RU2449445C1 - Driving controller for alternating current motor - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: control (17A) unit is configured to open shutting down contactor (16) of electric motor not at the moment when detected current condition is determined as abnormal but at the moment when moment when current condition is determined as normal even when basic "MKCO" command becomes switching-off command (L level).

EFFECT: creation of driving controller for alternating current motor which can prevent excessive voltage generation between electric motor lines and between electric motor shutting down contactor contacts, and continuous electric arc creation between shutting down contactor contacts.

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Description

Technical field

The present invention relates to a drive controller for an alternating current electric motor (AC) suitable for driving a permanent magnet synchronous electric motor integrated in an electric vehicle.

State of the art

A permanent magnet synchronous motor (hereinafter referred to simply as an “electric motor” until otherwise required special differences) is known as a highly efficient electric motor. Compared with induction motors traditionally used in various fields, a permanent magnet synchronous motor does not require any excitation current, since the magnetic flux is set by a permanent magnet built into the rotor, and secondary losses in copper do not occur, since the current does not flow in the rotor unlike induction motors. While electric vehicles have traditionally used induction motors, in recent years, the use of a permanent magnet synchronous motor in them has been studied to increase efficiency.

In electric vehicles, a drive controller for an AC motor and an electric motor are integrated in each of a plurality of combined vehicles. Even when a short circuit occurs in the drive controller of the AC motor of a certain vehicle when the vehicle is moving, the electric vehicle can continue to move through other drive controllers of the AC motors and the motors that are operating normally. An electric motor connected to a damaged drive controller of an AC electric motor continues to be driven by wheels. Therefore, the short circuit current caused by the induced voltage of the electric motor continues to flow in the part of the drive controller of the AC electric motor, where a short circuit occurred (shorted part).

When this condition remains as it is, the damaged part of the drive controller of the AC motor can expand further from the heat generated by the short circuit current, and the damaged part of the motor can generate heat or burn out, which is undesirable.

In order to take such cases into account, for example, Patent Document 1 discloses a method in which a trip contactor of an electric motor is provided, which serves as a switch on the electric motor side, which electrically disconnects the inverter from the electric motor. The control unit controls the contactor to open it to electrically disconnect the inverter from the motor when a fault is detected in the inverter. Thus, the inverter is not further damaged when a short circuit occurs in the inverter in the drive controller of the AC electric motor controlling the driving of the synchronous permanent magnet electric motor while the electric vehicle is moving.

Patent Document 1: Japanese Patent Application Laid-Open No. H8-182105

As, in general, it is known that since the zero-point transition point is formed in alternating current with a sinusoidal waveform for each half-wave of the current waveform, the current can be interrupted using the zero-point current transition point. The tripping motor contactor disclosed in Patent Document 1, mentioned above, is a contactor that interrupts the alternating current with a zero transition point for interrupting current. Examples of a contactor that interrupts alternating current typically include a vacuum contactor, to which a current interruption system is applied at points where the current passes through zero.

It was found that a phase in which a zero current transition point is not formed, and a phase in which a zero current transition point is formed, are sometimes present simultaneously in the fault current, depending on the type of malfunction that arose in the drive controller of the AC motor. The fault current is the current that flows between the inverter in the drive controller of the AC motor and the motor. When the aforementioned tripping motor contactor using the current interruption system at the zero current transition points interrupts the fault current, the phase current at which the zero current transition point exists is interrupted; however, the current cannot be interrupted in other phases that do not have points of current transition through zero, and thus the inverter remains electrically connected to the electric motor by a continuously formed electric arc.

In this condition of damage, the electric motor is brought into an unbalanced state, since only the phase in which the current is interrupted is disconnected from the inverter from the three phases. Therefore, excess voltage is generated between the lines of the motor and between the contacts of the trip contactor of the motor. This excess voltage can lead to destruction of the insulation of the coils in the electric motor, the tripping motor contactor and the cables connecting the tripping motor contactor to the motor. Additionally, since an electric arc continues to form between the contacts of the trip motor contactor, the trip motor contactor may be damaged.

Summary of the invention

An object of the present invention is to provide a drive controller for an AC motor. The drive controller is configured so that even when the phase in which the current transition point through zero is not formed, and the phase in which the current transition point through zero is formed, are present simultaneously in the fault current flowing between the inverter and the motor, the formation of excess voltage between the lines the motor and between the contacts of the trip contactor of the motor can be prevented, and the formation of a continuous electric arc between the contacts of the trip contactor of the motor can be prevented despite the type of malfunction that has occurred.

An aspect of the present invention is a drive controller for an alternating current electric motor, including: an inverter, which includes a plurality of switching elements with controlled on-off switching and converts direct current voltage (DC) to alternating current voltage (AC) with arbitrary frequency, for excitation AC electric motor; a switch on the motor side connected between the inverter and the AC motor; an electric quantity detector that detects an electric quantity from an output side of an inverter; and a control unit that controls the on-off of the switching elements in the inverter and controls the switch on the motor side to open and close it based on at least the current detected by the electric quantity detector, wherein the control unit includes: a state determination unit current, which generates a detection signal that determines whether the current detected by the electric quantity detector is in an abnormal state, and a contactor control unit that controls Based on the determination signal, the actual output torque upper-level instructions, which is formed for opening a switch on the motor side switch at the motor side.

According to the present invention, even when a phase in which a zero current transition point is not formed, and a phase in which a zero current transition point is formed, are present simultaneously in the fault current flowing between the inverter and the motor, excess voltage is generated between the motor lines and between the contacts of the trip contactor of the motor can be prevented, and the formation of a continuous electric arc between the contacts of the trip contactor of the motor can be Remedied despite the type of malfunction that occurred. Therefore, it is possible to obtain a drive controller for an alternating current motor, in which the insulation of the coils in the motor, the disconnecting motor contactor and the cables connecting the disconnecting motor contactor to the motor are not damaged, and the disconnecting motor contactor is not damaged by the electric arc formed between the contacts of the disconnecting motor contactor, despite the type of malfunction that occurred.

Brief Description of the Drawings

The invention is further explained in the description of the preferred embodiments with reference to the accompanying drawings, in which;

FIG. 1 is a block diagram of an example configuration of a drive controller for an AC motor according to a first embodiment of the present invention;

FIG. 2 is a diagram of an example configuration of the inverter shown in FIG. one;

FIG. 3 shows a waveform diagram of an exemplary malfunction that occurs when a phase in which a zero current transition point is not formed, and a phase in which a zero current transition point is formed, are simultaneously present in the fault current, current waveforms at the time of the malfunction, and the shape electric motor line voltage waves;

FIG. Figure 4 shows a characteristic diagram of the relationship between the amplitude of the current of the uninterrupted phase and the amplitude of the line voltage generated in the electric motor, the situation where the malfunction occurred, and the phase in which the transition point of the current through zero is not formed, and the phase in which the transition point of the current through zero is formed are present simultaneously in the fault current, and when the phase in which the current transition point through zero is formed is interrupted;

FIG. 5 is a block diagram of an example configuration of the control unit shown in FIG. one;

FIG. 6 is a structural diagram of an example configuration of a current state determining unit shown in FIG. 5;

FIG. 7 is a waveform diagram explaining a control operation of the first embodiment in which the current is interrupted by forming a current zero transition point in a phase having no current zero transition point when the fault shown in FIG. 3;

FIG. 8 is a block diagram of an example configuration of a drive controller for an alternating current motor according to a second embodiment of the present invention;

FIG. 9 is a structural diagram of an example configuration of a control unit shown in FIG. 8.

Description of preferred embodiments of the invention

Exemplary embodiments of a drive controller of an AC motor according to the present invention will be explained in detail below with reference to the accompanying drawings.

First Embodiment

FIG. 1 is a block diagram of an example configuration of a drive controller for an AC motor according to a first embodiment of the present invention. In FIG. 1, a current collector 1 is shown in contact with electric wires of a contact network in order to receive electric power in an electric vehicle. Reference number 2 denotes a rail, reference number 3 denotes a wheel of an electric vehicle, and reference number 6 denotes an AC electric motor. An AC motor 6 is integrated in the vehicle together with an AC motor drive controller 10A according to the first embodiment, and its rotating shaft is mechanically coupled to the wheel 3. The AC motor 6 is provided with a rotation detector 7.

