Power supply device

Abstract

To provide a power supply device which appropriately implements an initial check of a reverse connection protection relay in a configuration with no power supply relay.SOLUTION: A reverse connection protection relay 52 of a power supply device 10 is provided on a power supply line Lp between a battery 15 and input part capacitor 55, with a reflux diode for conducting current from a side of the battery 15 to a side of an inverter (power converter) 60 connected in parallel and blocks the current from the side of the inverter 60 to the side of the battery 15 in OFF. A booster circuit 20 implements "overboosting processing" for temporarily boosting a target voltage than a value in a normal operation in an initial check. A precharge circuit 30 applies a boosted voltage by the overboosting processing to an electrode on a high potential side of the input part capacitor 55. A monitoring circuit 40 detects an ON fastening abnormality or an OFF fastening abnormality of the reverse connection protection relay 52 according to a voltage Vry after relay as a voltage on the side of the inverter 60 of the reverse connection protection relay 52.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power supply device. [Background technology]

[0002] 2. Description of the Related Art In a conventional power supply device that converts DC power from a battery using a power converter such as an inverter and supplies the converted power to a load such as a three-phase motor, a configuration is known in which a power supply line between the battery and the power converter is provided with a reverse connection protection relay.

[0003] For example, in the device disclosed in Patent Document 1, a power relay (first FET) on the battery side of a power line and a reverse connection protection relay (second FET) on the inverter side are connected in series. A high potential electrode of a capacitor is connected between the reverse connection protection relay and the inverter. During an initial check, a control unit detects failures in the power relay and the reverse connection protection relay based on the voltage at point P1 between the power relay and the reverse connection protection relay and the voltage at point P2 between the reverse connection protection relay and the inverter while a voltage is charged to the high potential electrode of the capacitor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5311233 Summary of the Invention [Problem to be solved by the invention]

[0005] Assuming that the power relay is normal in the initial check of Patent Document 1, if the reverse connection protection relay is stuck on, the voltage between the relay (point P1) when turned off will be the capacitor charge voltage Vc. Also, if the reverse connection protection relay is stuck off, the voltage between the relay will be 0 [V] when turned on. In this way, the voltage between the relays is used to monitor for abnormalities.

[0006] However, there is a demand to eliminate the power relay in order to reduce the number of parts. By not providing a power relay, the battery voltage is applied to the capacitor at the inverter input even when the system is stopped, and there is an advantage in that the charging voltage is stable. However, without a power relay, it is not possible to monitor the voltage between the relays. Also, when the difference between the battery voltage and the capacitor's charging voltage is small, there is a possibility that detection errors, etc., may cause a mistake in distinguishing between normal and stuck-on or stuck-off abnormalities, making it difficult to detect abnormalities in the reverse connection protection relay.

[0007] The present invention has been made in consideration of the above-mentioned points, and an object of the present invention is to provide a power supply device that properly performs an initial check of a reverse connection protection relay in a configuration that does not include a power supply relay. [Means for solving the problem]

[0008] The power supply device of the present invention includes a power converter (60), an input capacitor (55), a boost circuit (20), a precharge circuit (30), and a reverse connection protection relay (52). The power converter includes one or more pairs of upper and lower arm switching elements (61-66) connected in series between a power supply line (Lp) connected to a battery (15) and a ground line (Lg), and converts the DC power of the battery and supplies it to a load (80).

[0009] The input capacitor is connected in parallel to the battery on the battery side of the power converter. The boost circuit boosts the input voltage supplied from the battery to a target voltage. The precharge circuit applies the boosted voltage output by the boost circuit to the high-potential electrode of the input capacitor to precharge it.

[0010] The reverse connection protection relay is provided in the power supply line between the battery and the input capacitor, has a return diode connected in parallel for conducting current from the battery side to the power converter side, and cuts off the current from the power converter side to the battery side when it is OFF. Furthermore, this power supply device does not include a power supply relay in the power supply line between the battery and the reverse connection protection relay for cutting off the current from the battery side to the power converter side when it is OFF.

[0011] The power supply device further includes a monitoring circuit (40) that detects a stuck-on abnormality or a stuck-off abnormality of the reverse connection protection relay during an initial check of the power supply device.

