JP4830557B2 - Power control device - Google Patents

Description

  The present invention relates to a power source control device capable of determining relay welding and failure determination of a voltage sensor used for welding determination.

  Recently, hybrid vehicles and electric vehicles have attracted attention as environmentally friendly vehicles. A hybrid vehicle is a vehicle that uses a DC power source, an inverter, and a motor driven by the inverter as a power source in addition to a conventional engine. In other words, a power source is obtained by driving the engine, a DC voltage from a DC power source is converted into an AC voltage by an inverter, and a motor is rotated by the converted AC voltage to obtain a power source.

  An electric vehicle is a vehicle that uses a DC power source, an inverter, and a motor driven by the inverter as a power source.

  That is, a hybrid vehicle and an electric vehicle are equipped with a motor drive device including a DC power source and an inverter. A capacitor is provided on the input side of the inverter in order to supply a DC voltage from which noise has been removed to the inverter. A system relay is provided between the DC power supply and the inverter (see, for example, Patent Documents 1 to 4).

Specifically, in Patent Document 1, the resistor 142 and the first system relay 140 connected in series to the positive electrode of the battery 130 and the resistor R and the first system relay 140 are connected in parallel to the positive electrode of the battery 130. The second system relay 150 and the third system relay 160 connected to the negative electrode of the battery 130 are disclosed. Then, based on the voltage VM across the capacitor 12 acquired by the voltmeter 170 when the capacitor 12 is discharged, the welding of the first and second system relays is determined.
JP 2004-303691 A JP 2004-311132 A International Publication WO01 / 060652 Pamphlet JP-A-8-212895

  However, since the method disclosed in Patent Document 1 determines the welding of individual system relays based on the detection value of the voltmeter 170, if any failure has occurred in the voltmeter 170 itself, the system is erroneously detected. Relay welding may be determined.

  In order to prevent erroneous welding determination in such a case, it is required that the failure of the voltmeter be accurately identified from the welding determination of the system relay.

  However, all of the above patent documents only disclose a method for determining the welding of the system relay based on the detection value from the voltage detection means or the current detection means, and a technique for determining the failure of these detection means. No consideration has been given to. Therefore, it cannot be avoided that the system relay is erroneously determined to be welded.

  Therefore, the present invention has been made to solve the above-described problems, and an object thereof is to provide a power supply control device capable of preventing erroneous determination of relay welding.

  According to the present invention, the power supply control device includes a first relay connected to one pole of the DC power supply, a second relay connected to the other pole of the DC power supply, and one terminal via the first relay. A capacitive element connected to one pole side of the DC power supply and having the other terminal connected to the other pole side of the DC power supply via a second relay, and a first voltage sensor for detecting a voltage across the capacitor element; A second voltage sensor for detecting a DC voltage from the DC power source, a current sensor for detecting a DC current flowing out from the DC power source, and a voltage detected by the first and second voltage sensors and a current sensor Welding determination means for determining welding of the first and second relays based on the current; the voltage detected by the first and second voltage sensors; and the first and second based on the current detected by the current sensor. And a determining failure determining means failure of voltage sensor.

  Preferably, the welding determination means turns off only the second relay and discharges the capacitive element so that a voltage difference lower than a predetermined reference value is detected by the first voltage sensor and the second voltage sensor. If a current sensor detects a current that is greater than or equal to a predetermined threshold value and is detected by a current sensor, it is determined that the second relay is welded. The failure determination means detects a voltage difference lower than a predetermined reference value between the detection value of the first voltage sensor and the detection value of the second voltage sensor when only the second relay is turned off, and When a current lower than a predetermined threshold is detected by the current sensor, it is determined that at least one of the first and second voltage sensors has failed.

  Preferably, in the welding determination unit, when only the second relay is turned on, a voltage equal to or higher than a predetermined reference value is detected by the first voltage sensor, and a current equal to or higher than a predetermined threshold is detected by the current sensor. It is determined that the first relay is welded. When the first voltage sensor detects a voltage equal to or higher than a predetermined reference value when only the second relay is turned on, and the current sensor detects a current lower than a predetermined threshold, It is determined that one voltage sensor has failed.

  Preferably, the welding determination means has a voltage difference lower than a predetermined reference value when the first and second relays are turned off to discharge the capacitive element, and the detected value of the first voltage sensor and the second voltage sensor. If the current sensor detects a current greater than or equal to a predetermined threshold value and a current greater than or equal to a predetermined threshold, it is determined that the first and second relays are welded. The failure determination means has a voltage difference lower than a predetermined reference value when the first and second relays are turned off to discharge the capacitive element, so that the detected value of the first voltage sensor and the detected value of the second voltage sensor And a current below a predetermined threshold is detected by the current sensor, it is determined that at least one of the first and second voltage sensors has failed.

  According to this invention, it is possible to prevent relay welding from being erroneously determined due to a failure of a voltage sensor used for relay welding determination. Further, in addition to the relay welding determination, it is possible to determine a failure of the voltage sensor. As a result, the reliability of the power supply control device can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

[Embodiment 1]
1 is a schematic block diagram of a motor drive device including a power supply control device according to Embodiment 1 of the present invention.

  Referring to FIG. 1, motor drive device 100 includes DC power supply B, system relays SMRB, SMRP, SMRG, resistor R, capacitor C2, inverter 20, current sensors 12, 24, voltage sensor 10, 13, a control device 30, a welding warning lamp 40, and a sensor failure warning lamp 42.

