JP2014087195A - Rotary electric machine for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary electric machine for a vehicle capable of quickly terminating high-voltage generation at load dump.SOLUTION: A load dump protection determination unit 140 monitors an output voltage, and when the output voltage becomes larger than a first threshold voltage V1, instructs a controller 100 to turn on a MOS transistor 51 configuring a lower arm. When the output voltage becomes lower than a second threshold voltage V2 lower than the first threshold voltage V1 after the output voltage becomes larger than the first threshold voltage V1, the load dump protection determination unit 140 determines that an intermediate timing of a timing when a drain voltage of the MOS transistor 51 becomes lower than a predetermined voltage and a timing when the drain voltage becomes larger than the predetermined voltage as a timing suitable for suppressing generation of a surge voltage, and waits for an arrival of this timing to instruct the controller 100 to turn off the MOS transistor 51.

Description

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

  Conventionally, each of the plurality of rectifier modules has a load dump protection determination unit, and when the output voltage exceeds the first threshold voltage, the lower arm MOS transistor is turned on. There is known a vehicular generator that turns off a MOS transistor at a timing suitable for suppressing the occurrence of a surge voltage when the voltage is lower than a threshold voltage (for example, see Patent Document 1). In addition, when the output voltage is lower than the second threshold voltage, the vehicular generator can detect a MOS transistor after a predetermined time if a timing suitable for suppressing the occurrence of surge voltage cannot be detected. Turn off.

JP 2012-29346 A

By the way, in the vehicle generator disclosed in Patent Document 1, when only one phase of the three-phase output of the armature winding turns on the lower arm MOS transistor, the electromotive voltage between the phases is the output voltage V _If it becomes _B or less, no phase current flows even if the AC voltage applied to the source of this MOS transistor becomes the minimum value. For this reason, the parasitic diode connected between the source and drain of the MOS transistor has a reverse bias voltage, and the drain voltage does not fall below 0V. As a result, even if the electromotive voltage between the phases is close to the output voltage V _B , it is impossible to detect the timing suitable for suppressing the generation of the surge voltage, and a surge voltage is generated depending on the timing when the MOS transistor is turned off after a predetermined time. There was a problem that. Even if the drain voltage detection threshold value is set to a value higher than 0V, it is conceivable that the set threshold value actually shifts to 0V or less due to a circuit error. Even in such a case, when the above-described electromotive force between the phases is equal to or lower than the output voltage, it is impossible to detect timing suitable for suppressing the generation of the surge voltage.

  The present invention was created in view of the above points, and an object of the present invention is to provide a vehicular rotating electrical machine capable of quickly terminating the generation of a high voltage during load dump.

  In order to solve the above-described problems, a rotating electrical machine for a vehicle according to the present invention includes an armature winding, a switching unit, a control unit, and a load dump protection determination unit. The armature winding has two or more phase windings. The switching unit configures a bridge circuit having a plurality of lower arms configured by switching elements having diodes connected in parallel, and rectifies the induced voltage of the armature winding. The control unit controls on / off of the switching element. The load dump protection determination unit monitors the output voltage of the switching unit, and gives an instruction to the control unit to turn on the switching element constituting the lower arm when the output voltage exceeds the first threshold voltage. The armature of the switching element constituting the lower arm when the output voltage becomes lower than the second threshold voltage lower than the first threshold voltage after exceeding the first threshold voltage An intermediate timing between the timing when the winding side voltage falls below the specified voltage and the timing when it exceeds the specified voltage is set as a timing suitable for suppressing the occurrence of surge voltage, and an instruction to turn off the switching elements constituting the lower arm is waited for the arrival of this timing Perform for the control unit.

  As a result, when the electromotive voltage between the phases becomes smaller than the output voltage, or when the armature winding side voltage of the switching element becomes 0 V or less, the accuracy of the detecting means is deteriorated, and the armature winding becomes Even when it is not possible to detect that the voltage has become 0 V or less even when the current is drawn, it is possible to detect a timing suitable for suppressing the occurrence of the surge voltage. Therefore, it is possible to prevent a large surge voltage from being generated when canceling the load dump protection operation, and to quickly terminate the generation of a high voltage during the load dump.