The AC motor drive controller 10A (FIG. 1) includes, as main components of the present invention, a contactor 11 for turning off the power supply, an inverter 12, current detectors 13, 14 and 15, disconnecting the motor contactor 16 and a control unit 17A.

One end of the contactor 11 for turning off the power supply is connected to the output terminal of the current collector 1, and the other end is connected via the positive side conductor P to the input terminal of the positive side inverter 12. Those. the contactor 11 for turning off the power supply is a switch on the side of the power source, capable of disconnecting the DC input side of the inverter 12 and the current collector 1 serving as the power source.

The input contact of the inverter 12 of the negative side is connected through the conductor N of the negative side to the wheel 3. This configuration allows you to apply DC power from the collector 1 through the contactor 11 to turn off the power and from the rail 2 through the wheel 3 to the inverter 12. The inverter 12 converts the DC power, supplied by the positive side conductor P and the negative side conductor N to the AC power by means of the configuration shown in FIG. 2, for example.

In FIG. 2 shows a diagram of an example configuration of the inverter 12 shown in FIG. 1. The inverter 12 is configured so that a so-called three-phase two-level inverter circuit is connected between the positive side conductor P and the negative side conductor N. The discharge circuit 18 and the filter capacitor 19 are provided in parallel between the positive side conductor P and the negative side conductor N.

The three-phase two-level inverter circuit is a bridge circuit of three switching elements of the positive side arm (UP element of the upper arm of the U-phase, element VP of the upper arm of the V-phase and element WP of the upper arm of the W-phase) connected to the positive side conductor P, and three switching the negative side arm elements (the U-phase lower arm element UN, the V-phase lower arm element VN, the W-phase lower arm element WN) connected to the negative side conductor N. The diode is connected counter-in parallel with each switching element. The connection points of the upper arm elements and the lower arm elements in the respective phases form three-phase output contacts, and these output contacts are connected to the U-phase UI conductor from the inverter side, the V-phase conductor VI from the inverter side and the W-phase conductor WI from the inverter side, respectively. Although in FIG. 2, a well-known IGBT is shown as a switching element; switching elements other than IGBT can be used. While a three-phase two-level inverter circuit is shown in FIG. 2, a multi-level inverter circuit such as a three-level inverter circuit may be used.

Although in FIG. 2, the inverter 12 is provided with an excitation circuit for receiving a gate signal GS output from the control unit 17A to the inverter 12 in FIG. 1. This drive circuit has the function of individually controlling the on / off of the six switching elements according to the gate signal GS.

As shown in FIG. 1, the three-phase output contacts of the inverter 12 are connected to the trip motor contactor 16 through the U-phase UI conductor from the inverter side, the V-phase conductor VI from the inverter side and the W-phase conductor WI from the inverter side. The tripping motor contactor 16 is connected to the alternating current motor 6 through the U-phase conductor UM from the motor side, the V-phase conductor VM from the motor side and the W-phase conductor WM from the motor side.

According to the inverter 12 with the configuration described above, the corresponding switching elements in the inverter circuit are turned on or off according to the gate signal GS input by the control unit 17A. Thus, the supplied DC voltage is converted into a three-phase AC voltage with an arbitrary frequency, and the AC motor 6 is driven through a trip contactor 16 of the electric motor. The AC motor 6 then rotates the mechanically coupled wheel 3 to move the electric vehicle along the rail 2.

The voltage at the terminals of the filter capacitor 19 is essentially equal to the voltage received from the collector 1 (voltage of the contact wire), and is approximately 600-3000 V DC in conventional electric vehicles.

Although detailed internal configurations are not shown, the discharge circuit 18 is configured by a series circuit formed from a resistor and a switch (including a semiconductor switch) and a circuit for discharging electric charges in the filter capacitor 19 based on the discharge command OV. A discharge command OV is inputted from a control unit 17A or a high-level device (not shown) in a predetermined case, such as when, for example, any malfunction occurs in the AC motor drive controller 10A. Although not shown when the discharge circuit 18 performs the discharge operation, the contactor 11 for turning off the power supply is controlled to open, at the same time, by the control unit 17A or a high-level device (not shown).

Turning to FIG. 1, current detectors 13, 14 and 15 are provided respectively on the U-phase UI conductor from the inverter side, the V-phase VI conductor from the inverter side and the W-phase WI conductor from the inverter side, which are connected between the output contacts of the three phases of the inverter 12 and the trip contactor 16 of the electric motor. The U-phase current IU, the V-phase IV current, and the W-phase IW current detected by the current detectors 13, 14 and 15 are respectively inputted to the control unit 17A. While the current detectors are configured to determine the corresponding three-phase output currents of the inverter 12 in FIG. 1, an arbitrary two-phase current can be detected. The current in the phase at which the current detector is not provided can be calculated.

The tripping motor contactor 16 is a motor-side switch capable of disconnecting the output contacts of the three phases of the inverter 12 from the AC motor 6 according to the instruction from the control unit 17A (contactor closing command MKC). The tripping motor contactor 16 is formed by a contactor capable of interrupting alternating current. Since the zero-current transition point is formed in alternating current in each half-waveform of this current waveform, a contactor that is capable of interrupting alternating current usually interrupts the current using the zero-current transition point.

The trip motor contactor 16 is configured such that when the MKC contactor closing command from the control unit 17A is activated, the closing coil is energized, the main contacts mechanically connected to the closing coil are closed to close the three phases, and thus, the inverter 12 is electrically connected to electric motor 6 of alternating current. Additionally, the trip motor contactor 16 is configured so that when the MKC command to close the contactor from the control unit 17A is deactivated, the closure coil is excluded, the main contact is opened to open the corresponding three phases, and thus, the inverter 12 is electrically disconnected from the variable motor 6 current.

The tripping motor contactor 16 may be configured to control the main contacts of the three phases by means of a single make-up coil, or may be configured to provide the make coils for the respective main contacts of the three phases. In the latter configuration, the moment of closing and opening can be set individually in the respective phases.

The rotation state of the AC motor 6 is detected by the rotation detector 7 and inputted to the control unit 17A. The so-called sensorless control system for controlling an AC motor 6 without a rotation detector 7 is also used in practice. When a sensorless control system is selected, rotation detector 7 is not needed. In the case of a sensorless control system, a voltage detector (not shown) can be provided in the input stage (from the U-phase UI conductor from the inverter to the W-phase WI conductor) or the output stage (from the U-phase UM conductor from the motor side to the WM conductor W phase) of the trip motor contactor 16 to detect the output voltage of the inverter 12 or the voltage at the terminals of the AC motor 6, and the voltage detector inputs the determination result to the control unit 17A.

In the present embodiment, as described above, it is assumed that the AC motor 6 is a permanent magnet synchronous motor. However, there is an electric motor in which a permanent magnet is enclosed in the rotor of an asynchronous electric motor. The present invention can be applied, in addition to a permanent magnet synchronous motor, to those motors in which a permanent magnet is integrated in the rotor.

As described above, the present inventors have found that a phase in which a zero current transition point is not formed, and a phase in which a zero current transition point is formed, are simultaneously present in a fault current that flows between the inverter 12 in the motor drive controller 10A alternating current and alternating current electric motor 6, depending on the type of malfunction that arose in the drive controller of the alternating current electric motor.

The control unit 17A is configured so that the generation of excess voltage between the lines of the AC motor 6 and between the contacts of the trip motor contactor 16 is prevented, and the formation of a continuous electric arc between the contacts of the trip motor contactor 16 is prevented based on three-phase currents IU, IV and IW detected by the detectors 13 , 14 and 15 of the current, the gate signal GS and the discharge command OV, which are applied to the inverter 12, and the base gate signal GC and the base Contactor circuit technological command MKCO from an external higher-level device (not shown). Thus, the tripping motor contactor 16, which interrupts the alternating current, can be opened reliably in three phases even when the fault current flows, and the phase in which the zero transition point is not formed, and the phase in which the current transition point through zero is formed, are present simultaneously.

