JP2013027131A - Power line control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid melting of an electromagnetic relay when switching between a motor drive power line and a generation power line by the electromagnetic relay.SOLUTION: A power line control device has: a motor power generator 22 switchable to any one of motor drive and power generation actuation; a motor drive power line Lm for sending a drive power required for the motor drive from a battery 19 to the motor power generator; a generation power line Lg for sending a generated power by the power generation actuation from the motor power generator to an electric load and the battery; an inverter 23 electrically connected between these power lines and the motor power generator; an electromagnetic relay 25 switching between both power lines; and short circuit control means controlling a switching element included in the inverter so as to short-circuit at least one of a U-phase coil, a V-phase coil and a W-phase coil included in the motor power generator to the ground. A switching operation of the electromagnetic relay is performed in a state that the ground short circuit is performed by the short circuit control means.

Description

  The present invention relates to a power line control device applied to a power supply system that switches a motor drive power line and a generated power line with an electromagnetic relay.

  2. Description of the Related Art Conventionally, a motor generator that makes an engine starter motor function also as a generator is known, particularly in a two-wheeled vehicle. Patent Document 1 describes that a motor drive power line and a power generation power line described below are switched by an electromagnetic relay in accordance with switching between motor drive and power generation operation.

  That is, when the motor is driven, the motor driving power line is set assuming that a large current flows, and the driving power required for motor driving is supplied from the battery to the motor generator (see FIG. 3A). . On the other hand, at the time of power generation, the motor generator is switched to a generated power line that directly flows generated power to an electric load (for example, a fuel pump, a fuel injection valve, an ignition device, etc.) (see FIG. 3B).

  As described above, according to the configuration in which the two power lines are switched, the power supply to the electric load can be performed directly from the motor generator, not from the battery. Therefore, current loss via the battery can be eliminated, and power can be reliably supplied irrespective of the battery state.

JP 2002-98032 A

  However, since a current always flows through the electromagnetic relay, an arc is generated at the relay contact when both power lines are switched by the electromagnetic relay, and there is a concern that the relay contact may be melted.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a power supply system that avoids melting of the electromagnetic relay when switching the motor drive power line and the generated power line with the electromagnetic relay. There is to do.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  According to the first aspect of the present invention, a motor generator that can be switched between a motor drive for rotating the output shaft of the internal combustion engine and a power generation operation by the output shaft, and the drive power required for the motor drive from the battery A motor drive power line flowing to the motor generator, a generated power line flowing the generated power from the motor generator to the electric load and the battery, the motor drive power line, the generated power line, and the motor power generation An inverter that is electrically connected to a motor, converts driving power from the battery from direct current to alternating current when the motor is driven, and converts power generated from the motor generator from alternating current to direct current during the power generation operation, and Select which of the motor drive power line and the generated power line is to be energized with the inverter. Assuming obtain an electromagnetic relay, to be applied to a power supply system comprising a.

  And a short control means for controlling a switching element of the inverter so that at least one of the U-phase coil, the V-phase coil and the W-phase coil of the motor generator is short-circuited to the ground. The electromagnetic relay is switched and operated in a short-circuited state.

  According to this, since the short control means for short-circuiting at least one of the phase coils of the motor generator is provided, the current flows from the motor generator to the ground by short-circuiting the ground, so that the current flows to both power lines. The current can be reduced. Since the electromagnetic relay is switched and operated in such a ground-shorted state (a state where the current flowing through both power lines is reduced), it is possible to suppress the occurrence of an arc at the relay contact of the electromagnetic relay, and to melt the relay contact. Loss can be avoided.

  According to a second aspect of the present invention, when switching from the motor drive power line to the generated power line when the rotational speed of the output shaft is in an extremely low speed state less than a predetermined value, the control by the short control means is performed. The electromagnetic relay is switched and operated without being performed.