[0012] During the initial check, the boost circuit performs an overboost process to temporarily raise the target voltage above the value during normal operation. The precharge circuit applies the boosted voltage (VS) generated by the overboost process to the high-potential electrode of the input capacitor. The monitoring circuit detects whether the reverse connection protection relay is stuck on or stuck off according to the post-relay voltage (Vry), which is the voltage on the power converter side of the reverse connection protection relay.

[0013] In the overvoltage boost process, for example, the battery voltage of about 12 [V] is boosted to about 22 [V] and precharged to the input capacitor. If the reverse connection protection relay is stuck on abnormal, the boost voltage applied when the reverse connection protection relay is turned off is not maintained, and the voltage after the relay becomes equivalent to the battery voltage. If the reverse connection protection relay is stuck off abnormal, the voltage after the relay does not decrease when the reverse connection protection relay is turned on. In the present invention, the target voltage of the overvoltage boost process is set sufficiently high relative to the battery voltage, making it possible to correctly distinguish between normal and stuck abnormal voltages. Therefore, the initial check of the reverse connection protection relay can be performed appropriately. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a circuit diagram of a power supply according to one embodiment. [Diagram 2] 2 is a block diagram showing the configuration of a monitoring circuit in the power supply device of FIG. 1; [Diagram 3] FIG. 4 is a diagram for explaining an initial check flow of a reverse connection protection relay in a normal state. [Figure 4] FIG. 4 is a diagram for explaining detection of an ON stuck abnormality of a reverse connection protection relay. [Diagram 5] 4 is a diagram for explaining detection of an abnormality in a reverse connection protection relay being stuck in the OFF state. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] A power supply device according to an embodiment of the present invention will be described with reference to the drawings. The power supply device of this embodiment converts DC power from a battery in an electric power steering device and supplies it to a steering assist motor as a "load." The steering assist motor is configured as a three-phase brushless motor.

[0016] Specifically, the ECU of the electric power steering device functions as the power supply device. The ECU is composed of a microcomputer, a pre-driver, etc., and is equipped with a CPU, ROM, I / O, and bus lines connecting these components (not shown). The ECU executes software processing by running a program stored in advance on the CPU, and executes control through hardware processing by a dedicated electronic circuit.

[0017] An ECU of an electric power steering device generally starts (i.e., starts driving) when the vehicle ignition signal is turned ON, and stops driving when the ignition signal is turned OFF. Hereinafter, operation during the initial check will be referred to as normal operation. In this embodiment, the motor control configuration during normal operation performed by a control unit (not shown) is similar to that of a general motor control device. In this embodiment, attention is particularly focused on the initial check when the ECU is started up.

[0018] (One embodiment) FIG. 1 shows the circuit configuration of the first embodiment. Although a single-system circuit configuration is illustrated, the present invention may be applied to a redundant two-system configuration. A power supply device 10 supplies three-phase AC power generated by an inverter 60 serving as a "power converter" to three-phase windings 81, 82, and 83 of a motor 80. For example, in the case of a Y-connected motor 80, the three-phase windings 81, 82, and 83 are connected at a neutral point 84. The three-phase windings 81, 82, and 83 may be Δ-connected.

[0019] The power supply device 10 includes an inverter 60, an input capacitor 55, a reverse connection protection relay 52, a boost circuit 20, a precharge circuit 30, a monitoring circuit 40, etc. The inverter 60 is connected to the positive electrode of the battery 15 via a power supply line Lp, and is connected to the negative electrode of the battery 15 via a ground line Lg. The inverter 60 includes three sets of upper and lower arm switching elements 61-66 connected in series between the power supply line Lp and the ground line Lg.

[0020] Specifically, switching elements 61, 62, 63 in the upper arms of the U-phase, V-phase, and W-phase and switching elements 64, 65, 66 in the lower arms are bridge-connected. Each of the switching elements 61-66 performs a switching operation in response to a gate signal commanded by the control unit, whereby the inverter 60 converts the DC power of the battery 15 and supplies it to the three-phase windings 81, 82, 83 of the motor 80.

[0021] In this embodiment, MOSFETs are used as the switching elements 61-66 of the inverter 60. In the switching elements 61-66, a free wheel diode that conducts a current from the low potential side to the high potential side is configured as a parasitic diode inside the element. Inter-arm connection points Nu, Nv, and Nw, which are connection points of the switching elements of the upper and lower arms of each phase, are connected to three-phase windings 81, 82, and 83 of the motor 80. A motor relay may be provided in the current path of each phase.

