JP2021044954A - Control device of ac rotary machine - Google Patents

Abstract

To provide a control device of an AC rotary machine capable of increasing the decrease rate of overvoltage DC voltage by increasing the copper loss while suppressing increase of torque compared to the case of performing a three-phase short circuit using multiple sets of armature windings.SOLUTION: A control device 1 of an AC rotary machine that is configured to execute an overvoltage control to apply a voltage to each armature winding so that, when an overvoltage of DC voltage Vdc is detected, the combined voltage vector of each set is non-zero for two or more sets, and when the combined voltage vectors of all sets are summed, the combined voltage vectors of each set is weakened each other.SELECTED DRAWING: Figure 1

Description

The present application relates to a control device for an AC rotating machine.

In the motor drive device of Patent Document 1, the sixth-order torque ripple generated in each winding group is generated between the winding groups by a trapezoidal voltage or current in which fifth-order and seventh-order harmonic components are superimposed on the fundamental wave. The phase difference between them cancels each other out and reduces the torque ripple of the motor drive device.

The fail-safe device of the inverter of Patent Document 2 is configured to perform a three-phase short circuit when an overvoltage is detected by an overvoltage detection circuit. In a three-phase short circuit, all the switching elements on the positive electrode side are turned on and all the switching elements on the negative electrode side are turned off, or all the switching elements on the positive electrode side are turned off and all the switching elements on the negative electrode side are turned off. All are turned on. Due to this three-phase short circuit, the terminals of the windings of each phase are short-circuited with each other, and no voltage is applied to the windings of each phase from the DC power supply.

Japanese Unexamined Patent Publication No. 2014-121189 JP-A-2015-198503

In Patent Document 1, the phase difference between the winding sets is set as a divisor obtained by dividing 60 deg by a divisor excluding 1 of the number of winding sets so that the sixth-order torque ripple can be canceled by the m sets of windings. Therefore, when the phase difference is another value, the canceling effect of the torque ripple cannot be obtained.

In Patent Document 2, power is consumed and the DC power supply voltage is lowered due to copper loss due to a three-phase short circuit, but only the case where one set of windings is provided is considered.

For example, when an AC rotating machine is generating power and the generated power is supplied to a DC power supply and various electric loads connected to the DC power supply, and the power consumption of the electric load suddenly decreases, the AC rotation is performed. The generated power of the machine is not absorbed by the DC power supply and the electric load, becomes surplus, and the DC voltage rises above the rated voltage. Alternatively, the DC voltage may rise due to some other factor. If the DC voltage rises too high, it can adversely affect the electrical load. Therefore, when the DC voltage becomes an overvoltage state, it is desired to immediately reduce the DC voltage.

Therefore, when a plurality of sets of armature windings are provided, copper loss is reduced while suppressing an increase in torque as compared with a case where a plurality of sets of armature windings are used to perform a three-phase short circuit. A control device for an AC rotating machine that can increase the rate of decrease of the overvoltage DC voltage is desired.

The control device of the first AC rotary machine according to the present application is an AC rotary machine having m sets (m is a natural number of 2 or more) and n-phase armature windings (n is a natural number of 2 or more). It is a control device for an AC rotating machine that is controlled via an inverter.
A voltage detector that detects the DC voltage supplied to the inverter of each set, and
A voltage application unit that applies a voltage to the armature winding of each phase of each set by turning on and off a plurality of switching elements of the inverter of each set.
An overvoltage determination unit for determining whether or not the DC voltage has exceeded the overvoltage determination threshold value is provided.
The voltage application unit has two sets of combined voltage vectors obtained by synthesizing the voltage applied to the n-phase armature winding for each set when it is determined that the DC voltage exceeds the overvoltage determination threshold. When the above is non-zero and the combined voltage vectors of all the sets are summed, the voltage is applied to the armature winding of each phase of each set so that the combined voltage vectors of each set weaken each other. It executes control at the time of overvoltage to be applied.

The control device for the second AC rotary machine according to the present application is an AC rotary machine having m sets (m is a natural number of 2 or more) and n-phase armature windings (n is a natural number of 2 or more). It is a control device for an AC rotating machine that is controlled via an inverter.
A voltage detector that detects the DC voltage supplied to the inverter of each set, and
A voltage application unit that applies a voltage to the armature winding of each phase of each set by turning on and off a plurality of switching elements of the inverter of each set.
An overvoltage determination unit for determining whether or not the DC voltage has exceeded the overvoltage determination threshold value is provided.
The voltage application unit uses a coordinate system consisting of a d-axis defined in the magnetic flux direction of the field and a q-axis defined in a direction π / 2 advanced by an electric angle from the d-axis as a dq-axis coordinate system.
The voltage command applied to the n-phase armature winding is defined as the dq-axis combined voltage vector by combining the d-axis voltage command and the q-axis voltage command represented by the dq-axis coordinate system for each set.
When it is determined that the DC voltage exceeds the overvoltage determination threshold, each set has a phase of the dq-axis combined voltage vector with respect to the d-axis larger than π and smaller than 2π. The d-axis voltage command and the q-axis voltage command are set, and for each set, overvoltage control for turning on and off a plurality of the switching elements is executed based on the d-axis voltage command and the q-axis voltage command. Is.

According to the control device of the first AC rotary machine according to the present application, the torque output by the armature windings of each set is set by applying a voltage so that the combined voltage vectors of each set weaken each other. By weakening each other, it is possible to suppress an increase in total torque as compared with a three-phase short circuit. Further, the total copper loss is not weakened between the sets, and can be increased by making the magnitude of the combined voltage vector of each set larger than zero as compared with the case of the three-phase short circuit. Therefore, as compared with the three-phase short circuit, the total copper loss can be increased while suppressing the increase in the total torque, and the rate of decrease of the overvoltage DC voltage can be increased.

According to the control device of the second AC rotating machine according to the present application, the d-axis voltage command and q of each set so that the phase of the dq-axis combined voltage vector of each set is larger than π and smaller than 2π. By setting the shaft voltage command, it is possible to increase the total copper loss while suppressing the increase in the total torque as compared with the three-phase short circuit, and it is possible to increase the rate of decrease of the overvoltage DC voltage. it can.

It is a schematic block diagram of the AC rotary machine and the control device of the AC rotary machine which concerns on Embodiment 1. FIG. It is a schematic diagram which shows the phase of the 1st set 3 phase armature winding and the 2nd set 3 phase armature winding which concerns on Embodiment 1. FIG. It is a schematic diagram of the AC rotary machine which was made into the generator motor for the vehicle which concerns on Embodiment 1. FIG. It is a schematic block diagram of the control device of the AC rotary machine which concerns on Embodiment 1. FIG. It is a hardware block diagram of the control device of the AC rotary machine which concerns on Embodiment 1. FIG. It is a schematic diagram which shows the setting of the combined voltage vector of each set which concerns on Embodiment 1. FIG. It is a figure which compares the behavior of three methods which concerns on Embodiment 2. It is a figure which shows the setting pattern of the applied voltage which is switched at a fixed time according to Embodiment 2. It is a figure which shows the setting pattern of the applied voltage which is switched at a fixed time according to Embodiment 2. It is a schematic diagram which shows the setting of the combined voltage vector of each set which concerns on Embodiment 3. It is a figure which compares the behavior of the two methods which concerns on Embodiment 3.

1. 1. Embodiment 1
The control device 1 (hereinafter, simply referred to as the control device 1) of the AC rotary machine according to the first embodiment will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an AC rotating machine 10 and a control device 1 according to the present embodiment.

1-1. AC rotating machine The AC rotating machine 10 includes a stator 18 and a rotor 14 arranged inside the stator 18 in the radial direction. The AC rotating machine 10 is a field winding type synchronous rotating machine. One stator 18 is wound with m sets (m is a natural number of 2 or more) of n-phase armature windings (n is a natural number of 2 or more). A field winding 25 is wound around the rotor 14, and an electromagnet is provided.

In the present embodiment, the m set is 2 sets and the n phase is 3 phases. The AC rotating machine 10 has three phases of armature windings Cu1, Cv1, Cw1 of the first set of U1, V1 and W1 phases, and three phases of the second set of U2, V2 and W2 phases. The armature windings Cu2, Cv2, and Cw2 of the above are provided. As shown in FIG. 1, the three-phase armature windings of each set may be star-connected or delta-connected.

As shown in a schematic diagram in FIG. 2, the first set of U1 phase winding Cu1, V1 phase winding Cv1, and W1 phase winding Cw1 are sequentially out of phase by 2π / 3 (120 deg) in electrical angle. .. The U2 phase winding Cu2, the V2 phase winding Cv2, and the W2 phase winding Cw2 of the second set are sequentially out of phase by 2π / 3 (120 deg) in electrical angle.