It is a figure which shows the structure of the generator for vehicles of one Embodiment. It is a figure which shows the detailed structure of a field control part. 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 diagram showing the relationship between the determination result of the output voltage V _B and the threshold voltage determining unit. It is a figure which shows the relationship between source-drain voltage Vds 'and reference voltage Vref'. It is a figure which shows the outline | summary of an intermediate | middle timing detection. It is explanatory drawing of the rectification resumption operation | movement using an intermediate | middle timing. It is a figure which shows the modification of an intermediate | middle timing detection.

  Hereinafter, a vehicular generator according to an embodiment to which a vehicular rotating electrical machine of the present invention is applied will be described with reference to the drawings. As shown in FIG. 1, the vehicle generator 1 according to the present embodiment includes two stator windings (armature windings) 2 and 3, field windings 4, two rectifier module groups 5 and 6, and field control. The unit 7 includes a Zener diode 20 and a diode 22. 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. By passing a field current, the field pole is magnetized. 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 the other 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 field control unit 7 controls the field current flowing through the field winding 4 connected via the F terminal in accordance with the output voltage of the rectifier module groups 5 and 6, and adjusts the field current to the vehicle. Control is performed so that the output voltage (output voltage of each rectifier module) V _{B of the} generator 1 for electric power becomes the adjustment voltage Vreg. For example, field control unit 7, the supply of the field current to the field winding 4 is stopped when the output voltage V _B is higher than the regulated voltage Vreg, it output voltage V _B is lower than the regulated voltage Vreg In this case, the field current is supplied to the field winding 4 so that the output voltage V _B is controlled to the adjustment voltage Vreg. The field controller 7 detects the rotation speed of the rotor based on any phase voltage (for example, the X phase) of the stator winding applied to the P terminal, and when the rotation stop is detected, the field winding The field current supplied to the line 4 is reduced. Specifically, a value corresponding to the initial excitation state (for example, a value around 2A) is set. Further, the field control unit 7 is connected to the ECU 8 (external control device) via the communication terminal L and the communication line, and uses bidirectional serial communication (for example, LIN (Local Interconnect Network) protocol) with the ECU 8. LIN communication) and transmit or receive a communication message.

  The Zener diode 20 is connected in parallel to the outputs of the two rectifier module groups 5 and 6. Specifically, the Zener diode 20 is arranged so that the output terminal side of the vehicle generator 1 is a cathode and the ground side is an anode. The Zener diode 20 is connected in series with a diode 22 as a current limiting element that blocks a current that flows when the battery 9 is reversely connected to the output side of the vehicle generator 1. The direction in which the current is blocked is such that the anode side of the diode 22 is the output terminal side of the vehicle generator 1. In FIG. 1, the diode 22 is disposed on the output terminal side of the vehicle generator 1, but the Zener diode 20 may be disposed on the output terminal side of the vehicle generator 1. The Zener diode 20 described above has a Zener voltage lower than the breakdown voltage of the switching element and the breakdown voltage of the field control unit 7.

  As shown in FIG. 2, the field controller 7 includes a MOS transistor 71, a freewheeling diode 72, resistors 73 and 74, a voltage comparison circuit 75, a field current control circuit 76, a rotation detection circuit 77, a communication circuit 78, a power supply circuit 79, A capacitor 80 is provided. The communication circuit 78 performs serial communication with the ECU 8. Thereby, data such as the adjustment voltage Vreg sent from the ECU 8 can be received.

  The resistors 73 and 74 constitute a voltage dividing circuit, and a voltage obtained by dividing the generated voltage (output voltage) of the vehicle generator 1 is input to the voltage comparison circuit 75. The voltage comparison circuit 75 compares the generated voltage divided by the resistors 73 and 74 with the reference voltage corresponding to the adjustment voltage Vreg received by the communication circuit 78. For example, as a comparison result, when the reference voltage is higher than the generated voltage, a high level signal is output. Conversely, when the generated voltage is higher than the reference voltage, a low level signal is output. .

  The field current control circuit 76 controls the MOS transistor 71 on and off with a PWM signal having a drive duty determined based on the output (voltage comparison result) of the voltage comparison circuit 75. Note that the field current control circuit 76 may perform gradual excitation control or the like that gradually changes the field current in order to suppress sudden fluctuations in the output current.