To facilitate understanding, the formation of a fault current in which a phase in which a zero current transition point is not formed, and a phase in which a zero current transition point is formed, are simultaneously present, and the formation of excess voltage is explained in detail first (Fig. 3 and 4 ) The configuration of the control unit 17A (FIGS. 5 and 6) and its operation (FIG. 7) are explained in detail below.

The following describes exemplary situations where a fault current is generated in which a phase in which a zero current transition point is not formed and a phase in which a zero current transition point is formed are present simultaneously. Damage current is generated when one or more switching elements of three elements (UP, VP and WP) of the upper arm connected to the positive side conductor P, and one or more switching elements of three elements (UN, VN and WN) of the lower arm connected with conductor N on the negative side, short circuit. In addition, a fault current is generated when these switching elements remain switched on due to damage or due to damage in the drive circuit (not shown).

In FIG. 3 shows a waveform diagram of an exemplary damage, in which a phase in which a zero current transition point is not formed, and a phase in which a zero current transition point is formed, are simultaneously present in the fault current, the current waveform at the time of the damage and the linear waveform motor voltage. FIG. 4 is a characteristic diagram of the relationship between the amplitude of the current of the uninterrupted phase and the amplitude of the line voltage generated in the electric motor. FIG. 4 shows the situation where the fault occurred, and the phase in which the current zero transition point is not formed, and the phase in which the zero current transition point is formed, are simultaneously present in the fault current, and when the phase in which the zero current transition point formed, interrupted.

For example, consider the case where a short circuit occurs in the UP element of the upper arm of the U-phase and the element VN of the lower arm of the V-phase, when the AC motor 6 is rotated by the action of the AC motor drive controller 10A. Additionally, all other switching elements (VP, WP, UN and WN) are turned off by the damage detection unit provided in the high-level device (not shown) in the control unit 17A.

In this case, a fault current flows between the AC motor 6 and the inverter 12 through the UP element of the upper arm of the U-phase and the element VN of the lower arm of the V-phase, still connected due to a short circuit, and diodes connected to the remaining switching elements ( VP, WN, UN and WN).

FIG. 3 shows the waveforms (1) through (3) of the current wave of the respective phases and the line voltage waveform (4) between the V phase and the W phase of the AC motor 6 when a short circuit occurs in the UP element of the upper arm of the U phase and the element The VN of the lower arm of the V-phase, and all other switching elements (VP, WP, UN and WN) are turned off as described above.

With reference to FIG. 3, the time T1B indicates a time when a short circuit occurs in the UP element of the upper arm of the U-phase and the element VN of the lower arm of the V-phase. Shoulder elements work normally before T1B. After time T1B, the shoulder elements operate in a state of damage. The tripping motor contactor 16 is closed by the contactor closing command MKC, which is activated, until time T2B immediately after the time T1B, and then opened at time T2B by the contactor closing command MKC, which becomes inactive.

Before time T1B, when a short circuit occurs in the UP element of the upper arm of the U-phase and the element VN of the lower arm of the V-phase, all switching elements in the inverter 12 are in a normal state, and the AC motor 6 is driven at a speed of 63 Hz The usual point of transition of the current through zero appears in the forms (1) - (3) of the current wave of the corresponding phases. The normal waveform of the positive-negative voltage appears in the form (3) of the line voltage wave between the V phase and the W phase of the AC motor 6.

In a state where the AC motor 6 is driven at a speed of 63 Hz, a short circuit occurs in the UP element of the upper arm of the U-phase and the element VN of the lower arm of the V-phase at the time T1B. The remaining switching elements (VP, WP, UN and WN) are thus controlled to be turned off. During the time interval between time T1B and time T2B, when the trip motor contactor 16 is opened, the U-phase current IU is strongly biased towards the positive side, as represented by waveform (1). The current IV of the V phase is strongly shifted to the negative side, as represented by waveform (2). The current IU of the U-phase and the current IV of the V-phase are in the form of a wave without any point where the current passes through zero. On the other hand, the current of the W phase IW shows an asymmetric change in current, which is shown by waveform (3) in which there is a zero transition point.

The reason why the current IU of the U-phase increases, significantly shifting in the positive direction, and the current IV of the V-phase increases, significantly shifting in the negative direction, is as follows. Since the U-phase upper arm element UP and the V-phase lower arm element VN maintain an on state, a DC voltage is applied from the filter capacitor 19 between the U phase and the V phase of the AC motor 6. With its help, the constant component is formed in the current IU of the U-phase and current IV of the V-phase. When such a state remains as it is, the DC components of the U-phase current IU and the V-phase IV current are further increased, resulting in damage to the AC motor drive controller 10A.

To avoid this problem, the contactor 11 for turning off the power supply is opened and, at the same time, the discharge circuit 18 is turned on in order to discharge the accumulated electric charges in the filter capacitor 19, so that the DC component is not applied to the AC motor 6. To prevent current from flowing from the AC motor 6 to the inverter 12, the trip motor contactor 16 must be open to quickly disconnect the inverter 12 from the AC motor 6.

Therefore, usually, a high-level device (not shown) that detected damage turns off the power of the closure coil of the trip motor contactor 16 so that it does not become excited immediately after the moment T1B when a short circuit occurs. The main contact of the trip contactor 16 of the motor is thus opened at time T2B.

With reference to FIG. 3, due to the above operation, the W-phase current IW indicated by the waveform (3) at which the zero transition point is formed is interrupted to become zero at time T3B immediately after the main contact of the trip motor contactor 16 is opened. Waveform (4) indicates that an excess line voltage is generated between the V phase and the W phase of the AC motor 6. Waveforms (1) and (2) indicate that the current IU of the U-phase and the current IV of the V-phase are shifted, and thus, the points of the transition of the current through zero do not exist in the corresponding currents. Thus, currents cannot be interrupted after time T2B, when the main contact of the trip contactor 16 of the motor opens, and still flow until T4B, when a zero transition point is formed.

When this state continues, an arc continues to form between the U-phase contacts of the trip motor contactor 16 and between its V-phase contacts, the trip motor contactor 16 may fail due to the heat generated by the arc. Gas from an electric arc can cause deterioration of the surrounding insulation and short circuits in the trip contactor 16 of the electric motor and its peripheral main circuits.

The excess voltage between the lines between the V phase and the W phase of the alternating current motor 6 is generated due to a characteristic feature of the permanent magnet synchronous motor configured by installing a permanent magnet in the rotor. In particular, the excess voltage is formed on the basis of the stator winding inductance, which varies according to the angle of rotation of the rotor, the change in inductance in time and the amplitude of the current and its change in time as the main factors. The amplitude of the overvoltage is indicated slightly less than the two rated voltages in FIG. 3. As described with reference to FIG. 4, however, since the current, when the main contact of the trip contactor 16 of the electric motor opens, becomes large, or as the rotational speed of the AC motor 6 increases, the amplitude of the excess voltage increases and its maximum value reaches ten times the rated voltage.

In FIG. 4 shows an example of the relationship between the amplitude of the current IU of the U-phase and the amplitude of the line voltage generated in the AC motor 6 when the current of the IW of the W-phase is interrupted. Reference number 50 denotes a characteristic when the FM frequency of rotation of the AC motor 6 is equal to 332 Hz. Reference number 51 denotes a characteristic when the FM frequency of rotation of the AC motor 6 is 63 Hz.

With reference to FIG. 4, when the U-phase current IU is approximately 1500 A at the point in time when the W-phase IW current is interrupted in characteristic 51, in which the FM speed of the AC electric motor 6 is 63 Hz, an excess voltage such as 5 kV or higher, applied between the lines of the AC motor 6. On the other hand, when the U-phase current IU is approximately 1500 A at a point in time when the W-phase IW current is interrupted in characteristic 50, in which the FM speed of the AC electric motor 6 is 332 Hz, which is the maximum frequency, the excess voltage such as 30 kV or higher, is applied between the lines of the AC motor 6.

The excess line voltage of characteristic 50 is approximately ten times greater than the rated voltage. The insulation of the AC motor 6 and the main circuits on the AC motor 6 side is lower current than the trip motor contactor 16 (e.g., trip motor contactor 16 and U-phase conductor UM on the motor side, V-phase conductor VM on the motor side and conductor WM of the W phase from the motor side connecting the disconnecting contactor 16 of the motor to the AC motor 6) may be violated accordingly, resulting in damage to the and an AC motor controller 10A.