In the present embodiment, there is no phase difference between the first set of three-phase armature windings Cu1, Cv1, Cw1 and the second set of three-phase armature windings Cu2, Cv2, Cw2. .. There is no phase difference between the first set of U1 phase winding Cu1 and the second set of U2 phase winding Cu2, and the first set of V1 phase winding Cv1 and the second set of V2 phase winding Cv2 There is no phase difference between them, and there is no phase difference between the first set of W1 phase windings Cw1 and the second set of W2 phase windings Cw2. The electric angle is the mechanical angle of the rotor 14 multiplied by the number of pole pairs of the magnet. In the following theoretical formula, the number of polar bodies is set to 1 for simplification.

The rotor 14 is provided with an angle sensor 15 that detects the rotation angle (magnetic pole position) of the rotor 14. The output signal of the angle sensor 15 is input to the control device 1. Various sensors are used for the angle sensor 15. For example, as the angle sensor 15, a position detector such as a resolver, a Hall element, a TMR element, or a GMR element, or a rotation detector such as an electromagnetic type, a magnetoelectric type, or a photoelectric type is used.

<Generator for vehicles>
In the present embodiment, the AC rotary machine 10 is a generator motor for a vehicle. The rotating shaft of the rotor 14 of the AC rotating machine 10 is connected to the internal combustion engine 54 via a connecting mechanism. Further, the rotating shaft of the AC rotating machine 10 is connected to the wheel 52 via a connecting mechanism. For example, as shown in FIG. 3, the rotating shaft of the AC rotating machine 10 is connected to the crankshaft of the internal combustion engine 54 via a pulley and a belt mechanism 53. The rotating shaft of the AC rotating machine 10 is connected to the wheels 52 via the internal combustion engine 54 and the transmission 55.

1-2. Inverters M sets of inverters are provided corresponding to m sets of armature windings. In the present embodiment, the first set of inverters 21 that convert the DC power of the DC power supply 16 and the AC power supplied to the first set of armature windings, the DC power of the DC power supply 16, and the second set of armatures. A second set of inverters 22 that convert the AC power supplied to the child windings is provided.

The first set of inverters 21 and the second set of inverters 22 have a positive electrode side switching element 23 connected to the positive electrode side of the DC power supply 16 and a negative electrode side switching element connected to the negative electrode side of the DC power supply 16, respectively. A series circuit in which 24 and 24 are connected in series is provided in three sets corresponding to the armature windings of each of the three phases. The connection points of the two switching elements in each series circuit are connected to the armature windings of the corresponding phases.

As the switching element, an IGBT (Insulated Gate Bipolar Transistor) in which diodes are connected in antiparallel, a bipolar transistor in which diodes are connected in antiparallel, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), and the like are used. The gate terminal of each switching element is connected to the control device 1 via a gate drive circuit or the like. Therefore, each switching element is turned on or off by the switching signal output from the control device 1.

The DC power supply 16 outputs a DC voltage Vdc to the inverters 21 and 22 of the first set and the second set. As the DC power supply 16, any device that outputs a DC voltage, such as a battery, a DC-DC converter, a diode rectifier, and a PWM rectifier, is used. A smoothing capacitor 19 is connected in parallel to the DC power supply 16. A voltage sensor 17 for detecting the DC voltage Vdc is provided. The output signal of the voltage sensor 17 is input to the control device 1.

The inverters 21 and 22 of the first set and the second set each include a current sensor 13 for detecting the current flowing through the armature winding of each phase. In the present embodiment, the current sensor 13 is a shunt resistor connected in series to the series circuit of the switching elements of each phase. The potential difference between both ends of each shunt resistor is input to the control device 1. For example, each shunt resistor is connected in series with the negative electrode side of the switching element on the negative electrode side. The current sensor 13 may be a Hall element or the like provided on the electric wire connecting the series circuit of the switching element of each phase and the armature winding.

In the present embodiment, a switching element 26 for the field winding that controls the supply of DC power to the field winding 25 is provided. The switching element 26 for the field winding is provided on the electric wire connecting the DC power supply 16 and the field winding 25. The field winding switching element 26 is turned on or off by the field winding switching signal output from the control device 1.

1-3. Control device 1
The control device 1 controls the AC rotating machine 10 via the inverters 21 and 22 of the first set and the second set. As shown in FIG. 4, the control device 1 includes control units such as a rotation detection unit 31, a voltage detection unit 32, a current detection unit 33, an overvoltage determination unit 34, and a voltage application unit 35. Each function of the control device 1 is realized by a processing circuit provided in the control device 1. Specifically, as shown in FIG. 5, the control device 1 has, as a processing circuit, an arithmetic processing unit 90 (computer) such as a CPU (Central Processing Unit), a storage device 91 for exchanging data with the arithmetic processing unit 90, and the like. The arithmetic processing unit 90 includes an input circuit 92 for inputting an external signal, an output circuit 93 for outputting a signal from the arithmetic processing unit 90 to the outside, a communication device 94 for data communication with the external device, and the like.

The arithmetic processing device 90 is provided with an ASIC (Application Specific Integrated Circuit), an IC (Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), various logic circuits, various signal processing circuits, and the like. You may. Further, as the arithmetic processing unit 90, a plurality of the same type or different types may be provided, and each processing may be shared and executed. As the storage device 91, a RAM (Random Access Memory) configured to be able to read and write data from the arithmetic processing device 90, a ROM (Read Only Memory) configured to be able to read data from the arithmetic processing device 90, and the like are used. It is equipped. The input circuit 92 includes an A / D converter or the like to which various sensors and switches such as an angle sensor 15, a voltage sensor 17, and a current sensor 13 are connected, and the output signals of these sensors and switches are input to the arithmetic processing device 90. ing. The output circuit 93 is connected to an electric load such as a gate drive circuit that drives the switching elements of the first set of inverters 21 and the second set of inverters 22 on and off, and outputs a control signal from the arithmetic processing device 90 to these electric loads. It is equipped with a drive circuit and the like. The communication device 94 communicates with an external device such as the vehicle integrated control device 27.

Then, in each function of the control units 31 to 35 and the like included in the control device 1, the arithmetic processing unit 90 executes software (program) stored in the storage device 91 such as ROM, and the storage device 91 and the input circuit 92. , And other hardware of the control device 1 such as the output circuit 93. The setting data such as the overvoltage determination threshold value and the voltage command used by each of the control units 31 to 35 and the like are stored in a storage device 91 such as a ROM as a part of software (program). Hereinafter, each function of the control device 1 will be described in detail.

<Each detector>
The rotation detection unit 31 detects the rotation angle θ (magnetic pole position θ) and the rotation angular velocity ω at the electric angle of the rotor 14. In the present embodiment, the rotation detection unit 31 detects the rotation angle θ (magnetic pole position θ) and the rotation angular velocity ω at the electric angle based on the output signal of the angle sensor 15. The rotation detection unit 31 is configured to estimate the rotation angle θ (magnetic pole position θ) based on the current information obtained by superimposing the harmonic component on the current command without using an angle sensor. It may be (so-called sensorless method).

The voltage detection unit 32 detects the DC voltage Vdc supplied from the DC power supply 16 to each set of inverters. In the present embodiment, the voltage detection unit 32 detects the DC voltage Vdc based on the output signal of the voltage sensor 17.

The current detection unit 33 detects the current flowing through the armature winding of each phase of each set. The current detection unit 33 detects the current flowing through the armature winding of each phase of each set based on the output signal of the current sensor 13.

1-3-1. The voltage application unit and the overvoltage determination unit The voltage application unit 35 applies a voltage to the armature windings of each phase of each set by turning on and off a plurality of switching elements included in each set of inverters. In the present embodiment, the voltage application unit 35 includes a normal voltage application unit 351 and an overvoltage voltage application unit 352.

1-3-1-1. Normal voltage application When it is determined by the overvoltage determination unit 34, which will be described later, that the DC voltage Vdc is not in the overvoltage state, the normal voltage application unit 351 executes normal time control for each set. In the present embodiment, the normal voltage application unit 351 calculates the voltage command to be applied to the armature winding of each phase in the normal time. Specifically, the normal voltage application unit 351 calculates the three-phase voltage commands Vu1, Vv1, and Vw1 for the first set, and calculates the three-phase voltage commands Vu2, Vv2, and Vw2 for the second set. .. For example, the normal voltage application unit 351 calculates the voltage command of each set of three phases by using a known vector control or V / f control.

