JP2012019655A - Vehicle power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle power generator for speedily terminating generation of high voltage in the case of load dump.SOLUTION: The vehicle power generator 1 includes: stator windings 2 and 3; two rectifier module groups 5 and 6 constituting a bridge circuit having a plurality of lower arms; a control portion 100 controlling ON/OFF of a MOS transistor included in the bridge circuit; a field winding 4; a power generation controller 7; and a load dump protection determining portion 140. When output voltage exceeds first threshold voltage, the load dump protection determining portion 140 gives an instruction to turn on the MOS transistor 51 constituting the lower arm to the control portion 100. When the output voltage becomes lower than second threshold voltage, the instruction for turning off the MOS transistor 51 is given to the control portion 100 by waiting for arrival of timing fitted to suppression of generation of surge voltage. A value higher than adjustment voltage controlling output voltage of the vehicle power generator 1 is set as the second threshold voltage.

Description

  The present invention relates to a vehicular generator mounted on a passenger car, a truck, or the like.

  The vehicular generator supplies charging power and operating power to a battery and various electric loads via a charging line connected to an output terminal. If the output terminal or the battery terminal is disconnected during the power generation operation of this vehicle generator, a transient high voltage called a load dump is generated. The voltage generated at this time may reach 100 V or more depending on the output current or the like. The high voltage generated in this way causes damage to various elements in the electric load and the vehicular generator, and some measures are required. As a conventional technique for taking such measures, for example, a low-side element of a bridge circuit of a vehicular generator is configured by a MOS transistor, and when the output voltage of the vehicular generator exceeds a reference voltage when a load dump occurs, these technologies are used. 2. Description of the Related Art A vehicular generator is known in which a protection operation for suppressing generation of a high voltage is performed by turning on a MOS transistor (see, for example, Patent Document 1). In this vehicular generator, when each MOS transistor as the low side element of the bridge circuit is turned on and the output voltage again becomes lower than the reference voltage, each MOS transistor is turned off again, and normal rectification operation by the bridge circuit is resumed. It has become so.

  In addition, as another conventional technique for suppressing the high voltage when a load dump occurs, the control mode of the power MOSFETs on the upper arm side (high side side) and the lower arm side (low side side) are reversed in phase when high voltage is detected. There is known a vehicular generator that is changed (see, for example, Patent Document 2). When the high voltage at the time of load dump occurrence is eliminated, the control mode is returned from the reverse phase to the normal state.

JP-A-9-219938 (page 5-9, FIG. 1-14) JP 2003-244864 A (page 4-10, FIG. 1-16)

  By the way, in the vehicular generator disclosed in Patent Document 1, when the output voltage becomes lower than the reference voltage and the normal rectification operation is started again, when the MOS transistor through which the current flows is turned off, the MOS transistor Since the current flowing in the connected stator coil is momentarily interrupted, a surge voltage is generated in this stator coil, and when this surge voltage exceeds the reference voltage, the protective operation is repeated again. There was a problem that operation was not stable. In particular, if the output voltage falls below the reference voltage and the MOS transistor as the low-side element is turned off before the energy at the time of load dump is sufficiently eliminated, the output voltage rises again, and a protective operation for suppressing high voltage is performed. Although it is repeated, since the surge voltage described above is generated in accordance with the timing when the output voltage becomes equal to or lower than the reference voltage, the protection operation may be further unstable.

  Further, in the vehicular generator disclosed in Patent Document 2, the on / off state of each of the power MOSFETs of the upper arm and the lower arm is switched when the protection operation is started when the load dump occurs or when the protection operation is canceled. Therefore, there is a problem that a surge voltage is generated at the time of switching if a current flows through the stator coil to which these power MOSFETs are connected. In particular, the on / off switching timings of the power MOSFETs of the upper arm and the lower arm vary somewhat from element to element, and if they are simultaneously turned off, the current flowing through the stator coil is momentarily interrupted. A high surge voltage will be generated. Therefore, the protection operation is repeatedly performed and released until the energy at the time of load dump is sufficiently eliminated, and the operation is particularly performed when the power MOSFETs of the upper arm and the lower arm are repeatedly switched on / off. The point of instability is the same as in the case of the invention of Patent Document 1.

  The present invention was created in view of the above points, and an object of the present invention is to provide a vehicular generator that can stabilize a protective operation for suppressing a high voltage during load dump. is there.

  In order to solve the above-described problems, a vehicle generator according to the present invention includes an armature winding having two or more phase windings and a plurality of lower arms configured by switching elements having diodes connected in parallel. A switching unit that rectifies the induced voltage of the armature winding, a first control unit that controls on / off of the switching element, a field winding that magnetizes the field pole of the rotor, and switching A second control unit that adjusts a current flowing through the field winding so that the output voltage of the unit becomes a predetermined adjustment voltage, and the output voltage of the switching unit is monitored, and the output voltage is set to the first threshold voltage. When it exceeds, the control unit is instructed to turn on the switching element constituting the lower arm, and after the first threshold voltage is exceeded, the second output voltage is lower than the first threshold voltage. Than the threshold voltage of A load dump protection determination unit for instructing the first control unit to turn off the switching element constituting the lower arm after waiting for the arrival of a timing suitable for suppressing the occurrence of surge voltage The second threshold voltage is set to a value higher than the adjustment voltage.

  By setting the voltage for releasing the protection operation (second threshold voltage) to a value higher than the adjustment voltage, the output voltage can be set to be higher than the adjustment voltage while the protection operation and the release operation are repeated. Thus, even when a load dump occurs, it is possible to maintain the supply of operating power to the electric load connected to the vehicle generator. In addition, even when the protection operation is repeatedly released multiple times, the timing for suppressing the generation of the surge voltage is determined each time, so that an increase in the output voltage due to the generation of the surge voltage can be suppressed. Can be stabilized.

  In addition, the vehicle generator of the present invention constitutes a bridge circuit having an armature winding having two or more phase windings and a plurality of lower arms constituted by switching elements having diodes connected in parallel, A switching unit that rectifies the induced voltage of the armature winding, a first control unit that controls on / off of the switching element, a field winding that magnetizes the field pole of the rotor, and an output voltage of the switching unit is a predetermined value A second control unit that adjusts the current flowing through the field winding so as to obtain an adjustment voltage, and the output voltage of the switching unit is monitored. When the output voltage exceeds the first threshold voltage, the lower arm The control unit is instructed to turn on the switching elements constituting the output voltage, and after the first threshold voltage is exceeded, the output voltage is lower than the second threshold voltage, which is lower than the first threshold voltage. When it becomes low, A load dump protection determination unit for instructing the first control unit to turn off a switching element constituting the lower arm after waiting for a timing suitable for suppressing the generation of voltage, and a second threshold. The value voltage is set to a value equal to or lower than the adjustment voltage.

  By setting the voltage for releasing the protection operation (second threshold voltage) to a value equal to or lower than the adjustment voltage, the excitation current flowing in the field winding when the protection operation is released can be increased. By increasing the flowing current and flowing the current through the switching element of the lower arm, it becomes easy to determine the timing suitable for suppressing the generation of the surge voltage. In addition, even when the protection operation is repeatedly released multiple times, the timing for suppressing the generation of the surge voltage is determined each time, so that an increase in the output voltage due to the generation of the surge voltage can be suppressed. Can be stabilized.