The voltage applied to the inverter 12 (bus voltage) and the voltage of the U-phase UI conductor from the inverter side, the V-phase conductor VI from the inverter side and the W-phase WI conductor from the inverter side connecting the inverter 12 to the disconnecting motor contactor 16 (linear voltage and ground voltage) do not increase to the voltage at the terminals of the filter capacitor 19 (voltage of the contact wire) or higher due to the diode element built into the switching element. Those. the insulation between the elements of the upper and lower arms of the inverter 12 and the insulation of the U-phase UI conductor from the inverter side, the V-phase conductor VI from the inverter side and the W-phase WI conductor from the inverter side connecting the inverter 12 to the disconnecting motor contactor 16 is not damaged.

The control unit 17A is configured based on the conclusions mentioned above. In FIG. 5 is a block diagram of the control unit 17A shown in FIG. 1. In FIG. 6 is a structural diagram of a current state determining unit 20 shown in FIG. 5.

As shown in FIG. 5, the control unit 17A includes, for example, a current state determination unit 20, a gate signal logic unit 30, and a contactor control unit 40A. These blocks are described below in this order.

Three-phase currents IU, IV and IW detected by the current detectors 13, 14 and 15 are inputted to the current state determining unit 20. The current state determining unit 20 monitors the states of the detected three-phase currents IU, IV, and IW and outputs a monitoring result as a current state signal FD serving as a determination signal by means of a configuration, which will be described later, shown in FIG. 6. The current state signal FD is output to the gate signal logic unit 30 and to the contactor control unit 40A. The current state signal FD is also output as a discharge command OV to the discharge circuit 18.

The configuration of the logic block 30 gating signal

The gate signal logic unit 30 includes a latch circuit 31, a logic circuit NOT (NOT) 32, and a logic circuit AND (AND) 33 with two inputs. The current state signal FD is supplied to the setting contact S of the latch circuit 31. The reset signal RST generated by the high-level device (not shown) is supplied to the reset contact R of the latch circuit 31. The output signal level held at the output terminal Q of the latch circuit 31, is inverted by the logic circuit NOT 32 to become one input signal of the logic circuit AND 33. Another input of the logic circuit AND 33 is the basic gate signal GC generated by an external high-level device (not shown). The output signal of the logic circuit And 33 is a gate signal GS to the inverter 12.

The base gate signal GC is a binary control signal for determining the on or off states of the six switching elements in the inverter 12. The base gate signal GC is generated in an external high-level device (not shown) using a vector control method or the like to obtain torque or the number of revolutions of the AC electric motor 6 required when accelerating or braking an electric vehicle.

The operation of the logic block 30 gating signal

When the current state signal FD has a low level (hereinafter “L-level”), which is an off state, the output signal of the logic circuit NOT 32 has a high level (hereinafter “H-level”), which is an on state . The AND 33 logic circuit thus outputs the logical value of the main gate signal GC as the gate signal GS. The inverter 12 then turns on or off the six switching elements in a predetermined manner.

When the current state signal FD changes from an L level to an H level, the output signal of the logic circuit NOT 32 becomes an L level signal. Accordingly, the AND 33 logic circuit outputs the L-level gate signal GS, despite the logical state of the base gate signal GC. The inverter 12 then turns off the six switching elements.

That is, when the current state signal FD once changes from the L level to the H level, the latch circuit 31 holds the H level. Accordingly, the L level (off state) of the gate signal GS is maintained, despite the logical state of the base gate signal GC. In order to control the on / off of the switching elements again, a high-level device (not shown) needs to generate a reset signal RST to release the latch circuit 31, so that the gate signal GS corresponding to the logical state of the base gate signal GC is output.

Configuration of contactor control unit 40A

The contactor control unit 40A includes the logic circuits NOT 41 and 42, the time delay element (ONTD) circuit 43, the AND logic 44 with two inputs, the OR logic circuit 45 with two inputs and the latch circuit 46. The basic MKCO contactor closing command, generated by a high-level device (not shown), is input to the HE 42 logic circuit and to the contact S of the latch circuit 46. The current state signal FD from the current state control unit 20 is input to the HE 41 logic circuit.

The time delay element circuit 43 delays the basic contactor MKCO circuit command, which is inverted by the logic circuit NOT 42, for a set time and outputs the MKCO command to one input contact of the OR logic circuit 45. The AND logic circuit 44 logically multiplies the basic MKCO contactor circuit command, which is inverted by the logic circuit NOT 42, and the current state signal FD, which is inverted by the logic circuit NOT 41, and outputs the result of the operation to another input terminal of the logic circuit OR 45. The output signal is logical OR circuit 45 is inputted to the reset contact R of the latch circuit 46. The signal level held at the output terminal Q of the latch circuit 46 is provided as an MKC command to close the contactor to the trip contactor 16 of the motor.

The basic MKCO contactor closing command is a binary control signal for instructing the control unit 17A to control the trip contactor 16 of the electric motor so that it is closed during operation of the AC motor 6, and to control the trip contactor 16 of the electric motor to be open when operation the AC motor 6 is stopped or when a malfunction occurs in the inverter 12.

The operation of the contactor control unit 40A

When the current state signal FD has an L level, the output of the logic circuit NOT 41 has an H level. In this case, the latch circuit 46 is reset and outputs the MKC contactor closing command, which becomes on (H-level) or off (L-level), synchronously with turning on (H-level) or turning off (L-level) the basic MKCO contactor closing command .

When the current state signal FD changes from the L level to the H level, the output signal of the logic circuit NOT 41 becomes an L level signal. When the basic MKCO contactor closing command has an H level under such circumstances, latch circuit 46 outputs an H-level contactor closing MKK command. However, when the base contactor MKCO command of the contactor closes changes to the L level, while the output of the logic circuit NOT 41 becomes an H-level signal, the latch circuit 46 is not reset until the set time in the circuit 43 of the time element has passed delays.

That is, when the current state signal FD changes from the L level to the H level, the latch circuit 46 holds the H level until the set time elapses in the time delay element circuit 43, even if the basic MKCO close command Contactor has changed to L-level. The MKC contactor closing command is thus not allowed to turn off (L-level). According to this case, the latch circuit 46 is reset by the output signal of the logic circuit AND 44 after the current state signal FD has changed from the H level to the L level, so that the contactor closing command MKC is turned off (L level).

In addition, when the current state signal FD still has an H level, the latch circuit 46 is reset when the set time in the time delay element circuit 43 expires after the basic contactor closing command MKCO has changed to the L level. Thus, the MKC contactor closing command becomes off (L-level). Therefore, when the current state signal FD continues to remain at the H level erroneously due to a case, the contactor closing command MKC may be forced to turn off.

The configuration and operations of the current state determining unit 20 are described below with reference to FIG. 6.

Configuration of current state determining unit 20

As shown in FIG. 6, the current state determination unit 20 includes a U-phase detection logic unit 25U, a V-phase detection logic unit 25V, a W-phase detection logic unit 25W, and a determination unit 27. The detected three-phase currents IU, IV, and IW are input to the corresponding U-phase detection logic 25U, the V-phase detection logic 25V and the W-phase detection logic 25W. The current state signal FD is output from the determination unit 27 into which the output signals of the respective detection logic units are input in parallel.

These three logical detection units have the same configuration, i.e. shown in the U-phase detection logic 25U. The U-phase detection logic 25U is explained below as exemplary.

The U-phase detection logic unit 25U includes a state-zero transition point state detecting unit 21, a peak current value state detecting unit 22, and an effective current value state detecting unit 23, in each of which a U-phase current IU is input. The V-phase detection logic unit 25V and the W-phase detection logic unit 25W have the same configuration.

The zero point transition state detecting unit 21 includes a zero current transition point detecting unit 21a, an oscillation block 21b, a counter 21c, and a comparator 21d. The state-zero transition point state detecting unit 21 generates and outputs a state-zero transition point state signal NZU based on the input U-phase current IU. The current peak value detection unit 22 includes a current peak value detection unit 22a and a comparator 22b. The current peak value state detecting unit 22 generates and outputs a current peak value state signal MXU based on the input U-phase current IU. The current-current-value-state-detection unit 23 includes a current-current-value-detecting unit 23a and a comparator 23b. The current-value-current-state-state detecting unit 23 generates and outputs a current-value-current-state-value signal RMU based on the input U-phase current IU.