  AC motor M1 is a drive motor for generating torque for driving drive wheels of a hybrid vehicle or an electric vehicle. The AC motor M1 is a motor that has a function of a generator driven by an engine and operates as an electric motor for the engine, and can start the engine, for example.

  System relay SMRB is connected in series between the positive electrode of DC power supply B and the positive electrode of capacitor C2. System relay SMRG is connected in series between the negative electrode of DC power supply B and the negative electrode of capacitor C2. System relay SMRP and resistor R are connected in parallel to system relay SMRG between the negative electrode of DC power supply B and the negative electrode of capacitor C2.

  The capacitor C <b> 2 is provided on the input side of the inverter 20. Inverter 20 includes U-phase arm 21, V-phase arm 22, and W-phase arm 23. U-phase arm 21, V-phase arm 22 and W-phase arm 23 are provided in parallel between the power supply line and the earth line.

  U-phase arm 21 includes IGBT elements Q1 and Q2 connected in series. V-phase arm 22 includes IGBT elements Q3 and Q4 connected in series. W-phase arm 23 includes IGBT elements Q5 and Q6 connected in series. Also, diodes D1 to D6 that flow current from the emitter side to the collector side are connected between the collectors and emitters of the IGBT elements Q1 to Q6, respectively.

  An intermediate point of each phase arm is connected to each phase end of each phase coil of AC motor M1. In other words, AC motor M1 is a three-phase permanent magnet motor, and is configured such that one end of three coils of U, V, and W phases is commonly connected to the midpoint. The other end of the U-phase coil is at the intermediate point between the IGBT elements Q1 and Q2, the other end of the V-phase coil is at the intermediate point between the IGBT elements Q3 and Q4, and the other end of the W-phase coil is at the intermediate point between the IGBT elements Q5 and Q6. Each is connected.

  The DC power source B is composed of a secondary battery such as nickel metal hydride or lithium ion. Current sensor 12 detects DC current Ib flowing through DC power supply B, and outputs the detected DC current Ib to control device 30. Voltage sensor 10 detects DC voltage Vb from DC power supply B and outputs the detected DC voltage Vb to control device 30.

  System relays SMRB, SMRP, SMRG are turned on / off by signals SEB, SEP, SEG from control device 30, respectively. More specifically, the system relays SMRB, SMRP, SMRG are turned on (corresponding to a conductive state) by H (logic high) signals SEB, SEP, SEG, respectively, and L (logic low) signals SEB, SEP, It is turned off (corresponding to a non-conducting state) by SEG.

  Capacitor C <b> 2 smoothes DC voltage Vb supplied from DC power supply B and supplies it to inverter 20. The voltage sensor 13 detects the voltage Vm across the capacitor C2 and outputs the detected voltage Vm to the control device 30.

  Inverter 20 converts the DC voltage from capacitor C2 into an AC voltage in accordance with signal PWM from control device 30 to drive AC motor M1, and converts the AC voltage generated by AC motor M1 into a DC voltage. The converted DC voltage is supplied to the DC power source B through the capacitor C2.

  Current sensor 24 detects motor current MCRT flowing through AC motor M1 and outputs the detected motor current MCRT to control device 30.

  Control device 30 receives DC current Ib from current sensor 12, DC voltage Vb from voltage sensor 10, voltage Vm from voltage sensor 13, and an external ECU (Electrical Control Unit) provided outside motor drive device 100. ), A signal IG from an ignition key (not shown), and a motor current MCRT from the current sensor 24.

  When control device 30 receives H-level signal IG from the ignition key, control device 30 controls system relays SMRB, SMRP, and SMRG so as to precharge capacitor C2 by a method described later.

  Then, after completion of precharging of capacitor C2, control device 30 generates signal PWM based on voltage Vm, torque command value TR, and motor current MCRT, and generates the generated signal PWM to IGBT elements Q1-Q6 of inverter 20. Output.

  More specifically, control device 30 calculates a voltage to be applied to each phase coil of AC motor M1 based on voltage Vm, torque command value TR, and motor current MCRT, and based on the calculation result, IGBT A signal PWM for actually turning on / off the elements Q1 to Q6 is generated.

  Further, when receiving the L level signal IG from the ignition key, the control device 30 starts discharging the charge stored in the capacitor C2 by a method described later. Specifically, the discharge of the capacitor C2 generates a signal PWM for turning on / off the IGBT elements Q1 to Q6 of the inverter 20 so that the electric charge stored in the capacitor C2 is consumed by the copper loss of the AC motor M1. The generated signal PWM is output to the IGBT elements Q1 to Q6.

  When discharging of capacitor C2 is started, control device 30 converts voltage Vm received from voltage sensor 13, DC voltage Vb received from voltage sensor 10 and DC current Ib received from current sensor 12 by a method described later. Based on this, welding of system relay SMRG is determined. When it is determined that system relay SMRG is welded, control device 30 generates signal EMG1 for lighting welding warning lamp 40 and outputs the signal to welding warning lamp 40. The welding warning lamp 40 is lit in response to a signal EMG1 from the control device 30.

  Further, control device 30 performs voltage Vm received from voltage sensor 13, DC voltage Vb received from voltage sensor 10, and DC received from current sensor 12 by the method described later when performing the above-described welding determination of system relay SMRB. The failure of the voltage sensors 10 and 13 is determined based on the current Ib. When it is determined that at least one of the voltage sensors 10 and 13 has failed, the control device 30 generates a signal EMG2 for lighting the sensor failure warning lamp 42 and outputs the signal EMG2 to the sensor failure warning lamp 42. The sensor failure warning lamp 42 is turned on in response to the signal EMG2 from the control device 30.

