Control device for rotating electric machines

Abstract

To provide a control device for a rotary electric machine that can accurately calculate a torque difference occurring due to deviation of a current detection value from a current command value.SOLUTION: A control device for a rotary electric machine uses a current torque characteristic function in which the current of armature winding and field winding or current of the armature winding is set to an argument and the torque of the rotary electric machine is set to a return value to calculate the torque of the return value calculated by inputting the present current command value to the argument as a command value corresponding torque, uses the current torque characteristic function to calculate the torque of the return value calculated by inputting a present current detection value to the argument as a detection value corresponding torque, and calculates a torque difference based on the command value corresponding torque and the detection value corresponding torque.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This application relates to a control device for a rotating electrical machine.

Background Art

[0002] When controlling the torque of a rotating electrical machine, it is necessary to determine whether the torque of the rotating electrical machine is as commanded. As a means of determining the torque, it is relatively easy to use a torque sensor that directly measures the torque of the rotating electrical machine. However, there are cases where such a torque sensor is not used or cannot be used. In such cases, it is necessary to indirectly estimate the torque from the detected value of the current flowing through the winding or the like.

[0003] In the motor control device of Patent Document 1, disturbance torque is estimated using a torque command and a motor speed ωB which is a feedback value, or disturbance torque is estimated from the difference between the inverse-calculated torque obtained by inverse calculation from the feedback value (motor speed ωB) and the torque command.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the motor control device of Patent Document 1, when the torque calculated from the motor speed ωB which is a feedback value includes a calculation error, the disturbance torque (torque difference) calculated using the torque command and the feedback value (motor speed ωB) includes the influence of that calculation error. As a result, even when no actual disturbance torque (torque difference) occurs, a disturbance torque (torque difference) can occur due to the calculation error.

[0006] Incidentally, control devices for rotating electric machines have been developed that set the current command value for the armature winding and field winding, or the armature winding, based on the torque command value, and turn the switching elements of the converter on and off based on at least the current command value for the armature winding and field winding, or the armature winding. If the current detection value, which represents the actual current of the armature winding and field winding, or the armature winding, deviates from the current command value, the actual torque will deviate from the torque command value, resulting in a torque difference. To detect the occurrence of this torque difference, it is conceivable to estimate the torque from the current detection value and calculate the torque difference from the torque command value and the estimated torque value. However, even if the current command value and the current detection value are the same, the torque command value and the estimated torque value estimated from the current detection value are not necessarily the same. This is because the relationship between the arguments and return values ​​is reversed between the function that calculates the current command value from the torque command value and the function that calculates the torque from the current, and they do not perfectly match. In particular, when these functions are constructed using map data, the interval of the map axis step in the map data argument of one function differs from the interval of the return value set for each step in the map data of the other function. As a result, the discrepancy becomes large due to errors caused by discrete data settings and errors caused by linear interpolation. Consequently, even if the current command value and the current detection value are the same, the torque difference will not be zero, and the accuracy of the torque difference calculation deteriorates.

[0007] Therefore, the present invention aims to provide a control device for a rotating electric machine that can accurately calculate the torque difference caused by the deviation of the current detection value from the current command value. [Means for solving the problem]

[0008] The control device for a rotating electric machine according to the present application is a control device for a rotating electric machine that controls an armature winding and a field winding, or an armature winding, via a converter, A current command value calculation unit calculates the current command value of the armature winding and the field winding, or the armature winding, based on the torque command value. A current detection unit that detects the current flowing through the armature winding and the field winding, or the armature winding, based on the output signal of the current sensor, At a minimum, a switching control unit that controls the on / off state of a plurality of switching elements in the converter based on the current command value, A torque difference calculation unit calculates the torque difference based on the command value and the torque, using a current-torque characteristic function in which the current of the armature winding and the field winding, or the current of the armature winding, is set as an argument and the torque of the rotating electric machine is set as the return value, inputting the current command value as an argument to calculate the return value torque as the command value corresponding torque, using the current-torque characteristic function and inputting the current detection value as an argument to calculate the return value torque as the detection value corresponding torque, and the torque difference is calculated based on the command value corresponding torque and the detection value corresponding torque. A torque estimation unit calculates a torque estimate value based on the torque command value and the torque difference, Equipped with 、 The torque estimation unit calculates the torque estimate by multiplying the sum of the torque command value and the torque difference by a first coefficient, and sets the first coefficient based on the detected value corresponding torque. It is. [Effects of the Invention]