Operation of the U-phase detection logic 25U

First, in the state zero transition point detection unit 21, the zero current transition point detection unit 21a compares the input U-phase current IU with zero and outputs the counter reset signal RST to the counter 21c each time the U-phase current crosses zero. The counter 21c counts using a clock pulse CLK output from the oscillation unit 21b in a predetermined period and outputs its calculated CNT value to the comparator 21d. Comparator 21d compares the calculated CNT value with the first set SET value. When the calculated CNT value exceeds the first set value SET1, the comparator determines that the zero current transition point has not been formed, and makes the state zero transition point state signal NZU turned on (H level). When the reset signal RST described above is input, the counter 21c is reset, and the calculated CNT value becomes the original value, such as zero.

When the inverter 12 is operating normally, the U-phase current IU has a sinusoidal waveform, regularly forming intersections with zero. The calculated CNT value of the counter 21c is thus reset to a predetermined value, i.e. returns to zero by the counter reset signal RST, which is formed synchronously with zero crossing. Such sequences of operations are repeated. In this case, the counted value CNT of the counter 21c does not exceed the first set value SET1, and the signal NZU of the state of the zero current transition point is still off (L level).

Meanwhile, when a fault occurs in the inverter 12 and the U-phase current IU is biased so that there is no intersection with zero, the counter reset signal RST is not generated synchronously with the zero crossing. Then, the calculated CNT value of the counter 21c continues to increase. The calculated CNT value of the counter 21c, therefore, exceeds the first set value SET1, so that the signal NZU state of the point of transition of the current through zero becomes on (H-level).

The first set value SET1 is preferably set so as not to be detected by mistake when the AC motor 6 rotates at a low speed (low frequency). When the number of revolutions of the AC motor 6 decreases, the frequency of the fundamental current harmonics decreases accordingly, and thus its period increases. Accordingly, the time between the intersections of the transition of the current through zero increases.

Thus, the first set value SET1 preferably varies depending on the rotational speed of the alternating current motor 6 and the fundamental frequency of the driving current of the alternating current motor 6. When the AC motor 6 is operating at a very low speed, the output of the NZU state signal of the zero current transition point is preferably masked to prevent the output of the state signal of the zero current transition point by mistake.

Further, in the current peak value state detecting unit 22, the current peak value detecting unit 22a detects the maximum value of the input U-phase current IU and outputs the value as the signal MX to the comparator 22b. The comparator 22b compares the input signal MX with the second set value SET2. When the MX signal exceeds the second set value SET2, the comparator 22b determines that the peak current value is higher, and makes the current peak value state signal MXU on (H level). The second set value SET2 is preferably set to slightly exceed the maximum current that is normally generated by the AC motor 6 when the inverter 12 is in a normal state, so that erroneous detection is prevented.

When the inverter 12 is in a normal state, the U-phase current value IU is not greater, and the signal MX of the current value IU is lower than the second set value SET2. The peak current state signal MXU is thus turned off (L level).

Meanwhile, when a malfunction occurs in the inverter 12, and the peak value of the U-phase current IU is excessive, as shown in FIG. 3, the amplitude signal MX exceeds the second set value SET2. Thus, the current peak value state signal MXU becomes on (H level).

Further, in the current-current-value-state-detecting unit 23, the current-current-value-detecting unit 23a detects the effective value of the input U-phase current IU and outputs the value to the comparator 23b as an amplitude signal RM. The comparator 23b compares the inputted signal RM with the third set value SET3. The comparator 23b determines that the effective current value is excessive when the RM signal exceeds the third set value SET3, and makes the effective current value state signal RMU on (H level). In order to prevent erroneous detection, the third set value SET3 is preferably set so as to exceed slightly the maximum current normally generated in the AC motor 6 when the inverter 12 is operating normally.

When the inverter 12 is functioning normally, the effective value of the U-phase current IU is not excessive, and the amplitude signal RM is lower than the third set value SET3. The current effective state value signal RMU is thus turned off (L level).

Meanwhile, when a malfunction occurs in the inverter 12, and the effective value of the U-phase current IU is excessive, as shown in FIG. 3, the amplitude signal RM exceeds the third set value SET3. In this case, the signal RMU status of the current value of the current becomes on (H-level).

Regarding the V-phase and W-phase, the same operation is performed in the V-phase detection logic unit 25V and in the W-phase detection logic unit 25W in the same manner as described above. Those. the V-phase detection logic 25V generates a state signal NZV of the zero transition point, a current peak value state signal MXV, and a current current value state signal RMV based on the IV phase current IV. The W-phase detection logic 25W generates a state signal NZW of the zero transition point, a current peak value state signal MXW, and a current current value state signal RMW based on the W-phase current IW.

The resulting signals NZU, MXU, RMU, NZV, MXV, RMV, NZW, MXW and RMW are input to the determination unit 27 in parallel. When any of these signals is on (H level), the determining unit 27 makes the current state signal FD on (H level) to indicate the occurrence of a malfunction. When all these signals then turn off (L level), the current state signal FD is turned off (L level) to indicate a normal state. When the inverter 12 is operating normally, the current state signal FD remains off (L level).

According to this configuration, the control unit 17A always understands the state of the phase currents IU, IV, and IW, and when a malfunction occurs, makes the gate signal GS off (L level). Additionally, the control unit 17A may issue an opening instruction to the tripping motor contactor 16, even if the basic MKCO contactor closing command is off (L level) when the current is in a state suitable for interruption, i.e., when a zero point is generated in the current , and its peak value and its effective value are less than predefined values.

The control operation performed by the control unit 17A using the configuration described above when a malfunction occurs is explained below with reference to FIG. 7. FIG. 7 is a waveform diagram explaining a control operation of the first embodiment in which a current is interrupted by forming a current zero transition point in a phase having no current zero transition point when a fault occurs, as shown in FIG. 3.

In FIG. 7 shows the waveforms (1) through (3) of the current wave of the respective phases and the waveform (4) of the linear voltage wave between the V phase and the W phase of the AC motor 6. These waveforms are in a state where a short circuit occurs in the UP element of the upper arm of the U-phase and the element VN of the lower arm of the V-phase, and all other switching elements (VP, WP, UN and WN) are turned off, as in FIG. 3.

In FIG. 7, the time T1A indicates the time when a short circuit occurs in the UP element of the upper arm of the U-phase and the element VN of the lower arm of the V-phase. The U-phase upper arm element UP and the V-phase lower arm element VN operate normally until time T1A and malfunction after time T1A. The trip contactor 16 of the motor is closed until time T2A after time T1A, since the contactor closing command MKC is on (H level). The contactor closing command MKC becomes off (L level) at time T2A, so that the trip motor contactor 16 is opened. As shown in FIG. 7, the time T2A when the trip contactor 16 of the electric motor opens, much later than the time T2B, according to the related technique shown in FIG. 3.

Before time T1A, when a short circuit occurs in the UP element of the upper arm of the U-phase and the element VN of the lower arm of the V-phase, all switching elements in the inverter 12 are normal, and the AC motor 6 is driven at a speed of 63 Hz. The usual point of transition of the current through zero appears in the forms (1) - (3) of the current wave of the corresponding phases. The normal waveform of the positive-negative voltage appears in the form (3) of the line voltage wave between the V phase and the W phase of the AC motor 6.

A short circuit occurs at time T1A in the UP element of the upper arm of the U-phase and the element VN of the lower arm of the V-phase, while the AC motor 6 is driven at a speed of 63 Hz. The remaining switching elements (VP, WP, UN and WN) are controlled in such a way as to be turned off. The current IU of the U phase is significantly shifted in the negative direction, as shown by waveform (1). The current of the IV V-phase is significantly shifted in the negative direction, as shown by the waveform (2). Forms (1) and (2) of the waves do not have any point where the current passes through zero. The W phase current IW indicates an asymmetric change, which is shown by waveform (3); however, there is a current zero transition point. The reason these waveforms are obtained is the same as that described with reference to FIG. 3.