  In addition, the load dump protection determination unit described above configures the lower arm after detecting that the output voltage has exceeded the first threshold voltage and waiting for the arrival of a timing suitable for suppressing the occurrence of the surge voltage. It is desirable to instruct the first control unit to turn on the switching element. As a result, not only when the protection operation is cancelled, but also when shifting to the protection operation, the protection operation can be performed while avoiding the timing at which the surge voltage is generated.

  In addition, the first threshold voltage and the second threshold voltage are consumed until the energy stored in the armature winding when the load dump occurs is consumed by passing a current through a path that turns on the switching element constituting the lower arm. It is desirable that the output voltage repeatedly rises and falls between the threshold voltage and the switching elements constituting the lower arm are repeatedly turned on and off. In this way, by repeatedly performing the protection operation and its release operation, the energy generated and accumulated in the armature winding during load dumping can be surely extinguished, and the normal operation of the electrical load as the output voltage can be achieved. It is possible to maintain the value required for.

  The timing for suppressing the generation of the surge voltage described above is a timing other than the timing at which current flows from the phase winding connected to the switching element to the switching element when the switching element constituting the lower arm is turned on. It is desirable that In particular, the timing for suppressing the generation of the surge voltage described above is the timing at which current flows from the switching element to the phase winding connected to the switching element when the switching element constituting the lower arm is turned on. Is desirable. As a result, instantaneous interruption or sudden change of the current flowing through the phase winding connected to the switching element whose on / off state is switched can be prevented, and generation of a high surge voltage in the phase winding can be suppressed.

  Further, the switching element described above is a MOS transistor, and the load dump protection determination unit includes a MOS voltage detection unit that detects the source-drain voltage of the MOS transistor, and the MOS based on the detected source-drain voltage. An energization direction detection unit that detects the direction of current flowing through the MOS transistor when the transistor is turned on, and a timing determination unit that determines a timing for suppressing generation of a surge voltage based on a detection result by the energization direction detection unit; It is desirable to provide. Since the MOS transistor has a predetermined source-drain voltage even when it is turned on, it is possible to detect the direction of the current by detecting this voltage, and to reliably determine the timing for suppressing the generation of the surge voltage. it can.

  In the case where the second threshold voltage is set to a value higher than the adjustment voltage, when the above-described output voltage exceeds the first threshold voltage and the switching element constituting the lower arm is turned on. The detection current is supplied to the field winding by the second control unit, and the detection current is preferably a current capable of detecting the source-drain voltage of the MOS transistor. By doing so, the current flowing through the armature winding does not become zero during the protective operation even if the second threshold voltage is not lower than the adjustment voltage. It becomes easy.

  Further, when the second threshold voltage is set to a value equal to or lower than the adjustment voltage, the second threshold voltage described above constitutes the lower arm with the output voltage exceeding the first threshold voltage. When the output voltage drops to the second threshold voltage after the switching element is turned on, a current capable of detecting the source-drain voltage of the MOS transistor is supplied to the field winding by the second control unit. It is desirable to set it to a certain value. By doing so, it is not necessary to communicate with the second control unit, and wiring between components becomes unnecessary. Further, the degree of freedom of the mounting layout is increased, the ease of assembly of the product is improved, and the size can be reduced.

  The timing for suppressing the occurrence of the surge voltage is preferably the timing when the source-drain voltage of the MOS transistor with respect to the source side becomes 0 V or less. This makes it possible to reliably and easily determine the direction of the current flowing through the MOS transistor. Further, since it is not necessary to add a shunt resistor for current detection in series with the MOS transistor, there is no loss due to the shunt resistor, and the power generation efficiency during normal power generation can be increased accordingly.

  The timing for suppressing the generation of the surge voltage is preferably a timing delayed for a predetermined period after the source-drain voltage of the MOS transistor with respect to the source side becomes 0 V or less. In particular, the predetermined period is desirably a period corresponding to ¼ of the period of the induced voltage of the phase winding. Due to the LC component of the circuit, there may be a phase shift between the detected voltage and current. Specifically, even when the source-drain voltage is 0 V, the current may be 0 A or more. Even in such a case, it is possible to reliably release the protection operation at the timing when the current flows from the source to the drain.

  The timing for suppressing the generation of the surge voltage described above is such that the direction of the current flowing through the switching element after the output voltage exceeds the first threshold voltage and the switching element constituting the lower arm is turned on is It is desirable that the timing be synchronized with the cycle of the timing that changes from the direction flowing from the phase winding to the direction flowing toward the phase winding. As a result, even when the output voltage decreases and the current flowing through the switching element decreases, the protection operation can be reliably canceled at a timing at which the generation of the surge voltage can be suppressed.

It is a figure which shows the structure of the generator for vehicles of one Embodiment. It is a figure which shows the structure of a rectifier module. It is a figure which shows the detailed structure of a control circuit. It is a figure which shows the transition state which transfers to protection operation at the time of load dump occurrence, and returns to normal rectification operation | movement again after that. It is a figure which shows the phase voltage of the generator for vehicles. It is a figure which shows the structure of a load dump protection determination part. It is a figure which shows the relationship between an output voltage and the determination result by a threshold voltage determination part. It is a figure which shows the relationship between the source-drain voltage and a reference voltage. It is a figure which shows a response | compatibility with the change of output voltage, protection operation | movement, and its cancellation | release operation in case protection operation | movement is cancelled | released when an output voltage becomes a value higher than an adjustment voltage. It is a figure which shows a response | compatibility with the change of output voltage, protection operation | movement, and its cancellation | release operation in case protection operation | movement is cancelled | released when an output voltage becomes a value below an adjustment voltage. It is a figure which shows the specific example of the output of a MOS voltage detection part when only one rectifier module transfers to protection operation. Changes in the output voltage, protection operation, and cancellation when the protection operation is canceled when the output voltage becomes higher than the adjustment voltage and the excitation current is forced to flow during the protection operation It is a figure which shows a response | compatibility with operation | movement.

  Hereinafter, a generator for vehicles of one embodiment to which the present invention is applied will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a vehicle generator according to an embodiment. As shown in FIG. 1, the vehicle generator 1 of this embodiment includes two stator windings (armature windings) 2, 3, a field winding 4, two rectifier module groups 5, 6, and power generation. A control device 7 is included. Two rectifier module groups 5 and 6 correspond to a switching unit.

  One stator winding 2 is a multiphase winding (for example, a three-phase winding composed of an X-phase winding, a Y-phase winding, and a Z-phase winding), and is wound around a stator core (not shown). It is disguised. Similarly, the other stator winding 3 is a multi-phase winding (for example, a three-phase winding composed of a U-phase winding, a V-phase winding, and a W-phase winding). The stator winding 2 is wound at a position shifted by 30 degrees in terms of electrical angle. In the present embodiment, a stator is constituted by these two stator windings 2 and 3 and the stator core.