  Here, when the rotation speed of the output shaft becomes extremely low (for example, lower than that during idle operation), it is impossible to obtain a power generation amount that exceeds various power losses, so that it is impossible to supply power from the motor generator to the electric load. . Therefore, when switching from the motor drive power line to the generated power line, at such an extremely low speed, there is no possibility of the electromagnetic relay being melted even if the ground short-circuit is not performed by the short control means. Further, since the rotational load on the motor generator is large during the ground short, the rotation speed of the output shaft is further reduced when the ground short is performed at an extremely low speed.

  In the above invention in view of these points, when switching from the motor drive power line to the generated power line at an extremely low speed, the electromagnetic relay is switched and operated without performing the short control, so that the above-described reduction in the rotational speed can be avoided. .

  The invention according to claim 3 is characterized in that the switching operation of the electromagnetic relay is started after a predetermined standby time has elapsed from the start of the control by the short control means (short control).

  Here, it takes a short time (for example, several milliseconds) until the relay current becomes zero after the short control is started. For this reason, if the electromagnetic relay is switched simultaneously with the start of the short control, the electromagnetic relay is switched in a state in which a current is still flowing through the electromagnetic relay, and it is impossible to reliably avoid melting of the relay contact. In the above-mentioned invention in view of this point, since the switching operation of the electromagnetic relay is started after the standby time has elapsed since the start of the short control, it is possible to reliably suppress the melting of the relay contact.

  The invention according to claim 4 is characterized in that the standby time is set longer as the relay current flowing through the electromagnetic relay is larger when the control by the short control means is started.

  As described above, during the ground short, the rotational load on the motor generator is large. Therefore, it is desirable to set the standby time as short as possible to shorten the ground short period. However, if the standby time is set too short, the reliability of switching the electromagnetic relay while the relay current is zero is impaired. In short, the standby time is required to be set to the minimum necessary length from the viewpoint of reducing rotational load and avoiding melting damage.

  In view of these points, in the above invention, the larger the relay current at the start of the short control, the longer the time required from the start of the short control until the relay current decreases, and thus the standby time is set longer. Therefore, it is possible to accurately set the waiting time to the minimum necessary length.

  The invention according to claim 5 is characterized in that the standby time is set considering that the relay current is larger as the rotational speed of the output shaft at the start of the control by the short control means is higher.

  The higher the rotational speed NE of the output shaft, the greater the generated power or drive power. That is, NE and the relay current have a high correlation. In the above invention in view of this point, since the standby time is set assuming that the faster the NE is, the larger the relay current is, the standby time can be set to the minimum necessary length without using a sensor for detecting the relay current. .

  The invention according to claim 6 is characterized in that the short control means short-circuits all of the U-phase coil, the V-phase coil and the W-phase coil.

  Here, when two or one of the coils in each phase is grounded contrary to the above invention, the electromagnetic relay can be switched and operated with less current flowing in both power lines, whereas all coils According to the above-described invention in which the ground is short-circuited, the electromagnetic relay is switched and operated in a state where no current flows in both power lines. Therefore, it is possible to reliably avoid the occurrence of an arc at the relay contact of the electromagnetic relay, and to melt the relay contact. The certainty of loss avoidance can be improved.

The schematic diagram which shows the engine system of the two-wheeled vehicle to which the electric power line control apparatus concerning this invention is applied. The figure explaining the control content of the inverter by ECU shown in FIG. 2A is a diagram showing a current flow when the motor generator shown in FIG. 2 is driven by a motor, FIG. 2B is a power generation operation, and FIG. 3C is a diagram showing a current flow when each phase coil is grounded. The flowchart which shows the procedure of the short control concerning FIG.3 (c). The figure which shows the test result which clarified the effect by this invention.

  Hereinafter, an embodiment in which a power line control device according to the present invention is applied to a power supply system for a two-wheeled vehicle will be described with reference to the drawings.

  FIG. 1 is a schematic diagram showing an engine 10 (internal combustion engine) mounted on a two-wheeled vehicle, and assumes an ignition ignition type single-cylinder engine.