[0009] According to the control device for a rotating electric machine of this invention, since the same current-torque characteristic function is used, if the current command value and the current detection value are the same, then basically the torque corresponding to the command value and the torque corresponding to the detection value will be the same, and the torque difference will be 0. On the other hand, even if the current command value and the current detection value are the same, the torque command value and the torque corresponding to the detection value will not be the same. This is because the function that calculates the current command value from the torque command value and the current-torque characteristic function that calculates the torque from the current have the opposite relationship between their arguments and return values, and therefore do not perfectly match. Accordingly, by using the same current-torque characteristic function, the calculation error of the torque difference caused by the deviation of the current detection value from the current command value can be reduced. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of the rotating electric machine, inverter (converter corresponding to the armature winding), and control device according to Embodiment 1. [Figure 2] This is a schematic block diagram of the control device according to Embodiment 1. [Figure 3]This is a hardware configuration diagram of the control device according to Embodiment 1. [Figure 4] This figure illustrates the map data of the torque current setting function according to Embodiment 1. [Figure 5] This figure illustrates the map data of the current-torque characteristic function according to Embodiment 1. [Figure 6] This is a diagram illustrating the setting of the first coefficient according to Embodiment 1. [Figure 7] This is a schematic diagram of the rotating electric machine, inverter (converter corresponding to the armature winding), converter (converter corresponding to the field winding), and control device according to Embodiment 2. [Figure 8] This is a schematic block diagram of the control device according to Embodiment 2. [Modes for carrying out the invention]

[0011] 1. Embodiment 1 The control device 30 of the rotating electric machine according to Embodiment 1 (hereinafter simply referred to as the control device 30) will be described with reference to the drawings. Figure 1 is a schematic diagram of the rotating electric machine 1, inverter 5, and control device 30 according to this embodiment.

[0012] 1-1. Rotating Electric Machine 1 The rotating electric machine 1 comprises a cylindrical stator 18 and a rotor 14 positioned radially inward of the stator 18. The stator 18 is provided with a multi-phase armature winding 12 (in this example, three phases of armature windings: U-phase, V-phase, and W-phase (Cu, Cv, Cw)). The rotor 14 is provided with magnets. In this embodiment, the magnets are permanent magnets, and the rotating electric machine 1 is a permanent magnet type synchronous rotating electric machine. The three phase armature windings may be star-connected or delta-connected.

[0013] The rotor 14 is provided with a rotation sensor 15 that detects the rotation angle (magnetic pole position) of the rotor 14. The output signal of the rotation sensor 15 is input to the control device 30. Various sensors such as a Hall element, a resolver, or an encoder are used for the rotation sensor 15. A rotation sensor 15 that detects the rotation speed of the rotor 14 may be used. Even if the rotation sensor 15 is not provided, it may be configured to estimate the rotation angle (magnetic pole position) based on current information obtained by superimposing a harmonic component on a current command value described later (so-called sensorless method).

[0014] 1-2. DC power supply 2 The DC power supply 2 outputs a DC voltage Vdc to the inverter 5. As the DC power supply 2, any device that outputs a DC voltage, such as a battery, a DC-DC converter, a diode rectifier, or a PWM rectifier, is used. A smoothing capacitor 3 is connected in parallel to the DC power supply 2.

[0015] 1-3. Inverter 5 The inverter 5 has a plurality of switching elements and performs power conversion between the DC power supply 2 and the armature winding 12. For each phase, the inverter 5 provides a series circuit in which a high-potential-side switching element SP connected to the high-potential side of the DC power supply 2 and a low-potential-side switching element SN connected to the low-potential side of the DC power supply 2 are connected in series. The connection point of the two switching elements in each series circuit is connected to the armature winding of the corresponding phase. Three sets of series circuits are provided corresponding to the armature windings of each of the three phases.

[0016] Specifically, in a U-phase series circuit, the high-potential switching element SPu and the low-potential switching element SNu of the U-phase are connected in series, and the connection point of the two switching elements SPu and SNu is connected to the armature winding Cu of the U-phase. In a V-phase series circuit, the high-potential switching element SPv and the low-potential switching element SNv of the V-phase are connected in series, and the connection point of the two switching elements SPv and SNv is connected to the armature winding Cv of the V-phase. In a W-phase series circuit, the high-potential switching element SPw of the W-phase and the low-potential switching element SNw of the W-phase are connected in series, and the connection point of the two switching elements SPw and SNw is connected to the armature winding Cw of the W-phase.

[0017] Each switching element in the inverter 5 functions as an antiparallel-connected diode. For example, each switching element may be an IGBT (Insulated Gate Bipolar Transistor) with antiparallel-connected diodes, a bipolar transistor with antiparallel-connected diodes, or a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) with antiparallel-connected parasitic diodes. The gate terminal of each switching element is connected to the control device 30 via a gate drive circuit or the like. Therefore, each switching element is turned on or off by a control signal output from the control device 30.

[0018] The current sensor 8 is a current detection circuit that detects the current flowing through the armature windings Cu, Cv, and Cw of each phase. In this embodiment, the current sensor 8 is mounted on the wire connecting the series circuit of the switching elements of each phase to the armature winding. The output signals of the current sensor 8 of each phase are input to the control device 30. The current sensor 8 is a current sensor such as a Hall element or a shunt resistor. The current sensor 8 may also be connected in series with the series circuit of the switching elements of each phase.