When a short circuit occurs at time T1A, a high-level device (not shown) that detected a malfunction opens the contactor 11 to turn off the power supply immediately after time T1A, as described with reference to FIG. 3. Also, the high-level device includes a discharge circuit 18 to discharge electric charges in the filter capacitor 19 in order to prevent the application of DC voltage to the AC motor 6. A high-level device (not shown) also makes the MKCO basic contactor closing command off (L level) to prevent current from flowing from the AC motor 6 to the inverter 12.

The control unit 17A according to the first embodiment holds the on state (H level) of the contactor closing command MKC even after the basic contactor closing MKCO command is turned off (L level). While the ON state of the contactor closing command MKC is held, the contactor 11 for turning off the power supply is opened, and the filter capacitor 19 is discharged by the discharge circuit 18, so that the application of the DC voltage to the AC motor 6 is suppressed.

Thus, as shown by waveforms (1) - (3), the U-phase current IU and the IV-phase current IV are weakened, so that the zero-point transition points are formed in the U-phase IU current, V-phase IV current, and current IW W-phase. During (T2A time), when the peak current value and the effective current value are less than the predetermined values, the contactor closing command MKC is turned off (L level). Thus, the closing coil of the trip motor contactor 16 is not energized and de-energized.

Thus, the main contact of the trip contactor 16 of the motor opens at the time T3A immediately after the moment T2A. The current IW of the W phase is thus interrupted first at the point where the current passes through zero. The V phase IV current and the U phase IU current are then interrupted at their current zero transition points in this order. Three-phase currents are interrupted at T4A.

With this operation, when the W-phase current IW is interrupted at the point where the current passes through zero at the time T3A, the excess voltage is not generated in the linear voltage of the AC motor 6 by the above operation, as shown by waveform (4). Accordingly, the insulation of the AC motor 6 and the main circuits on the AC motor side is provided further downstream than the trip motor contactor 16 (for example, the trip motor contactor 16 and the U-phase conductor UM on the motor side, the V-phase conductor VM the motor side and the W-phase conductor WM on the motor side connecting the disconnecting contactor 16 of the motor to the AC motor 6) is not violated, and the drive an AC motor controller 10A can be prevented.

Since the main contact of the trip contactor 16 of the motor is opened after the points of current zero crossing are formed in all phases, the time when an electric arc arises between the contacts of the trip contactor 16 of the motor is short, i.e. from moment T2A to moment T4A. In contrast to the case of the related technique shown in FIG. 3, the appearance of an electric arc for a long time (from moment T2B to moment T4B) can be prevented, and thus damage to the trip contactor 16 of the motor caused by the generated heat can be prevented. Since damage to the surrounding insulation caused by electric arc gas can be prevented, short circuits in the trip contactor 16 of the motor and peripheral main circuits can be prevented.

It is understood that even when the trip contactor 16 (Fig. 7) of the electric motor remains closed after the moment T1A, when a short circuit occurs, the U-phase current IU, V-phase IV current and W-phase current IW have a large temporal amplitude immediately after the moment T1A; however, their amplitudes decrease thereafter by the discharge of the filter capacitor 19, which results in the formation of points of the transition of current through zero in three phases.

Since the trip contactor 16 of the motor remains closed after the time T1A, the short circuit current cannot be interrupted quickly. This appears to be the opposite of the original purpose that the trip motor contactor 16 provides. Even when the trip motor contactor 16 remains closed, the excess current does not flow continuously. Damage to short-circuited parts may not increase. Conversely, excess voltage generated when the tripping motor contactor 16 is opened can be suppressed. Those. the configuration of the control unit 17A described above intelligently uses the characteristics of the phase current. Of course, the contactor 11 for shutting off the power supply must be open, and the filter capacitor 19 must be discharged by the discharge circuit 18 before the disconnecting motor contactor 16 is opened.

As described above, there are many current components IU of the U phase, i.e. the existence of a zero transition point, the state of the peak value and the state of the effective value. With their help, even when due to a malfunction a complicated and curved current waveform is formed from a sine wave, the current abnormality state can be reliably studied. At least one of the presence of a zero transition point, a peak value state, and an effective value state can be observed. However, when only the state of the effective current value is observed, for example, the waveform of the current, whose peak value is large, but whose effective value is small due to a malfunction, cannot be detected.

Suppose the case when the current state signal FD maintains the on state (H level) in a situation where the abnormality of the U-phase current IU and V-phase IV current does not disappear due to the electric charges of the filter capacitor 19 not being discharged due to failure of the discharge circuit 18 and the contactor 11 for shutting off the power supply. In such a case, the contactor closing command MKC can be forcedly turned off after the set delay time of the time delay element circuit 43 has expired by the operation of the ONTD circuit 43 and the OR logic circuit 45 shown in FIG. 5. Therefore, the continuous formation of short-circuited circuits including an AC motor 6 can be prevented.

As described above, when the fault current, in which the phase in which the current transition point through zero is not formed, and the phase in which the current transition point through zero is formed, are present simultaneously, flows between the inverter 12 and the AC motor 6, the formation of excess voltage between the lines of the AC motor 6 and between the contacts of the trip contactor 16 of the motor can be prevented, and the formation of a continuous electric arc between the contacts of the trip contactor of the electric an engine can be prevented, despite the type of malfunction that occurred in the first embodiment. It is possible to provide a drive controller for an AC motor in which the insulation of the coils in the motor, the trip motor contactor and the cables connecting the trip motor contactor to the motor are not damaged, and the trip motor contactor is not damaged by the electric arc between the contacts of the trip motor contactor, despite the type of occurrence malfunctions.

Second Embodiment

In FIG. 8 is a block diagram of an example configuration of a drive controller for an AC motor according to a second embodiment of the present invention. In FIG. 8, similar reference numbers indicate components similar to those shown in FIG. 1 (first embodiment). Parts related to the second embodiment are mainly explained below.

As shown in FIG. 8, according to the drive controller 10B of the AC electric motor of the second embodiment, a control unit 17B is provided instead of the control unit 17A in the configuration shown in FIG. 1 (first embodiment). The control unit 17B has, for example, the configuration shown in FIG. 9.

The configuration and operations of the control unit 17B are explained below with reference to FIG. 9. In FIG. 9, similar reference numbers indicate components similar to those shown in FIG. 5 (first embodiment). Parts related to the second embodiment are mainly explained below.

As shown in FIG. 9, the control unit 17B is configured such that a contactor control unit 40B is provided instead of the contactor control unit 40A in the configuration of FIG. 5 (first embodiment). In the contactor control unit 40B, a one-shot circuit 47 is provided in the input stage of the logic circuit NOT 41, the time delay element circuit 43 and the OR logic 45 are excluded, and the output of the logic circuit AND 44 is directly supplied to the reset contact R of the latch circuit 46 in block 40A contactor control. Accordingly, the operation of the contactor control unit 40B is explained as the operation of the control unit 17B.

Operation of the contactor control unit 40B

When the current state signal FD has an L level, the output of the logic circuit NOT 41 has an H level. The latch circuit 46 is thus reset and outputs the MKC contactor closing command, which becomes on (H-level) or off (L-level) synchronously with turning on (H-level) or turning off (L-level) the basic MKCO closing command contactor.

When the current state signal FD changes from an L level to an H level, the output of the one-shot circuit 47 becomes on (H level) for a predetermined set time, and the output of the logic circuit NOT 41 becomes L level for a predetermined set time . Accordingly, the latch circuit 46 is not reset.

That is, when the current state signal FD changes from the L level to the H level, the contactor closing command MKC does not turn off (L level) for a predetermined time during which the output of the one-shot operation circuit 47 is turned on (H -level), even if the basic MKCO contactor closing command is turned off (L-level). When the output of the one-shot operation circuit 47 becomes turned off (L level), the output of the logic circuit NOT 41 becomes the H level. The latch circuit 46 is thus reset, and the contactor closing command MKC becomes turned off (L level).

The time period during which the one-shot operation circuit 47 is turned on (H level) is preferably calculated and set in advance by simulating the time before the current abnormality disappears after a malfunction in the inverter 12. In particular, about 100 ms pass according to the example of waveforms, shown in FIG. 7.