  The fuel in the fuel tank 11 is supplied to the fuel injection valve 13 by the fuel pump 12. The fuel injection valve 13 is a port injection type attached to the intake pipe 14, and the fuel injected from the fuel injection valve 13 becomes an air-fuel mixture together with the intake air whose inflow is adjusted by the throttle valve 15, and the combustion chamber 16. Flow into. Further, by controlling the primary current of the ignition coil device 17, a secondary current is caused to flow through the spark plug 18 to cause spark to ignite the air-fuel mixture.

  The fuel pump 12, the fuel injection valve 13, and the ignition coil device 17 correspond to “electric loads” and are driven by being supplied with electric power from the battery 19. Further, the operation of these electric loads 12, 13, and 17 is controlled by the ECU 20.

  The starter motor that rotationally drives the crankshaft 21 (output shaft) when the engine is started also functions as a generator that is rotationally driven by the crankshaft 21 to generate electricity. That is, a starter motor (hereinafter referred to as a motor generator 22) is driven by a motor when the engine is started, and generates power after the engine is started. Further, after the engine is started, when the rotational speed NE of the crankshaft 21 becomes a low speed less than a predetermined value, the motor generator 22 is driven by a motor to increase NE, and the crankshaft 21 is driven by the motor driving force in addition to the engine output. Assists in rotation.

  The motor generator 22 employs a three-phase AC brushless motor. The motor generator 22 includes a stator 22a having a U-phase coil 22U, a V-phase coil 22V, and a W-phase coil 22W, and a rotor having a permanent magnet. 22b and a hall element 22c provided corresponding to each phase.

  In the example of FIG. 2, an inner rotor type motor in which the rotor 22b is located inside the stator 22a is adopted, but an outer rotor type motor in which the rotor 22b is located outside the stator 22a may be adopted. When the rotor 22b is arranged coaxially with the crankshaft 21 and directly connected to the crankshaft 21, the rotor 22b may function as a flywheel.

  The ECU 20 includes an inverter 23 mainly composed of a plurality of switching elements 23Ua, 23Ub, 23Va, 23Vb, 23Wa, and 23Wb, and a microcomputer (microcomputer 24) that controls the operation of the inverter 23. The drive power discharged from the battery 19 is converted from direct current to alternating current when the motor is driven, and the generated power from the motor generator 22 is converted from alternating current to direct current when generating power. Incidentally, specific examples of the switching elements 23Ua to 23Wb include MOSFET and IGBT semiconductor elements.

  FIG. 2 is a schematic diagram for explaining the control of the switching elements 23Ua to 23Wb by the microcomputer 24, and the lower part of the drawing shows a drive signal that the microcomputer 24 outputs to the switching elements 23Ua to 23Wb. As illustrated, the microcomputer 24 controls the energization timing of the switching elements 23Ua to 23Wb based on the output of the hall element 22c of each phase.

  More specifically, one set of switching elements 23Ua and 23Ub is an element for controlling on / off of energization to U-phase coil 22U. When energization is turned on for switching element 23Ub, U-phase coil 22U is connected to the ground. Current flows through the U-phase coil 22U in the direction indicated by the arrow. On the other hand, when switching element 23Ua is energized, U-phase coil 22U is connected to battery 19, and a current flows through U-phase coil 22U in the direction opposite to the arrow in the figure.

  The switching elements 23Va and 23Vb are elements for controlling on / off of energization to the V-phase coil 22V. When the switching elements 23Vb and 23Wb are energized on, the V-phase coil 22V and W-phase coil 22W are connected to the ground. Current flows in the direction indicated by the arrow. On the other hand, when the switching elements 23Va and 23Wa are turned on, the V-phase coil 22V and the W-phase coil 22W are connected to the battery 19 and a current flows in the direction opposite to the arrow in the figure.

  As indicated by an arrow in FIG. 3A, when the motor generator 22 is driven by a motor, a current flows from the battery 19 to the inverter 23 through the motor drive power line Lm. On the other hand, when the motor generator 22 is generating power, current flows from the inverter 23 to the electric loads 12, 13, 17 and the battery 19 through the generated power line Lg as indicated by the arrows in FIG.