  That is, the power supply control device according to the present invention performs the welding determination of system relay SMRG and the failure determination of voltage sensors 10 and 13 during the period of discharging capacitor C2. Then, either the welding warning lamp 40 or the sensor failure warning lamp 42 is turned on according to the determination result.

  FIG. 2 is a timing chart for explaining the welding determination operation of system relay SMRG and the failure determination operation of voltage sensors 10 and 13 shown in FIG.

  Referring to FIG. 2, when signal IG from the external ECU is switched from L level to H level at timing t1 and the ignition key is turned on, control device 30 generates only H level signal SEP at timing t2. To the system relay SMRP. Thereby, only system relay SMRP is turned on (corresponding to a conductive state).

  Next, control device 30 generates H-level signal SEB at subsequent timing t3 and outputs it to system relay SMRB. Thus, DC power supply B is connected to capacitor C2 via system relay SMRB, system relay SMRP and resistor R. Then, the DC power source B starts precharging the capacitor C2.

  When the precharge of the capacitor C2 is started at the timing t3 and the DC voltage Vb is supplied from the DC power source B to the capacitor C2, the DC current Ib rises steeply and then gradually decreases. The voltage Vm gradually increases and reaches a predetermined precharge voltage. The predetermined precharge voltage is substantially equal to the DC voltage Vb from the DC power supply B.

  If it is determined that voltage Vm has reached the precharge voltage, control device 30 generates H level signal SEG at timing t4 and outputs it to system relay SMRG, and generates L level signal SEP at timing t5. To the system relay SMRP. When H level signal SEG is output to system relay SMRG at timing t4, DC power supply B supplies DC voltage Vb to capacitor C2 via system relays SMRB and SMRG, so that precharging of capacitor C2 ends. .

  With the configuration as described above, the system relay SMRP is turned off after the system relay SMRG is turned on, so that an inrush current to the capacitor C2 can be prevented and a DC voltage can be supplied from the DC power supply B to the capacitor C2. Capacitor C <b> 2 smoothes DC voltage Vb from DC power supply B and supplies it to inverter 20.

  Next, when the signal IG from the external ECU is switched from the H level to the L level at timing t6 in response to the stop of the vehicle system and the ignition key is turned off, the control device 30 causes the capacitor C2 at the subsequent timing t7. The signal DCH for instructing execution of the discharge is switched from the L level to the H level. Thereby, discharging of the capacitor C2 is started.

  At this time, control device 30 generates an L level signal SEG at timing t7 and outputs it to system relay SMRG. As a result, system relay SMRG is turned off and only system relay SMRB is turned on.

  Here, control device 30 determines whether or not system relay SMRG is welded based on voltage Vm from voltage sensor 13 and DC voltage Vb from voltage sensor 10 after timing t7 when discharge of capacitor C2 is started. Determine whether.

  More specifically, when the system relay SMRG is turned off at timing t7 and the DC power source B is cut off from the capacitor C2, a DC voltage is supplied from the capacitor C2 to the inverter 20 and discharging of the capacitor C2 is started. Decreases gradually from the precharge voltage (substantially DC voltage Vb) as shown by a curve k5.

  However, if system relay SMRG is welded, capacitor C2 is connected to DC power supply B via system relay SMRB and system relay SMRG, and is supplied with power from DC power supply B. In this case, the voltage Vm maintains a higher value than the voltage level indicated by the curve k5, as indicated by the curve k3.

  Therefore, control device 30 determines welding of system relay SMRG based on voltage Vm and DC voltage Vb in discharging capacitor C2 performed when the vehicle system is stopped. Specifically, control device 30 determines whether or not system relay SMRG is welded based on the voltage difference between voltage Vm from voltage sensor 13 and DC voltage Vb from voltage sensor 10 in period T1 after timing t7. Determine whether.

  Specifically, after the system relay SMRG is turned off at timing t7, as indicated by a curve k5, a predetermined reference value ΔVstd or more is present between the voltage Vm from the voltage sensor 13 and the DC voltage Vb from the voltage sensor 10. When the voltage difference is detected, control device 30 determines that system relay SMRG is not welded.

  On the other hand, when a voltage difference lower than a predetermined reference value ΔVstd is detected between the voltage Vm from the voltage sensor 13 and the DC voltage Vb from the voltage sensor 10 during the period T1, as shown by the curve k3, the control is performed. Device 30 determines that system relay SMRG is welded.

  However, in the method for determining the welding of the system relay SMRG based on the voltages Vm and Vb from the voltage sensors 13 and 10 as described above, if one of the voltage sensors 10 and 13 fails, the system relay SMRG itself Although it is normal, there is a possibility that it is determined that it is welded by mistake.

  Specifically, for example, when a failure occurs in the voltage sensor 13, the voltage Vm from the voltage sensor 13 has a high voltage value as shown by the curve k4, although the capacitor C2 is discharged after time t7. Continue to be fixed to. Therefore, control device 30 determines that system relay SMRG is welded, assuming that the voltage difference between voltage Vm and DC voltage Vb is less than reference value ΔVstd.

  Although illustration is omitted, even when a failure occurs in the voltage sensor 10, similarly, the system relay SMRG is welded on the assumption that the voltage difference between the voltage Vm and the DC voltage Vb is less than the predetermined reference value ΔVstd. May be determined.