[0022] The input capacitor 55 is connected in parallel to the battery 15 on the battery 15 side of the inverter 60. During normal operation, the input capacitor 55 smoothes the input voltage supplied from the battery 15 and also suppresses the switching noise of the inverter 60 from being transmitted to the outside. The high potential side electrode of the input capacitor 55 is connected to the precharge circuit 30.

[0023] A reverse connection protection relay 52 is provided in the power supply line Lp between the battery 15 and the input capacitor 55. A free wheel diode that conducts a current from the battery 15 side to the inverter 60 side is connected in parallel to the reverse connection protection relay 52. ​​In this embodiment, a parasitic diode of a MOSFET that constitutes the reverse connection protection relay 52 conducts a current from the battery 15 side to the inverter 60 side. When the reverse connection protection relay 52 is turned off, it cuts off the current from the inverter 60 side to the battery side. The voltage drop due to the parasitic diode is denoted as Vf.

[0024] The reverse connection protection relay 52 corresponds to the second FET 32 disclosed in Fig. 1 of Patent Document 1 (Japanese Patent No. 5311233). Incidentally, in Fig. 1 of Patent Document 1, a first FET 31, which is a "power supply relay," is provided in the power supply line between the battery and the reverse connection protection relay. This power supply relay is connected so that the orientation of the parasitic diode is opposite to that of the reverse connection protection relay, and when it is turned off, it cuts off the current from the battery side to the inverter side.

[0025] In contrast, the power supply device 10 of this embodiment does not have a power relay at the position X indicated by the two-dot chain line. This allows the number of power relay components to be reduced in this embodiment. Also, even when the power supply device 10 is stopped and the system is stopped, the battery voltage is applied to the input capacitor 55, and the charging voltage is stabilized. On the other hand, the disadvantage of not having a power relay will be described later.

[0026] Next, the boost circuit 20 boosts the input voltage supplied from the battery to a target voltage. The boost circuit 20 is a chopper type boost circuit including a reactor 21, a boost switching element 22, a diode 23, and a boost capacitor 24. The boost switching element 22 is composed of an N-channel MOSFET.

[0027] One end of the reactor 21 is connected to the positive electrode of the battery 15 via the diode 19, and a voltage obtained by subtracting the voltage drop of the diode 19 from the battery voltage (for example, about 12 [V]) is applied as an input voltage. The boost switching element 22 is connected between the other end of the reactor 21 and the ground. The anode of the diode 23 is connected to a connection point N between the reactor 21 and the boost switching element 22. The boost capacitor 24 has a high-potential electrode connected to the cathode of the diode 23, and is charged with the boosted voltage.

[0028] The boost circuit 20 boosts and outputs the input voltage by the reactor 21 repeatedly storing and releasing inductive energy due to the PWM operation of the boost switching element 22. The boost switching element 22 is feedback-controlled so that the output boost voltage VS coincides with a target voltage.

[0029] The precharge circuit 30 applies the boosted voltage VS output by the boost circuit 20 to the high potential side electrode of the input capacitor 55 to precharge it. The boosted voltage VS output by the boost circuit 20 is output to the precharge circuit 30 as well as to driver circuits such as the reverse connection protection relay 52, the upper arm elements 61-63 of the inverter 60, and the motor relay via a charge pump. The boosted voltage VS is also output to the driver circuits of the lower arm elements 64-66 of the inverter 60 without passing through a charge pump. Each driver circuit outputs a gate signal to each switch using the boosted voltage VS.

[0030] The monitoring circuit 40 detects an ON-fixed abnormality or an OFF-fixed abnormality of the reverse connection protection relay 52 during an initial check of the power supply device 10. Here, the voltage on the battery 15 side of the reverse connection protection relay 52 is the "battery voltage Vb," and the voltage on the inverter 60 side of the reverse connection protection relay 52 is the "post-relay voltage Vry." During the initial check, the voltage applied from the pre-charge circuit 30 to the high potential side electrode of the input capacitor 55 becomes the post-relay voltage Vry.