[0019] 1-4. Control device 30 The control device 30 controls the rotating electric machine 1 via the inverter 5. As shown in Figure 2, the control device 30 includes processing units such as a rotation detection unit 31, a current detection unit 32, a current command value calculation unit 33, a switching control unit 34, a torque difference calculation unit 35, a torque estimation unit 36, and an abnormality determination unit 37. Each process of the control device 30 is realized by the processing circuit provided in the control device 30. Specifically, as shown in Figure 4, the control device 30 includes a processing circuit such as a CPU (Central Processing Unit) or other arithmetic processing unit 90 (computer), a storage device 91 that exchanges data with the arithmetic processing unit 90, an input circuit 92 that inputs external signals to the arithmetic processing unit 90, an output circuit 93 that outputs signals from the arithmetic processing unit 90 to the outside, and a communication circuit 94 that performs data communication with an external device.

[0020] The arithmetic processing unit 90 may include an ASIC (Application Specific Integrated Circuit), an IC (Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), various logic circuits, and various signal processing circuits. Furthermore, multiple arithmetic processing units 90 of the same or different types may be provided, with each unit performing a portion of the processing. The storage device 91 may include a RAM (Random Access Memory) configured to read and write data from the arithmetic processing unit 90, and a ROM (Read Only Memory) configured to read data from the arithmetic processing unit 90. The input circuit 92 is connected to various sensors such as a rotation sensor 15 and a current sensor 8, and includes an A / D converter that inputs the output signals from these sensors to the arithmetic processing unit 90. The output circuit 93 is connected to electrical loads such as gate drive circuits that drive the switching elements of the inverter 5 on and off, and includes drive circuits that output control signals from the arithmetic processing unit 90 to these electrical loads. The communication circuit 94 communicates with external devices.

[0021] The various processes of the control unit 30, such as those in units 31 to 37, are realized by the arithmetic processing unit 90 executing software (programs) stored in a storage device 91 such as a ROM, and working in cooperation with other hardware of the control unit 30, such as the storage device 91, input circuit 92, and output circuit 93. The setting data, such as the current-torque characteristic function and torque-current setting function used by each of the control units 31 to 37, is stored in the storage device 91 such as a ROM. The processes of the control unit 30 will be described in detail below.

[0022] 1-4-1. Rotation detection unit 31 The rotation detection unit 31 detects the rotor's magnetic pole position θ (rotor rotation angle θ) and rotational angular velocity ω in electrical angle. In this embodiment, the rotation detection unit 31 detects the rotor's magnetic pole position θ (rotation angle θ) and rotational angular velocity ω based on the output signal of the rotation sensor 15. The magnetic pole position is set to the direction of the north pole of the electromagnet provided on the rotor. The rotation detection unit 31 may also be configured to estimate the rotation angle (magnetic pole position) without using a rotation sensor, based on current information obtained by superimposing harmonic components on the current command value (so-called sensorless method).

[0023] 1-4-2. Current detection unit 32 The current detection unit 32 detects the currents Iudet, Ivdet, and Iwdet flowing through the three-phase armature windings based on the output signal of the current sensor 8. Here, Iudet is the detected value of the current Iu of the U-phase armature winding, Ivdet is the detected value of the current Iv of the V-phase armature winding, and Iwdet is the detected value of the current Iw of the W-phase armature winding. Alternatively, the current sensor 8 may be configured to detect the currents of two phases of armature windings, and the current of the remaining one phase of armature winding may be calculated based on the detected values ​​of the currents of the two phases. For example, the current sensor 8 may detect the currents Ivdet and Iwdet of the V-phase and W-phase armature windings, and the current Iudet of the U-phase armature winding may be calculated as Iudet = -Ivdet - Iwdet.

[0024] 1-4-3. Current command value calculation unit 33 The current command value calculation unit 33 calculates the current command value of the armature winding based on the torque command value Tref. The torque command value Tref may be calculated internally by the control device 30 or transmitted from an external control device.

[0025] The current command value calculation unit 33 uses a torque-current setting function in which the torque command value Tref is set as an argument and the current command value is set as the return value. It takes the current torque command value Tref as an argument and calculates the return value current command value. The torque-current setting function is stored in a memory device such as ROM.

[0026] In this embodiment, the current command value calculation unit 33 calculates the d-axis current command value Idref and the q-axis current command value Iqref based on the torque command value Tref. The d-axis is defined in the direction of the magnetic pole (N pole) of the magnet, and the q-axis is defined in the direction 90 degrees ahead of the d-axis in electrical angle. The current command value calculation unit 33 uses, as torque current setting functions, a torque current setting function for the d-axis in which the torque command value Tref is set as an argument and the d-axis current command value Idref is set as a return value, and a torque current setting function for the q-axis in which the torque command value Tref is set as an argument and the q-axis current command value Iqref is set as a return value.