When vector control is used, the normal voltage application unit 351 calculates a d-axis current command and a q-axis current command based on the torque command transmitted from the vehicle integrated control device 27 or the like for each set. The normal voltage application unit 351 converts the three-phase current detection value into the d-axis current detection value and the q-axis current detection value on the dq-axis coordinate system based on the magnetic pole position for each set, and dq. On the axis coordinate system, the d-axis voltage command and the q-axis voltage command are issued by PI control or the like so that the d-axis current detection value and the q-axis current detection value approach the d-axis current command and the q-axis current command. Perform changing current feedback control. The normal voltage application unit 351 does not use the current detection value for each set, but uses the specifications of the AC rotating machine based on the d-axis current command and the q-axis current command, and uses the d-axis voltage command and the q-axis. Feed forward control that changes the voltage command may be executed. Then, the normal voltage application unit 351 coordinates the d-axis voltage command and the q-axis voltage command into three-phase voltage commands based on the magnetic pole positions for each set. The normal voltage application unit 351 may apply modulation such as space vector modulation and two-phase modulation so that the line voltage does not change to the three-phase voltage command.

The dq-axis coordinate system is a coordinate system consisting of a d-axis defined in the magnetic flux direction of the field and a q-axis defined in a direction π / 2 advanced by an electric angle from the d-axis. In the present embodiment, the magnetic flux direction of the field is the direction of the north pole of the magnet provided on the rotor 14. The magnetic pole position of the first set is the lead angle of the d-axis with respect to the armature winding Cu1 of the U1 phase of the first set, and the magnetic pole position of the second set is the armature winding of the U2 phase of the second set. It is the lead angle of the d-axis with respect to the wire Cu2. In the present embodiment, since there is no phase difference between the first set of U1 phase armature winding Cu1 and the second set of U2 phase armature winding Cu2, there is no phase difference between the first set of magnetic pole positions and the first set. It will be the same as the two sets of magnetic pole positions.

When V / f control is used, the normal voltage application unit 351 determines the amplitude V of the voltage command for each set based on the rotation frequency command f of the AC rotor transmitted from the vehicle integrated control device 27 or the like. To do. Then, the normal voltage application unit 351 calculates the three-phase voltage command for each set based on the phase obtained by integrating the amplitude V of the voltage command and the rotation frequency command f.

The normal voltage application unit 351 turns on and off a plurality of switching elements by PWM (Pulse Width Modulation) control based on a three-phase voltage command for each set. The normal-time voltage application unit 351 generates a switching signal for turning on / off the switching element of each phase by comparing each of the three-phase voltage commands with the carrier wave for each set. The carrier wave is a triangular wave that vibrates at a carrier frequency in the amplitude of the DC voltage Vdc, that is, between + Vdc / 2 and −Vdc / 2. The normal voltage application unit 351 turns on the switching signal when the voltage command exceeds the carrier wave, and turns off the switching signal when the voltage command falls below the carrier wave. The switching signal is transmitted to the switching element 23 on the positive electrode side as it is, and the switching signal in which the switching signal is inverted is transmitted to the switching element 24 on the negative electrode side. Each switching signal is input to the gate terminal of each switching element of the inverters 21 and 22 of the first set and the second set via the gate drive circuit, and each switching element is turned on or off.

<Voltage application of field winding>
The normal voltage application unit 351 applies a voltage to the field winding 25 when the normal control is executed. For example, the normal voltage application unit 351 generates a PWM signal having an on-duty ratio for normal control and outputs it as a switching signal for field winding. The on-duty ratio for normal control may be changed according to the operating state such as the rotational angular velocity of the rotor. The switching signal for the field winding is input to the gate terminal of the switching element 26 for the field winding via the gate drive circuit, and the switching element 26 for the field winding is turned on or off.

1-3-1-2. Applying voltage during overvoltage <Issues of overvoltage>
When the AC rotating machine 10 is generating power and the generated power is supplied to the DC power supply 16 and various electric loads (negatively shown) connected to the DC power supply 16, the power consumption of the electric load is suddenly reduced. , The generated power of the AC rotating machine 10 is not absorbed by the DC power supply 16 and the electric load, becomes a surplus, and the DC voltage Vdc rises above the rated voltage. If the DC voltage Vdc rises too much, it may adversely affect the electrical load. Therefore, when the DC voltage Vdc becomes an overvoltage state, it is desired to immediately reduce the DC voltage Vdc.

Therefore, when the DC voltage Vdc rises too much, the power generation of the AC rotating machine 10 may be stopped, but the DC voltage Vdc may not be rapidly lowered only by stopping the power generation. Therefore, it is conceivable that the DC voltage Vdc is rapidly lowered by causing the AC rotating machine 10 to consume the surplus electric power.

<Overvoltage judgment>
The overvoltage determination unit 34 determines whether or not the DC voltage Vdc is equal to or greater than the overvoltage determination threshold value. The overvoltage determination threshold value is preset to a voltage larger than the rated voltage of the DC power supply 16.

<Control at overvoltage>
The voltage application unit 35 is configured to execute overvoltage control when it is determined by the overvoltage determination unit 34 that the DC voltage Vdc is equal to or higher than the overvoltage determination threshold value. The overvoltage control will be described in detail below.

<Theoretical explanation of overvoltage control>
The voltage equation on the dq-axis coordinate system when having two sets of three-phase armature windings can be expressed by the following equation.

Here, Vd1 and Vq1 are d-axis voltage and q-axis voltage representing the voltage applied to the first set of three-phase armature windings in the dq-axis coordinate system, and Vd2 and Vq2 are the second set of three-phase armature windings. The voltage applied to the three-phase armature winding is the d-axis voltage and the q-axis voltage represented by the dq-axis coordinate system. Id1 and Iq1 are d-axis currents and q-axis currents representing the currents flowing through the first set of three-phase armature windings in the dq-axis coordinate system, and Id2 and Iq2 are the second set of three-phase armature windings. The d-axis current and the q-axis current representing the current flowing through the line in the dq-axis coordinate system. R is the resistance of the armature winding, Ld is the self-inductance of the d-axis of each set, Lq is the self-inductance of the q-axis of each set, and Md is the mutual d-axis between the sets. It is an inductance. Mq is the mutual inductance of the q-axis between the sets. ω is the rotational angular velocity at the electric angle of the rotor. ψ is the interlinkage magnetic flux of the magnet, and p is the differential operator. In this embodiment, each set of armature windings has the same inductance and resistance.

In the steady state, the term of the differential operator p in the equation (1) becomes zero, and the equation (1) becomes as in the equation (2).

Here, as shown in FIG. 6 and the following equation, the first set of dq-axis combined voltage vectors Vdq1 obtained by combining the first set of dq-axis voltages Vd1 and Vd2 and the second set of dq-axis voltages Vd2 and Vd2 are combined. The second set of dq-axis combined voltage vectors Vdq2 is set to have opposite phases so as to cancel each other out. As a result, the dq-axis total combined voltage vector, which is the sum of the two sets of dq-axis combined voltage vectors Vdq1 and Vdq2, becomes zero.

Then, at high rotation, the equation (4) holds, and when the equation (2) is modified, the equations of the dq-axis currents Id1, Iq1, Id2, and Iq2 of each set of the equation (5) are obtained.

At this time, the first set of torque T1 output by the first set of armature windings and the second set of torque T2 output by the second set of armature windings are expressed by using the dq axis current. Calculated according to 6). The total torque T, which is the sum of the torque T1 of the first set and the torque T2 of the second set, is obtained by substituting the formula (5) into the formula (6) to obtain the formula (7).

Here, as in the equation (3), the q-axis voltage Vq1 of the first set and the q-axis voltage Vq2 of the second set are set to positive / negative inverted values so as to cancel each other, thereby setting the equation (5). The second term of the numerator of the first set of q-axis current Iq1 and the second term of the numerator of the second set of q-axis current Iq2 are positive and negative inverted values, and cancel each other out in the calculation of the total torque T. Further, by setting the d-axis voltage Vd1 of the first set and the d-axis voltage Vd2 of the second set to positive and negative inverted values so as to cancel each other out, in the calculation of the total torque T, the first set of the equation (5) The first term of the numerator of the set of d-axis current Id1 and the first term of the molecule of the numerator of the second set of d-axis current Id2 become positive and negative inverted values, and cancel each other out in the calculation of the total torque T. Therefore, as shown in equation (3), by applying a voltage so that the combined voltage vectors of the respective sets cancel each other out, the torque T1 of the first set and the torque T2 of the second set weaken each other, and the total The torque T can be reduced.

Further, the total copper loss Pc caused by the resistance of the armature windings of the first set and the second set is given by the equation (8).

As shown in the equation (8), the copper loss of each set is calculated by the square of the d-axis current and the square of the q-axis current. The squared values of the second term of the molecules of Iq1 and Iq2 are not canceled out from each other, and the squared values of the first term of the molecules of the two sets of d-axis currents Id1 and Id2, which are positive and negative inverted values, cancel each other out. It will not be possible. Therefore, the total torque T is reduced by the weakening between the groups, but the total copper loss Pc is not weakened between the groups and is increased by increasing the torque of each group.