[0031] Fig. 2 shows a detailed configuration of the monitoring circuit 40. In Fig. 2, compared to Fig. 1, parts other than the monitoring circuit 40 and the reverse connection protection relay 52 are shown in simplified blocks. The configuration of the monitoring circuit 40 in Fig. 2 corresponds to [detection method 2] described below, and monitors both the battery voltage Vb and the post-relay voltage Vry. On the other hand, when [detection method 1] is adopted, it is also possible to monitor only the post-relay voltage Vry without monitoring the battery voltage Vb.

[0032] The monitoring circuit 40 includes a first monitoring unit 41 that monitors the battery voltage Vb, a second monitoring unit 42 that monitors the post-relay voltage Vry, and an abnormality determination unit 44. The first monitoring unit 41 has a monitoring switch MS1 and upper and lower voltage dividing resistors R1u and R1d connected in series between the battery 15 side of the reverse connection protection relay 52 and ground. The second monitoring unit 42 has a monitoring switch MS2 and upper and lower voltage dividing resistors R2u and R2d connected in series between the inverter 60 side of the reverse connection protection relay 52 and ground. The monitoring switches MS1 and MS2 are composed of, for example, MOSFETs. The monitoring switches MS1 and MS2 are turned off except when detecting voltage, thereby preventing current from flowing to ground through the voltage dividing resistors R1u, R1d, R2u, and R2d.

[0033] When the monitoring switch MS1 of the first monitoring unit 41 is turned ON, a first monitor voltage Vm1 at the connection point of the voltage dividing resistors R1u and R1d is acquired by the abnormality determination unit 44. When the monitoring switch MS2 of the second monitoring unit 42 is turned ON, a second monitor voltage Vm2 at the connection point of the voltage dividing resistors R2u and R2d is acquired by the abnormality determination unit 44. As shown in the following equations, the first monitor voltage Vm1 and the second monitor voltage Vm2 respectively reflect the battery voltage Vb and the post-relay voltage Vry.

[0034] Vm1 = Vb × R1d / (R1u + R1d) Vm2 = Vry × R2d / (R2u + R2d)

[0035] The abnormality determination unit 44 detects a sticking abnormality of the reverse connection protection relay 52 by a detection method described later, based on the battery voltage Vb and the post-relay voltage Vry obtained by converting the first monitor voltage Vm1 and the second monitor voltage Vm2. When using [detection method 2], the monitoring circuit 40 monitors the battery voltage Vb and the post-relay voltage Vry with the same configuration, so that the variation can be suppressed. Furthermore, at least some of the elements constituting the monitoring circuit 40 may be provided inside an ASIC (i.e., a customized IC). This reduces the board mounting area and the mounting man-hours.

[0036] Incidentally, in the initial check of Patent Document 1, failures in the power supply relay and reverse connection protection relay are detected based on the voltage at point P1 between the power supply relay (first FET 31) and the reverse connection protection relay (second FET 32). However, in this embodiment, since there is no power supply relay, it is not possible to monitor the voltage between the relays. Also, when the difference between the battery voltage Vb and the post-relay voltage Vry is small, there is a possibility that a detection error or the like may cause an error in distinguishing between a normal state and a stuck-ON or stuck-OFF abnormal state, making it difficult to detect an abnormality in the reverse connection protection relay 52.

[0037] Therefore, in this embodiment, the following process is performed during the initial check. The boost circuit 40 performs an "overboost process" that temporarily increases the target voltage above the value during normal operation. For example, an input voltage of about 12 [V] is boosted to about 16 [V] during normal operation, but is boosted to about 22 [V] in the overboost process.

[0038] The precharge circuit 30 applies the boosted voltage VS resulting from the overvoltage processing to the high potential side electrode of the input capacitor 55. Therefore, the boosted voltage VS resulting from the overvoltage processing is applied to the inverter 60 side of the reverse connection protection relay 52. ​​In this state, the monitoring circuit 40 detects an ON-fixed abnormality or an OFF-fixed abnormality of the reverse connection protection relay 52 according to the post-relay voltage Vry.