[0027] For example, map data is used as a torque-current setting function. Map data is used in which the torque command value Tref is the map axis of the argument, and the current command values ​​Idref and Iqref for the d-axis or q-axis are the map setting data of the return value.

[0028] In this embodiment, the rotational angular velocity ω is added as an argument to the torque command value Tref in addition to the torque command value Tref. As shown in Figure 4, the map axis of the argument for the torque command value Tref is set with multiple steps Tref1, Tref2, Tref3, ... set to discrete values, and the map axis of the argument for the rotational angular velocity ω is set with multiple steps ω1, ω2, ω3, ... set to discrete values, and for each combination (grid point) of the step on the map axis of the argument for the torque command value Tref and the step on the map axis of the argument for the rotational angular velocity ω, the current command values ​​Idref1, Idref2, Idref3, ..., Iqref1, Iqref2, Iqref3, ... are set for the d axis or q axis. If the current torque command value Tref etc. input as an argument does not match the step on the map axis, linear interpolation is performed and a return value is calculated.

[0029] In addition to the torque command value Tref and rotational angular velocity ω, other parameters such as DC voltage Vdc may be added as arguments to the torque current setting function. In this case, a map axis for the argument of the added parameter may be added. Alternatively, map data may be provided for each step of the added parameter, and the return value of each map data may be linearly interpolated to calculate the final return value.

[0030] 1-4-4. Switching control unit 34 The switching control unit 34 controls the on / off state of at least the multiple switching elements of the inverter 5 based on the current command value.

[0031] In this embodiment, the switching control unit 34 changes the voltage command value so that the detected current value approaches the current command value, and controls the on / off state of multiple switching elements based on the voltage command value.

[0032] The switching control unit 34 converts the current detection values ​​Iudet, Ivdet, and Iwdet of the three-phase armature windings into a d-axis current detection value Iddet and a q-axis current detection value Iqdet based on the magnetic pole position θ. In this embodiment, the switching control unit 34 converts the current detection values ​​Iudet, Ivdet, and Iwdet of the three-phase armature windings into a d-axis current detection value Iddet and a q-axis current detection value Iqdet based on the magnetic pole position θ by performing known three-phase to two-phase conversion and rotational coordinate conversion.

[0033] The switching control unit 34 changes the voltage command value Vdref for the d axis and the voltage command value Vqref for the q axis so that the detected current values ​​Iddet and Iqdet for the d axis and q axis approach the current command values ​​Idref and Iqref for the d axis and q axis, respectively. Alternatively, the switching control unit 34 may perform feedforward control, which changes the voltage command values ​​Vdref and Vqref for the d axis and q axis using the electrical constants of the rotating electric machine based on the current command values ​​Idref and Iqref for the d axis and q axis.

[0034] The switching control unit 34 converts the d-axis and q-axis voltage command values ​​Vdref and Vqref into three-phase voltage command values ​​Vuref, Vvref, and Vwref by performing known fixed coordinate transformations and two-phase to three-phase transformations based on the magnetic pole position θ. Known modulations may be applied to the three-phase voltage command values.

[0035] Furthermore, the switching control unit 34 may control the current directly on the three-phase coordinate system without controlling the current on the d-axis and q-axis rotation coordinate system. That is, the current command value calculation unit 33 may calculate the three-phase current command values, and the switching control unit 34 may change the three-phase voltage command values ​​Vuref, Vvref, and Vwref so that the three-phase current detection values ​​approach the three-phase current command values.

[0036] The switching control unit 34 controls the on / off state of multiple switching elements of the inverter 5 by PWM control based on the three-phase voltage command values ​​Vuref, Vvref, and Vwref. The switching control unit 34 uses known carrier comparison PWM or space vector PWM.

[0037] When carrier comparison PWM is used, the switching control unit 34 compares the carrier wave with the voltage command values ​​Vuref, Vvref, and Vwref for each phase, and turns on and off the high-potential and low-potential switching elements SP and SN for each phase based on the comparison result. For each phase, a short-circuit prevention period (dead time) may be provided between the on-period of the high-potential switching element and the on-period of the low-potential switching element, in which both the positive-side and low-potential switching elements are turned off.

[0038] When spatial vector PWM is used, the switching control unit 34 generates a voltage command vector from the three-phase voltage command values ​​Vuref, Vvref, and Vwref, determines the output time distribution of the seven basic voltage vectors in the PWM period based on the voltage command vector, and turns each switching element on and off in the PWM period based on the output time distribution of the seven basic voltage vectors.

[0039] The switching control unit 34 may also perform known hysteresis control, which turns the switching elements on and off so that the error between the current detection value and the current command value falls within a certain range.