  In view of this, the power supply control device according to the present invention, in order to prevent erroneous determination of the welding of the system relay due to such a failure of the voltage sensor, together with the welding determination operation of the system relay, The configuration is such that the failure determination operation is also executed. According to this, it is possible to prevent erroneous determination of welding of the system relay and to detect a failure of the voltage sensor.

  Specifically, in the period T1 after timing t7, the control device 30 adds the direct current from the current sensor 12 in addition to the voltage difference between the voltage Vm from the voltage sensor 13 and the direct current voltage Vb from the voltage sensor 10 described above. Based on Ib, it is determined whether or not system relay SMRG is welded and whether or not voltage sensors 13 and 10 are out of order.

  Specifically, when system relay SMRG is turned off at timing t7, DC current Ib is set to a constant value (substantially zero) as shown by curve k2 in response to disconnection of DC power supply B from capacitor C2. Become.

  However, if system relay SMRG is welded, DC power supply B is connected to capacitor C2 via system relay SMRB and system relay SMRG, and supplies power to capacitor C2 being discharged. In this case, the direct current Ib gradually increases as shown by the curve k1.

  Therefore, the controller 30 discharges the capacitor C2, based on the voltage difference between the voltage Vm from the voltage sensor 13 and the DC voltage Vb from the voltage sensor 10 and the DC current Ib from the current sensor 12, based on the system relay SMRG. The welding of the voltage sensors 13 and 10 is determined.

  Specifically, in the period T1 from the timing t7 to the timing t8, after the system relay SMRG is turned off at the timing t7, the voltage Vm from the voltage sensor 13 and the DC voltage from the voltage sensor 10 are shown as a curve k5. When a voltage difference equal to or greater than a predetermined reference value ΔVstd is detected with respect to Vb, control device 30 determines that system relay SMRG is not welded.

  On the other hand, during the period T1, as indicated by the curve k3, a voltage difference below a predetermined reference value ΔVstd is detected between the voltage Vm from the voltage sensor 13 and the DC voltage Vb from the voltage sensor 10. And when the direct current Ib more than the predetermined threshold value Istd is detected by the current sensor 12 as shown by the curve k1, the control device 30 determines that the system relay SMRG is welded.

  Further, during this period T1, the control device 30 detects a voltage difference below a predetermined reference value ΔVstd between the voltage Vm from the voltage sensor 13 and the DC voltage Vb from the voltage sensor 10 as indicated by a curve k4. When the current sensor 12 detects a DC current Ib that falls below a predetermined threshold value Istd as indicated by the curve k2, the control device 30 indicates that at least one of the voltage sensors 10, 13 has failed. It is determined that

  As described above, according to the power supply control device of the present invention, it is possible to prevent the system relay SMRG from being erroneously determined to be welded, so that the reliability can be improved with respect to the conventional welding determination method. Furthermore, it is possible to determine the failure of the voltage sensors 10 and 13.

  FIG. 3 is a flowchart for explaining an operation for determining welding of system relay SMRG shown in FIG. 1 and an operation for determining failure of voltage sensors 13 and 10.

  Referring to FIG. 3, when the ignition key is turned off (step S01), control device 30 generates and outputs L level signal SEG to system relay SMRG, and turns off only system relay SMRG (step S02). ). Further, control device 30 starts discharging capacitor C2 in response to switching of signal DCH to the H level (step S02).

  When discharging of capacitor C2 is started, control device 30 receives DC current Ib from current sensor 12 (step S04), receives voltage Vm from voltage sensor 13, and receives DC voltage Vb from voltage sensor 10 (step S04). S05). In parallel with acquiring the detection value from each sensor, the control device 30 counts the elapsed time from the timing when the discharge of the capacitor C2 is started using a timing unit (not shown).

  The control device 30 then determines the voltage difference | Vm between the voltage Vm from the voltage sensor 13 and the DC voltage Vb from the voltage sensor 10 at the timing when the period T1 has elapsed from the timing when the discharge of the capacitor C2 is started (step S06). It is determined whether −Vb | is greater than or equal to a reference value ΔVstd (step S07).

  In step S07, when voltage difference | Vm−Vb | is equal to or larger than reference value ΔVstd, control device 30 determines that system relay SMRG is normal (not welded) (step S08).

  On the other hand, when the voltage difference | Vm−Vb | is less than the reference value ΔVstd in step S07, the control device 30 subsequently determines whether or not the direct current Ib is equal to or greater than the threshold value Istd (step S09).

  In step S09, when the direct current Ib is greater than or equal to the threshold value Istd, that is, when the voltage difference | Vm−Vb | is less than a predetermined reference value ΔVstd and the direct current Ib is greater than or equal to the threshold value Istd, Control device 30 determines that system relay SMRG is welded (step S10). Then, control device 30 generates signal EMG1 and outputs it to welding warning lamp 40. The welding warning lamp 40 is turned on in response to the signal EMG1 (step S11).

  On the other hand, in step S09, when the direct current Ib is lower than the threshold value Istd, that is, when the voltage difference | Vm−Vb | is lower than a predetermined reference value ΔVstd, and the direct current Ib is lower than the threshold value Istd. At this time, the control device 30 determines that at least one of the voltage sensors 13 and 10 has failed (step S12). Then, the control device 30 generates the signal EMG2 and outputs it to the sensor failure warning lamp 42. The sensor failure warning lamp 42 is turned on in response to the signal EMG2 (step S13).