[0039] 3 to 5, a method for detecting a stuck abnormality in the reverse connection protection relay 52 during the initial check will be described in detail. Each figure shows, from the top to bottom, the ON / OFF state of the ignition switch ("IG" in the figure), the boost voltage VS and the post-relay voltage Vry, the potential difference before and after the relay ΔV, the ON / OFF state of pre-charge, and the ON / OFF state of the reverse connection protection relay 52. ​​The potential difference before and after the relay ΔV is defined as the potential difference (ΔV=Vry-Vb) obtained by subtracting the battery voltage Vb from the post-relay voltage Vry, and corresponds to the potential difference between both ends of the reverse connection protection relay 52.

[0040] 3 to 5 are common except for the voltage after the relay Vry and the potential difference before and after the relay ΔV. Fig. 3 shows the behavior of the voltage after the relay Vry and the potential difference before and after the relay ΔV in normal operation, Fig. 4 shows the behavior of the voltage after the relay Vry and the potential difference before and after the relay ΔV in the event of an ON-fixed abnormality, and Fig. 5 shows the behavior of the voltage after the relay Vry and the potential difference before and after the relay ΔV in the event of an OFF-fixed abnormality. Before starting up the power supply device 10, the ignition switch is OFF, precharge by the precharge circuit 30 is ON, and the reverse connection protection relay 52 is OFF.

[0041] First, the boost voltage VS indicated by the two-dot chain line in all the figures will be described. Here, the battery voltage is 12 [V], the boost voltage VS during normal operation is 16 [V], and the boost voltage VS due to the overboost process is 22 [V]. When the ignition switch is turned on at time to, the boost voltage VS rises from 12 [V] to 16 [V]. After that, between time ts and time te, the boost circuit 20 performs the overboost process, and the boost voltage VS temporarily rises to 22 [V]. When the overboost process ends at time te, the boost voltage VS returns to the normal operation level of 16 [V].

[0042] At time te, the boost circuit 20 ends the overboost process, and at the same time, the precharge to the input capacitor 55 by the precharge circuit 30 is turned off. Also, at time te, the reverse connection protection relay 52 is turned on from the OFF state. The period from time ts to time te is the ON-fixed detection timing. After that, the period from time te to time tc is the OFF-fixed detection timing.

[0043] 3, in the normal state, before time ts, the reverse connection protection relay 52 is OFF, and the current from the battery 15 to the inverter 60 flows only through the parasitic diode. The voltage Vry after the relay is the battery voltage Vb minus the voltage drop Vf of the parasitic diode (Vb-Vf). At this time, the potential difference ΔV before and after the relay is 0 [V] minus the voltage drop Vf of the parasitic diode (-Vf).

[0044] After time ts, if things are normal, the voltage Vry after the relay follows the rise in the boost voltage VS with a delay, and eventually rises to the maximum voltage (≒VS-Vf). Along with this, the potential difference ΔV before and after the relay increases beyond 0 [V] to the maximum positive value. However, as shown in FIG. 4, if the reverse connection protection relay 52 is stuck-on abnormal, the voltage Vry after the relay is not maintained and always becomes equivalent to the battery voltage Vb. Also, the potential difference ΔV before and after the relay is always 0 [V].

[0045] When the precharge is turned OFF at time te, in a normal case, the post-relay voltage Vry drops due to the discharge of the input capacitor 55. In addition, because the reverse connection protection relay 52 is turned ON, the post-relay voltage Vry gradually converges toward the battery voltage Vb. Accordingly, the potential difference ΔV across the relay decreases toward 0 [V]. However, as shown in FIG. 5, in the case where the reverse connection protection relay 52 is stuck OFF, the post-relay voltage Vry does not drop from the maximum voltage due to the overvoltage processing. In addition, the potential difference ΔV across the relay does not drop from its maximum value.

[0046] Based on the above behavior, the monitoring circuit 40 can perform two types of fixation abnormality detection methods: [detection method 1] based on the relay post-voltage Vry, and [detection method 2] based on the relay pre- and post-potential difference ΔV.

[0047] [Detection method 1] In detection method 1, the voltage threshold Vth is set to a value (for example, about 18 [V]) slightly higher than 16 [V], which is the boost voltage VS during normal operation. Then, when the reverse connection protection relay 52 is normal, a predetermined boost time TA is set based on the time it takes for the relay post-voltage Vry to boost to the voltage threshold Vth after time ts. Also, a predetermined step-down time TD is set based on the time it takes for the relay post-voltage Vry to drop to the voltage threshold Vth after time te. Detection errors and variations are taken into consideration when setting the boost time TA and step-down time TD.