[0040] 1-4-5. Torque difference calculation unit 35 The torque difference calculation unit 35 uses a current-torque characteristic function in which the armature winding current is set as an argument and the torque of the rotating electric machine is set as the return value. It inputs the current command value as an argument and calculates the return value torque as the command value-corresponding torque (Tiref). The torque difference calculation unit 35 also uses the same current-torque characteristic function and inputs the current detection value as an argument to calculate the return value torque as the detection value-corresponding torque (Tidet). The torque difference calculation unit 35 then calculates the torque difference (Tdiff) based on the command value-corresponding torque (Tiref) and the detection value-corresponding torque (Tidet). Here, the current-torque characteristic function used to calculate the command value-corresponding torque (Tiref) and the current-torque characteristic function used to calculate the detection value-corresponding torque (Tidet) are the same. The current-torque characteristic function is pre-stored in a memory device such as ROM.

[0041] With this configuration, since the same current-torque characteristic function is used, if the current command value and the current detection value are the same, the command value-corresponding torque Tiref and the detection value-corresponding torque Tidet will be the same, and the torque difference Tdiff will be 0. On the other hand, even if the current command value and the current detection value are the same, the torque command value Tref and the detection value-corresponding torque Tidet will not be the same. This is because the torque-current setting function, which calculates the current command value from the torque command value Tref, and the current-torque characteristic function, which calculates the torque from the current, have inverse relationships between their arguments and return values, and therefore do not perfectly match. When these functions are constructed using map data, the interval of the map axis steps in the arguments of one map data differs from the interval of the return values ​​set for each step in the other map data. As a result, the mismatch becomes large due to errors caused by discrete data settings and errors caused by linear interpolation. Therefore, by using the same current-torque characteristic function, the calculation error of the torque difference Tdiff caused by the deviation of the current detection value from the current command value can be reduced.

[0042] In this embodiment, the torque difference calculation unit 35 calculates the torque difference Tdiff based on the difference between the command value-corresponding torque Tiref and the detected value-corresponding torque Tidet. For example, as shown in the following equation, the torque difference calculation unit 35 calculates the difference between the command value-corresponding torque Tiref and the detected value-corresponding torque Tidet as the torque difference Tdiff. Tdiff = Tidet - Tiref ... (1)

[0043] In this embodiment, the torque difference calculation unit 35 uses the d-axis current command value Idref and the q-axis current command value Iqref as current command values, the d-axis current detection value Iddet and the q-axis current detection value Iqdet as current detection values, and uses a current-torque characteristic function in which the d-axis current Id and the q-axis current Iq are set as arguments and torque is set as the return value. The torque difference calculation unit 35 then uses the current-torque characteristic function and calculates the return value torque calculated by inputting the current d-axis current command value Idref and the current q-axis current command value Iqref as arguments, and calculates the command value corresponding torque Tiref. The torque difference calculation unit 35 then uses the current-torque characteristic function and calculates the return value torque calculated by inputting the current d-axis current detection value Iddet and the current q-axis current detection value Iqdet as arguments, and calculates the detection value corresponding torque Tidet.

[0044] As shown in Figure 5, the current-torque characteristic function uses map data where the current Id on the d axis and the current Iq on the q axis are the argument map axes, and the torque T is the return value map setting data. Multiple step sizes Id1, Id2, Id3, ... are set to discrete values ​​on the argument map axis of the current Iq on the q axis, and multiple step sizes Iq1, Iq2, Iq3, ... are set to discrete values ​​on the argument map axis of the current Iq on the q axis. For each combination (grid point) of the step size on the argument map axis of the current Id on the d axis and the step size on the argument map axis of the current Iq on the q axis, torques T11, T12, T13, ... are set.

[0045] The torque difference calculation unit 35 searches the map data for four step combinations (grid points) surrounding the current d-axis current command value Idref and the current q-axis current command value Iqref input as arguments. It then linearly interpolates the torque T set for each of the four step combinations (grid points) using the current d-axis and q-axis current command values ​​Idref and Iqref to calculate the command value corresponding torque Tiref. If the current value matches a step, linear interpolation is not performed, and the torque set for the matching step is used.

[0046] Similarly, the torque difference calculation unit 35 searches the map data for four step combinations (grid points) surrounding the current d-axis current detection value Iddet and the current q-axis current detection value Iqdet input as arguments. It then linearly interpolates the torque T set for each of the four step combinations (grid points) using the current d-axis and q-axis current detection values ​​Iddet and Iqdet to calculate the detected value corresponding torque Tidet. If the current value matches a step, linear interpolation is not performed, and the torque set for the matching step is used.

[0047] 1-4-6. Torque Estimation Unit 36 The torque estimation unit 36 ​​calculates a torque estimate Test based on the torque command value Tref and the torque difference Tdiff. The torque estimate Test may be transmitted to an external device.

[0048] When the detected current value, which represents the actual current, deviates from the current command value, the actual torque deviates from the torque command value Tref. As described above, by using the same current-torque characteristic function to calculate the command value-corresponding torque Tiref and the detected value-corresponding torque Tidet, the calculation error of the torque difference Tdiff caused by the deviation of the detected current value from the current command value can be reduced. Therefore, based on the torque command value Tref and the torque difference Tdiff, which has a small calculation error, a torque estimate value Test that closely resembles the behavior of the actual torque can be calculated with high accuracy.