The rotation detection circuit 77 is connected to the X-phase winding of one of the stator windings 2 via the P terminal. Specifically, the rotation detection circuit 77 is based on the phase voltage V _P appearing at the end of the X-phase winding. The rotation is detected by detecting that the magnitude relationship between the phase voltage and the reference voltage for rotation detection changes periodically. When the short circuit failure has not occurred in the rectifier module 5X, the stator winding 2 or the like, the phase voltage V _P having a predetermined amplitude appears at the P terminal during power generation. Therefore, rotation detection based on the phase voltage V _P is performed. It becomes possible.

  The field current control circuit 76 receives the rotation detection result from the rotation detection circuit 77 and outputs a PWM signal necessary for supplying the field winding 4 with a field current necessary for the power generation operation during the rotation detection. When the rotation is stopped (rotation cannot be detected) for a predetermined time (or period) or longer, a PWM signal necessary for setting the field current to a value corresponding to the initial excitation state is output.

  The power supply circuit 79 supplies an operating voltage to each circuit included in the field control unit 7. The capacitor 80 is for removing noise entering from the output terminals of the rectifier module groups 5 and 6, and has a capacity of about 1 μF, for example.

  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. The rectifier module 5X and the other rectifier modules 5Y, 5Z, 6U, 6V, 6W have the same configuration. Hereinafter, details of the rectifier module 5X will be described. As shown in FIG. 3, the rectifier module 5 </ b> X 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.

  As shown in FIG. 4, 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 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 field controller 7, and can be realized 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 includes a differential amplifier and an analog-digital converter (AD) that converts the output into digital data. The battery voltage detection unit 110 is connected to the output terminal of the vehicle generator 1 via the charging line 12. The data corresponding to the voltage of the positive terminal of the battery 9 is output.

  The operation detection unit 120 includes a differential amplifier and an analog-digital converter (AD) that converts an output thereof into digital data. The operation detection unit 120 includes a source-drain voltage of the high-side MOS transistor 50 (FIG. 3 and FIG. 3). 4), data corresponding to the voltage between terminals B and C is output. 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 thereof into digital data, and the source-drain voltage (FIGS. 3 and 4) 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 to start the protection operation (protection start instruction) is issued when V1 (for example, 20 V) is exceeded, and then the B terminal voltage is lowered by this protection operation and is lower than the first threshold voltage V1. An instruction to stop the protection operation (protection stop instruction) is made when the voltage falls below the threshold voltage V2 (for example, 16.5 V). The control unit 100 executes a protection operation or a rectification operation after the protection operation is canceled in accordance with a protection start / protection stop instruction or the like by 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 communication circuit 78 of the field control unit 7, and is commonly connected to a communication terminal and a communication line that connect between the field control unit 7 and the ECU 8. Serial communication (for example, LIN communication using the LIN protocol), and a communication message is transmitted or received.

  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. .

  In the transition state diagram shown in FIG. 5, “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. In FIG. 6, (A) shows the phase voltage at the normal time, and (B) shows the phase voltage when the load dump occurs.

  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 this occurs, the high-side MOS transistor 50 is turned on, and the low-side MOS transistor 51 is turned on when the phase voltage Vx drops below -α (FIG. 6A).

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 occurs in which the phase voltages of 2 and 3 are temporarily increased (FIG. 6B). 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, the field controller 7 or various electric loads 10 in the vehicle generator 1 are protected. In order to do this, after going through the “protection preparation” procedure, the process proceeds to the protection operation (FIG. 5).

  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 changes in a range from -α to + α (-0.1 V to +0.1 V) as indicated by Vp in FIG.

  Incidentally, in the range indicated by A in FIG. 6, 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, A large surge voltage is generated because the current that is flowing is interrupted.

  In the range indicated by B in FIG. 6, 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 this 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 it is in the ranges indicated by A and B in FIG. 6, in this embodiment, it is included in the range indicated by C in FIG. 6. 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. 6B is generated. In this state, turning off the low-side MOS transistor cuts off a large phase current that has been flowing through the MOS transistor 51 in the range indicated by A and B. 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. 6, as in the above-described “protection preparation” procedure. 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.

