicle-mounted device 1 determines whether to rotate the vehicle-mounted load 4 in the forward direction (S102). The vehicle-mounted load 4 is, for example, an actuator for a door rearview mirror opening and closing device or a seat moving device, including a motor 41 whose rotation direction corresponds to both forward and reverse directions. The control unit 11 of the vehicle-mounted device 1 determines, for example, whether to rotate the motor 41 included in the vehicle-mounted load 4 in the forward or reverse direction based on the message ID of the acquired message or the control value contained in the payload.

[0064] When the vehicle load 4 is rotated forward (S102: Yes), the control unit 11 of the vehicle device 1 controls multiple semiconductor switches in a manner that causes the vehicle load 4 to rotate forward (S103). When the vehicle load 4 (motor 41) is rotated forward, the control unit 11 of the vehicle device 1, when set to a manner that causes the vehicle load 4 to rotate forward, turns on the first upstream semiconductor switch 71 and the second downstream semiconductor switch 82 (ON), and turns off the second upstream semiconductor switch 72 and the first downstream semiconductor switch 81 (OFF). Based on this, the control unit 11 of the vehicle device 1 starts PWM control for one of the paired first upstream semiconductor switch 71 and second downstream semiconductor switch 82, and keeps the other semiconductor switch on (ON).

[0065] Without causing the vehicle load 4 to rotate forward (S102: No), that is, when causing the motor 41 of the vehicle load 4 to rotate in reverse, the control unit 11 of the vehicle device 1 controls multiple semiconductor switches in a manner that causes the vehicle load 4 to rotate in reverse (S1021). When causing the vehicle load 4 (motor 41) to rotate in reverse, the control unit 11 of the vehicle device 1, when set to the manner that causes the vehicle load 4 to rotate in reverse, turns off (disconnects) the first upstream semiconductor switch 71 and the second downstream semiconductor switch 82, and turns on (connects) the second upstream semiconductor switch 72 and the first downstream semiconductor switch 81. Based on this, the control unit 11 of the vehicle device 1 starts PWM control for one of the paired second upstream semiconductor switch 72 and the first downstream semiconductor switch 81, and keeps the other semiconductor switch on (connected).

[0066] The control unit 11 of the vehicle-mounted device 1 determines whether a switching cycle has elapsed (S104). The switching cycle is stored, for example, in the storage unit 12 of the vehicle-mounted device 1, and the control unit 11 obtains the value of this switching cycle by referring to the storage unit 12. The switching cycle can be set, for example, to 8 times the switching cycle (the sum of a single on-time and off-time) during PWM control, or between 5 and 10 times the switching cycle. The control unit 11 of the vehicle-mounted device 1 has a clock function, measuring the elapsed time from the start of PWM control to the current time, or the elapsed time from the last switching time to the current time, and determines whether the elapsed time has reached the switching cycle.

[0067] If no switching cycle has occurred (S104: No), the control unit 11 of the vehicle-mounted device 1 performs cyclic processing to execute S104 again. Therefore, during the period before the switching cycle occurs, PWM control based on the current state continues. That is, if the current control mode is one where the upstream semiconductor switch 7 is PWM controlled and the downstream semiconductor switch 8 is kept on (closed), this control mode continues. Alternatively, if the current control mode is one where the upstream semiconductor switch 7 is kept on (closed) and the downstream semiconductor switch 8 is PWM controlled, this control mode continues. When the vehicle-mounted load 4 (motor 41) rotates forward, the upstream semiconductor switch 7 is equivalent to the first upstream semiconductor switch 71, and the downstream semiconductor switch 8 is equivalent to the second downstream semiconductor switch 82. When the vehicle-mounted load 4 (motor 41) rotates in reverse, the upstream semiconductor switch 7 is equivalent to the second upstream semiconductor switch 72, and the downstream semiconductor switch 8 is equivalent to the first downstream semiconductor switch 81.

[0068] When a switching cycle has elapsed (S104: Yes), the control unit 11 of the vehicle-mounted device 1 uses discontinuous control during the disconnection period to switch between the semiconductor switch performing PWM control and the semiconductor switch that is turned on (connected) (S105). The control unit 11 of the vehicle-mounted device 1 switches between the semiconductor switch performing PWM control and the semiconductor switch that is turned on (connected) when a switching cycle has elapsed since the start time of PWM control using either the upstream semiconductor switch 7 or the downstream semiconductor switch 8, or when a switching cycle has elapsed since the last switching time. When switching between the semiconductor switch performing PWM control and the semiconductor switch that is turned on (connected), the control unit 11 of the vehicle-mounted device 1 performs discontinuous control during the disconnection period, thereby controlling the disconnection period of both the upstream semiconductor switch 7 and the downstream semiconductor switch 8 to be discontinuous before and after the switching.