By the way, as in Patent Document 2, in the case of performing a three-phase short circuit in which the terminals of the armature windings of each phase are short-circuited with each other, the applied voltage of the armature windings of each phase of each set becomes zero. The dq-axis voltage is given by the equation (9), the total torque T is given by the equation (10), and the total copper loss Pc is given by the equation (11).

In the method of the present embodiment in which the voltage is applied so that the combined voltage vectors of each set weaken each other as in the equation (3), the second equation (8) is compared with the equation (11) of the three-phase short circuit. The total copper loss can be increased by the amount of the item and the item 3, and the power consumption of the AC rotating machine can be increased. Since the second and third terms of the equation (8) are roughly proportional to the square of the combined voltage vector of each set, the combined voltage vector of each set should be increased and the magnitude of torque of each set should be increased. Therefore, the total copper loss can be increased. Therefore, the rate of decrease of the overvoltage DC voltage Vdc can be increased.

On the other hand, regarding the total torque, the magnitude (absolute value) of the total torque is larger by the amount of the second term of the equation (7) than the equation (10) of the three-phase short circuit, but it is weakened between the groups. Since they match, it is possible to suppress an increase in the magnitude of the total torque as compared with an increase in the total copper loss.

In the above, two sets of three-phase armature windings have been described as an example, but even in the case of m sets of n-phase armature windings other than two sets of three phases, the combined voltage vectors of each set are mutually exclusive. If a voltage is applied so as to weaken each other, the torque can be weakened between the groups to suppress an increase in the total torque and increase the total copper loss.

<Configuration of overvoltage control>
Therefore, when the overvoltage determination unit 34 determines that the DC voltage Vdc is equal to or higher than the overvoltage determination threshold value, the overvoltage voltage application unit 352 applies a voltage to the n-phase (three-phase in this example) armature winding. , So that the combined voltage vector of each set becomes non-zero for two or more sets, and the combined voltage vectors of each set weaken each other when the combined voltage vectors of all the sets are totaled. Executes overvoltage control in which a voltage is applied to the armature windings of each phase of.

In this way, if a voltage is applied so that the combined voltage vectors of each set weaken each other, as described above, the torques output by the armature windings of each set are weakened by each other and totaled. The increase in torque can be suppressed. Further, the total copper loss is not weakened between the sets and can be increased by making the combined voltage vector and the magnitude of the torque of each set larger than zero. Therefore, as compared with the three-phase short circuit, the total copper loss can be increased while suppressing the increase in the total torque, and the rate of decrease of the overvoltage DC voltage Vdc can be increased.

In the present embodiment, the overvoltage voltage application unit 352 sets the armature winding of each phase of each set so that the total combined voltage vector, which is the sum of the combined voltage vectors of all the sets, becomes zero in the overvoltage control. It is configured to apply a voltage to.

According to this configuration, the effect of weakening the torque between the groups can be enhanced, and an increase in the magnitude of the total torque can be suppressed.

In the present embodiment, the overvoltage voltage application unit 352 issues a voltage command to be applied to the n-phase (three-phase in this example) armature winding for each set in the overvoltage control, and dq-axis coordinates for each set. It is configured to set the d-axis voltage command and the q-axis voltage command represented by the system. Therefore, in the overvoltage voltage application unit 352, when the dq-axis combined voltage vector of each set becomes non-zero for two or more sets and the dq-axis combined voltage vectors of all the sets are totaled, the dq-axis of each set is combined. Each set of d-axis voltage command and q-axis voltage command is set so that the combined voltage vectors weaken each other. In particular, the overvoltage voltage application unit 352 sets the d-axis voltage command and the q-axis voltage command of each set so that the dq-axis total combined voltage vector becomes zero as in the equation (3).

Then, similarly to the normal voltage application unit 351, the overvoltage voltage application unit 352 converts the d-axis voltage command and the q-axis voltage command into three-phase voltage commands based on the magnetic pole position θ for each set. To do. The overvoltage voltage application unit 352 may apply modulation such as space vector modulation and two-phase modulation so that the line voltage does not change to the three-phase voltage command.

Then, similarly to the normal voltage application unit 351, the overvoltage voltage application unit 352 turns on and off a plurality of switching elements for each set based on the three-phase voltage command. The overvoltage voltage application unit 352 generates a switching signal for turning on / off the switching element of each phase by comparing each of the three-phase voltage commands with the carrier wave for each set.

In the present embodiment, the overvoltage voltage application unit 352 sets the d-axis voltage command and the q-axis voltage command to constant values for each set in the overvoltage control.

If the d-axis voltage command and the q-axis voltage command are set to constant values, as can be seen from the equations (3), (5), and (7), the d-axis current and the q-axis current are constant in the steady state. It becomes a value, and the total torque becomes a constant value. Therefore, it is possible to suppress the occurrence of a ripple component in the total torque of the overvoltage control.

In the present application, the constant value means a value that does not change periodically according to the rotation angle of the rotor at the electric angle. The overvoltage voltage application unit 352 may change the d-axis voltage command and the q-axis voltage command of each set according to the operating state such as the rotation angular velocity ω of the rotor and the DC voltage Vdc. For example, the overvoltage voltage application unit 352 sets the d-axis voltage of each set so that the magnitude of the dq-axis combined voltage vector of each set increases as the amount of increase in the DC voltage Vdc from the overvoltage determination threshold increases. The command and the q-axis voltage command may be changed.

ここで、Ｖｄｑ＿ｆは、第１組及び第２組のｄｑ軸合成電圧ベクトルの大きさ（絶対値）であり、βは、ｄ軸に対する第１組のｄｑ軸合成電圧ベクトルの位相である。 <Phase setting of dq-axis combined voltage vector>
As shown in equation (3), the d-axis voltage command and q-axis voltage command of each set are set so that the dq-axis total combined voltage vector becomes zero, and the d-axis voltage command and q-axis voltage command are set to constant values. When set to, the constant value V1 of the d-axis voltage command and the constant value V2 of the q-axis voltage command of the first set can be expressed by the following equations.

Here, Vdq_f is the magnitude (absolute value) of the first set and the second set of dq-axis combined voltage vectors, and β is the phase of the first set of dq-axis combined voltage vectors with respect to the d-axis.

Substituting Eq. (12) into Eqs. (7) and (8) gives Eqs. (13) and (14). As shown in the formulas (13) and (14), the magnitudes of the total torque T and the total copper loss Pc can be changed by the magnitude Vdq_f and the phase β of the dq-axis combined voltage vector. Therefore, a larger total copper loss can be obtained than in the case of a three-phase short circuit, and the total copper loss can be changed to a desired value by changing the magnitude Vdq_f and the phase β of the dq-axis combined voltage vector. Can be done.

In a typical AC rotary machine with salient, self-inductance Ld of the d-axis is smaller than the self-inductance Lq of the q-axis, Cos2beta coefficients {1 / ^(Lq-Mq) of formula (14) 2 -1 / (Ld-Mq) ² } has a negative value. Therefore, in order to increase the total copper loss Pc, as shown in the equation (15), cos2β may be set to a negative value, and the condition of the phase β for making cos2β a negative value is set to the equation (16). )become. Therefore, if the phase β of the first set of dq-axis combined voltage vectors is set to π / 4 <β <3π / 4, the phase of the second set of dq-axis combined voltage vectors is 5π / which is the opposite phase. 4 <β <7π / 4 is set.

Therefore, the overvoltage voltage application unit 352 sets the phase of the dq-axis combined voltage vector of the first set with respect to the d-axis larger than π / 4 and smaller than 3/4 π in the overvoltage control, and sets the second set. The phase of the dq-axis combined voltage vector with respect to the d-axis is set to be larger than 5π / 4 and smaller than 7 / 4π. The phase of the first set and the phase of the second set may be interchanged.

In order to maximize the total copper loss Pc, cos2β may be set to -1 and the phase β may be set as in the equation (17).

Therefore, the overvoltage voltage application unit 352 sets the phase of the dq-axis combined voltage vector of the first set to π / 2 in the overvoltage control, and sets the d-axis of the dq-axis combined voltage vector of the second set to π / 2. The phase with respect to is set to 3π / 2. The phase of the first set and the phase of the second set may be interchanged.

<Polarity>
When there is no salient polarity of the AC rotating machine, the equation (18) holds, and the second term of the equation (7) expressing the total torque becomes zero, which is the same as the total torque in the case of a three-phase short circuit. Therefore, an AC rotating machine having no salient polarity may be used. By using an AC rotating machine having no salient polarity, it is possible to reduce the magnitude of the total torque when the overvoltage control is executed.

<Fixed switching element on or off>
Even if an offset voltage is applied to the three-phase voltage command of each set, the line voltage does not change, so that the same total torque and total copper loss results can be obtained. Therefore, in the overvoltage control, the overvoltage voltage application unit 352 fixes at least one of the switching elements on the positive electrode side and the switching element on the negative electrode side of at least one phase to ON and the other to OFF for each set. According to this configuration, switching loss can be reduced.