  Further, when the phase current flowing during the protection operation is small (when the excitation current just before entering the protection operation is small or when the rotation speed is low), the phase voltage Vp as shown in FIG. Thus, it is difficult to determine the return timing based on the phase voltage Vp. In this embodiment, the protection operation is forcibly released in such a case. Details of the forced protection operation cancellation will be described later.

  Next, details of the load dump protection determination unit 140 that performs the protection preparation operation and the recovery preparation operation will be described. As shown in FIG. 7, 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, a conduction direction detection unit 144, a MOS voltage Va detection unit 145, an intermediate timing. A detection unit 146, an OR circuit 147, and timing determination units 148 and 149 are provided.

The B voltage detector 141 detects the output voltage (B terminal voltage) V _B of the vehicle generator 1 (rectifier module groups 5 and 6). The threshold voltage determining unit 142, the output voltage V _B is whether it is higher than the first threshold voltage V1, once the first output voltage V _B which is higher than the threshold voltage V1 second It is determined whether or not the threshold voltage is lower.

In FIG. 8, the horizontal axis represents the output voltage V _B , and the vertical axis represents the determination result of the threshold voltage determination unit 142. As shown in FIG. 8, when the output voltage V _B increases and exceeds the first threshold voltage V1 (for example, 20V), the threshold voltage determination unit 142 changes the output from the low level (L). Switch to high level (H). Further, when the output voltage V _B once exceeding V1 becomes low and becomes lower than the second threshold voltage V2 (for example, 16.5 V), 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. 3 and 4) 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 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. The fact 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. 6. 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.

  In FIG. 9, 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. 9, −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.

  The energization direction detection unit 144 compares the output voltage Vds ′ of the MOS voltage detection unit 143 with the reference voltage Vref ′, and outputs when Vds ′ is Vref ′ or less (when the source-drain voltage Vds is 0 V or less). Is set to high level, and if it is high, output is set to low level. 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 148, when the output of the energization direction detection unit 144 changes to high level after the output of the threshold voltage determination unit 142 changes from low level to high level, that is, with the occurrence of a load dump. When the output voltage V _B becomes higher than the first threshold voltage V1 and is determined to be in the range indicated by C in FIG. 6, the output is set to the high level. The high level output of the timing determination unit 148 corresponds to the “protection start instruction”, and when this protection start instruction is output, the control unit 100 drives the driver 170 to drive 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 149 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 V _B once exceeding the first threshold voltage V1 is again lower than the second threshold voltage V2 and is in the range indicated by C in FIG. Set the output to high level. The high level output of the timing determination unit 149 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. This point applies to both of the two timing determination units 148 and 149. A function of delaying the timing of changing to the high level for a predetermined period may be provided to at least one of the timing determination units 148 and 149, and the timing may be changed in these.

  In the examples shown in FIGS. 6B and 9, the source-drain voltage Vds when the MOS transistor 51 is turned on is assumed to change in the range of −0.1 V to +0.1 V. When the phase current (source-drain current) is small, the source-drain voltage Vds becomes small, and the source-drain voltage Vds ′ may not become lower than the reference voltage Vref ′ during recovery preparation. Then, the output of the energization direction detection unit 144 does not change to a high level, the output of the timing determination unit 149 also maintains a low level, and a rectification restart instruction is not issued. Assuming such a case, in this embodiment, a MOS voltage Va detector 145, an intermediate timing detector 146, and an OR circuit 147 are provided.

The MOS voltage Va detection unit 145 detects both the timing when the drain voltage V _D that is the armature winding side voltage of the low-side MOS transistor 51 falls below and exceeds the predetermined voltage Va of 0 V or more during the load dump protection operation. To do. The intermediate timing detection unit 146 calculates a required time Ta from the timing when the drain voltage V _D, which is the armature winding side voltage of the MOS transistor 51 on the low side, falls below the predetermined voltage Va to the timing when it next rises. The point in time when Ta / 2 has elapsed after the drain voltage V _D has fallen below the predetermined voltage Va is detected as an intermediate timing, and the output is changed from a low level to a high level when the intermediate timing arrives.