  An electromagnetic relay 25 is provided between the power lines Lm, Lg and the inverter 23, and the operation of the electromagnetic relay 25 switches which of the two power lines Lm, Lg is energized. More specifically, the ECU 20 controls the energization of the excitation coil 25a of the electromagnetic relay 25 according to whether the power generation operation or the motor drive, thereby determining which of the power lines Lm and Lg is energized. Can be switched. An ignition switch 26 is provided on the generated power line Lg.

  In this way, by switching the two power lines Lm and Lg, it is possible to supply power to the electric loads 12, 13 and 17 directly from the motor generator 22 instead of from the battery 19. Yes. Therefore, current loss via the battery can be eliminated, and power supply to the electric loads 12, 13, and 17 can be reliably performed regardless of the storage state of the battery.

  By the way, when a current (relay current) is flowing through the relay contact 25b of the electromagnetic relay 25 and the power line Lm, Lg is switched by switching the energization state to the exciting coil 25a, an arc is generated at the relay contact 25b, There is a concern about melting of the relay contact 25b.

  Therefore, in the present embodiment, short-circuit control that operates the inverter 23 is performed so that all the phase coils 22U, 22V, and 22W of the motor generator 22 are short-circuited to the ground. If this short control is performed, as indicated by the arrow in FIG. 3C, a current flows to the ground side of the battery 19, and no current flows through the electromagnetic relay 25 and the power lines Lm, Lg. Therefore, the electromagnetic relay 25 is switched and operated in a state in which the ground is short-circuited by the short control to avoid the occurrence of an arc.

  The details of the short control will be described. Of the six switching elements 23Ua to 23Wb of the inverter 23, all of the switching elements 23Ua, 23Va, and 23Wa that control energization between the phase coils 22U, 22V, and 22W and the battery 19 are turned off. To. On the other hand, all the switching elements 23Ub, 23Vb, and 23Wb that control energization between the phase coils 22U, 22V, and 22W and the ground are turned on. If the short control is performed in this way, the respective phase coils 22U, 22V, 22W are short-circuited to the ground, and a current flows through all the coils 22U, 22V, 22W simultaneously in the direction indicated by the arrows in FIG.

  FIG. 4 is a flowchart showing a processing procedure of the short control by the microcomputer of the ECU 20, and the processing is repeatedly executed at a predetermined cycle.

  First, in step S10 shown in FIG. 4, it is determined whether or not the motor generator 22 is driving the motor. If the motor is being driven (S10: YES), it is determined in step S11 whether a power generation request has occurred. If a power generation request has occurred (S11: YES), the process proceeds to the next step S12, and whether or not the engine speed NE at that time is an extremely low speed state that is less than a predetermined value (for example, less than the rotation speed during idle operation). Determine.

  Here, when the engine rotational speed NE is extremely low, even if power is generated by the motor generator 22, a power generation amount exceeding various power losses cannot be obtained. Power cannot be supplied to 12, 13, 17 and the battery 19. The predetermined value is set as a threshold value as to whether or not it is an NE region (non-chargeable region) that cannot be charged in this way.

  If it is determined that it is not in the non-chargeable region (S12: NO), the short control described above is performed in the subsequent step S13 (short control means). That is, all three upper phase switching elements 23Ua, 23Va, and 23Wa are turned off, and all three lower phase switching elements 23Ub, 23Vb, and 23Wb are turned on.

  In the subsequent step S14, it is determined whether or not a predetermined time Ta (standby time) has elapsed since the start of the short control. When the predetermined time Ta is reached, the process proceeds to the next step S16, where the motor drive power line Lm is set. The operation of the electromagnetic relay 25 is switched from the energized state to the energized state of the generated power line Lg. In the present embodiment, the relay contact 25b is switched to a position where the motor drive power line Lm is energized when energization of the excitation coil 25a is turned on. Therefore, in step S16, the energization to the exciting coil 25a is switched from on to off.