The overvoltage voltage application unit 352 changes the maximum value in the three-phase voltage command to + Vdc / 2 or the minimum value in the three-phase voltage command to -Vdc / 2 for each set. In addition to the three-phase voltage command, one of the switching elements on the positive electrode side and the negative electrode side of the one phase that has become + Vdc / 2 or -Vdc / 2 is fixed on and the other is fixed off. .. When the voltage command is + Vdc / 2, the switching element on the positive electrode side is fixed on and the switching element on the negative electrode side is fixed off. When the voltage command is −Vdc / 2, the switching element on the positive electrode side is fixed to off, and the switching element on the negative electrode side is fixed to on.

<Voltage application of field winding>
The overvoltage voltage application unit 352 applies a voltage to the field winding 25 when the overvoltage control is executed. For example, the overvoltage voltage application unit 352 generates an on-duty ratio PWM signal for overvoltage control and outputs it as a switching signal for field winding.

Since the first term of the equation (8) expressing the total copper loss is proportional to the square of the magnetic flux ψ of the magnet, the total copper loss is further increased by increasing the field current flowing through the field winding. Is possible. Therefore, the overvoltage voltage application unit 352 increases the applied voltage of the field winding when the overvoltage control is executed as compared with the non-execution of the overvoltage control (in this example, when the normal control is executed). .. In the present embodiment, the on-duty ratio for overvoltage control is set to a value larger than the on-duty ratio for normal control.

2. Embodiment 2
Next, the AC rotary machine 10 and the control device 1 according to the second embodiment will be described. The description of the same components as in the first embodiment will be omitted. The basic configuration of the AC rotating machine 10 and the control device 1 according to the present embodiment is the same as that of the first embodiment, but the method of setting the voltage command in the overvoltage control is different from that of the first embodiment.

<Theoretical explanation of overvoltage control>
In the first embodiment, the theoretical explanation was given for the case where the d-axis voltage command and the q-axis voltage command of each set are set to constant values on the dq-axis coordinate system, but in the present embodiment, the following equation is used. As shown, a theoretical explanation will be given for the case where the voltage command of each set of three phases is set to a constant value.

As shown in the following equation, the first set of combined voltage vectors obtained by combining the first set of three-phase voltage commands Vu1, Vv1, and Vw1 and the second set of three-phase voltage commands Vu2, Vv2, and Vw2 were combined. The second set of combined voltage vectors are set in opposite phases so as to cancel each other out. As a result, the total combined voltage vector, which is the sum of the two sets of combined voltage vectors, becomes zero. In equation (19), the sum of the three-phase voltage commands of each set is set to be zero, but the line voltage such as space vector modulation and two-phase modulation changes with respect to the three-phase voltage commands. Modulation may be applied that does not.

Here, Vu1 is a U1 phase voltage command, Vv1 is a V1 phase voltage command, Vw1 is a W1 phase voltage command, Vu2 is a U2 phase voltage command, and Vv2 is. It is a V2 phase voltage command, and Vw2 is a W2 phase voltage command. Vuvw_f is the magnitude (absolute value) of the combined voltage vector of each set, and is set to a constant value. β is the phase of the U1 phase voltage command Vu1 with respect to the U1 phase armature winding, and is set to a constant value. For each set, the phase of the voltage command of each phase is shifted by 2π / 3 from each other.

When the three-phase voltage command of each set of the formula (19) is coordinate-converted to the d-axis voltage command and the q-axis voltage command on the dq-axis coordinate system based on the magnetic pole position θ, the formula (20) is obtained. Then, based on the equations (20), (2), and (4), the equations of the dq-axis currents Id1, Iq1, Id2, and Iq2 of each set are derived, and the equations (6) and (8) are derived. By substituting into the first equation, the equation of the total torque T of the equation (21) and the equation of the total copper loss Pc of the equation (22) can be obtained.

The total torque T fluctuates by the amount of the AC component of the second term of the equation (21) when compared with the case of the three-phase short circuit of the equation (10). However, the second term of the equation (21) is a component of a frequency (secondary) twice the rotation frequency of the magnetic pole position θ, and the average value of one cycle of the electric angle becomes zero. Further, the total copper loss Pc is larger by the amount of the DC component of the second term of the formula (22) when compared with the case of the three-phase short circuit of the formula (11), and the AC of the third term of the formula (22). It fluctuates by the amount of the ingredients. However, the third term of the equation (22) is a component having a frequency twice the rotation frequency of the magnetic pole position θ, and the average value of one cycle of the electric angle becomes zero.

<Comparison example (in-phase setting)>
As a comparative example, the first set of combined voltage vectors obtained by synthesizing the first set of three-phase voltage commands and the second set of combined voltage vectors obtained by combining the second set of three-phase voltage commands are set to be in phase. Consider the case of doing. When the three-phase voltage command of this comparative example is coordinate-converted to the d-axis voltage command and the q-axis voltage command on the dq-axis coordinate system, the equation (23) is obtained. Then, by deriving the dq-axis current, the total torque, and the total copper loss of each set based on the equation (23), the equations (24), (25), and (26) are obtained.

In the case of the in-phase comparative example, the total torque T of the equation (25) is added by the amount of the AC component of the third term of the equation (25) to the equation (21) in the case of the opposite phase. The third term of the equation (25) is a component of the rotation frequency (first order) of the magnetic pole position θ. Further, in the total copper loss Pc of the formula (26), the amount of the AC component of the fourth term of the formula (26) is added to the formula (22) in the case of the opposite phase. The fourth term of the equation (26) is a component of the rotation frequency (first order) of the magnetic pole position θ.

<Comparison of three methods>
Next, when the three-phase voltage commands of the first set and the second set are set to the opposite phase as in the equation (19) (hereinafter referred to as the case of the opposite phase voltage), the first set as in the equation (23). The case where the three-phase voltage command of the set and the second set is set to the same phase (hereinafter referred to as the case of the in-phase voltage) and the case of the three-phase short circuit are compared. FIG. 7 shows the behavior of the total torque, the total copper loss, and the power supply current flowing from the inverters of the first set and the second set to the DC power supply 16 for the three cases. The horizontal axis indicates the magnetic pole position θ.

In the case of a three-phase short circuit, the total torque has a negative DC component, the total copper loss has a positive DC component, and the power supply current is near zero. In the case of the common mode voltage of the comparative example, the primary AC component is large with respect to the total torque, the total copper loss, and the power supply current. In particular, the total torque fluctuates up to the positive torque, which has a large effect on an external engine such as an internal combustion engine.

On the other hand, in the case of a reverse phase voltage, a secondary AC component is generated with respect to the total torque, the total copper loss, and the power supply current. However, the amplitude of the secondary AC component is significantly smaller than the amplitude of the primary AC component of the common mode voltage of the comparative example, and the total torque fluctuates in the range of negative torque. Therefore, the influence on an external engine such as an internal combustion engine is suppressed. Further, the average value of the total torque of the reverse phase voltage in one cycle is the same as in the case of the three-phase short circuit. On the other hand, the average value of the total copper loss in one cycle of the reverse phase voltage is higher than that in the case of the three-phase short circuit. Therefore, in the case of a reverse-phase voltage, the vibration of the total torque is suppressed, the average value of the total torque is suppressed to the same level as in the case of the three-phase short circuit, and the average value of the total copper loss is suppressed as compared with the case of the three-phase short circuit. It can be increased, and the rate of decrease of the overvoltage DC voltage Vdc can be increased.

<Configuration of overvoltage control>
Therefore, as in the first embodiment, when the overvoltage determination unit 34 determines that the DC voltage Vdc is equal to or higher than the overvoltage determination threshold, the overvoltage voltage application unit 352 has an n-phase (three phases in this example). When the combined voltage vector obtained by combining the voltage applied to the armature winding for each set becomes non-zero for two or more sets and the combined voltage vectors of all sets are totaled, the combined voltage vector of each set becomes. Overvoltage control is performed by applying a voltage to the armature windings of each phase of each set so as to weaken each other.

Further, the overvoltage voltage application unit 352 applies a voltage to the armature windings of each phase of each set so that the total combined voltage vector, which is the sum of the combined voltage vectors of all the sets, becomes zero in the overvoltage control. To do.

Here, the combined voltage vector and the total combined voltage vector may be calculated on the three-phase coordinate system, the dq-axis coordinate system, or the αβ-axis coordinate system. Good. The αβ-axis coordinate system consists of an α-axis defined in the winding direction of the U1 phase (or U2 phase) and a β-axis defined in a direction advanced by 90 ° (π / 2) in electrical angle from the α-axis.