  The field winding 4 is wound around a field pole (not shown) disposed opposite to the inner peripheral side of the stator core to constitute a rotor. The field pole is magnetized by passing an exciting current. The stator windings 2 and 3 generate an alternating voltage by a rotating magnetic field generated when the field pole is magnetized.

  One rectifier module group 5 is connected to one stator winding 2 to form a three-phase full-wave rectifier circuit (bridge circuit) as a whole, and the alternating current induced in the stator winding 2 is converted into direct current. Convert to current. The rectifier module group 5 includes rectifier modules 5X, 5Y, and 5Z corresponding to the number of phases of the stator winding 2 (three in the case of a three-phase winding). The rectifier module 5 </ b> X is connected to the X-phase winding included in the stator winding 2. The rectifier module 5 </ b> Y is connected to a Y-phase winding included in the stator winding 2. The rectifier module 5Z is connected to the Z-phase winding included in the stator winding 2.

  The other rectifier module group 6 is connected to one stator winding 3 to form a three-phase full-wave rectifier circuit (bridge circuit) as a whole, and the alternating current induced in the stator winding 3 is converted into direct current. Convert to current. The rectifier module group 6 includes a number of rectifier modules 6U, 6V, and 6W corresponding to the number of phases of the stator winding 3 (three in the case of a three-phase winding). The rectifier module 6U is connected to a U-phase winding included in the stator winding 3. The rectifier module 6V is connected to a V-phase winding included in the stator winding 3. The rectifier module 6 </ b> W is connected to the W-phase winding included in the stator winding 3.

  The power generation control device 7 is an excitation control circuit that controls the excitation current that flows through the field winding 4, and the output voltage of the vehicle generator 1 (the output voltage of each rectifier module) is adjusted by adjusting the excitation current. The voltage is controlled to be Vreg. For example, the power generation control device 7 stops supplying the excitation current to the field winding 4 when the output voltage becomes higher than the adjustment voltage Vreg, and the field when the output voltage becomes lower than the adjustment voltage Vreg. By supplying an exciting current to the magnetic winding 4, the output voltage is controlled to become the adjustment voltage Vreg. The power generation control device 7 is connected to the ECU 8 (external control device) via a communication terminal and a communication line, and uses bidirectional serial communication (for example, a LIN (Local Interconnect Network) protocol) with the ECU 8. LIN communication) and transmit or receive a communication message. This power generation control device 7 corresponds to a second control unit.

  The vehicle generator 1 of the present embodiment has such a configuration, and details of the rectifier module 5X and the like will be described next.

  FIG. 2 is a diagram illustrating a configuration of the rectifier module 5X. The other rectifier modules 5Y, 5Z, 6U, 6V, and 6W have the same configuration. As shown in FIG. 2, the rectifier module 5X includes two MOS transistors 50 and 51 and a control circuit 54. The MOS transistor 50 has an upper arm (high side) whose source is connected to the X-phase winding of the stator winding 2 and whose drain is connected to the electrical load 10 and the positive terminal of the battery 9 via the charging line 12. Switching element. The MOS transistor 51 is a switching element on the lower arm (low side) whose drain is connected to the X-phase winding and whose source is connected to the negative terminal (earth) of the battery 9. A diode is connected in parallel between the source and drain of each of the MOS transistors 50 and 51. This diode is realized by a parasitic diode (body diode) of the MOS transistors 50 and 51, but a diode as another component may be further connected in parallel. Note that at least one of the upper arm and the lower arm may be configured using a switching element other than a MOS transistor.

  FIG. 3 is a diagram showing a detailed configuration of the control circuit 54. As shown in FIG. 3, the control circuit 54 includes a control unit 100, a power source 102, a battery voltage detection unit 110, an operation detection unit 120 and 130, a load dump protection determination unit 140, a temperature detection unit 150, drivers 170 and 172, and a communication. A circuit 180 is provided. The control unit 100 corresponds to the first control unit.

  The power supply 102 starts operation when a predetermined phase voltage is generated in the X-phase winding of the stator winding 2 as the engine is started, and supplies the operating voltage to each element included in the control circuit 54. This operation itself is the same as the operation conventionally performed in the power generation control device 7, and can be realized by using the same technique.

  The driver 170 has an output terminal (G1) connected to the gate of the high-side MOS transistor 50, and generates a drive signal for turning on and off the MOS transistor 50. Similarly, the driver 172 has an output terminal (G2) connected to the gate of the low-side MOS transistor 51, and generates a drive signal for turning the MOS transistor 51 on and off.

  The battery voltage detection unit 110 (battery voltage detection means) includes a differential amplifier and an analog-digital converter (AD) that converts the output into digital data. The output terminal of the vehicular generator 1 and the charging line 12 outputs data corresponding to the voltage of the positive terminal of the battery 9 connected via the terminal 12.

  The operation detection unit 120 includes a differential amplifier and an analog-to-digital converter (AD) that converts the output into digital data, and the source-drain voltage of the high-side MOS transistor 50 (FIGS. 2 and 2). 3 corresponding to the voltage between the B and C terminals 3). Based on this data, the control unit 100 monitors the operating state of the MOS transistor 50 corresponding to the driving state of the driver 170, and appropriately controls the MOS transistor 50 and detects a failure.

  The operation detection unit 130 includes a differential amplifier and an analog-digital converter (AD) that converts the output into digital data. The operation detection unit 130 includes a source-drain voltage (FIGS. 2 and 3) of the MOS transistor 51 on the low side. Data corresponding to the voltage between the C and D terminals). Based on this data, the control unit 100 monitors the operating state of the MOS transistor 51 corresponding to the driving state of the driver 172, and appropriately controls the MOS transistor 51 and detects a failure.

  The load dump protection determination unit 140 monitors the output voltage (B terminal voltage) of the vehicular generator 1 (rectifier module groups 5 and 6), and the B terminal voltage is a first threshold voltage for determining the occurrence of load dump. An instruction (protection start instruction) to start the protection operation after exceeding V1 (for example, 20V) is performed, and then the B terminal voltage is lowered by this protection operation and is lower than the first threshold voltage V1. After falling below a threshold voltage V2 (a specific example will be described later), the protection operation is stopped and an instruction to resume normal rectification operation (rectification resumption instruction) is issued. For example, the load dump protection determination unit 140 is preferably configured by an analog circuit in which various active elements and passive elements are combined because it is necessary to perform quick processing. The control unit 100 executes the protection operation and the rectification operation after the protection operation is released in accordance with the protection start / rectification restart instruction from the load dump protection determination unit 140. Details of the configuration and protection operation of the load dump protection determination unit 140 will be described later.

  The temperature detection unit 150 includes a constant current source, a diode, a differential amplifier, and an analog-digital converter (AD) that converts the output into digital data, and copes with a forward voltage drop of the diode that changes with temperature. Output data. The control unit 100 detects the temperature of the rectifier module 5X based on this data.

  The communication circuit 180 is a communication means similar to the power generation control device 7, and is commonly connected to a communication terminal and a communication line that connect between the power generation control device 7 and the ECU 8, and is bidirectional with the ECU 8. Serial communication (for example, LIN communication using the LIN protocol) is performed, and a communication message is transmitted or received.