This configuration provides the ability to configure the function, as in the first embodiment, through fewer logical processes.

Among the functional elements of the control unit 17A shown in the first embodiment and the control unit 17B shown in the second embodiment, the current state determination unit 20 and the contactor control units 40A and 40B can be integrated into the trip contactor 16 of the electric motor.

A delay mechanism may be provided in the trip contactor 16 of the motor to open its main contact after the predetermined delay time elapses when the contactor closing command MKC entered by the control units 17A and 17B becomes off (L level).

Such a delay mechanism can prevent the application of excess voltage to the AC motor 6, since a predetermined delay time can be provided before the main contact of the trip contactor 16 of the electric motor opens. This configuration is useful when a malfunction occurs, for example, in a controlled power source (not shown) supplying power to the control units 17A and 17B, and thus, the control units 17A and 17B cannot perform the predetermined logic processes described in the first and the second embodiment, which results in the MKC closing contactor command becoming off (L level).

Needless to say, the controlled power source that supplies power to the control units 17A and 17B preferably has a backup function capable of supplying electric power to the control units 17A and 17B for some time during a malfunction.

According to the control performed by the control units 17A and 17B with the configuration described above during the failure, the generation of excess voltage can be prevented by opening the trip contactor 16 of the motor. When the set time in the time delay element circuit 43 and the one-time operation circuit 47 is exceeded or when a malfunction occurs in the control units 17A and 17B in a state where the current state signal FD is kept on (H-level) for some reason that trips the motor contactor 16 possibly opens despite current condition. In order to protect current detectors 13, 14 and 15 and another voltage detector (not shown) from damage even in the above state, they are preferably provided on the U-phase UI conductor on the inverter side, V-phase conductor VI on the inverter side and WI W- conductor phase on the inverter side.

The reason is that, as described above, it is possible that the insulation of the current detectors 13, 14 and 15 and the other voltage detector is broken and damaged by the excess voltage that is generated when the trip motor contactor 16 is controlled to open during a fault in the inverter 12 in the U-phase UM conductor from the motor side, the V-phase VM conductor from the motor side and the W-phase WM conductor from the motor side. Meanwhile, excess voltage is not generated in the U-phase UI conductor from the inverter side, the V-phase VI conductor from the inverter side and the W-phase conductor WI from the inverter side in this case, and thus, current detectors 13, 14 and 15 and other voltage detectors are not damaged.

The configurations described in the above embodiments are merely examples of the contents of the present invention, and can be combined with other known technologies. It is needless to mention that these configurations can be modified without departing from the purpose of the present invention, such as, for example, deleting part of the configurations.

For example, this specification explains the configuration of receiving DC voltage from the current collector 1 and direct voltage input through the contactor 11 to turn off the power supply to the inverter 12. It is also possible to provide the configuration of receiving AC voltage from the current collector 1, input AC voltage through the contactor 11 to shut supplying power to a converter circuit that converts AC voltage to DC voltage, and inputting DC voltage OK as the output signal of the converter to inverter circuit 12. This configuration is suitable for electric vehicles for AC electrification sections.

While the present specification describes the present invention as an invention applied to a drive controller for an alternating current motor integrated in an electric vehicle, the scope of the present invention is not limited to this. Needless to say, the invention can be applied to other synchronous motor excitation systems, such as related technologies including electric vehicles.

Industrial applicability

As described above, a drive controller for an AC motor according to the present invention is useful as a drive controller for an AC motor. Even when the phase at which the zero-point transition point is not formed, and the phase at which the zero-point transition point is formed, are simultaneously present in the fault current that flows between the inverter and the motor, the insulation of the motor coils, disconnecting the motor contactor and the cables connecting the disconnecting contactor of the electric motor with the electric motor is not broken, and the disconnecting contactor of the electric motor is not damaged by the electric arc between the contacts of the disconnecting contactor of the electric odvigatelya, regardless of the type of the fault. The present invention is particularly useful when an AC electric motor integrated in an electric vehicle is a permanent magnet synchronous electric motor.

Explanation of alphabetic or numerical references

1 - Current collector

2 - Rail

3 - Wheel

6 - AC motor

7 - rotation detector

10A, 10B - AC Motor Drive Controller

11 - Contactor for turning off the power supply

12 - Inverter

13, 14, 15 - Current Detector

16 - tripping motor contactor

17A, 17B - Control Unit

18 - discharge circuit

19 - Filter Capacitor

20 - Current state determination unit

21 - Block detecting the state of the transition point of the current through zero

21a - Block detecting the current transition point through zero

21b - Block oscillation

21c - Counter

21d - Comparator

22 - Block detecting the state of the peak current value

22a Peak Current Detection Unit

22b - Comparator

23 - Block detecting the state of the current value of the current

23a - Block detection of the current value of the current

23b - Comparator

25U - U-phase detection logic unit

25V - V-phase detection logic unit

25W - W-phase detection logic unit

27 - Definition block

30 - Gate block logic

31 - Latch

33 - Logic NOT (NOT)

33 - The logical circuit And (And)

40A, 40B - Contactor control unit

41, 42 - Logic NOT (NOT)

43 - Time Delay Element Circuit (ONTD)

44 - The logical circuit And (And)

45 - Logic diagram OR (OR)

46 - Latch

47 - Scheme of single operation

P - Positive Side Conductor

N - Negative Side Conductor

UI - U-phase conductor on the inverter side

VI - U-phase conductor on the inverter side

WI - W-phase conductor on the inverter side

UM - U-phase conductor on the motor side

VM - V-phase conductor on the motor side

WM - W-phase conductor on motor side

UP - U-phase upper arm element

VP - Element of the upper arm of the V-phase

WP - element of the upper arm of the W-phase

UN - element of the lower arm of the U-phase

VN - element of the lower arm of the V-phase

WN - element of the lower arm of the W-phase

Claims (13)