[0049] <First calculation method> Although several calculation methods are possible, the first calculation method will be explained. As shown in the following equation, the torque estimation unit 36 ​​calculates the torque estimate Test based on the sum of the torque command value Tref and the torque difference Tdiff. Test = Tref + Tdiff ···(2)

[0050] <Second calculation method> Next, the second calculation method will be explained. As shown in the following equation, the torque estimation unit 36 ​​calculates the torque estimate value Test by multiplying the sum of the torque command value Tref and the torque difference Tdiff by the first coefficient K1. Test=K1×(Tref+Tdiff) ···(3)

[0051] The torque estimation unit 36 ​​sets a first coefficient K1 based on the detected value-corresponding torque Tidet. In this embodiment, the torque estimation unit 36 ​​sets the first coefficient K1 based on the current 0-corresponding torque Ti0, which is the torque when the current in the armature winding is 0, and the detected value-corresponding torque Tidet. For example, the torque estimation unit 36 ​​sets the first coefficient K1 based on the difference between the current 0-corresponding torque Ti0 and the detected value-corresponding torque Tidet.

[0052] For example, as shown in Figure 6, the torque estimation unit 36 ​​sets the first coefficient K1 to 0 when the absolute value |Tidet-Ti0| of the difference between the current 0 corresponding torque Ti0 and the detected value corresponding torque Tidet is 0, and increases the first coefficient K1 from 0 to 1 as the absolute value |Tidet-Ti0| increases from 0 to the boundary value Th, and sets the first coefficient K1 to 1 when the absolute value |Tidet-Ti0| is greater than or equal to the boundary value Th. For example, the boundary value Th is preset to a value less than or equal to 10% of the maximum value within the range of possible values ​​of the absolute value |Tidet-Ti0|. Therefore, when the absolute value |Tidet-Ti0| is near 0, the first coefficient K1 is set to less than 1, and when the absolute value |Tidet-Ti0| becomes large enough, the first coefficient K1 is set to 1. The current 0 corresponding torque Ti0 may be preset, or it may be set using a current-torque characteristic function.

[0053] Map data as shown in Figure 6 may be set, but if set by equation, it can be configured as shown in equations (4) and (5). That is, as shown in equation (4), the torque estimation unit 36 ​​sets the value obtained by multiplying the absolute value |Tidet-Ti0|, which is the difference between the torque Ti0 corresponding to current 0 and the torque Tidet corresponding to the detected value, by a tailing coefficient Kt that is set to a positive value in advance, as the first coefficient K1' before the limit. By increasing or decreasing the tailing coefficient Kt, the boundary value Th in Figure 6 can be increased or decreased. K1' = Kt × |Tidet - Ti0| ... (4)

[0054] Furthermore, as shown in the following equation, the torque estimation unit 36 ​​limits the first coefficient K1' before the restriction to an upper and lower limit within the range of 0 or more and 1 or less. K1 = MAX(0, MIN(1, K1') ... (5)

[0055] Here, MAX(a,b) is a function that outputs the largest value between a and b (or the same value if both are equal), and MIN(a,b) is a function that outputs the smallest value between a and b (or the same value if both are equal).

[0056] The first coefficient K1 can take values ​​from 0 to 1. Furthermore, the first coefficient K1 changes toward 0 as the detected torque Tidet approaches the torque Ti0 corresponding to current 0. Note that the method for generating the first coefficient K1 is not limited to this, and can be modified to produce a desirable behavior for the torque estimate Test depending on the application.

[0057] Let me explain why we use the first coefficient K1 calculated in this way. When the detected value corresponding torque Tidet is 0, but both the torque command value Tref and the command value corresponding torque Tiref are non-zero and Tref≠Tiref, if we calculate the torque estimate Test using the torque command value Tref + torque difference Tdiff, then the torque estimate Test will be Tref-Tiref≠0. However, since the detected value corresponding torque Tidet is 0, it is natural that the torque estimate Test should also be 0. Therefore, by setting the first coefficient K1 as described above, we ensure that when the detected value corresponding torque Tidet is close to 0, the torque estimate Test is also close to 0, and when the detected value corresponding torque Tidet is 0, the torque estimate Test is also 0.

[0058] Furthermore, if the difference between the torque command value Tref and the corresponding torque Tire (due to calculation error) is small, setting the estimated torque Test to the sum of the torque command value Tref and the torque difference Tdiff, as in the first calculation method, will result in less unnatural behavior of the estimated torque. In this case, the process of generating and multiplying by the first coefficient K1 can be omitted, thus simplifying the calculation process.

[0059] 1-4-7. Abnormality determination section 37 <Anomaly detection using torque difference (Tdiff)> The abnormality determination unit 37 determines whether or not there is an abnormality based on the torque difference Tdiff.