[0069] When the control unit 11 of the vehicle-mounted device 1 performs discontinuous control during the disconnection period, it can also synchronize the on / off cycles of the PWM control for the paired upstream semiconductor switch 7 and downstream semiconductor switch 8, that is, apply the same pulse width duty cycle. The control unit 11 of the vehicle-mounted device 1 can also output control signals (on signal (Hi signal) and off signal (Lo signal)) to both the upstream semiconductor switch 7 and the downstream semiconductor switch 8 with the same on / off cycle (synchronizing the pulse width duty cycle), and for a certain semiconductor switch that is being controlled to conduct (maintain the on state), the control signal is shielded and the output is forcibly set to on.

[0070] Alternatively, when the control unit 11 of the vehicle-mounted device 1 performs discontinuous control during the disconnection period, it acquires the current value output from the current detection unit 61 provided on the full bridge 6, thereby determining whether or not the vehicle-mounted load 4 is energized before the switch. If the control unit 11 of the vehicle-mounted device 1 energizes the vehicle-mounted load 4 before the switch, it determines that the semiconductor switch controlled by PWM is turned on before the switch. If the control unit 11 of the vehicle-mounted device 1 does not energize the vehicle-mounted load 4 before the switch, it determines that the semiconductor switch controlled by PWM is turned off before the switch.

[0071] When the control unit 11 of the vehicle-mounted device 1 determines that the semiconductor switch controlled by PWM is turned on just before the switch, it starts PWM control on the semiconductor switch that is being PWM controlled immediately after the switch from being turned off. When it determines that the semiconductor switch is turned off, it starts PWM control from being turned on. As a result, the signal levels (H / L) output to the upstream semiconductor switch 7 and the downstream semiconductor switch 8 are different before and after the switch.

[0072] Alternatively, when the control unit 11 of the vehicle-mounted device 1 performs discontinuous control during the disconnection period, it starts PWM control from the turn-on state for all semiconductor switches that have just been switched. By switching semiconductor switches in this way, PWM control of the switched semiconductor switches starting from the turn-on state can reliably prevent continuous current flow during the disconnection period when the current does not flow through the upstream semiconductor switch 7 and the downstream semiconductor switch 8 before and after the switch.

[0073] As described above, when performing discontinuous control during disconnection, the control unit 11 of the vehicle-mounted device 1 can use multiple control methods (discontinuous control modes during disconnection). The storage unit 12 of the vehicle-mounted device 1 stores setting flags indicating which control method (discontinuous control mode during disconnection) to apply among the multiple control methods (discontinuous control modes during disconnection). The control unit 11 of the vehicle-mounted device 1 can also determine the applied control method (discontinuous control mode during disconnection) based on the setting flags. In this case, when the vehicle-mounted device 1 is connected to multiple full-bridges 6, and each of these full-bridges 6 is connected to a vehicle-mounted load 4, the control method for discontinuous control during disconnection in each full-bridge 6 can also be determined according to the setting flags corresponding to each full-bridge 6. Therefore, the discontinuous control mode during disconnection can be applied according to the specifications or characteristics of the vehicle-mounted load 4 connected to the full-bridge 6, improving the usability of the vehicle-mounted device 1.

[0074] Figure 4 This is an explanatory diagram illustrating the method of alternately performing PWM control on the upstream semiconductor switch 7 and the downstream semiconductor switch 8. The above-described process is summarized through the illustrations in this embodiment.

[0075] exist Figure 4 In this process, the semiconductor switches included in the full bridge 6 are controlled to make the on-board load 4 (motor 41) rotate in the forward direction, so that the first upstream semiconductor switch 71 (SW1) and the second downstream semiconductor switch 82 (SW4) are turned on, and the second upstream semiconductor switch 72 (SW2) and the first downstream semiconductor switch 81 (SW3) are turned off. Based on this, the first upstream semiconductor switch 71 (SW1) and the second downstream semiconductor switch 82 (SW4) are alternately controlled by PWM.