  Note that the determination of welding of the system relay SMRG by the control device 30 is actually executed by the CPU, and the CPU reads a program including each step shown in FIG. 3 from the ROM and executes each step shown in FIG. Determine welding of relay SMRG.

  Therefore, the ROM corresponds to a computer (CPU) readable recording medium in which a program for causing a computer (CPU) to execute control for determining welding of the system relay SMRG is recorded.

  In the present embodiment, the operation for determining welding of system relay SMRG has been described. However, it is obvious that the welding of system relay SMRB can also be determined by performing the same operation. Specifically, the welding of the system relay SMRB can be determined by turning off only the system relay SMRB and discharging the capacitor C2.

  As described above, according to the first embodiment of the present invention, it is possible to prevent the system relay from being erroneously determined to be welded due to the failure of the voltage sensor.

  Furthermore, it becomes possible to determine the failure of the voltage sensor in conjunction with the determination of welding of the system relay.

[Embodiment 2]
FIG. 4 is a timing chart for explaining the operation of determining welding of system relay SMRB shown in FIG. As described below, welding determination of system relay SMRB is executed in precharging of capacitor C2 that is performed when the vehicle system is started.

  Referring to FIG. 4, when the ignition key is turned on at timing t1, only system relay SMRP is turned on in a subsequent period T2 from timing t2 to timing t20, and welding of system relay SMRB is determined. Further, in this period T2, the failure of the voltage sensors 13, 10 is determined.

  More specifically, when the H level signal SEP is generated at timing t2 after the ignition key is turned on at timing t1 and only the system relay SMRP is turned on, the voltage from the voltage sensor 13 is output in a period T2 after timing t2. Based on Vm and DC current Ib from current sensor 12, welding of system relay SMRB is determined.

  Specifically, when only system relay SMRP is turned on at timing t2, if system relay SMRB is welded, voltage Vm across capacitor C2 gradually increases as shown by curve k14, and thereafter , And changes so as to maintain a predetermined precharge voltage.

  On the other hand, when system relay SMRB is not welded, voltage Vm does not increase after timing t2, as shown by curve k15, and maintains a constant value.

  Therefore, control device 30 determines that system relay SMRB is not welded when voltage sensor 13 detects voltage Vm that is equal to or higher than a predetermined reference value Vstd in period T2 after timing t2.

  On the other hand, when voltage Vm lower than predetermined reference value Vstd is detected by voltage sensor 13 during period T2, control device 30 determines that system relay SMRB is welded.

  However, in the method of determining the welding of the system relay SMRB based on the voltage Vm from the voltage sensor 13, if the failure occurs in the voltage sensor 13, the system relay SMRB itself is normal, but the welding is erroneously performed. May be determined.

  That is, when the voltage sensor 13 is out of order, the voltage Vm from the voltage sensor 13 is fixed to a high voltage value after time t2, as indicated by the curve k14. Therefore, control device 30 determines that system relay SMRB is welded, assuming that voltage Vm is equal to or higher than reference value Vstd. As a result, it is determined that the system relay SMRB is erroneously welded due to the failure of the voltage sensor 13.

  Therefore, in order to prevent such a misjudgment, the control device 30 determines the system based on the direct current Ib from the current sensor 12 in addition to the voltage Vm from the voltage sensor 13 in the period T2 after the timing t2. It is determined whether relay SMRB is welded and whether voltage sensor 13 is faulty.

  Specifically, when only system relay SMRP is turned on at timing t2, DC current Ib becomes a constant value (substantially zero) as shown by curve k11.

  However, if system relay SMRB is welded, DC power supply B is connected to capacitor C2 via system relay SMRB and system relay SMRP, and supplies power to capacitor C2. In this case, as indicated by the curve k10, the direct current Ib increases sharply and then decreases.

  Therefore, control device 30 determines whether or not system relay SMRB is welded and determines whether or not voltage sensor 13 is faulty based on voltage Vm from voltage sensor 13 and DC current Ib from current sensor 12.

  Specifically, in the period T2 after the timing t2, after the system relay SMRP is turned on at the timing t2, the voltage sensor 13 detects a voltage Vm lower than a predetermined reference value Vstd as shown by a curve k15. Control device 30 determines that system relay SMRB is not welded.

  When it is determined that system relay SMRB is not welded, control device 30 generates H level signal SEB at subsequent timing t3 and outputs it to system relay SMRB. Thus, DC power supply B is connected to capacitor C2 via system relay SMRB, system relay SMRP, and resistor R. Then, the DC power source B starts precharging the capacitor C2. When it is determined that voltage Vm from voltage sensor 13 has reached the precharge voltage, control device 30 generates H level signal SEG at timing t4 and outputs it to system relay SMRG. A level signal SEP is generated and output to the system relay SMRP.

  On the other hand, during the period T2, as indicated by the curve k13, when the voltage Vm equal to or higher than the predetermined reference value Vstd is detected by the voltage sensor 13, and as indicated by the curve k10, the predetermined threshold value Istd or higher. When the direct current Ib is detected by the current sensor 12, the control device 30 determines that the system relay SMRB is welded.

  Furthermore, in the period T2, the control device 30 is when the voltage sensor 13 detects a voltage Vm that is equal to or higher than a predetermined reference value Vtsd as indicated by a curve k14, and as indicated by a curve k11. When the direct current Ib below the predetermined threshold value Istd is detected by the current sensor 12, the control device 30 determines that the voltage sensor 13 has failed.

  FIG. 5 is a flowchart for explaining an operation for determining welding of system relay SMRG shown in FIG. 4 and an operation for determining failure of voltage sensor 13.