  Then, after the electromagnetic relay 25 is switched from on to off in this way, in the next step S17, the short control is terminated and the control content of the inverter 23 is switched according to the request. In this case, the motor drive state is switched to the power generation operation state in accordance with the power generation request in step S11.

  On the other hand, if it is determined in step S12 that the region is not chargeable (S12: YES), the short control is prohibited in the subsequent step S15, and then the switching operation of the electromagnetic relay 25 in step S16 is performed. When the short control is prohibited in step S15, the control content of the inverter 23 is switched from the motor drive state to the power generation operation state without performing the short control end in step S17.

  Next, if it is determined in step S10 that the motor is not being driven, that is, if it is determined that the power generation operation is being performed (S10: NO), whether or not a motor drive request is generated in the next step S18. Determine whether. If a motor drive request is generated (S18: YES), the process proceeds to the next step S19 (short control means), and short control similar to step S13 is performed.

  In the following step S20, it is determined whether or not a predetermined time Tb (standby time) has elapsed since the start of the short control. When the predetermined time Tb is reached, the process proceeds to the next step S21 to energize the generated power line Lg. The operation of the electromagnetic relay 25 is switched from a state to be energized to a state to energize the motor drive power line Lm. Specifically, the energization to the exciting coil 25a is switched from off to on.

  Then, after the electromagnetic relay 25 is switched from OFF to ON in this way, in the next step S17, the short control is terminated and the control content of the inverter 23 is switched according to the request. In this case, the power generation operation state is switched to the motor drive state in accordance with the motor drive request in step S18.

  FIG. 5 is a test result showing various changes when switching to the power generation operation immediately after the motor generator 22 is driven to start the engine, and FIG. 5A is a short circuit contrary to the present embodiment. Various changes when the electromagnetic relay 25 is switched without performing control are shown, and FIG. 5B shows test results when the electromagnetic relay 25 is switched during the short-circuit control. Reference numerals (1) to (3) in the figure indicate voltage changes applied to the U-phase coil 22U, V-phase coil 22V, and W-phase coil 22W, respectively, and reference numeral (4) indicates a current (relay) that flows through the relay contact. (5) shows a change in current flowing through the exciting coil 25a.

  In the test shown in FIG. 5A, the current to the exciting coil 25a is turned off at time t1 while any of the phase coils 22U, 22V, and 22W is connected to the battery 19 and voltage is applied. The electromagnetic relay 25 is switched from the motor drive power line Lm to the generated power line Lg. And it represents that a surge current flows to the relay contact 25b at the time of this switching. For this reason, the relay contact 25b may be melted.

  On the other hand, in the test shown in FIG. 5B, there is a short control period Ts in which the voltages of the phase coils 22U, 22V, and 22W are all at the ground level due to the execution of the short control, and this short control period Ts. During this time, the current to the exciting coil 25a is turned off at time t1, and the electromagnetic relay 25 is switched from the motor drive power line Lm to the generated power line Lg. Therefore, no surge current is generated.

  Since there is a response delay from time t1 when the current to the exciting coil 25a is switched to time t2 when the current of the relay contact 25b becomes zero, the short control period Ts is shorter than the response delay time t1 to t2. The predetermined times Ta and Tb in FIG. 4 are set so as to be longer.

  In addition, the response delay becomes longer as the peak value Ipeak of the current of the relay contact 25b at the time t1 or immediately after the time when the current to the exciting coil 25a is switched is higher. Therefore, it is desirable to set the predetermined times Ta and Tb used in the processing of FIG. 4 longer as the peak value Ipeak is higher. Note that the peak value Ipeak increases as the engine speed NE at time t1 increases. In view of this point, the predetermined times Ta and Tb may be set longer as the engine rotational speed NE at time t1 is higher. This eliminates the need for a current sensor that detects the current peak value Ipeak of the relay contact 25b.

  As described above, according to the present embodiment, the short-circuit control is performed to short-circuit all the phase coils 22U, 22V, and 22W (S13, S19), and the ground-shorted state (currents in both power lines Lm and Lg). And the electromagnetic relay 25 is switched and operated (S16, S21). Therefore, generation | occurrence | production of an arc can be avoided with the relay contact 25b, and the melting damage avoidance of the relay contact 25b can be aimed at.