[0076] The intervals in which the first upstream semiconductor switch 71 (SW1) and the second downstream semiconductor switch 82 (SW4) are alternately controlled by PWM are roughly divided into intervals A and B. In interval A, the second downstream semiconductor switch 82 (SW4) is controlled by PWM, while the first upstream semiconductor switch 71 (SW1) remains in the ON state. In interval B, the first upstream semiconductor switch 71 (SW1) is controlled by PWM, while the second downstream semiconductor switch 82 (SW4) remains in the ON state.

[0077] The switching period for which the semiconductor switch to be controlled by the PWM is switched is set to an integer multiple of the switching period (the sum of a single on-time and off-time). In this embodiment, it is set to 8 times as an example. After the switching period has elapsed from the start time of the PWM control or a previous switching time, the control unit 11 of the vehicle device 1 switches the semiconductor switch to be controlled by the PWM from the first upstream semiconductor switch 71 (SW1) to the second downstream semiconductor switch 82 (SW4), or from the second downstream semiconductor switch 82 (SW4) to the first upstream semiconductor switch 71 (SW1).

[0078] When the semiconductor switch to be controlled by PWM, i.e., when switching from interval A to interval B or from interval B to interval A, the control unit 11 of the vehicle-mounted device 1 performs discontinuous control during the disconnection period to prevent current from flowing through the first upstream semiconductor switch 71 (SW1) and the second downstream semiconductor switch 82 (SW4). The control unit 11 of the vehicle-mounted device 1 may also perform discontinuous control during the disconnection period in any of the control methods described above.

[0079] By implementing discontinuous control during this disconnection period, the disconnection period can be made discontinuous, so that during the switching timing of the interval before and after the switching moment, no duty cycle (pulse) is output, and the period during which the load current to the vehicle load 4 is disconnected (the period during which no load current flows) is not continuous. That is, during the switching timing of the interval, from the state of the second downstream semiconductor switch 82 (SW4) being open (Lo) to the state of the first upstream semiconductor switch 71 (SW1) being open (Lo), the open (Lo) state of the semiconductor switches before and after these switching can be effectively prevented from continuing.

[0080] The control unit 11 of the vehicle-mounted device 1 determines whether a message related to the drive stop of the vehicle-mounted load 4 has been obtained (S106). The control unit 11 of the vehicle-mounted device 1 obtains the message related to the drive stop of the vehicle-mounted load 4, for example, by continuously receiving signals from various switches or messages from the vehicle-mounted ECU 2. If no message related to the drive stop of the vehicle-mounted load 4 is obtained (S106: No), the process from S104 onwards is repeated.

[0081] Upon receiving a message related to the drive stop of the vehicle load 4 (S106: Yes), the control unit 11 of the vehicle device 1 turns off (opens) all semiconductor switches contained in the full bridge 6 (S107). When the control unit 11 of the vehicle device 1 receives a message related to the drive stop of the vehicle load 4 from, for example, various switches or the vehicle ECU 2, it stops powering to the vehicle load 4 by turning off (opening) all semiconductor switches contained in the full bridge 6.

[0082] (Implementation Method 2)

[0083] Figure 5 This is a flowchart illustrating the processing (start of PWM control) of the control unit 11 of the vehicle-mounted device 1 according to Embodiment 2. When the vehicle C stops or starts, the control unit 11 of the vehicle-mounted device 1 performs the following processing, for example, based on signals from various switches or messages from the vehicle-mounted ECU 2.

[0084] The control unit 11 of the vehicle-mounted device 1 obtains a message related to the start of driving the vehicle-mounted load 4 (S201). The control unit 11 of the vehicle-mounted device 1 determines whether to make the vehicle-mounted load 4 rotate forward (S202). The control unit 11 of the vehicle-mounted device 1 performs the processing of S201 to S202 in the same way as the processing of S101 to S102 in Embodiment 1.

[0085] When the vehicle load 4 is rotated forward (S202: Yes), multiple semiconductor switches are controlled in a manner that causes the vehicle load 4 to rotate forward (S203). When the control unit 11 of the vehicle device 1 controls multiple semiconductor switches in a manner that causes the vehicle load 4 to rotate forward, it may also not perform PWM control, but instead turn on the first upstream semiconductor switch 71 and the second downstream semiconductor switch 82, and turn off the second upstream semiconductor switch 72 and the first downstream semiconductor switch 81. That is, the control unit 11 of the vehicle device 1 maintains the on state through DC drive without periodic switching, causing the load current to flow forward through the vehicle load 4, thus causing the motor 41 of the vehicle load 4 to rotate forward.