[0048] At the timing of stuck-ON detection, if the relay post voltage Vry after the voltage rise time TA from time ts is equal to or greater than the voltage threshold Vth, it is determined to be normal, as shown in Fig. 3. If the relay post voltage Vry after the voltage rise time TA from time ts is smaller than the voltage threshold Vth, it is determined to be stuck-ON.

[0049] At the timing of OFF-stuck detection, if the relay post voltage Vry after the step-down time TD from time te is equal to or less than the voltage threshold Vth, it is determined to be normal, as shown in Fig. 3. If the relay post voltage Vry after the step-down time TD from time te is greater than the voltage threshold Vth, it is determined to be OFF-stuck abnormal, as shown in Fig. 5.

[0050] Thus, in detection method 1, the monitoring circuit 40 detects the ON-fixed abnormality of the reverse connection protection relay 52 based on the post-relay voltage Vry after a predetermined voltage-boost time TA has elapsed from time ts when application of the boosted voltage VS by the overvoltage processing started while the reverse connection protection relay 52 is turned OFF. The monitoring circuit 40 then turns ON the reverse connection protection relay 52, and detects the OFF-fixed abnormality of the reverse connection protection relay 52 based on the post-relay voltage Vry after a predetermined voltage-drop time TD has elapsed from time te when application of the boosted voltage VS by the overvoltage processing ended.

[0051] [Detection method 2] In detection method 2, the potential difference threshold ΔVth is set to a value slightly larger than 0 [V], which indicates that both ends of the reverse connection protection relay 52 are at the same potential. Then, when the reverse connection protection relay 52 is normal, a predetermined potential difference increase time Taa is set based on the time for the potential difference ΔV across the relay to increase to the potential difference threshold ΔVth after time ts. Also, a predetermined potential difference reduction time Tdd is set based on the time for the potential difference ΔV across the relay to reduce to the potential difference threshold ΔVth after time te. Detection errors and variations are taken into consideration when setting the potential difference increase time Taa and the potential difference reduction time Tdd.

[0052] At the timing of stuck-ON detection, if the potential difference ΔV across the relay after the potential difference expansion time Taa from time ts is equal to or greater than the potential difference threshold ΔVth, it is determined to be normal, as shown in Fig. 3. If the potential difference ΔV across the relay after the potential difference expansion time Taa from time ts is smaller than the potential difference threshold ΔVth, it is determined to be stuck-ON.

[0053] At the time of OFF-stuck detection, if the potential difference ΔV across the relay after the potential difference reduction time Tdd from time te is equal to or smaller than the potential difference threshold ΔVth, it is determined to be normal, as shown in Fig. 3. If the potential difference ΔV across the relay after the potential difference reduction time Tdd from time te is greater than the potential difference threshold ΔVth, it is determined to be OFF-stuck abnormal, as shown in Fig. 5.

[0054] In this way, in detection method 2, the monitoring circuit 40 detects the ON-fixed abnormality of the reverse connection protection relay 52 based on the potential difference ΔV across the relay after a predetermined potential difference increasing time Taa has elapsed from the time ts when the application of the boosted voltage VS by the overvoltage processing started while the reverse connection protection relay 52 is turned OFF. The monitoring circuit 40 then turns ON the reverse connection protection relay 52, and detects the OFF-fixed abnormality of the reverse connection protection relay 52 based on the potential difference ΔV across the relay after a predetermined potential difference reducing time Tdd has elapsed from the time te when the application of the boosted voltage VS by the overvoltage processing ended.

[0055] In detection method 1, it takes time for the relay post-voltage Vry to rise to the voltage threshold Vth in detecting an ON-stick abnormality. In particular, when the battery voltage Vb is low, charging takes time, and abnormality detection is delayed. In contrast, in detection method 2, when application of the boosted voltage VS by the overboost process begins, the relay post-voltage difference ΔV immediately reaches the potential difference threshold ΔVth under normal conditions, regardless of the battery voltage Vb. In other words, the potential difference increase time Taa in detection method 2 can be set shorter than the boost time TA in detection method 1, which has the advantage of allowing for earlier detection of an ON-stick abnormality.