  Further, when the power generation amount sufficient to charge the battery 19 is not obtained (S12: YES), the short-circuit control is prohibited and the motor drive power line Lm is switched to the generated power line Lg. Therefore, since a ground short that increases the rotational load is not unnecessarily performed, the chance of the engine speed NE being reduced due to the ground short can be reduced.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be modified as follows. Moreover, you may make it combine the characteristic structure of each embodiment arbitrarily, respectively.

  In the flowchart shown in FIG. 4, only when switching from the motor drive power line Lm to the generated power line Lg, the short control prohibition at the extremely low speed of the motor is performed, but the generated power line Lg is changed to the motor drive power line Lm. Even in the case of switching, prohibition of short control at the time of motor extremely low speed may be performed.

  In the above embodiment, as the peak value Ipeak of the relay current is higher, the predetermined times Ta and Tb used in the processing of FIG. 4 are set longer. However, the predetermined times Ta and Tb are fixed to preset times. May be used.

  In the motor driving or power generation operation, each phase coil 22U, 22V, 22W may be controlled by a 120 degree energization method or by a 180 degree energization method.

  In the above embodiment, the power line control device according to the present invention is applied to a vehicle using the engine 10 as a driving force. However, the present invention is also applicable to a hybrid vehicle using at least one of the engine and the traveling motor as a driving force. In this case, the motor generator may function as a traveling motor or may function as a starter motor.

  In the above embodiment, the electromagnetic relay 25 is switched and operated after all the phase coils are shorted to ground. However, in implementing the present invention, either one or two of the phase coils are shorted to ground. The electromagnetic relay 25 may be switched and operated.

DESCRIPTION OF SYMBOLS 21 ... Crankshaft (output shaft), 22 ... Motor generator, 23 ... Inverter, 25 ... Electromagnetic relay, Lg ... Power generation power line, Lm ... Motor drive power line, S13, S19 ... Short control means, Ta, Tb ... Standby Time, 22U ... U phase coil, 22V ... V phase coil, 22W ... W phase coil.

Claims (6)

A motor generator that can be switched between a motor drive for rotating the output shaft of the internal combustion engine and a power generation operation by the output shaft;
A motor drive power line for flowing drive power required for driving the motor from a battery to the motor generator;
The generated power by the power generation operation, the generated power line that flows from the motor generator to the electric load and the battery,
Electrically connected between the motor drive power line and the generated power line and the motor generator. When the motor is driven, the drive power from the battery is converted from direct current to alternating current, and during the power generation operation, from the motor generator. An inverter that converts the generated power from AC to DC,
An electromagnetic relay for switching which of the motor drive power line and the generated power line is energized with the inverter;
Applied to a power supply system comprising:
Short control means for controlling a switching element of the inverter so as to short-circuit at least one of a U-phase coil, a V-phase coil, and a W-phase coil of the motor generator;
The power line control device, wherein the electromagnetic relay is switched and operated in a state in which the ground is short-circuited by the short control means. When switching from the motor drive power line to the generated power line when the rotation speed of the output shaft is in a very low speed state below a predetermined value,
The power line control device according to claim 1, wherein the electromagnetic relay is switched and operated without performing control by the short control means.   3. The power line control device according to claim 1, wherein a switching operation of the electromagnetic relay is started after a predetermined standby time has elapsed since the start of the control by the short control unit.   4. The power line control device according to claim 3, wherein the standby time is set longer as the relay current flowing through the electromagnetic relay is larger when the control by the short control unit is started. 5.   5. The power line control device according to claim 4, wherein the standby time is set by considering that the relay current is larger as the rotation speed of the output shaft at the start of the control by the short control unit is faster.   6. The power line control device according to claim 1, wherein the short control unit short-circuits all of the U-phase coil, the V-phase coil, and the W-phase coil.

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