  For example, considering a case where a communication message is transmitted / received to / from the ECU 8 at a communication frequency of about 20 ms per communication, communication can be performed 50 times per second. Therefore, even if six communication modules 5X and the like are added in this embodiment and the transmission / reception of communication messages therefor increases, communication messages and diagnostic information including the power generation state between the power generation control device 7 and the ECU 8 are displayed. It can be said that there is no problem in power generation control for transmitting and receiving communication messages.

  The rectifier module 5X and the like according to the present embodiment have such a configuration. Next, details of the protection operation when a load dump occurs and the operation of returning from the protection operation to the normal power generation (rectification) state will be described. .

  FIG. 4 is a diagram illustrating a transition state in which the operation shifts to the protection operation when a load dump occurs and then returns to the normal rectification operation again. In FIG. 4, “rectification” indicates a rectification operation performed in a normal time when no load dump occurs, and “protection” indicates a protection operation performed when a load dump occurs. FIG. 5 is a diagram showing the phase voltage of the vehicular generator 1. FIG. 5 (A) shows the normal phase voltage, and FIG. 5 (B) shows the phase voltage when the load dump occurs. It is shown.

  When the terminal voltage of the battery 9 is Vbatt and the source-drain voltage when the MOS transistors 50 and 51 are on is α, the phase voltage Vx of the X-phase winding exceeds Vbatt + α, for example, at normal times when no load dump occurs. When the high-side MOS transistor 50 is turned on, the low-side MOS transistor 51 is turned on when the phase voltage Vx drops below -α (FIG. 5A).

In such a state, when the connection between the output terminal of the vehicle generator 1 and the charging wire 12 or the connection between the positive terminal of the battery 9 and the charging wire 12 is disconnected, the stator winding of the vehicle generator 1 A load dump in which the phase voltages of 2 and 3 are temporarily increased occurs (FIG. 5B). Since the phase voltage V _{LD at} this time is higher than the terminal voltage Vbatt of the battery 9 (for example, 100 V or more), the rectifier module 5X in the vehicular generator 1, the power generation control device 7, or various electric loads 10 are applied. In order to protect, after going through the procedure of “Preparation for protection”, it shifts to a protection operation (FIG. 4).

  Specifically, the process proceeds to the “protection preparation” procedure when the phase voltage exceeds the first threshold voltage V1. This protection preparation is an operation for determining an optimum timing for entering the protection operation, and a protection start instruction is issued in accordance with a timing at which generation of a surge voltage when entering the protection operation can be suppressed. Further, assuming that a lead storage battery having a rated voltage of 12V is used as the battery 9, the first threshold voltage is set to 20V, for example. The first threshold voltage V1 is set to a value at which the electric load 10 does not cause an abnormality such as a failure. Even if the output voltage temporarily rises to the first threshold voltage, the electric load 10 10 can maintain normal operation.

  In the present embodiment, when the phase voltage exceeds 20 V when load dump occurs, the low-side MOS transistor 51 is turned on, and at the same time, the high-side MOS transistor 50 is turned off to perform the protection operation. Thereafter, the on / off states of these MOS transistors 50 and 51 are continued until the high voltage resulting from the load dump is eliminated. During this protection operation, the phase voltage shifts in the range of −α to + α (−0.1 V to +0.1 V) as indicated by Vp in FIG.

  In the range indicated by A in FIG. 5, the high-side MOS transistor 50 is on and the low-side MOS transistor 51 is off before the protection operation shifts. If the switch is turned off instantaneously, a large surge voltage may be generated in the phase winding. For example, the on / off switching timing of the MOS transistors 50 and 51 actually varies from element to element, and if only the timing for turning off the high-side MOS transistor 50 that has been turned on becomes slightly earlier, Since the flowing current is interrupted, a large surge voltage is generated.

  In the range indicated by B in FIG. 5, no current flows through the phase winding, but the potential difference between the source and drain is large in the low-side MOS transistor 51, and when the MOS transistor 51 is turned on, the current instantaneously Therefore, a large surge voltage is generated against the change in the phase current.

  As described above, since there is a possibility that a large surge voltage is generated when the protection operation is started when the protection operation is in the ranges indicated by A and B in FIG. 5, in the present embodiment, it is included in the range indicated by C in FIG. 5. After confirming that this is done, the protection operation is started. In “protection preparation”, when it is within the range indicated by C, it is determined that it is the optimum timing to enter the protection operation.

  On the other hand, when the high voltage generated at the time of load dump is eliminated and the normal operation is restored from the protection operation, the procedure of “recovery preparation” is similarly performed. Specifically, when the phase voltage that has become high at the time of load dumping falls again and falls below the second threshold voltage, the procedure proceeds to the “recovery preparation” procedure. This recovery preparation is an operation for determining an optimum timing for entering a normal rectification operation, and a rectification restart instruction is issued in accordance with a timing at which generation of a surge voltage upon entering the rectification operation can be suppressed. When the commutation restart instruction is issued, the control unit 100 turns off the low-side MOS transistor 51, and then the normal rectification operation (synchronous rectification control operation) by the control unit 100 is performed.

  Incidentally, during the protection operation, the low-side MOS transistor 51 is always on, and a phase voltage indicated by Vp in FIG. 5B is generated. In this state, turning off the low-side MOS transistor means that the large phase current that has been flowing through the MOS transistor 51 in the range indicated by A and B is momentarily interrupted. Will occur. Therefore, in the present embodiment, the normal rectification operation is started after confirming that it is included in the range indicated by C in FIG. In “recovery preparation”, when it is within the range indicated by C, it is determined that it is the optimum timing to enter the rectifying operation.

  Next, details of the load dump protection determination unit 140 that performs the protection preparation operation and the recovery preparation operation will be described. FIG. 6 is a diagram illustrating a configuration of the load dump protection determination unit 140. As shown in FIG. 6, the load dump protection determination unit 140 includes a B voltage detection unit 141, a threshold voltage determination unit 142, a MOS voltage detection unit 143, an energization direction detection unit 144, and timing determination units 145 and 146. Yes.

  The B voltage detector 141 detects the output voltage (B terminal voltage) VB of the vehicle generator 1 (rectifier module groups 5 and 6). The threshold voltage determination unit 142 determines whether or not the output voltage VB is higher than the first threshold voltage V1, and the output voltage VB once higher than the first threshold voltage V1 is the second threshold voltage. It is determined whether or not the voltage has become lower than the threshold voltage.

  FIG. 7 is a diagram illustrating the relationship between the output voltage VB and the determination result by the threshold voltage determination unit 142. In FIG. 7, the horizontal axis represents the output voltage VB, and the vertical axis represents the determination result of the threshold voltage determination unit 142. As shown in FIG. 7, the threshold voltage determination unit 142 changes the output from a low level (L) to a high level when the output voltage VB increases and exceeds a first threshold voltage V1 (for example, 20 V). Switch to level (H). Further, when the output voltage VB once exceeding V1 becomes low and becomes lower than the second threshold voltage V2, the output is switched from the high level to the low level.

  The MOS voltage detector 143 detects the source-drain voltage Vds (voltage between the C-D terminals in FIGS. 2 and 3) of the low-side MOS transistor 51. The energization direction detector 144 determines the direction of the current flowing between the source and drain when the MOS transistor 51 is turned on based on the source-drain voltage Vds of the MOS transistor 51 detected by the MOS voltage detector 143. .