  Referring to FIG. 5, when the ignition key is turned on (step S21), control device 30 generates H level signal SEP and outputs it to system relay SMRP, and turns on only system relay SMRP (step S22). ).

  Further, control device 30 receives DC current Ib from current sensor 12 (step S23) and also receives voltage Vm from voltage sensor 13 (step S24). In parallel with acquiring the detection value from each sensor, the control device 30 counts the elapsed time from the timing when only the system relay SMRP is turned on by using a timing unit (not shown).

  Then, control device 30 determines whether or not voltage Vm from voltage sensor 13 is equal to or higher than reference value Vstd at the timing when period T2 has elapsed from the timing when only system relay SMRP is turned on (step S25). S26).

  In step S26, when voltage Vm is lower than reference value Vstd, control device 30 determines that system relay SMRB is normal (not welded) (step S27). Furthermore, control device 30 generates H level signal SEB and turns on system relay SMRB. Thus, DC power supply B is connected to capacitor C2 via system relay SMRB, system relay SMRP and resistor R, and starts precharging of capacitor C2.

  On the other hand, when the voltage Vm is greater than or equal to the reference value ΔVstd in step S26, the control device 30 subsequently determines whether or not the direct current Ib is greater than or equal to the threshold value Istd (step S28).

  In step S28, when the direct current Ib is equal to or greater than the threshold value Istd, that is, when the voltage Vm is equal to or greater than the predetermined reference value ΔVstd and the direct current Ib is equal to or greater than the threshold value Istd, the control device 30 It is determined that SMRB is welded (step S29). Then, control device 30 generates signal EMG1 and outputs it to welding warning lamp 40. The welding warning lamp 40 is turned on in response to the signal EMG1 (step S30).

  On the other hand, when the direct current Ib is lower than the threshold value Istd in step S28, that is, when the voltage Vm is equal to or higher than the predetermined reference value ΔVstd and the direct current Ib is lower than the threshold value Istd, the control device 30 It is determined that the voltage sensor 13 has failed (step S31). Then, the control device 30 generates the signal EMG2 and outputs it to the sensor failure warning lamp 42. The sensor failure warning lamp 42 is turned on according to the signal EMG2 (step S32).

  Note that the determination of welding of the system relay SMRB by the control device 30 is actually executed by the CPU, and the CPU reads a program including each step shown in FIG. 5 from the ROM and executes each step shown in FIG. Determine welding of relay SMRB.

  Therefore, the ROM corresponds to a computer (CPU) readable recording medium that records a program for causing the computer (CPU) to execute control for determining welding of the system relay SMRB.

  As described above, according to the second embodiment of the present invention, it is possible to prevent the system relay from being erroneously determined to be welded due to the failure of the voltage sensor.

  Furthermore, it becomes possible to determine the failure of the voltage sensor in conjunction with the determination of welding of the system relay.

[Embodiment 3]
FIG. 6 illustrates an operation for determining welding between system relay SMRB arranged on the positive electrode side of DC power supply B shown in FIG. 1 and system relays SMRG and SMRP arranged on the negative electrode side of DC power supply B. It is a timing chart.

  Referring to FIG. 6, after the ignition key is turned on at timing t1, in a period T3 from timing t10 to timing t11, all of system relays SMRB, SMRP, SMRG are turned off and capacitor C2 is discharged. . Then, when this capacitor C2 is discharged, the welding between the system relay SMRB and the system relays SMRP, SMRG is determined.

  More specifically, when the ignition key is turned on at timing t1, the signal DCH for instructing the discharge of the capacitor C2 is detected in response to the voltage sensor 13 detecting a voltage Vm that is equal to or higher than a predetermined reference value Vstd1. The L level is switched to the H level. Then, in a period T3 after the timing t10 when the discharge of the capacitor C2 is started, the system relay SMRB and the system relay SMRB are based on the voltage Vm from the voltage sensor 13, the DC voltage Vb from the voltage sensor 10, and the DC current Ib from the current sensor 12. Welding between system relays SMRP and SMRG is determined.

  Specifically, when discharge of the capacitor C2 is started at the timing t10, if the system relay SMRB and the system relays SMRP and SMRG are not welded, the voltage Vm across the capacitor C2 is represented by a curve k23. As shown, the voltage gradually decreases from a predetermined precharge voltage, and then changes so as to maintain substantially zero.

  On the other hand, when system relay SMRB and system relays SMRP and SMRG are welded, DC power supply B is connected to capacitor C2 via system relay SMRB and system relay SMRP (or SMRG), and from DC power supply B Electric power is supplied to the capacitor C2. Therefore, the voltage Vm does not decrease after the timing t10 and maintains a constant value as indicated by a curve k25.

  Therefore, in the period T3 after the timing t10, the control device 30 has a voltage equal to or higher than a predetermined reference value ΔVstd between the voltage Vm from the voltage sensor 13 and the DC voltage Vb from the voltage sensor 10, as indicated by a curve k23. When the difference is detected, control device 30 determines that system relay SMRB and system relays SMRP and SMRG are not welded.

  On the other hand, when a voltage difference lower than a predetermined reference value ΔVstd is detected between the voltage Vm from the voltage sensor 13 and the DC voltage Vb from the voltage sensor 10 during the period T3, as shown by the curve k25, the control is performed. Device 30 determines that system relay SMRB and system relays SMRP and SMRG are welded.