As shown in FIG. 10, the drain voltage V _D of the MOS transistor 51 on the low side changes up and down around 0V. The intermediate timing detection unit 146 calculates a required time Ta from the timing t1 when the drain voltage V _D falls below the predetermined voltage Va to the next timing t2 when the drain voltage V _D falls below the predetermined voltage Va, and then the drain voltage V _D falls below the predetermined voltage Va. A time point at which the time Ta / 2 has elapsed from the timing t3 is detected as an intermediate timing tm. In this example, in order to detect the intermediate timing tm, the required time Ta before one cycle is used, but the required time Ta before two cycles or more may be used.

The OR circuit 147 has two input terminals, and outputs a high level when a high level signal is input to at least one of the input terminals. The output of the energization direction detection unit 144 is input to one input terminal. The output of the intermediate timing detector 146 is input to the other input terminal. Therefore, when the phase voltage V _LD enters the range indicated by C in FIG. 6 and the output of the energization direction detection unit 144 changes from the low level to the high level, or when the intermediate timing tm is detected and the intermediate timing detection unit 146 When the output changes from low level to high level, the output of the OR circuit 147 becomes high level. The output of the OR circuit 147 is input to timing determination units 148 and 149.

  That is, the timing determination unit 149 to which the output of the OR circuit 147 is input does not cause the output of the energization direction detection unit 144 to become high level after the output of the threshold voltage determination unit 142 changes from high level to low level. However, when the intermediate timing tm arrives and the output of the intermediate timing detection unit 146 becomes high level, a commutation restart instruction is output. When this commutation restart instruction is output, the control unit 100 drives the driver 172 to turn off the low-side MOS transistor 51 (FIG. 11). Thereafter, the control unit 100 resumes the synchronous rectification control operation.

As described above, in the vehicle generator 1 of the present embodiment, the output voltage V _B becomes lower than the second threshold voltage V2 lower than the first threshold voltage V1 during the load dump protection operation. Sometimes, the intermediate timing between the timing when the stator winding side voltage (drain voltage V _D ) of the switching element (MOS transistor 51) constituting the lower arm falls below and exceeds the predetermined voltage Va is used to suppress the generation of the surge voltage. The control unit 100 is instructed to turn off the switching elements constituting the lower arm after setting the appropriate timing and waiting for the arrival of this timing. As a result, the accuracy of the detection means (MOS voltage detection unit 143) for detecting that the electromotive voltage between the phases is smaller than the output voltage or that the stator winding side voltage of the switching element has become 0 V or less is deteriorated. Even when it is not possible to detect that the voltage is 0 V or less even when the current is drawn into the stator winding, it is possible to detect a timing suitable for suppressing the occurrence of the surge voltage. Therefore, it is possible to prevent a large surge voltage from being generated when canceling the load dump protection operation, and to quickly terminate the generation of a high voltage during the load dump.

  In particular, the load dump protection determination unit 140 determines that ½ of the required period Ta from the timing when the stator winding side voltage of the switching element falls below the predetermined voltage Va set to 0 V or higher to the timing when it exceeds the stator voltage. The control unit 100 is instructed to turn off the switching element at a timing after the winding-side voltage has dropped. As a result, the surge protection operation can be terminated at a timing at which the generation of the surge voltage when the switching element is turned off can be minimized.

  The timing determination unit 149 in the load dump protection determination unit 140 is suitable for suppressing the occurrence of surge voltage when the stator winding side voltage (source-drain voltage Vds of the MOS transistor 51) becomes 0 V or less. It is set as timing. As a result, when the electromotive voltage is sufficiently generated or when it is possible to accurately detect that the armature winding side voltage of the switching element has become 0 V or less, the generation of the surge voltage is surely suppressed. The switching element can be turned off at a timing that can be performed.

Further, the timing determination unit 148 in the load dump protection determination unit 140 detects that the output voltage V _B exceeds the first threshold voltage V1, and then at a timing suitable for suppressing the occurrence of the surge voltage. The control unit 100 is instructed to turn on the switching elements constituting the lower arm. As a result, it is possible to suppress the occurrence of surge voltage even at the start of the load dump protection operation.

  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.

  In the above-described embodiment, the rectifier module corresponding to each phase winding is provided and the synchronous rectification control is performed for each rectifier module. However, the synchronous rectification control is performed using a common control device. The present invention can also be applied to the configuration.

  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.