In a state when a load dump occurs and before the protection operation is started (before the low-side MOS transistor 51 is turned on), the phase voltage V _LD corresponding to the range indicated by A or B in FIG. Become. Therefore, if it is desired to know whether or not it is in the range indicated by C (whether or not current flows in the direction opposite to the forward direction of the diode connected in parallel to the MOS transistor 51 when the MOS transistor 51 is turned on), What is necessary is just to check whether or not the phase voltage V _LD , that is, the source-drain voltage Vds of the MOS transistor 51 is lower than a predetermined reference voltage Vref lower than 0V. That the source-drain voltage Vds is lower than the reference voltage Vref indicates that the phase voltage V _LD is in the range indicated by C in FIG. 5. In this case, the output of the energization direction detection unit 144 is Become high level.

  Actually, the MOS voltage detector 143 accurately detects a voltage in the range of −0.1 to +0.1 V, and the energization direction detector 144 uses the reference voltage Vref near 0 V to accurately compare the voltages. Is difficult. For this reason, the MOS voltage detection unit 143 outputs the voltage Vds ′ after the detected source-drain voltage Vds is amplified with a predetermined gain to convert the voltage level, and the energization direction detection unit 144 outputs the voltage Vds ′. Is used to compare the voltage.

  FIG. 8 is a diagram showing the relationship between the source-drain voltage Vds 'and the reference voltage Vref'. In FIG. 8, the vertical axis indicates the converted voltage Vds', and the horizontal axis indicates the source-drain voltage Vds before conversion. Since the voltage comparison range in the energization direction detection unit 144 is the source-drain voltage Vds included in the range of −0.1 to +0.1 V, this range is amplified, for example, 20 times. In the example shown in FIG. 8, −0.1 V corresponds to 0 V, +0.1 V corresponds to +5 V, and the voltage therebetween linearly corresponds to 1: 1. When the source-drain voltage Vds is lower than −0.1 V or higher than +0.1 V, the output voltage of the MOS voltage detector 143 is clipped (fixed) to 0 V or +5 V. ). For example, the reference voltage Vref ′ = 2.5V (Vds = 0V) is set. In order to accurately determine the timing included in the range indicated by C in FIG. 5, the reference voltage Vref 'needs to be set to a value close to + 5V.

  The energization direction detection unit 144 compares the output voltage Vds ′ of the MOS voltage detection unit 143 with the reference voltage Vref ′, sets the output to a high level when Vds ′ is lower than Vref ′, and sets the output to a low level when it is high To. Note that the energization direction detection unit 144 may delay the timing for setting the output to a high level for a predetermined period. In general, a phase shift may occur between the detected source-drain voltage Vds and the actual current flowing between the source and drain due to the LC component of the circuit such as the rectifier module 5X. Specifically, even when the source-drain voltage is 0 V, the current may be 0 A or more. In consideration of such a case, the timing of changing to the high level may be delayed for a predetermined period. As the predetermined period, for example, a period corresponding to ¼ of the period of the induced voltage (phase voltage) of the phase winding is used.

  One timing determination unit 145 changes the output of the energization direction detection unit 144 to a high level after the output of the threshold voltage determination unit 142 changes from a low level to a high level, that is, with the occurrence of a load dump. When the output voltage VB becomes higher than the first threshold voltage V1 and is determined to be in the range indicated by C in FIG. 5B, the output is set to the high level. The high level output of the timing determination unit 145 corresponds to the “protection start instruction”, and when this protection start instruction is output, the control unit 100 drives the driver 170 to perform the high-side MOS transistor 50. Is turned off and the driver 172 is driven to turn on the low-side MOS transistor 51, thereby starting a protection operation when a load dump occurs.

  The other timing determination unit 146 changes the output of the energization direction detection unit 144 to a high level after the output of the threshold voltage determination unit 142 changes from a high level to a low level, that is, with the occurrence of a load dump. When it is determined that the output voltage VB once exceeding the first threshold voltage V1 is again lower than the second threshold voltage V2 and is within the range indicated by C in FIG. To high level. The high level output of the timing determination unit 146 corresponds to the “rectification resumption instruction”. When this rectification resumption instruction is output, the control unit 100 drives the driver 172 to activate the low-side MOS transistor 51. Turn off. Thereafter, the control unit 100 resumes the synchronous rectification control operation.

  Note that the case where the timing at which the output of the energization direction detection unit 144 changes to the high level is delayed for a predetermined period is intended to be the timing corresponding to the vicinity of the center of the range indicated by C in FIG. In this regard, at least one of the timing determination units 145 and 146 has a function of delaying the timing of changing to the high level for a predetermined period, which is applicable to both of the two timing determination units 145 and 146. Changes may be made.

  By the way, in the present embodiment, as the second threshold voltage V2 used for the timing determination for releasing the protection operation, (1) when a value higher than the adjustment voltage Vreg is set, or (2) the adjustment voltage It is assumed that a value less than Vreg is set.

(1) When a value higher than the adjustment voltage Vreg is set as the second threshold voltage V2 When the connection between the positive terminal of the battery 9 and the charging line 12 is disconnected, the output voltage of the vehicle generator 1 The protection operation is started when the voltage becomes higher than the first threshold voltage V1, but the output voltage becomes a temporary phenomenon, and when the protection operation is canceled, the electrical load 10 is immediately applied. On the other hand, it is necessary to continue to supply operating power. By setting the second threshold voltage V2 to a value higher than the adjustment voltage Vreg, immediately after the protection operation is canceled, the generator controller 7 supplies the exciting current to the field winding 4 and at the same time the rectifier The rectification operation by the module 5X or the like can be resumed, and stable power supply to the electric load 10 can be continued.

(2) When setting a value equal to or lower than the adjustment voltage Vreg as the second threshold voltage V2 In this case, the output voltage that has become higher as it exceeds the first threshold voltage V1 during load dumping subsequently decreases. Therefore, before the protection operation is released, supply of the excitation current by the power generation control device 7 is started. Since the low-side MOS transistor 51 is turned on before the protection operation is released, even if an exciting current is supplied to the field winding 4 and a new electromotive force is generated in the stator winding 2 or the like, the low-side MOS transistor 51 is turned on. Since only the power consumed through the MOS transistor 51 is increased, it can be considered useless. However, by setting the second threshold voltage V2 to be equal to or lower than the adjustment voltage Vreg and causing the exciting current to flow before the protection operation is canceled, the MOS voltage detection unit 143 can detect the source-drain voltage Vds. Since the current flowing through the low-side MOS transistor 51 can be increased, it is possible to accurately determine the energization direction detection unit 144. For example, when the exciting current flowing in the field winding 4 is 0 A when the output voltage falls below the second threshold voltage, and the phase currents of the stator windings 2 and 3 are also almost 0 A. Since no current flows between the source and drain of the low-side MOS transistor 51, the source-drain voltage Vds becomes small. Depending on the set value of the reference voltage Vref ′ shown in FIG. Although it may occur that the determination cannot be made accurately, such a situation can be avoided by setting a value equal to or lower than the adjustment voltage Vreg as the second threshold voltage V2. Note that the point of continuing stable power supply to the electric load 10 is the same as in the case of (1) described above, and therefore the second voltage is set to be equal to or higher than the minimum voltage that can guarantee normal operation. The value of the threshold voltage V2 is set. Further, it can be said that the exciting current that flows through the field winding 4 during the protection operation does not contribute to the power supply to the electric load 10 and is essentially useless. Therefore, it is desirable that the second threshold voltage V2 is close to the adjustment voltage Vreg. For this reason, for example, the second threshold voltage V2 is controlled by the minimum current that can detect the source-drain voltage Vds of the low-side MOS transistor 51 (for example, about 0.5 A equivalent to the initial excitation current). The value supplied to the field winding 4 by the device 7 is set.