Unlike the first embodiment, the overvoltage voltage application unit 352 is configured to set the voltage command applied to the armature winding of each phase to a constant value for each set in the overvoltage control. Then, similarly to the normal voltage application unit 351, the overvoltage voltage application unit 352 turns on and off a plurality of switching elements for each set based on the three-phase voltage command. The overvoltage voltage application unit 352 generates a switching signal for turning on / off the switching element of each phase by comparing each of the three-phase voltage commands with the carrier wave for each set.

In the present embodiment, the overvoltage voltage application unit 352 is set to Vu2 = −Vu1, Vv2 = −Vv1, Vw2 = −Vw1 as shown in the equation (19). According to this configuration, as shown in FIG. 7, the vibration of the total torque is suppressed, the average value of the total torque is suppressed to the same level as in the case of the three-phase short circuit, and the average value of the total copper loss is three-phase. It can be increased more than in the case of a short circuit.

<Vibration in the negative torque range of total torque>
As shown in FIG. 7, in order to vibrate the total torque in the negative torque range, the maximum value of the total torque T of the equation (21) (the maximum value is obtained when sin (2θ-2β) = -1). Should be zero or less (T ≦ 0). From equation (21), the following equation is obtained.

Therefore, the overvoltage voltage application unit 352 may set the magnitude Vuvw_f of the combined voltage vector of each set so that the positive torque is not generated over one cycle of the electric angle in the overvoltage control. Specifically, it is preferable that the magnitude Vuvw_f of each set of combined voltage vectors is set so as to satisfy the equation (27). According to this configuration, the AC rotating machine can generate a negative torque on the safety side that decelerates the vehicle. If the output of positive torque can be tolerated, the equation (27) may not be satisfied.

<Polarity>
If there is no salient polarity of the AC rotating machine, the equation (18) holds, the second term of the equation (21) representing the total torque becomes zero, the secondary AC component can be eliminated, and a three-phase short circuit occurs. It will be the same as the total torque in the case. Therefore, also in the second embodiment, an AC rotating machine having no polarity may be used.

<Fixed switching element on or off>
Even if an offset voltage is applied to the three-phase voltage command of each set, the line voltage does not change, so that the same total torque and total copper loss results can be obtained. Therefore, in the overvoltage control, the overvoltage voltage application unit 352 fixes at least one of the switching elements on the positive electrode side and the switching element on the negative electrode side of at least one phase to ON and the other to OFF for each set. According to this configuration, switching loss can be reduced.

The overvoltage voltage application unit 352 changes the maximum value in the three-phase voltage command to + Vdc / 2 or the minimum value in the three-phase voltage command to -Vdc / 2 for each set. In addition to the three-phase voltage command, one of the switching elements on the positive electrode side and the negative electrode side of the one phase that has become + Vdc / 2 or -Vdc / 2 is fixed on and the other is fixed off. .. When the voltage command is + Vdc / 2, the switching element on the positive electrode side is fixed on and the switching element on the negative electrode side is fixed off. When the voltage command is −Vdc / 2, the switching element on the positive electrode side is fixed to off, and the switching element on the negative electrode side is fixed to on.

Alternatively, the overvoltage voltage application unit 352 may fix one of the switching element on the positive electrode side and the switching element on the negative electrode side of each phase on and the other off for each set. According to this configuration, the switching loss can be significantly reduced.

For example, as the voltage command of each set of three phases satisfying the equation (19), it is set to 2Vdc / 3 or −Vdc / 3 as shown in the equation (28). Then, as shown in the equation (29), if the offset voltage is set to -Vdc / 6 or Vdc / 6 and added to the voltage command of each set of three phases, the final Vdc / 2 or -Vdc / 2 is obtained. Three-phase voltage commands for each set are set. When the voltage command is Vdc / 2 for each phase, the switching element on the positive electrode side is turned on and the switching element on the negative electrode side is turned off. When the voltage command is −Vdc / 2 for each phase, the switching element on the positive electrode side is turned off and the switching element on the negative electrode side is turned on.

<Switching of voltage command>
When the voltage command of each phase is set to a constant value, there is a concern that heat generation is concentrated on the switching element on the positive electrode side of the phase having a large voltage command or the switching element on the negative electrode side of the phase having a small voltage command. Further, when the switching element is fixed on or off, there is a concern that heat generation is concentrated on the switching element fixed on. Therefore, the overvoltage voltage application unit 352 may switch the applied voltage to the armature winding of each phase of each set at regular time intervals in the overvoltage control. According to this configuration, it is possible to suppress the bias of heat generation of the switching element.

For example, in the example of FIG. 8, from time 0 to time t1, Vu1, Vv2, and Vw2 are set to Vk / 2, and Vv1, Vw1, and Vu2 are set to −Vk / 2. From time t1 to time t2, the first set of three-phase voltage commands and the second set of three-phase voltage commands are exchanged, Vu1, Vv2, and Vw2 are set to -Vk / 2, and Vv1, Vw1, and Vu2 are set to Vk. Set to / 2. After that, these are carried out alternately. Vk is set to a value greater than 0 and less than or equal to Vdc.

For example, in the example of FIG. 9, from time 0 to time t1, Vu1, Vv2, and Vw2 are set to Vdc / 2, the switching element on the positive electrode side is fixed on, and Vv1, Vw1, and Vu2 are set to Vdc / 2-. Set to Vk. From time t1 to time t2, the offset direction of the voltage command is changed, Vv1, Vw1 and Vu2 are set to -Vdc / 2, the switching element on the negative electrode side is fixed on, and Vu1, Vv2 and Vw2 are set to -Vdc. Set to / 2 + Vk. From time t2 to time t3, the first set of three-phase voltage commands and the second set of three-phase voltage commands from time 0 to time t1 are exchanged, Vv1, Vw1, and Vu2 are set to Vdc / 2, and Vu1 , Vv2, Vw2 are set to Vdc / 2-Vk. From time t3 to time t4, the first set of three-phase voltage commands and the second set of three-phase voltage commands from time t1 to time t2 are exchanged, and Vu1, Vv2, and Vw2 are set to -Vdc / 2. Set Vv1, Vw1, and Vu2 to -Vdc / 2 + Vk. After that, these are carried out alternately. Vk is set to a value greater than 0 and less than or equal to Vdc.

<At the time of short-circuit failure or open failure of switching element>
Further, as shown in FIG. 9, since there are various methods for setting the voltage command to obtain the same total copper loss, overvoltage control can be performed even when any of the switching elements has a short-circuit failure or an open failure. Is. The control device 1 detects a short-circuit failure and an open failure of each switching element. For example, the control device 1 detects a failure of each switching element based on the on / off control information of each switching element and the current detection value.

When overvoltage control is performed while a short-circuit failure of one switching element is detected, the overvoltage voltage application unit 352 turns off the switching element in which the short-circuit failure has not occurred in the phase in which the short-circuit failure has occurred. A voltage is applied to the armature windings of the phase in which the short-circuit failure has not occurred, taking into account the combined voltage vector of each set including the phase in which the short-circuit failure has occurred.

For example, if the switching element on the positive electrode side of the U1 phase fails due to a short circuit, a through current will flow when the switching element on the negative electrode side of the U1 phase is turned on. Vu1 is fixed to Vdc / 2. Then, the voltage command of the phase in which the short-circuit failure does not occur may be set in consideration of the combined voltage vector of each set. For example, the voltage command from time 0 to time t1 in FIG. 9 may be set so that the total combined voltage vector becomes zero.

When the overvoltage voltage application unit 352 performs overvoltage control in a state where an open failure of one switching element is detected, the switching element in which the open failure has not occurred is turned on for the phase in which the open failure has occurred. A voltage is applied to the armature winding of the phase in which the open failure has not occurred, taking into consideration the combined voltage vector of each set including the phase in which the open failure has occurred.

For example, when the switching element on the positive electrode side of the U1 phase fails to open, Vu1 is fixed to −Vdc / 2 in order to turn on the switching element on the negative electrode side of the U1 phase. Then, the voltage command of the phase in which the open failure does not occur may be set in consideration of the combined voltage vector of each set. For example, the voltage command from time t3 to time t4 in FIG. 9 may be set so that the total combined voltage vector becomes zero.

<When the phase difference of the armature winding between the sets is other than zero>
In the present embodiment, the case where there is no phase difference between the first set of three-phase armature windings and the second set of three-phase armature windings has been described. There may be an arbitrary phase difference between the first set of three-phase armature windings and the second set of three-phase armature windings. Even in this case, the voltage command of each phase of each set should be set so that the combined voltage vectors of each set weaken each other, and the total combined voltage vector of the total of the combined voltage vectors of each set becomes zero. , The voltage command of each phase of each set may be set.

For example, if there is a π / 3 phase difference between the first set of three-phase armature windings and the second set of three-phase armature windings, the overvoltage voltage application unit 352 Set to Vu2 = Vw1, Vv2 = Vu1, Vw2 = Vv1 so that the total combined voltage vector becomes zero.