  However, when at least one of the voltage sensors 13 and 10 is out of order, it is determined that the controller 30 is erroneously welded even though the system relay SMRB and the system relays SMRP and SMRG are normal. there's a possibility that.

  Specifically, for example, when the voltage sensor 13 is out of order, the voltage Vm from the voltage sensor 13 is fixed to a high value after time t10 as shown by a curve k24. Therefore, control device 30 assumes that there is a voltage difference equal to or greater than a predetermined reference value ΔVstd between voltage Vm from voltage sensor 13 and DC voltage Vb from voltage sensor 10, and system relay SMRB and system relays SMRP and SMRG It is determined that the gap is welded.

  Therefore, in order to prevent such a misjudgment, the control device 30 adds the DC current from the current sensor 12 in addition to the voltage Vm and the DC voltage Vb from the voltage sensors 13 and 10 described above in the period T3 after the timing t10. Based on Ib, it is determined whether or not system relay SMRB is welded and whether or not voltage sensors 13 and 10 are out of order.

  Specifically, when the discharge of the capacitor C2 is started at the timing t10, the DC current Ib is a constant value (substantially zero) as shown by the curve k21 in response to the DC power supply B being cut off from the capacitor C2. )

  However, if the system relay SMRB and the system relays SMRP, SMRG are welded, the DC power source B is connected to the capacitor C2 via the system relay SMRB and the system relay SMRG (or SMRP), and the discharging capacitor Power will be supplied to C2. In this case, the direct current Ib gradually increases as shown by the curve k20.

  Therefore, the controller 30 discharges the capacitor C2 based on the voltage difference between the voltage Vm from the voltage sensor 13 and the DC voltage Vb from the voltage sensor 10 and the DC current Ib from the current sensor 12, based on the system relay SMRB. And the system relays SMRP, SMRG, and the failure of the voltage sensors 13, 10 are determined.

  Specifically, in the period T3 after the timing t10, after the discharge of the capacitor C2 is started at the timing t10, the voltage Vm from the voltage sensor 13 and the DC voltage Vb from the voltage sensor 10 are changed as shown by the curve k23. When a voltage difference equal to or greater than a predetermined reference value ΔVstd is detected during this period, control device 30 determines that system relay SMRB and system relays SMRP and SMRG are not welded.

  On the other hand, during the period T3, as indicated by the curve k25, a voltage difference below a predetermined reference value ΔVstd is detected between the voltage Vm from the voltage sensor 13 and the DC voltage Vb from the voltage sensor 10. As shown by the curve k20, when the direct current Ib equal to or greater than the predetermined threshold value Istd is detected by the current sensor 12, the control device 30 welds the system relay SMRB to the system relays SMRP and SMRG. It is determined that

  Further, in this period T3, the control device 30 detects a voltage difference below a predetermined reference value ΔVstd between the voltage Vm from the voltage sensor 13 and the DC voltage Vb from the voltage sensor 10, as indicated by a curve k24. When the current sensor 12 detects a DC current Ib that falls below a predetermined threshold value Istd as indicated by the curve k21, the control device 30 indicates that at least one of the voltage sensors 10 and 13 has failed. It is determined that

  FIG. 7 is a flowchart for explaining an operation for determining welding between system relay SMRB and system relays SMRP and SMRG shown in FIG. 6 and an operation for determining failure of voltage sensors 13 and 10. .

  Referring to FIG. 7, when the ignition key is turned on (step S41), control device 30 determines whether or not voltage Vm from voltage sensor 13 is equal to or higher than a predetermined reference value Vstd1 (step S42). . When voltage Vm is equal to or higher than predetermined reference value Vstd1, control device 30 starts discharging capacitor C2 in response to signal DCH being switched to H level (step S43).

  When discharging of capacitor C2 is started, control device 30 receives DC current Ib from current sensor 12 (step S44), receives voltage Vm from voltage sensor 13, and receives DC voltage Vb from voltage sensor 10 (step S44). S45). In parallel with acquiring the detection value from each sensor, the control device 30 counts the elapsed time from the timing when the discharge of the capacitor C2 is started using a timing unit (not shown).

  The control device 30 then determines the voltage difference | Vm between the voltage Vm from the voltage sensor 13 and the DC voltage Vb from the voltage sensor 10 at the timing when the period T3 has elapsed from the timing at which the discharge of the capacitor C2 is started (step S46). It is determined whether −Vb | is greater than or equal to a reference value ΔVstd (step S47).

  In step S47, when voltage difference | Vm−Vb | is greater than or equal to reference value ΔVstd, control device 30 determines that system relay SMRB and system relays SMRP and SMRG are normal (not welded). (Step S48).

  On the other hand, when the voltage difference | Vm−Vb | is lower than the reference value ΔVstd in step S47, the control device 30 subsequently determines whether or not the direct current Ib is equal to or greater than the threshold value Istd (step S49).

  In step S49, when the direct current Ib is greater than or equal to the threshold value Istd, that is, when the voltage difference | Vm−Vb | is less than a predetermined reference value ΔVstd and the direct current Ib is greater than or equal to the threshold value Istd, Control device 30 determines that system relay SMRB and system relays SMRP and SMRG are welded (step S50). Then, control device 30 generates signal EMG1 and outputs it to welding warning lamp 40. The welding warning lamp 40 is turned on in response to the signal EMG1 (step S51).