[0060] If the current detection value, which represents the actual current, deviates from the current command value due to some abnormality, the actual torque will deviate from the torque command value Tref. As described above, by using the same current-torque characteristic function to calculate the command value-corresponding torque Tiref and the detection value-corresponding torque Tidet, the calculation error of the torque difference Tdiff due to the difference between the current command value and the current detection value can be reduced. Therefore, it is possible to accurately determine whether or not an abnormality has occurred in the output torque based on the torque difference Tdiff, which has a small calculation error.

[0061] For example, if the DC voltage Vdc drops below the specified voltage, and it becomes impossible to apply the voltage corresponding to the voltage command value to the armature winding, the current detection value will no longer be able to follow the current command value, and the torque difference Tdiff will increase. Alternatively, if an abnormality occurs in the inverter 5 or the armature winding, and it becomes impossible to supply the current corresponding to the voltage command value to the armature winding, the current detection value will no longer be able to follow the current command value, and the torque difference Tdiff will increase.

[0062] The abnormality detection unit 37 determines that an abnormality has occurred if the torque difference Tdiff deviates from the detection range. The detection range is set to a range that includes 0, for example. Multiple detection ranges may be set, and each detection range may be set to a range different from one another depending on the abnormality level and type of abnormality to be determined.

[0063] <Anomaly detection using torque estimation test> The abnormality determination unit 37 determines whether or not there is an abnormality based on the torque command value Tref and the torque estimate value Test.

[0064] If the current detection value, which represents the actual current, deviates from the current command value due to some abnormality, the actual torque will deviate from the torque command value Tref. As described above, by using the same current-torque characteristic function to calculate the command value-corresponding torque Tiref and the detection value-corresponding torque Tidet, the calculation error of the torque difference Tdiff due to the difference between the current command value and the current detection value can be reduced, and a torque estimate value Test that closely resembles the actual torque behavior can be accurately calculated based on the torque command value Tref and the torque difference Tdiff with less calculation error. Therefore, it is possible to accurately determine whether or not an abnormality has occurred in the output torque based on the torque command value Tref and the torque estimate value Test.

[0065] The abnormality determination unit 37 determines that an abnormality has occurred if the difference between the torque command value Tref and the torque estimate value Test deviates from the determination range. The determination range is set to a range that includes 0, for example. Multiple determination ranges may be set, and each determination range may be set to a different range from one another depending on the abnormality level and type of abnormality to be determined.

[0066] For example, the abnormality detection unit 37 transmits the result of determining whether or not an abnormality exists to an external device of the control device 30. Alternatively, the abnormality detection unit 37 transmits the result of determining whether or not an abnormality exists to another processing unit of the control device 30. For example, the switching control unit 34 changes the control content according to the result of determining whether or not an abnormality exists. If the abnormality level is high, the switching control unit 34 may stop the on / off control of the multiple switching elements of the inverter 5.

[0067] 2. Embodiment 2 Next, the rotating electric machine 1 and control device 30 according to Embodiment 2 will be described. The same components as in Embodiment 1 will not be described. The basic configuration of the rotating electric machine 1 and control device 30 according to this embodiment is the same as in Embodiment 1. However, unlike Embodiment 1, the rotating electric machine 1 is provided with a field winding 4, and a converter 9 is provided as a converter corresponding to the field winding.

[0068] In this embodiment, as shown in Figure 7, a field winding 4 is provided in place of, or together with, a permanent magnet to generate magnetic flux in the rotor 14. The converter 9 has one or more switching elements SW (four in this example) and performs power conversion between the DC power supply 2 and the field winding 4. Any number of switching elements SW may be provided.

[0069] As shown in Figure 8, the control device 30 further comprises a field winding current detection unit 38, a field winding current command value calculation unit 39, and a converter control unit 40. The field winding current detection unit 38 detects the current Ifdet flowing through the field winding 4 based on the output signal of the field winding current sensor 6.

[0070] The field winding current command value calculation unit 39 calculates the field winding current command value Ifref based at least on the torque command value Tref. In this example, the field winding current command value Ifref is calculated based on the rotational angular velocity ω in addition to the torque command value Tref. Furthermore, the field winding current command value Ifref may also be calculated based on the DC voltage Vdc.

[0071] The converter control unit 40 controls the switching element SW of the converter 9 on and off based on the field winding current command value Ifref. In this embodiment, the converter control unit 40 changes the field voltage command value so that the detected field current value Ifdet, detected by the field winding current sensor 6, approaches the field winding current command value Ifref, and controls the switching element SW on and off by PWM control based on the field voltage command value.