[0086] Without causing the vehicle load 4 to rotate forward (S202: No), that is, without causing the motor 41 of the vehicle load 4 to rotate in reverse, the control unit 11 of the vehicle device 1 controls multiple semiconductor switches in a manner that causes the vehicle load 4 to rotate in reverse (S2021). When the control unit 11 of the vehicle device 1 controls multiple semiconductor switches in a manner that causes the vehicle load 4 to rotate in reverse, it may also not perform PWM control, but instead turn off (disconnect) the first upstream semiconductor switch 71 and the second downstream semiconductor switch 82, and turn on (connect) the second upstream semiconductor switch 72 and the first downstream semiconductor switch 81. That is, the control unit 11 of the vehicle device 1 maintains the on state through DC drive without periodic switching, causing the load current to flow in the opposite direction to the vehicle load 4, thus causing the motor 41 of the vehicle load 4 to rotate in reverse.

[0087] The control unit 11 of the vehicle-mounted device 1 determines whether to start PWM control (S204). For example, the control unit 11 of the vehicle-mounted device 1 determines to start PWM control when suppressing inrush current flowing through the vehicle-mounted load 4. The control unit 11 of the vehicle-mounted device 1 may also determine to start PWM control when, for example, upon receiving a signal or message indicating or requesting the start of drive of the vehicle-mounted load 4, a predetermined event causing the generation of inrush current for the vehicle-mounted load 4 (motor 41) is detected by making the stationary vehicle-mounted load 4 (motor 41) movable (rotating).

[0088] Alternatively, the control unit 11 of the vehicle-mounted device 1 determines to start PWM control when the rotational speed of the motor 41 included in the vehicle-mounted load 4 becomes variable. When the control unit 11 of the vehicle-mounted device 1 receives signals from various switches or receives messages from the vehicle-mounted ECU 2 via the vehicle network 3, etc., and changes the driving mode of the vehicle-mounted load 4 based on the received messages, it can also determine to start PWM control when the rotational speed of the motor 41 included in the vehicle-mounted load 4 becomes variable.

[0089] Alternatively, the control unit 11 of the vehicle-mounted device 1 determines to start PWM control when the temperature of the wires or semiconductor switches included in the full bridge 6 exceeds a predetermined temperature threshold. The control unit 11 of the vehicle-mounted device 1 uses the current detection function of the current detection unit 61 provided in the full bridge 6 or the IPD (Intelligent Power Device) constituting the semiconductor switch to periodically acquire the current value flowing through the full bridge 6, such as the current flowing through the wires or energized semiconductor switches between the full bridge 6 and the vehicle load 4. Based on the periodically acquired multiple current values, the control unit 11 of the vehicle-mounted device 1 derives the temperature of the wires or semiconductor switches included in the full bridge 6. The control unit 11 of the vehicle-mounted device 1 may also determine to start PWM control when the derived temperature exceeds a predetermined temperature threshold.

[0090] Alternatively, the control unit 11 of the vehicle-mounted device 1 determines to start PWM control upon receiving a temperature warning message indicating that the temperature in the full bridge 6 exceeds a predetermined temperature threshold. The control unit 11 of the vehicle-mounted device 1 is communicatively connected to a drive circuit (driver IC) via, for example, an input / output I / O circuit 14. This drive circuit generates and outputs drive signals such as gate signals to the IPDs constituting the semiconductor switches included in the full bridge 6, or to the semiconductor switches included in the full bridge 6. These IPDs or the drive circuit (driver IC) have a temperature warning function, which outputs a temperature warning message indicating that the temperature in the full bridge 6 exceeds a predetermined temperature threshold to the control unit 11 of the vehicle-mounted device 1. The control unit 11 of the vehicle-mounted device 1 can also determine to start PWM control upon receiving temperature warning information from an IPD or the drive circuit.

[0091] In this embodiment, the control unit 11 of the vehicle-mounted device 1 is described to determine whether to rotate forward and whether to start PWM control through different processes, but it is not limited to this. The control unit 11 of the vehicle-mounted device 1 may also determine whether to start PWM control at the same time as determining whether to rotate forward.

[0092] If it is determined that PWM control has started (S204: Yes), the control unit 11 of the vehicle device 1 starts PWM control (S205). If the control unit 11 of the vehicle device 1 determines that PWM control has started based on any of the above-described determination criteria, the control unit 11 of the vehicle device 1 starts PWM control for the semiconductor switch controlled by a DC drive that maintains an on state without periodic switching. Alternatively, if PWM control has already started, the control unit 11 of the vehicle device 1 continues the PWM control.