  In the above-described embodiment, the Zener diode 20 and the diode 22 are provided outside the field control unit 7, but these (or a part) may be provided in the field control unit 7. As a result, it is not necessary to mount the Zener diode 20 or the diode 22 as a single component on the vehicle generator 1, and thus the configuration can be simplified. Further, although the capacitor 80 is provided in the field control unit 7, it may be provided outside the field control unit 7.

In the above-described embodiment, the time ½ of the required time Ta from the timing when the drain voltage V _D of the MOS transistor 51 is lower than the predetermined voltage Va to the timing when the drain voltage V _D is higher than the predetermined voltage Va elapses from the next lower timing than the predetermined voltage Va. The timing tm is determined as the timing at which the generation of the surge voltage can be suppressed, but instead of this elapsed time (Ta / 2), an elapsed time obtained by subtracting a predetermined time α from Ta / 2 (Ta shown in FIG. 12). / 2-α) may be used. As a result, when the MOS transistor 51 is used as the switching element, the surge protection operation can be terminated at a timing at which generation of a surge voltage is suppressed.

  In particular, as the predetermined time α in this case, a value corresponding to a delay time from when the load dump protection determination unit 140 instructs the control unit 100 to turn off the MOS transistor 51 to when the MOS transistor 51 is turned off is used. Is desirable. Thereby, when the MOS transistor 51 is used as the switching element, the MOS transistor 51 can be turned off and the surge protection operation can be completed at a timing at which the generation of the surge voltage can be minimized.

  As described above, according to the present invention, the accuracy of the detection means for detecting when the electromotive voltage between the phases becomes smaller than the output voltage or when the armature winding side voltage of the switching element becomes 0 V or less. Even if it becomes worse and it is not possible to detect that the voltage has fallen to 0 V or less even when the current is drawn into the armature winding, it is possible to detect a timing suitable for suppressing the occurrence of the surge voltage. Therefore, it is possible to prevent a large surge voltage from being generated when canceling the load dump protection operation, and to quickly terminate the generation of a high voltage during the load dump.

2, 3 Stator winding 5, 6 Rectifier module group 51 MOS transistor 100 Control unit 140 Load dump protection determination unit 146 Intermediate timing detection unit 148, 149 Timing determination unit

Claims (6)

An armature winding (2, 3) having two or more phase windings;
A switching unit (5, 6) that configures a bridge circuit having a plurality of lower arms configured by switching elements (51) connected in parallel with a diode, and rectifies an induced voltage of the armature winding;
A control unit (100) for controlling on / off of the switching element;
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, The switching element constituting the lower arm when the output voltage becomes lower than a second threshold voltage lower than the first threshold voltage after exceeding a first threshold voltage An intermediate timing between the timing at which the armature winding side voltage of the armature winding is lower than the predetermined voltage and the timing at which the armature winding side voltage exceeds the predetermined voltage is set as a timing suitable for suppressing the generation of the surge voltage. A load dump protection determination unit (140, 146, 148, 149) for instructing the control unit to turn off,
A vehicular rotating electrical machine comprising: In claim 1,
The load dump protection determination unit is configured such that a half of a required period from a timing when the armature winding side voltage of the switching element falls below the predetermined voltage set to 0 V or more to a timing when the voltage exceeds the predetermined voltage is the armature winding. A rotating electrical machine for a vehicle, wherein the controller is instructed to turn off the switching element at a timing after the line-side voltage has dropped. In claim 1 or 2,
The switching element is a MOS transistor;
The load dump protection determination unit turns off the MOS transistor at a timing obtained by subtracting a predetermined time from a half of the time required until the drain voltage of the MOS transistor is lower than the predetermined voltage. The rotating electrical machine for a vehicle is characterized in that an instruction is given to the control unit. In claim 3,
The predetermined time is a value corresponding to a delay time from when the load dump protection determination unit instructs the control unit to turn off the MOS transistor until the MOS transistor is turned off. Rotating electric machine. In any one of Claims 1-4,
The load dump protection determination unit (149) sets the timing suitable for suppressing the generation of the surge voltage even when the armature winding side voltage is 0V or less. Rotating electric machine. In any one of Claims 1-5,
The load dump protection determination unit (148) configures the lower arm at a timing suitable for suppressing generation of a surge voltage after detecting that the output voltage exceeds the first threshold voltage. A rotating electrical machine for a vehicle, wherein an instruction to turn on the switching element is given to the control unit.

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