Further, when there is a phase difference of π / 6 between the first set of three-phase armature windings and the second set of three-phase armature windings, the overvoltage voltage application unit 352 may be used. Vu2 = (Vw1-Vu1) / √3, Vv2 = (Vu1-Vv1) / √3, Vw2 = (Vv1-Vw1) / √3, so that the total combined voltage vector becomes zero.

3. 3. Embodiment 3
Next, the AC rotary machine 10 and the control device 1 according to the third embodiment will be described. The description of the same components as in the first embodiment will be omitted. The basic configuration of the AC rotating machine 10 and the control device 1 according to the present embodiment is the same as that of the first embodiment, but the method of setting the voltage command in the overvoltage control is different from that of the first embodiment.

<Theoretical explanation of overvoltage control>
In the first embodiment, a theoretical explanation has been given for a case where the d-axis voltage command and the q-axis voltage command of each set are set in opposite phases on the dq-axis coordinate system. However, in the present embodiment, as shown in FIG. 10 and the following equation, a theoretical explanation will be given for the case where the d-axis voltage command and the q-axis voltage command of each set are set to be in phase. In this case, the total combined voltage vector, which is the sum of the two sets of combined voltage vectors, is not zero.

Based on the equations (30), (2), and (4), the equations of the dq-axis currents Id1, Iq1, Id2, and Iq2 of each set are derived as shown in the following equations.

When the dq-axis voltage command is given with a constant value, it can be expressed as in the equation (12). Substituting the equations (31) and (12) into the first equations of the equations (6) and (8), the equation of the total torque T of the equation (32) and the equation of the total copper loss Pc of the equation (33). Is obtained.

In the region where the rotational angular velocity ω is high, the latter term is dominant in the term ^{(Vdq_f / ω) 2 and the term Vdq_f / ω in the equation (33).} Therefore, in order to increase the total copper loss Pc as compared with the case of the three-phase short circuit of the equation (11), it is necessary to set the term of Vdq_f / ω of the equation (33) to a positive value. For that purpose, as shown in the equation (34), sin β may be set to a negative value, and the phase β of the dq-axis combined voltage vector needs to be larger than π and smaller than 2π. Here, the phase β of the dq-axis combined voltage vector in the equation (12) is the phase of the dq-axis combined voltage vector with respect to the d-axis.

If sinβ is set to -1, the total copper loss Pc is maximized. Therefore, it is necessary to set the phase β to 3π / 2 as shown in the equation (35). With this setting, the d-axis voltage command becomes zero for each set, and only the q-axis voltage command set to a negative value becomes available. Further, the second and third terms of the equation (32) of the total torque T become zero, which is equivalent to the total torque of the equation (10) in the case of a three-phase short circuit.

<Comparison of two methods>
Next, the case where the phase β of the dq-axis combined voltage vector of each set is set as in the equation (35) (hereinafter, referred to as the case where only the q-axis voltage is used) and the case where the three-phase short circuit is performed are compared. FIG. 11 shows the behavior of the total torque, the total copper loss, and the power supply current flowing from the inverters of the first set and the second set to the DC power supply 16 in the two cases. The horizontal axis indicates the magnetic pole position θ.

In the case of a three-phase short circuit, the total torque has a negative DC component, the total copper loss has a positive DC component, and the power supply current is near zero. On the other hand, in the case of only the q-axis voltage, the total torque is the same as in the case of the three-phase short circuit because no AC component is generated. The total copper loss is higher than in the case of a three-phase short circuit. The power supply current is the same as in the case of a three-phase short circuit. Therefore, in the case of only the q-axis voltage, the total copper loss can be increased as compared with the case of the three-phase short circuit while making the total torque the same as in the case of the three-phase short circuit, and the overvoltage DC voltage Vdc is lowered. The speed can be increased.

<Configuration of overvoltage control>
Therefore, when the overvoltage determination unit 34 determines that the DC voltage Vdc is equal to or higher than the overvoltage determination threshold value, the overvoltage voltage application unit 352 sets the phase β of the dq-axis combined voltage vector of each set with respect to the d-axis from π. The overvoltage control that sets the d-axis voltage command and the q-axis voltage command of each set is executed so that the value is large and smaller than 2π.

According to this configuration, as described using the equations (34) and (33), the total copper loss can be increased as compared with the case of the three-phase short circuit, and the overvoltage DC voltage Vdc is lowered. The speed can be increased.

In the overvoltage control, the overvoltage voltage application unit 352 issues the d-axis voltage command and the q-axis voltage command of each set so that the phase β of the dq-axis combined voltage vector of each set with respect to the d-axis is 3π / 2. You can set it. According to this configuration, the total torque can be suppressed to the same level as in the case of the three-phase short circuit, the total copper loss can be increased as compared with the case of the three-phase short circuit, and the rate of decrease of the overvoltage DC voltage Vdc can be increased. it can.

Then, similarly to the normal voltage application unit 351, the overvoltage voltage application unit 352 converts the d-axis voltage command and the q-axis voltage command into three-phase voltage commands based on the magnetic pole positions for each set. .. The overvoltage voltage application unit 352 may apply modulation such as space vector modulation and two-phase modulation so that the line voltage does not change to the three-phase voltage command.

Then, similarly to the normal voltage application unit 351, the overvoltage voltage application unit 352 turns on and off a plurality of switching elements for each set based on the three-phase voltage command. The overvoltage voltage application unit 352 generates a switching signal for turning on / off the switching element of each phase by comparing each of the three-phase voltage commands with the carrier wave for each set.

[Other embodiments]
Finally, other embodiments of the present application will be described. The configurations of the respective embodiments described below are not limited to those applied independently, and can be applied in combination with the configurations of other embodiments as long as there is no contradiction.

(1) In each of the above embodiments, the case where there are two sets of m = 2 and three phases of n = 3 has been described as an example. However, m = 3, 4 mag, m may be set to any natural number of 2 or more, and n = 2, 4 mag, n may be set to any natural number of 2 or more.

(2) In the above-described first and second embodiments, the voltage application unit 35 controls each phase of each set so that the total combined voltage vector, which is the sum of the combined voltage vectors of all the sets, becomes zero in the overvoltage control. The case where a voltage is applied to the armature winding of the above has been described as an example. However, the embodiments of the present application are not limited to this. That is, in the voltage application unit 35, when the combined voltage vector becomes non-zero for two or more sets and the combined voltage vectors of all the sets are summed in the overvoltage control, the combined voltage vectors of each set weaken each other. A voltage may be applied to the armature windings of each phase of each set to match, and the total combined voltage vector does not have to be zero.

(3) In the third embodiment, the voltage application unit 35 sets d of each set so that the phase β of the dq-axis combined voltage vector of each set with respect to the d-axis becomes 3π / 2 in the overvoltage control. The case of setting the axis voltage command and the q-axis voltage command has been described as an example. However, the embodiments of the present application are not limited to this. That is, the voltage application unit 35 receives the d-axis voltage command and the d-axis voltage command of each set so that the phase β of the dq-axis combined voltage vector of each set with respect to the d-axis is larger than π and smaller than 2π in the overvoltage control. The q-axis voltage command may be set, and the phase β does not have to be 3π / 2.

(4) In each of the above embodiments, the case where the AC rotating machine 10 has the field winding 25 in the rotor 14 has been described as an example. However, the AC rotating machine 10 may be a permanent magnet type synchronous rotating machine having a permanent magnet in the rotor 14, or may be an induction rotating machine.

(5) In each of the above embodiments, the case where there is no phase difference between the first set of three-phase armature windings and the second set of three-phase armature windings will be described as an example. did. However, an arbitrary phase difference may be provided between the first set of three-phase armature windings and the second set of three-phase armature windings.

(6) In each of the above embodiments, the case where the AC rotary machine 10 is a generator motor for a vehicle has been described as an example. However, the AC rotary machine 10 may be an AC rotary machine for various purposes other than the generator motor for vehicles.

Although the present application describes various exemplary embodiments and examples, the various features, embodiments, and functions described in one or more embodiments are applications of a particular embodiment. It is not limited to, but can be applied to embodiments alone or in various combinations. Therefore, innumerable variations not illustrated are envisioned within the scope of the techniques disclosed herein. For example, it is assumed that at least one component is modified, added or omitted, and further, at least one component is extracted and combined with the components of other embodiments.