[0093] If it is determined that PWM control should not be started (S204: No), the control unit 11 of the vehicle device 1 stops PWM control (S2041). If the control unit 11 of the vehicle device 1 determines that PWM control should not be started, such as when any of the above-mentioned determination criteria are not met, it stops PWM control of the semiconductor switch and starts DC drive. If PWM control has already been stopped, the control unit 11 of the vehicle device 1 maintains the stopped state of PWM control (DC drive state).

[0094] After executing S205, the control unit 11 of the vehicle device 1 determines whether a switching cycle has passed (S206). If a switching cycle has passed (S206: Yes), the control unit 11 of the vehicle device 1 uses discontinuous control during the disconnection period to switch between the semiconductor switch that performs PWM control and the semiconductor switch that performs conduction (connection) (S207).

[0095] After executing S2041 or S207, the control unit 11 of the vehicle-mounted device 1 determines whether a message related to the drive stop of the vehicle-mounted load 4 has been obtained (S208). If a message related to the drive stop of the vehicle-mounted load 4 has been obtained (S208: Yes), the control unit 11 of the vehicle-mounted device 1 turns off (opens) all semiconductor switches contained in the full bridge 6 (S209). If no switching cycle has been completed (S206: No), or if no message related to the drive stop of the vehicle-mounted load 4 has been obtained (S208: No), a loop process is performed in order to repeat the process from S204. The control unit 11 of the vehicle-mounted device 1 performs the processes S206 to S209 in the same way as the processes S104 to S107 of Embodiment 1.

[0096] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the invention is not as described above, but is defined by the claims and is intended to include all modifications equivalent to and within the scope of the claims.

[0097] The claims listed in the claims statement can be combined with each other regardless of their form of reference. The claims statement may also include multiple dependent claims that are subordinate to multiple claims. Even if multiple dependent claims are not listed, this does not limit the inclusion of multiple dependent claims that are subordinate to multiple dependent claims.

[0098] Explanation of reference numerals in the attached figures

[0099] Vehicle C

[0100] S vehicle in-vehicle system

[0101] 1 vehicle-mounted device

[0102] 10 Microcomputers (μC)

[0103] 11 Control Department

[0104] 12 Storage Units

[0105] M recording medium

[0106] P control program (program product)

[0107] 13Ministry of Communications

[0108] 14 Input / Output I / F

[0109] 140 signal line

[0110] 2. Vehicle ECU

[0111] 3. In-vehicle network

[0112] 4 Vehicle-mounted load

[0113] 41 motors

[0114] 5 Power Supply Unit

[0115] 51 Power Line

[0116] 6 full bridges

[0117] 61 Current Detection Section

[0118] 7. Upstream semiconductor switches (FET, IPD)

[0119] 71 First upstream semiconductor switch

[0120] 72 Second upstream semiconductor switch

[0121] 8. Downstream semiconductor switches (FET, IPD)

[0122] 81 First downstream semiconductor switch

[0123] 82 Second downstream semiconductor switch.

Claims

1. A vehicle-mounted device for driving and controlling a vehicle-mounted load connected to a full-bridge composed of multiple semiconductor switches, wherein, The vehicle-mounted device includes a control unit that performs PWM control for the vehicle-mounted load. The semiconductor switches of the full bridge include: an upstream semiconductor switch, composed of a first upstream semiconductor switch and a second upstream semiconductor switch; and a downstream semiconductor switch, composed of a first downstream semiconductor switch and a second downstream semiconductor switch. When the control unit allows current to flow forward through the vehicle load, it turns on the first upstream semiconductor switch and the second downstream semiconductor switch, and turns off the second upstream semiconductor switch and the first downstream semiconductor switch. When the current flows through the vehicle load in the reverse direction, the control unit turns off the first upstream semiconductor switch and the second downstream semiconductor switch, and turns on the second upstream semiconductor switch and the first downstream semiconductor switch. When the control unit performs PWM control on the vehicle-mounted load, it performs PWM control on one of the upstream and downstream semiconductor switches to be turned on, and turns on the other semiconductor switch. The control unit switches between the semiconductor switch being PWM controlled and the semiconductor switch being turned on according to the elapsed time of a predetermined period, thereby alternately performing PWM control on the upstream semiconductor switch and the downstream semiconductor switch.