  In the case of (1) and (2) described above, the protection operation is canceled and the high-side MOS transistor 50 is turned on again before the output voltage sufficiently decreases. If the energy generated in the stator windings 2 and 3 at times is not sufficiently eliminated, the output voltage rises again and reaches the first threshold voltage V1, and the protection operation and its release operation are performed. It will be repeated several times.

  FIG. 9 shows the correspondence between the change in the output voltage, the protection operation, and the release operation when the protection operation is released when the output voltage becomes higher than the adjustment voltage Vreg (case (1)). FIG. In FIG. 9 (the same applies to FIG. 10 described below), “VB” indicates the output voltage of the vehicular generator 1. The “142 determination result” indicates the output of the threshold voltage determination unit 142 shown in FIG. 6. When the output voltage VB becomes higher than the first threshold voltage V1, the output voltage It is shown that when VB becomes lower than the second threshold voltage, it becomes low level. “If” indicates an exciting current flowing in the field winding 4. Further, the horizontal axis (t) indicates the passage of time.

  As shown in FIG. 9, when the energy generated in the stator windings 2 and 3 at the time of load dumping is not eliminated by the protection operation, the protection operation and its release operation are performed a plurality of times until the energy is eliminated (shown in FIG. 9). Repeated 4 times in case). When the second threshold voltage V2 is set to a value higher than the adjustment voltage Vreg, the output voltage VB is maintained at the adjustment voltage Vreg or higher while the protection operation and the release operation are repeated. For this reason, the excitation current If is not supplied from the power generation control device 7 to the field winding 4, and the excitation current If gradually decreases.

  FIG. 10 is a diagram showing the correspondence between the change in the output voltage, the protection operation, and the release operation when the protection operation is released when the output voltage becomes equal to or lower than the adjustment voltage Vreg (case (2)). It is. As shown in FIG. 10, when the energy generated in the stator windings 2 and 3 at the time of load dumping is not eliminated by the protection operation, the protection operation and its release operation are performed a plurality of times until the energy is eliminated (shown in FIG. 10). Repeated 5 times in case). When the second threshold voltage V2 is set to a value equal to or less than the adjustment voltage Vreg, the output voltage VB becomes equal to or less than the adjustment voltage Vreg before the protection operation is released, and the power generation control device 7 Since the supply of the exciting current If to the field winding 4 is temporarily resumed, the exciting current If slightly increases during this time.

  As described above, in the vehicular generator 1 according to the present embodiment, the protection operation and its release operation are performed by setting the voltage (second threshold voltage V2) for releasing the protection operation to a value higher than the adjustment voltage Vreg. The output voltage can be set to be equal to or higher than the adjustment voltage while the operation is repeated, and the supply of operating power to the electric load 10 connected to the vehicle generator 1 is maintained even when a load dump occurs. can do. In addition, even when the protection operation is repeatedly released multiple times, the timing for suppressing the generation of the surge voltage is determined each time, so that an increase in the output voltage due to the generation of the surge voltage can be suppressed. Can be stabilized.

  Further, in the vehicle generator 1 of the present invention, the voltage (second threshold voltage V2) for releasing the protection operation is set to a value equal to or lower than the adjustment voltage Vreg, so that the field winding flows when the protection operation is released. The exciting current can be increased, and the current flowing through the stator windings 2 and 3 is increased to flow the current through the MOS transistor 51 of the lower arm, thereby making it easy to determine the timing suitable for suppressing the generation of surge voltage. Become. In addition, even when the protection operation is repeatedly released multiple times, the timing for suppressing the generation of the surge voltage is determined each time, so that an increase in the output voltage due to the generation of the surge voltage can be suppressed. Can be stabilized.

  Further, not only when the protection operation is released, but also when the protection operation is performed, the protection operation can be performed while avoiding the timing at which the surge voltage is generated. Further, by repeatedly performing the protection operation and the release operation thereof, the energy generated and accumulated in the stator windings 2 and 3 at the time of load dump can be surely eliminated, and the output voltage of the electric load 10 can be reduced. It becomes possible to maintain a value necessary for normal operation.

  Further, as a timing for suppressing the generation of the surge voltage, when the MOS transistor 51 is turned on, a current flows from the phase winding connected to the MOS transistor 51 to the MOS transistor 51 (A and B in FIG. 5). A timing other than the range shown in (1) is set. As a result, instantaneous interruption or sudden change of the current flowing through the phase winding connected to the MOS transistor 51 whose on / off state is switched can be prevented, and generation of a high surge voltage in the phase winding can be suppressed.

  Further, since the MOS transistor 51 has a predetermined source-drain voltage even when it is turned on, it is possible to detect the direction of the current by detecting this voltage, and to reliably determine the timing for suppressing the generation of the surge voltage. can do.

  By the way, in this embodiment, since the transition timing to the protection operation is determined for each rectifier module, a defective portion that causes the occurrence of load dump (for example, the output terminal of the vehicle generator 1 is disconnected or the battery 9 Depending on whether the positive terminal is disconnected) or the magnitude of the phase current at that time, only one rectifier module corresponding to the one-phase phase winding may shift to the protective operation. For example, when one stator winding 2 is considered, only the rectifier module 5X may shift to the protective operation, and the other rectifier modules 5Y and 5Z may not shift to the protective operation. During the protection operation in such a case, only the low-side MOS transistor 51 of the rectifier module 5X is turned on, and the low-side MOS transistors 51 of the other rectifier modules 5Y and 5Z continue to be in the off state. For this reason, in the lower arms (low side) of the rectifier modules 5Y and 5Z in the off state, a current flows only through the diode connected in parallel with the MOS transistor 51, and the rectifier module 5X in the on state. For the MOS transistor 51, a phenomenon has been confirmed in which current does not flow in the direction from the source to the drain (the direction in which the current flows from the MOS transistor 51 toward the X-phase winding). In such a case, the source-drain voltage Vds of the MOS transistor 51 that is turned on becomes 0 V or less.

FIG. 11 is a diagram illustrating a specific example of the output of the MOS voltage detection unit 143 when only one rectifier module shifts to the protection operation. As shown in FIG. 11, when the B terminal voltage exceeds the first threshold voltage V1 at t _{0 and} only one rectifier module shifts to the protection operation, the output voltage Vds ′ of the MOS voltage detector 143 is always 2 .5V (0V for Vds) or more is maintained. Assuming such a case, the reference voltage Vref ′ used in the energization direction detection unit 144 may be replaced with a reference voltage Vref ″ higher than 2.5V. Thus, even when only one rectifier module shifts to the protection operation, even when the B terminal voltage exceeding the first threshold voltage V1 becomes equal to or lower than the second threshold voltage V2, it is normal. It is possible to return to the rectifying operation.