[0056] (summary) As described above, in this embodiment, the target voltage of the overboost process by the boost circuit 20 is set sufficiently higher than the battery voltage Vb, so that the voltage can be correctly distinguished between normal and stuck abnormal conditions. Therefore, the initial check of the reverse connection protection relay 52 can be properly performed.

[0057] (Other embodiments) (a) The load of the power supply device 10 is not limited to the three-phase motor 80, but may be a single-phase motor or a multi-phase motor other than three-phase, or may be an actuator other than a motor or other load. The number of switching elements in the upper and lower arms of the inverter is not limited to three sets, but may be one set or more. As the "power converter", an H-bridge circuit or the like may be used instead of a multi-phase inverter.

[0058] (b) The reverse connection protection relay 52 and other switching elements are not limited to MOSFETs and may be composed of other types of transistors, etc.

[0059] (c) As described in the above embodiment, at least some of the elements constituting the monitoring circuit 40 may be provided inside an ASIC.

[0060] The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the present invention.

[0061] The control unit and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described in the present disclosure may be realized by one or more special-purpose computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by a computer. [Explanation of symbols]

[0062] 15 Battery, 20... Boost circuit, 30... Precharge circuit, 40... Monitoring circuit, 52 Reverse polarity protection relay, 55 Input capacitor, 60... Inverter (power converter), 61-66... ​​Switching element, 80 Motor (load), Lp···Power line, Lg···Ground line.

Claims

1. a power converter (60) including one or more pairs of upper and lower arm switching elements (61-66) connected in series between a power supply line (Lp) connected to a battery (15) and a ground line (Lg), for converting DC power of the battery and supplying the converted power to a load (80); an input capacitor (55) connected in parallel with the battery on the battery side of the power converter; a boost circuit (20) that boosts an input voltage supplied from the battery to a target voltage; a precharge circuit (30) that applies the boosted voltage output by the boost circuit to a high potential side electrode of the input capacitor to precharge it; a reverse connection protection relay (52) that is provided in the power supply line between the battery and the input capacitor, has a diode connected in parallel to conduct a current from the battery side to the power converter side, and cuts off the current from the power converter side to the battery side when the relay is turned off; Equipped with A power supply device in which a power supply relay that cuts off a current from the battery side to the power converter side when the power supply relay is turned off is not provided in the power supply line between the battery and the reverse connection protection relay, The power supply device further includes a monitoring circuit (40) for detecting an ON-fixed abnormality or an OFF-fixed abnormality of the reverse connection protection relay during an initial check of the power supply device, During an initial check, the boost circuit performs an over-boost process to temporarily raise the target voltage above the value during normal operation, the pre-charge circuit applies the boosted voltage (VS) by the over-boost process to the high-potential electrode of the input capacitor, and the monitoring circuit detects an ON-stuck abnormality or an OFF-stuck abnormality of the reverse connection protection relay in accordance with a post-relay voltage (Vry) which is the voltage on the power converter side of the reverse connection protection relay.

2. The monitoring circuit includes: With the reverse connection protection relay in an OFF state, a fixed ON abnormality of the reverse connection protection relay is detected based on a voltage after the relay after a predetermined boost time (TA) has elapsed since the time (ts) when the application of the boosted voltage by the overboost process is started, Then, the reverse connection protection relay is turned on, and an OFF-fixed abnormality of the reverse connection protection relay is detected based on the post-relay voltage after a predetermined voltage drop time (TD) has elapsed since the application of the boosted voltage by the overvoltage processing is ended (te). The power supply device according to claim 1.

3. If the potential difference obtained by subtracting the battery voltage (Vb) from the relay voltage is defined as the relay front-rear potential difference (ΔV), then The monitoring circuit includes: With the reverse connection protection relay in an OFF state, a fixed ON abnormality of the reverse connection protection relay is detected based on a potential difference across the relay after a predetermined potential difference increase time (Taa) has elapsed since the time (ts) when the application of the boosted voltage by the overvoltage processing is started, Then, the reverse connection protection relay is turned on, and an OFF-fixed abnormality of the reverse connection protection relay is detected based on the potential difference across the relay after a predetermined potential difference reduction time (Tdd) has elapsed since the application of the boosted voltage by the overvoltage processing is ended (te). The power supply device according to claim 1.

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