  On the other hand, in step S49, when the direct current Ib is lower than the threshold value Istd, that is, when the voltage difference | Vm−Vb | is lower than a predetermined reference value ΔVstd, and the direct current Ib is lower than the threshold value Istd. At this time, the control device 30 determines that at least one of the voltage sensors 13 and 10 has failed (step S52). Then, the control device 30 generates the signal EMG2 and outputs it to the sensor failure warning lamp 42. The sensor failure warning lamp 42 is turned on according to the signal EMG2 (step S53).

  It should be noted that the determination of welding of system relay SMRG by control device 30 is actually executed by the CPU, and the CPU reads the program including the steps shown in FIG. 7 from the ROM and executes the steps shown in FIG. Welding between relay SMRB and system relays SMRP, SMRG is determined.

  Therefore, the ROM corresponds to a computer (CPU) readable recording medium that records a program for causing the computer (CPU) to execute control for determining welding between the system relay SMRB and the system relays SMRP and SMRG.

  As described above, according to the third embodiment of the present invention, it is possible to prevent the system relay from being erroneously determined to be welded due to the failure of the voltage sensor.

  Furthermore, it becomes possible to determine the failure of the voltage sensor in conjunction with the determination of welding of the system relay.

  In the present invention, system relays SMRB, SMRG, SMRP, current sensor 12, capacitor C2, voltage sensors 10, 13 and control device 30 constitute a “power supply control device” according to the present invention.

  Control device 30 constitutes “welding judgment means” for judging welding of system relays SMRB, SMRG, and SMRP, and constitutes “failure judgment means” for judging failure of voltage sensors 10 and 13.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is applied to a power supply control device capable of preventing erroneous determination of relay welding.

It is a schematic block diagram of a motor drive device provided with the power supply control device by Embodiment 1 of this invention. 5 is a timing chart for explaining a welding determination operation of system relay SMRG and a failure determination operation of voltage sensors 10 and 13 shown in FIG. 1. 2 is a flowchart for explaining an operation for determining welding of system relay SMRG shown in FIG. 1 and an operation for determining failure of voltage sensors 13 and 10; 2 is a timing chart for explaining an operation for determining welding of system relay SMRB shown in FIG. 1. 5 is a flowchart for explaining an operation for determining welding of system relay SMRG shown in FIG. 4 and an operation for determining failure of voltage sensor 13; 3 is a timing chart for explaining an operation for determining welding between system relay SMRB and system relays SMRG and SMRP shown in FIG. 1. 7 is a flowchart for explaining an operation for determining welding between system relay SMRB and system relays SMRP and SMRG shown in FIG. 6 and an operation for determining failure of voltage sensors 13 and 10;

Explanation of symbols

  B DC power supply, 12, 24 Current sensor, 10, 13 Voltage sensor, 20 Inverter, 21 U-phase arm, 22 V-phase arm, 23 W-phase arm, 30 Control device, 40 Welding warning lamp, 42 Failure warning lamp, 100 Motor Driving device, SMRB, SMRP, SMRG System relay, R resistance, Q1-Q6 IGBT element, D1-D6 diode, M1 AC motor.

Claims (4)

A power supply control device for a DC power supply ,
A first relay connected to one pole of the DC power supply;
A second relay connected to the other pole of the DC power supply;
A capacitive element having one terminal connected to one pole side of the DC power supply via the first relay and the other terminal connected to the other pole side of the DC power supply via the second relay;
A first voltage sensor for detecting a voltage across the capacitive element;
A second voltage sensor for detecting a DC voltage from the DC power supply;
A current sensor for detecting a direct current flowing from the direct current power source;
Based on the voltages detected by the first and second voltage sensors, the presence or absence of abnormality of the power supply control device is determined, and when the power supply control device is determined to be abnormal, it is detected by the current sensor. Determining means for determining whether at least one of the welds of the first and second relays is welded or at least one of the first and second voltage sensors has failed based on the measured current. A power supply control device. Before SL-size constant means, said second relay only off to the detected value and the second voltage of said first voltage sensor is a voltage difference lower than the predetermined reference value when discharging the capacitive element is detected between the detection value of the sensor, and, when Jo Tokoro above the threshold current is detected by the current sensor, it determines that the second relay is welded,
Is detected between the detection value of the predetermined said lower voltage difference than the reference value the first voltage detection value and the second voltage sensors of the sensor when the off only before Symbol second relay, and The power supply control device according to claim 1, wherein when a current lower than the predetermined threshold is detected by the current sensor, it is determined that at least one of the first and second voltage sensors is out of order. Before SL-size constant means, the second voltage not lower than a predetermined reference value when only the turns on the relay is detected by said first voltage sensor, and detects more than a predetermined threshold value of current by said current sensor If it is determined that the first relay is welded,
It detected the predetermined reference value or more voltage when turned only before Symbol second relay by said first voltage sensor, and when the current falls below the predetermined threshold value is detected by said current sensor, The power supply control device according to claim 1, wherein it is determined that the first voltage sensor has failed. Before SL-size constant means, said voltage difference lower than the predetermined reference value when discharging the capacitive element by turning off the first and second relay and the detection value of said first voltage sensor first is detected between the detection value of the second voltage sensor, and, when Jo Tokoro above the threshold current is detected by the current sensor, determining that the first and second relay is welded,
Before SL of the first and second of said second voltage sensor the voltage difference lower than a predetermined reference value and the detected value of said first voltage sensor when discharging the capacitive element and turns off the relay And determining that at least one of the first and second voltage sensors is faulty when a current that is detected between a detected value and less than the predetermined threshold is detected by the current sensor. Item 4. The power supply control device according to Item 1.

Images