  In addition, the phenomenon in which the protection operation by only one rectifier module described above is performed may occur when the protection operation is canceled and the normal rectification operation is restored. That is, since the timing for returning to the normal rectifying operation is also determined for each rectifier module, when the protective operation is canceled first for two of the three rectifier modules, only the remaining one rectifier module is protected. Will be maintained. In this way, it has been confirmed that the source-drain voltage Vds of the MOS transistor 51 of the rectifier module maintaining the protective operation may not be lower than 0V.

  Even in such a case, since the B terminal voltage is already lower than the second threshold voltage V2, if it is clear that it is in the range of C shown in FIG. The normal rectification operation may be restored at the timing. For example, during the protection operation by all the rectifier modules, the timing at which the output of the energizing direction detection unit 144 alternately repeats the high level and the low level and changes from the low level to the high level is indicated by C in FIG. Corresponds to the vicinity of the left end of the range. The rotation speed before and after releasing the protection operation can be considered to be substantially constant for several rotations. Therefore, the timing determination unit 146 detects and holds the period T in which the output of the energization direction detection unit 144 changes to a high level, and immediately before the B terminal voltage becomes lower than the second threshold voltage V2. A timing is determined by determining when a cycle T or an integral multiple (2T, etc.) has elapsed from the timing when the output of the energization direction detection unit 144 changes from low level to high level (when Vds ′ becomes lower than Vref ′). The output of the determination unit 146 may be changed to a high level (a rectification restart instruction is output). Similarly, the timing determination unit 145 detects and holds the period T in which the output of the energization direction detection unit 144 changes to a high level, and energizes immediately before the B terminal voltage exceeds the first threshold voltage V1. Timing determination is performed by determining when the period T or an integral multiple (2T, etc.) has elapsed from the timing when the output of the direction detection unit 144 changes from low level to high level (when Vds 'becomes lower than Vref'). The output of the unit 145 may be changed to a high level (a protection start instruction is output).

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, in the above-described embodiment, the two stator windings 2 and 3 and the two rectifier module groups 5 and 6 are provided. However, the vehicle including one stator winding 2 and one rectifier module group 5 is provided. The present invention can also be applied to power generators.

  Further, in the above-described embodiment, the case where the rectifying operation (power generation operation) is performed using each rectifier module 5X or the like has been described. However, it is applied from the battery 9 by changing the on / off timing of the MOS transistors 50 and 51. The generated DC current may be converted into an AC current and supplied to the stator windings 2 and 3 to cause the vehicle generator 1 to perform an electric operation.

  In the above-described embodiment, each of the two rectifier module groups 5 and 6 includes three rectifier modules. However, the number of rectifier modules may be other than three.

  Further, in the above-described embodiment, the timing at which the source-drain voltage Vds of the MOS transistor 51 is detected and the protection operation is shifted based on the detected value, or the timing at which the protection operation is canceled and the normal rectification operation is shifted. However, the same timing determination may be performed by directly detecting the direction and value of the current flowing through the MOS transistor 51. For example, a current detection element (such as a resistor) may be inserted on the source side or drain side of the MOS transistor 51, and the same determination may be made based on the voltage across the element. In this case, the timing at which current flows into the phase winding through the MOS transistor 51 or a diode connected in parallel with the MOS transistor 51 (range indicated by D in FIG. 5) is reliably detected to shift to the protection operation or to perform the protection operation. Release can be made. Thereby, the instantaneous interruption and sudden change of the electric current which flows into a phase winding can be prevented, and it can suppress that a high surge voltage generate | occur | produces in a phase winding.

  In the above-described embodiment, the load dump protection determination unit 140 shown in FIG. 6 is provided for each rectifier module. Among them, the B voltage detection unit 141 and the threshold voltage determination unit 142 are Instead of providing each rectifier module, one may be provided as a whole or one for each of the rectifier module groups 5 and 6. In addition to the case where a rectifier module corresponding to each phase winding is provided and synchronous rectification control is performed for each rectifier module, the present invention is applied to a configuration where synchronous rectification control is performed using a common control device. can do. However, even in this case, the MOS voltage detection unit 143, the energization direction detection unit 144, and the timing determination units 145 and 146 shown in FIG. 6 need to be provided for each lower arm (low side) MOS transistor.

  In the embodiment described above, MOS transistors are used for both the upper arm and the lower arm. However, only the lower arm may be a MOS transistor, and the upper arm may be formed of a diode.

  Further, in the above-described embodiment, when “(1) a value higher than the adjustment voltage Vreg is set as the second threshold voltage V2”, the output voltage becomes higher than the adjustment voltage Vreg during the protection operation. Therefore, the supply of the excitation current from the power generation control device 7 to the field winding 4 is stopped, but a constant excitation current may be supplied from the power generation control device 7 to the field winding 4 even during the protection operation. .

  FIG. 12 shows the change in the output voltage when the protection operation is canceled when the output voltage becomes higher than the adjustment voltage Vreg, and when the excitation current is forced to flow during the protection operation. It is a figure which shows a response | compatibility with protection operation | movement and its cancellation | release operation | movement. The meaning of “VB” and the like is the same as in FIG. 9 and FIG. As shown in FIG. 12, a predetermined excitation current (detection current) Ifmin is supplied from the power generation control device 7 to the field winding 4 while the protection operation is repeatedly performed. As a result, by increasing the current flowing through the stator windings 2 and 3 when the protective operation is released and causing the current to flow through the MOS transistor 51 of the lower arm, it is easy to determine the timing suitable for suppressing the occurrence of surge voltage. The exciting current Ifmin is preferably small. For example, a minimum current value (for example, about 0.5 A equivalent to the initial exciting current) that can detect the source-drain voltage Vds of the MOS transistor 51 is set. .

Specifically, a signal indicating the timing at which the output level of the threshold voltage determination unit 142 in the load dump protection determination unit 140 has changed (timing indicated by t _{1 to} t ₈ in FIG. 12) is sent from the control unit 100. Transmission is performed toward the power generation control device 7 via the communication circuit 180. The power generation control device 7 determines whether or not the protection operation is being repeatedly performed based on these signals sent from each rectifier module, and when it is being performed, the output voltage is higher than the adjustment voltage Vreg. Even in this case, the exciting current Ifmin is forced to flow through the field winding 4.

  As described above, according to the present invention, the voltage for releasing the protection operation (second threshold voltage V2) is set to a value higher than the adjustment voltage Vreg, so that the protection operation and the release operation are repeated. The output voltage can be set to be equal to or higher than the adjustment voltage, and even when a load dump occurs, the supply of operating power to the electric load 10 connected to the vehicle generator 1 can be maintained. . In addition, even when the protection operation is repeatedly released multiple times, the timing for suppressing the generation of the surge voltage is determined each time, so that an increase in the output voltage due to the generation of the surge voltage can be suppressed. Can be stabilized.