2. The vehicle-mounted device according to claim 1, wherein, When the control unit switches the semiconductor switch under PWM control between the upstream semiconductor switch and the downstream semiconductor switch, it performs discontinuous control during the disconnection period. This discontinuous control during the disconnection period ensures that the current does not flow through the upstream semiconductor switch and the downstream semiconductor switch during the disconnection period before and after the switch.

3. The vehicle-mounted device according to claim 2, wherein, Before and after the switching, the control unit performs discontinuous control during the disconnection period by synchronizing the on / off cycles in the PWM control of the upstream semiconductor switch and the downstream semiconductor switch.

4. The vehicle-mounted device according to claim 2, wherein, When the control unit switches the PWM-controlled semiconductor switch between the upstream semiconductor switch and the downstream semiconductor switch, it performs discontinuous control during the disconnection period in the following manner: To determine whether the on-board load is powered on before the upcoming switchover. When the vehicle-mounted load is powered on, PWM control begins on the semiconductor switch that becomes the object of PWM control after switching, starting from the point of disconnection. Without power to the vehicle load, PWM control begins from the moment the semiconductor switch, which becomes the object of PWM control after switching, is turned on.

5. The vehicle-mounted device according to claim 2, wherein, When the control unit switches the PWM-controlled semiconductor switch between the upstream semiconductor switch and the downstream semiconductor switch, it performs discontinuous control during the disconnection period in the following manner: For the semiconductor switch that has just been switched and is subject to PWM control, PWM control begins from the moment it is turned on.

6. The vehicle-mounted device according to any one of claims 1 to 5, wherein, The control unit initiates PWM control while suppressing the flow of inrush current to the vehicle load.

7. The vehicle-mounted device according to any one of claims 1 to 5, wherein, The control unit initiates PWM control when the rotational speed of the motor included in the vehicle load is variable.

8. The vehicle-mounted device according to any one of claims 1 to 5, wherein, The control unit obtains the current value flowing through the full bridge, and based on the obtained current value, derives the temperature of the wires or semiconductor switches included in the full bridge. If the derived temperature exceeds a predetermined temperature threshold, PWM control is started.

9. The vehicle-mounted device according to any one of claims 1 to 5, wherein, The semiconductor switches or control unit included in the full bridge have a temperature warning function that outputs a temperature warning message when the temperature in the full bridge exceeds a predetermined temperature threshold. Upon receiving the temperature warning information, the control unit initiates PWM control.

10. An information processing method, wherein a computer that performs drive control on an on-board load connected to a full bridge consisting of an upstream semiconductor switch comprising a first upstream semiconductor switch and a second upstream semiconductor switch, and a downstream semiconductor switch comprising a first downstream semiconductor switch and a second downstream semiconductor switch, performs the following processing: When current flows forward through the vehicle load, the first upstream semiconductor switch and the second downstream semiconductor switch are turned on, and the second upstream semiconductor switch and the first downstream semiconductor switch are turned off. When the current flows through the vehicle load in the reverse direction, the first upstream semiconductor switch and the second downstream semiconductor switch are turned off, and the second upstream semiconductor switch and the first downstream semiconductor switch are turned on. When performing PWM control on the vehicle load, among the upstream and downstream semiconductor switches to be turned on, PWM control is applied to one of them, while turning on the other. The semiconductor switch that is PWM controlled and the semiconductor switch that is turned on are switched according to the elapsed period of a specified period, thereby alternately performing PWM control on the upstream semiconductor switch and the downstream semiconductor switch.

11. A program that causes a computer, which performs drive control on an on-board load connected to a full bridge consisting of an upstream semiconductor switch comprising a first upstream semiconductor switch and a second upstream semiconductor switch, and a downstream semiconductor switch comprising a first downstream semiconductor switch and a second downstream semiconductor switch, to perform the following processing: When current flows forward through the vehicle load, the first upstream semiconductor switch and the second downstream semiconductor switch are turned on, and the second upstream semiconductor switch and the first downstream semiconductor switch are turned off. When the current flows through the vehicle load in the reverse direction, the first upstream semiconductor switch and the second downstream semiconductor switch are turned off, and the second upstream semiconductor switch and the first downstream semiconductor switch are turned on. When performing PWM control on the vehicle load, among the upstream and downstream semiconductor switches to be turned on, PWM control is applied to one of them, while turning on the other. The semiconductor switch that is PWM controlled and the semiconductor switch that is turned on are switched according to the elapsed period of a specified period, thereby alternately performing PWM control on the upstream semiconductor switch and the downstream semiconductor switch.

Images