1. A drive controller (10A; 10V) for an alternating current motor, comprising:
an inverter (12), which includes many switching elements (UP, VP, WP, VN, UN, WN) with controlled on-off and converts DC voltage to AC voltage with arbitrary frequency to excite the AC motor (6) ; a switch (16) on the motor side connected between the inverter (12) and the alternating current motor (6); an electric quantity detector (13, 14, 15) that detects an electric quantity on the output side of the inverter (12); a control unit (17A; 17B) that controls the on / off of the switching elements (UP, VP, WN, VN, UN, WN) in the inverter (12) and controls the switch (16) on the motor side to open and close it based at least a current detected by an electric quantity detector (13, 14, 15); and a switch (11) on the side of the power supply provided between the DC input side of the inverter (12) and the power supply (1), the control unit (17A; 17B) comprising:
a current state determining unit (20) that generates a determination signal determining whether the current detected by the electric magnitude detector (13, 14, 15) is in an abnormal state, and
a contactor control unit (40A; 40B) that controls, based on a determination signal, the moment of actual issuing of a high-level instruction that is generated for the switch (16) on the motor side to open the switch (16) on the motor side, and
the switch (11) on the side of the power supply is configured to open so as to disconnect the DC input side of the inverter (12) from the power source (1) before the switch (16) on the motor side opens. 2. A drive controller (10A; 10V) for an alternating current electric motor, comprising: an inverter (12), which includes a plurality of switching elements (UP, VP, WP, VN, UN, WN) with controlled on-off switching and converts DC voltage current to an alternating current voltage with an arbitrary frequency, to excite an alternating current electric motor (6); a switch (16) on the motor side connected between the inverter (12) and the alternating current motor (6); an electric quantity detector (13, 14, 15) that detects an electric quantity on the output side of the inverter (12);
a control unit (17A; 17B) that controls the on / off of the switching elements (UP, VP, WP, VN, UN, WN) in the inverter (12) and controls the switch (16) on the motor side to open and close it based at least a current detected by an electric quantity detector (13, 14, 15); and
a discharge circuit (18) connected in parallel with a capacitor (19) provided between the positive side conductor and the negative side conductor of the inverter (12), to which a DC voltage is applied, while
the control unit (17A; 17B) contains:
a current state determining unit (20) that generates a signal determining whether the current detected by the electric quantity detector (13, 14, 15) is in an abnormal state, and
a contactor control unit (40A; 40B) that controls, based on a determination signal, the moment of actual issuing of a high-level instruction that is generated for the switch (16) on the motor side to open the switch (16) on the motor side, and
a discharge circuit (18) configured to control to discharge the electric charges of the capacitor (19) before the switch (16) on the motor side opens. 3. The drive controller (10A; 10V) for an AC motor according to claim 1 or 2, in which
the control unit (17A; 17B) includes a gate signal logic unit (30), which generates a gate signal, not only controlling the on-off, but also controlling the switching-off of the switching elements (UP, VP, WP, VN, UN, WN) on based signal definition. 4. The drive controller (10A; 10V) for an AC motor according to claim 1 or 2, in which
the current state determination unit (20) compares at least one of: an indicator related to the existence of a zero crossing of the detected current, an indicator related to the peak value of the detected current, and an indicator related to the actual value of the detected current with the corresponding set value and generates a determination signal based on the comparison result. 5. The drive controller (10A; 10V) for an AC motor according to claim 1 or 2, in which
the current state determination unit (20) determines that the current is in an abnormal state, and generates a determination signal indicating the current abnormality when the indicator relating to the existence of a zero crossing of any of the detected three-phase currents exceeds the first set value, since the zero crossing does not exist, when the indicator related to the peak value of the detected current exceeds the second set value, or when the indicator related to the current value of the detected t OK, exceeds the third set value. 6. The drive controller (10A; 10V) for an AC motor according to claim 1 or 2, in which
the current state determination unit (20) determines that the current is in a normal state and generates a determination signal indicating a normal current state when the indicator relating to the existence of a zero crossing in all detected three-phase currents is lower than the first set value, since the transition point current through zero exists, an indicator related to the peak value of the detected current is lower than the second set value, and an indicator related to the current value of the detected current, lower than the third setpoint. 7. The drive controller (10A; 10V) for an AC motor according to claim 1 or 2, in which
the contactor control unit (40A; 40B) does not control the opening of the switch (16) on the motor side when the current state determination unit (20) determines that the detected current is in an abnormal state. 8. The drive controller (10A; 10V) for an AC motor according to claim 1 or 2, in which
the contactor control unit (40A; 40B) controls the delay time for opening the switch (16) on the motor side from the time when the current state determination unit (20) determines that the detected current is in an abnormal state until the moment when the state changes to the state when the state is suitable for opening the switch (16) on the motor side, or when it is estimated that a change has been made. 9. The drive controller (10A; 10V) for an AC motor according to claim 1 or 2, in which
an electric magnitude detector (13, 14, 15) is provided in the circuit that is provided between the inverter (12) and the switch (16) on the motor side. 10. A drive controller (10A; 10V) for an alternating current motor, comprising:
an inverter (12), which includes many switching elements (UP, VP, WP, VN, UN, WN) with controlled on-off and converts DC voltage to AC voltage with arbitrary frequency to excite the AC motor (6) ; a switch (16) on the motor side connected between the inverter (12) and the alternating current motor (6); an electric quantity detector (13, 14, 15) that detects an electric quantity on the output side of the inverter (12); a control unit (17A; 17B) that controls the on / off of the switching elements (UP, VP, WN, VN, UN, WN) in the inverter (12) and controls the switch (16) on the motor side to open and close it based at least the current detected by the detector (13, 14, 15) of electrical magnitude, while
the control unit (17A; 17B) contains:
a current state determining unit (20) that generates a determination signal determining whether the current detected by the electric magnitude detector (13, 14, 15) is in an abnormal state, and
a contactor control unit (40A; 40B) that controls, based on the determination signal, the moment of the actual issuing of a high-level instruction that is formed to open the switch (16) on the electric motor side to the switch (16) on the electric motor side,
the current state determination unit (20) determines that the current is in an abnormal state, and generates a determination signal indicating the current abnormality when the indicator relating to the existence of a zero crossing of any of the detected three-phase currents exceeds the first set value, since the zero crossing does not exists when the indicator related to the peak value of the detected current exceeds the second set value, or when the indicator related to the current value of the detected current annogo current exceeds a third set value. 11. A drive controller (10A; 10V) for an alternating current motor, comprising:
an inverter (12), which includes many switching elements (UP, VP, WP, VN, UN, WN) with controlled on-off and converts DC voltage to AC voltage with an arbitrary frequency, to excite an AC motor (6 ); a switch (16) on the motor side connected between the inverter (12) and the alternating current motor (6); an electric quantity detector (13, 14, 15) that detects an electric quantity on the output side of the inverter (12); and a control unit (17A; 17B) that controls the on / off of the switching elements (UP, VP, WN, VN, UN, WN) in the inverter (12) and controls a switch (16) on the motor side to open and close it to based on at least the current detected by the detector (13, 14, 15) of electrical magnitude, while
the control unit (17A; 17B) contains:
a current state determining unit (20) that generates a determination signal determining whether the current detected by the electric magnitude detector (13, 14, 15) is in an abnormal state, and
a contactor control unit (40A; 40B), which controls, based on a determination signal, the moment of actual issuing of a high-level instruction that is formed to open the switch (16) on the electric motor side to the switch (16) on the electric motor side,
the current state determination unit (20) determines that the current is in a normal state and generates a determination signal indicating the normal current state when the indicator related to the existence of a zero crossing in all detected three-phase currents is lower than the first set value, since a zero transition point exists, an indicator related to the peak value of the detected current is lower than the second set value, and an indicator related to the actual value of the detected current current, lower than the third setpoint. 12. A drive controller (10A; 10V) for an alternating current motor, comprising:
an inverter (12), which includes many switching elements (UP, VP, WP, VN, UN, WN) with controlled on-off and converts DC voltage to AC voltage with an arbitrary frequency, to excite an AC motor (6 ); a switch (16) on the motor side connected between the inverter (12) and the alternating current motor (6); an electric quantity detector (13, 14, 15) that detects an electric quantity on the output side of the inverter (12); and a control unit (17A; 17B) that controls the on / off of the switching elements (UP, VP, WN, VN, UN, WN) in the inverter (12) and controls a switch (16) on the motor side to open and close it to based on at least the current detected by the detector (13, 14, 15) of electrical magnitude, while
the control unit (17A; 17B) contains:
a current state determining unit (20) that generates a determination signal determining whether the current detected by the electric magnitude detector (13, 14, 15) is in an abnormal state, and
a contactor control unit (40A; 40B) that controls, based on a determination signal, the moment of actual issuing of a high-level instruction that is formed to open the switch (16) on the motor side, the switch (16) on the motor side,
however, the contactor control unit (40A; 40B) does not control the opening of the switch (16) on the motor side at the moment when the current state determination unit (20) determines that the detected current is in an abnormal state. 13. A drive controller (10A; 10V) for an alternating current motor, comprising:
an inverter (12), which includes many switching elements (UP, VP, WP, VN, UN, WN) with controlled on-off and converts DC voltage to AC voltage with an arbitrary frequency, to excite an AC motor (6 ); a switch (16) on the motor side connected between the inverter (12) and the alternating current motor (6); an electric quantity detector (13, 14, 15) that detects an electric quantity on the output side of the inverter (12); and a control unit (17A; 17B) that controls the on / off of the switching elements (UP, VP, WN, VN, UN, WN) in the inverter (12) and controls a switch (16) on the motor side to open and close it to based on at least the current detected by the detector (13, 14, 15) of electrical magnitude, while
the control unit (17A; 17B) contains:
a current state determining unit (20) that generates a determination signal determining whether the current detected by the electric magnitude detector (13, 14, 15) is in an abnormal state, and
a contactor control unit (40A; 40B), which controls, based on a determination signal, the moment of actual issuing of a high-level instruction that is formed to open the switch (16) on the electric motor side to the switch (16) on the electric motor side,
wherein the contactor control unit (40A; 40B) controls the delay of the opening time of the switch (16) on the motor side from the time when the current state determination unit (20) determines that the detected current is in an abnormal state until the time when the state changes to a state suitable for opening the switch (16) on the motor side, or when it is estimated that the change has been made.

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