1 AC rotating machine control device, 10 AC rotating machine, 25 field winding, 31 rotation detection unit, 32 voltage detection unit, 33 current detection unit, 34 overvoltage determination unit, 35 voltage application unit, β phase

Claims (20)

It is a control device for an AC rotating machine that controls an AC rotating machine having m sets (m is a natural number of 2 or more) and n-phase armature windings (n is a natural number of 2 or more) via an inverter of m sets. hand,
A voltage detector that detects the DC voltage supplied to the inverter of each set, and
A voltage application unit that applies a voltage to the armature winding of each phase of each set by turning on and off a plurality of switching elements of the inverter of each set.
An overvoltage determination unit for determining whether or not the DC voltage has exceeded the overvoltage determination threshold value is provided.
The voltage application unit has two sets of combined voltage vectors obtained by synthesizing the voltage applied to the n-phase armature winding for each set when it is determined that the DC voltage exceeds the overvoltage determination threshold. When the above is non-zero and the combined voltage vectors of all the sets are summed, the voltage is applied to the armature winding of each phase of each set so that the combined voltage vectors of each set weaken each other. A control device for an AC rotating machine that performs control when an overvoltage is applied. The voltage application unit applies a voltage to the armature winding of each phase of each set so that the total combined voltage vector, which is the sum of the combined voltage vectors of all the sets, becomes zero in the overvoltage control. The control device for an AC rotating machine according to claim 1. The voltage application unit uses a coordinate system consisting of a d-axis defined in the magnetic flux direction of the field and a q-axis defined in a direction π / 2 advanced by an electric angle from the d-axis as a dq-axis coordinate system.
In the overvoltage control, the voltage command applied to the n-phase armature winding is set to a constant value for each set of the d-axis voltage command and the q-axis voltage command represented by the dq-axis coordinate system.
The control device for an AC rotating machine according to claim 1 or 2, wherein a plurality of the switching elements are turned on and off based on the d-axis voltage command and the q-axis voltage command for each set. There are two m groups,
The voltage application unit uses a vector represented by the dq-axis coordinate system for each set as a dq-axis combined voltage vector for a voltage command applied to the n-phase armature winding.
In the overvoltage control, the phase of the dq-axis combined voltage vector of the first set with respect to the d-axis is set to be larger than π / 4 and smaller than 3/4 π, and the dq-axis combined voltage vector of the second set is set. The control device for an AC rotor according to claim 3, wherein the phase with respect to the d-axis is set to be larger than 5π / 4 and smaller than 7 / 4π. In the overvoltage control, the voltage application unit sets the phase of the dq-axis combined voltage vector of the first set to π / 2 and the d of the dq-axis combined voltage vector of the second set. The control device for an AC rotating machine according to claim 4, wherein the phase with respect to the shaft is set to 3π / 2. The voltage application unit sets the voltage command applied to the armature winding of each phase to a constant value in the overvoltage control.
The control device for an AC rotating machine according to claim 1 or 2, wherein for each set, a plurality of the switching elements are turned on and off based on the voltage command of each phase. In each set of the inverter, the switching element on the positive electrode side connected to the positive electrode side of the DC power supply and the switching element on the negative electrode side connected to the negative electrode side of the DC power supply are connected in series, and the connection points of the series connection correspond to each other. A series circuit connected to the winding of the phase to be used is provided with n sets corresponding to the n phase.
In the overvoltage control, the voltage application unit fixes at least one of the positive electrode side switching element and the negative electrode side switching element of each set of the inverters to ON and the other to OFF in the overvoltage control. The control device for an AC rotating machine according to claim 1 or 2. The m group is 2 groups, the n phase is 3 phases, and
Between the first set of U1, V1 and W1 phase three-phase armature windings and the second set of U2, V2 and W2 phase three-phase armature windings There is no phase difference,
The voltage application unit is used in the overvoltage control.
U2 phase voltage command = -U1 phase voltage command,
V2 phase voltage command = -V1 phase voltage command,
W2 phase voltage command = -W1 phase voltage command,
Set to
The control device for an AC rotating machine according to claim 2, wherein a plurality of the switching elements are turned on and off for each set based on the voltage command of each phase. The m group is 2 groups, the n phase is 3 phases, and
Between the first set of U1, V1 and W1 phase three-phase armature windings and the second set of U2, V2 and W2 phase three-phase armature windings There is a phase difference of π / 3,
The voltage application unit is used in the overvoltage control.
U2 phase voltage command = W1 phase voltage command,
V2 phase voltage command = U1 phase voltage command,
W2 phase voltage command = V1 phase voltage command,
Set to
The control device for an AC rotating machine according to claim 2, wherein a plurality of the switching elements are turned on and off for each set based on the voltage command of each phase. In each set of the inverter, the switching element on the positive electrode side connected to the positive electrode side of the DC power supply and the switching element on the negative electrode side connected to the negative electrode side of the DC power supply are connected in series, and the connection points of the series connection correspond to each other. Three sets of series circuits connected to the windings of the corresponding phases are provided corresponding to the three phases.
In the overvoltage control, the voltage applying unit fixes one of the switching element on the positive electrode side and the switching element on the negative electrode side of each phase to ON and the other to OFF for each set of the inverters. Item 8. The control device for the AC rotating machine according to Item 8. The m group is 2 groups, the n phase is 3 phases, and
Between the first set of U1, V1 and W1 phase three-phase armature windings and the second set of U2, V2 and W2 phase three-phase armature windings There is a phase difference of π / 6,
The voltage application unit is used in the overvoltage control.
U2 phase voltage command = (W1 phase voltage command-U1 phase voltage command) / √3,
V2 phase voltage command = (U1 phase voltage command-V1 phase voltage command) / √3,
W2 phase voltage command = (V1 phase voltage command-W1 phase voltage command) / √3,
Set to
The control device for an AC rotating machine according to claim 2, wherein a plurality of the switching elements are turned on and off for each set based on the voltage command of each phase. The voltage application unit sets the magnitude of the combined voltage vector of each set so that positive torque is not generated over one cycle of the electric angle in the overvoltage control. The control device for an AC rotating machine according to any one of the items. The AC rotating machine according to any one of claims 6 to 12, wherein the voltage applying unit switches the applied voltage of each phase of each set to the armature winding in the overvoltage control at regular intervals. Control device. When the overvoltage control is performed in a state where a short-circuit failure of one of the switching elements is detected, the voltage application unit turns off the switching element in which the short-circuit failure has not occurred in the phase in which the short-circuit failure has occurred. Fixed to
Claims 1, 2, and 6 to 13 in which a voltage is applied to the armature winding of the phase in which the short-circuit failure has not occurred in consideration of the combined voltage vector of each set including the phase in which the short-circuit failure has occurred. The control device for the AC rotating machine according to any one of the above items. When the overvoltage control is performed in a state where an open failure of one of the switching elements is detected, the voltage applying unit turns on the switching element in which the open failure has not occurred in the phase in which the open failure has occurred. Fixed to
Claims 1, 2, and 6 to 14 of applying a voltage to the armature winding of the phase in which the open failure has not occurred, in consideration of the combined voltage vector of each set including the phase in which the open failure has occurred. The control device for the AC rotating machine according to any one of the above items. It is a control device for an AC rotating machine that controls an AC rotating machine having m sets (m is a natural number of 2 or more) and n-phase armature windings (n is a natural number of 3 or more) via an inverter of m sets. hand,
A voltage detector that detects the DC voltage supplied to the inverter of each set, and
A voltage application unit that applies a voltage to the armature winding of each phase of each set by turning on and off a plurality of switching elements of the inverter of each set.
An overvoltage determination unit for determining whether or not the DC voltage has exceeded the overvoltage determination threshold value is provided.
The voltage application unit uses a coordinate system consisting of a d-axis defined in the magnetic flux direction of the field and a q-axis defined in a direction π / 2 advanced by an electric angle from the d-axis as a dq-axis coordinate system.
The voltage command applied to the n-phase armature winding is defined as the dq-axis combined voltage vector by combining the d-axis voltage command and the q-axis voltage command represented by the dq-axis coordinate system for each set.
When it is determined that the DC voltage exceeds the overvoltage determination threshold, each set has a phase of the dq-axis combined voltage vector with respect to the d-axis larger than π and smaller than 2π. The d-axis voltage command and the q-axis voltage command are set, and for each set, an AC that executes overvoltage control for turning on and off a plurality of the switching elements based on the d-axis voltage command and the q-axis voltage command. Rotating machine control device. In the overvoltage control, the voltage application unit sets the d-axis voltage command and the q-axis voltage of each set so that the phase of the dq-axis combined voltage vector of each set with respect to the d-axis is 3π / 2. The control device for an AC rotating machine according to claim 16, wherein a command is set. The AC rotating machine has a field winding and has a field winding.
The voltage application unit applies a voltage to the field winding to apply a voltage.
The control device for an AC rotor according to any one of claims 1 to 17, wherein when the overvoltage control is executed, the applied voltage of the field winding is increased as compared with the non-execution of the overvoltage control. .. The control device for an AC rotating machine according to any one of claims 1 to 18, wherein the AC rotating machine has no projecting polarity. The control device for an AC rotary machine according to any one of claims 1 to 19, wherein the AC rotary machine is a generator motor for a vehicle.

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