DESCRIPTION OF SYMBOLS 1 Vehicle generator 2, 3 Stator winding 4 Field winding 5, 6 Rectifier module group 5X, 5Y, 5Z, 6U, 6V, 6W Rectifier module 7 Power generation control apparatus 8 ECU
DESCRIPTION OF SYMBOLS 9 Battery 10 Electric load 12 Charging line 50, 51 MOS transistor 54 Control circuit 100 Control part 140 Load dump protection determination part 141 B voltage detection part 142 Threshold voltage determination part 143 MOS voltage detection part 144 Current direction detection part 145,146 Timing determination unit 170, 172 driver

Claims (18)

An armature winding having two or more phase windings;
A switching circuit configured to rectify an induced voltage of the armature winding by configuring a bridge circuit having a plurality of lower arms configured by switching elements having diodes connected in parallel;
A first control unit for controlling on / off of the switching element;
A field winding for magnetizing the rotor field poles;
A second control unit for adjusting a current flowing through the field winding so that an output voltage of the switching unit becomes a predetermined adjustment voltage;
The output voltage of the switching unit is monitored, and when the output voltage exceeds a first threshold voltage, an instruction to turn on the switching element constituting the lower arm is given to the control unit, Suitable for suppressing generation of surge voltage when the output voltage becomes lower than the second threshold voltage lower than the first threshold voltage after exceeding the first threshold voltage A load dump protection determination unit that instructs the first control unit to turn off the switching element constituting the lower arm after waiting for timing,
And the second threshold voltage is set to a value higher than the adjustment voltage. In claim 1,
The load dump protection determination unit configures the lower arm after detecting that the output voltage has exceeded the first threshold voltage and waiting for a timing suitable for suppressing the occurrence of a surge voltage. A vehicular generator characterized in that an instruction to turn on the switching element is given to the first control unit. In claim 1 or 2,
Until the energy stored in the armature winding at the time of load dump is consumed by passing a current through a path for turning on the switching element constituting the lower arm, the first threshold voltage and the The vehicular generator, wherein the output voltage repeatedly rises and falls between the second threshold voltage and the switching elements constituting the lower arm are repeatedly turned on and off. In any one of Claims 1-3,
The timing for suppressing the generation of the surge voltage is a timing other than the timing at which current flows from the phase winding connected to the switching element to the switching element when the switching element constituting the lower arm is turned on. A vehicular generator characterized by that. In claim 4,
The timing for suppressing the generation of the surge voltage is the timing at which current flows from the switching element to the phase winding connected to the switching element when the switching element constituting the lower arm is turned on. A vehicular generator. In claim 4 or 5,
The switching element is a MOS transistor;
The load dump protection determination unit is configured to detect a MOS voltage detector that detects a source-drain voltage of the MOS transistor, and to turn on the MOS transistor when the MOS transistor is turned on based on the detected source-drain voltage. A vehicle comprising: an energization direction detection unit that detects a direction of a current flowing through the vehicle; and a timing determination unit that determines a timing for suppressing the generation of the surge voltage based on a detection result by the energization direction detection unit. Generator. In claim 6,
When the output voltage exceeds the first threshold voltage and the switching element constituting the lower arm is turned on, the second control unit applies a detection current to the field winding. Supply is made,
The vehicle generator according to claim 1, wherein the detection current is a current capable of detecting a source-drain voltage of the MOS transistor. An armature winding having two or more phase windings;
A switching circuit configured to rectify an induced voltage of the armature winding by configuring a bridge circuit having a plurality of lower arms configured by switching elements having diodes connected in parallel;
A first control unit for controlling on / off of the switching element;
A field winding for magnetizing the rotor field poles;
A second control unit for adjusting a current flowing through the field winding so that an output voltage of the switching unit becomes a predetermined adjustment voltage;
The output voltage of the switching unit is monitored, and when the output voltage exceeds a first threshold voltage, an instruction to turn on the switching element constituting the lower arm is given to the control unit, Suitable for suppressing generation of surge voltage when the output voltage becomes lower than the second threshold voltage lower than the first threshold voltage after exceeding the first threshold voltage A load dump protection determination unit that instructs the first control unit to turn off the switching element constituting the lower arm after waiting for timing,
And the second threshold voltage is set to a value equal to or lower than the adjustment voltage. In claim 8,
The load dump protection determination unit configures the lower arm after detecting that the output voltage has exceeded the first threshold voltage and waiting for a timing suitable for suppressing the occurrence of a surge voltage. A vehicular generator characterized in that an instruction to turn on the switching element is given to the first control unit. In claim 8 or 9,
Until the energy stored in the armature winding at the time of load dump is consumed by passing a current through a path for turning on the switching element constituting the lower arm, the first threshold voltage and the The vehicular generator, wherein the output voltage repeatedly rises and falls between the second threshold voltage and the switching elements constituting the lower arm are repeatedly turned on and off. In any one of Claims 8-10,
The timing for suppressing the generation of the surge voltage is a timing other than the timing at which current flows from the phase winding connected to the switching element to the switching element when the switching element constituting the lower arm is turned on. A vehicular generator characterized by that. In claim 11,
The timing for suppressing the generation of the surge voltage is the timing at which current flows from the switching element to the phase winding connected to the switching element when the switching element constituting the lower arm is turned on. A vehicular generator. In claim 11 or 12,
The switching element is a MOS transistor;
The load dump protection determination unit is configured to detect a MOS voltage detector that detects a source-drain voltage of the MOS transistor, and to turn on the MOS transistor when the MOS transistor is turned on based on the detected source-drain voltage. A vehicle comprising: an energization direction detection unit that detects a direction of a current flowing through the vehicle; and a timing determination unit that determines a timing for suppressing the generation of the surge voltage based on a detection result by the energization direction detection unit. Generator. In claim 13,
The second threshold voltage is equal to or higher than the second threshold voltage after the output voltage exceeds the first threshold voltage and the switching element constituting the lower arm is turned on. A vehicle in which a current capable of detecting a source-drain voltage of the MOS transistor when the voltage is lowered to a voltage is set to a value supplied to the field winding by the second control unit. Generator. In any one of Claims 6, 7, 13, and 14,
The vehicular generator is characterized in that the timing of suppressing the generation of the surge voltage is a timing at which the source-drain voltage of the MOS transistor with respect to the source side becomes 0 V or less. In any one of Claims 6, 7, 13, and 14,
The vehicular generator is characterized in that the timing of suppressing the generation of the surge voltage is a timing delayed by a predetermined period after the source-drain voltage of the MOS transistor with respect to the source side becomes 0 V or less. In claim 16,
The vehicle generator according to claim 1, wherein the predetermined period is a period corresponding to a quarter of a period of the induced voltage of the phase winding. In any one of Claims 1-3 and 8-10,
The timing for suppressing the generation of the surge voltage is such that the direction of the current flowing through the switching element after the output voltage exceeds the first threshold voltage and the switching element constituting the lower arm is turned on. A vehicle generator characterized in that the timing is synchronized with a cycle of timing that changes from a direction flowing from the phase winding to a direction flowing toward the phase winding.

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