[0072] In this embodiment, the current torque characteristic function is modified to include the field winding current If in addition to the armature winding current. The torque difference calculation unit 35 uses the current torque characteristic function to calculate the return torque, which is obtained by inputting the current command value of the armature winding and the current command value of the field winding Ifref as arguments, and calculates the return torque, which is obtained by inputting the current detection value of the armature winding and the current detection value of the field winding Ifdet as arguments, and calculates the detected value-corresponding torque Tidet. Based on the command value-corresponding torque Tiref and the detected value-corresponding torque Tidet, the torque difference Tdiff is calculated.

[0073] This configuration allows for accurate calculation of the torque difference Tdiff caused by the deviation of the field winding current detection value Ifdet from the field winding current command value Ifref.

[0074] The current-torque characteristic function is composed of map data, similar to Embodiment 1. For example, the map axis of the argument for the field winding current If is set to multiple discrete values, and for each step of the field winding current, map data of the armature winding current and torque is provided, as shown in Figure 5 of Embodiment 1. The torque difference calculation unit 35 selects map data for two field winding current steps that are close to the current command value Ifref or current detection value Ifdet of the current field winding input as an argument, and uses each of the two selected map data to input the current command value or current detection value of the armature winding as an argument to calculate the return value torque. The torque of the return values ​​of the two map data is linearly interpolated using the current command value Ifref or current detection value Ifdet of the current field winding to calculate the final return value, and the final return value is calculated as the command value corresponding torque Tiref or detection value corresponding torque Tidet.

[0075] Alternatively, since the current command value Ifref of the field winding is set based on the torque command value Tref, etc., similar to the current command value of the armature winding, the current command value Ifref of the field winding corresponding to each current command value of the armature winding may be uniquely determined. In this case, since the current If of the field winding corresponding to each current of the armature winding is known in advance, the current torque characteristic function can be set without adding the current If of the field winding to the argument of the current torque characteristic function. In other words, even when a field winding is provided, the torque difference calculation unit 35 may have the same configuration as in Embodiment 1.

[0076] In this embodiment, the torque when at least one of the currents in the armature winding and the field winding is 0 is defined as the torque Ti0 corresponding to 0 current. This is because the torque of a rotating electric machine having armature windings and field windings is determined by the currents in both the armature winding and the field winding, but the current conditions under which the torque of a rotating electric machine is 0 (or close to 0) differ depending on the characteristics of the rotating electric machine.

[0077] An example of a case where the torque will not be zero unless the current in both the armature winding and the field winding is zero is when the field has salient polarity (which allows for the output of reluctance torque generated solely by the armature winding current, even without field flux), and when there is iron loss torque generated by the field flux due to the field winding current.

[0078] An example of a case where the torque becomes zero simply by the armature winding current becoming zero is when there is no iron loss torque generated by the field winding current or the magnetic flux from the magnets installed on the field side.

[0079] An example of a case where the torque becomes zero simply by the current in the field winding becoming zero is when there is no salient polarity in the field (making it impossible to output the reluctance torque mentioned above (paragraph 0077)) and there is no magnetic flux from the field provided on the field side.

[0080] Thus, since the conditions under which the torque of a rotating electric machine becomes zero differ depending on the characteristics of the rotating electric machine, the definition of the torque Ti0 corresponding to zero current also needs to be appropriately modified accordingly. Here, assuming that the torque of the rotating electric machine becomes zero when at least one of the currents of the armature winding and the field winding is zero, the torque Ti0 corresponding to zero current is defined as described above (paragraph 0076).

[0081] <Summary of the various aspects of this application> The various aspects of this application are summarized below as an appendix. (Note 1) A control device for a rotating electric machine that controls an armature winding and a field winding, or a rotating electric machine having an armature winding, via a converter, A current command value calculation unit calculates the current command value of the armature winding and the field winding, or the armature winding, based on the torque command value. A current detection unit that detects the current flowing through the armature winding and the field winding, or the armature winding, based on the output signal of the current sensor, At a minimum, a switching control unit that controls the on / off state of a plurality of switching elements in the converter based on the current command value, A control device for a rotating electric machine, comprising: a torque difference calculation unit that uses a current-torque characteristic function in which the current of the armature winding and the field winding, or the current of the armature winding, is set as an argument, and the torque of the rotating electric machine is set as a return value, calculates the return value torque calculated by inputting the current command value as an argument, calculates the return value torque calculated by inputting the current detection value as an argument, and calculates the detection value torque using the current-torque characteristic function, and calculates the torque difference based on the command value torque and the detection value torque.

[0082] (Note 2) The control device for a rotating electric machine as described in Appendix 1, wherein the torque difference calculation unit calculates the torque difference based on the difference between the detected value-corresponding torque and the command value-corresponding torque.

[0083] (Note 3) The control device for a rotating electric machine as described in Appendix 1, wherein the torque difference calculation unit calculates the difference between the detected value-corresponding torque and the command value-corresponding torque as the torque difference.

[0084] (Note 4) A control device for a rotating electric machine according to any one of the appendices 1 to 3, further comprising an abnormality determination unit that determines whether or not there is an abnormality based on the torque difference.

[0085] (Note 5) The control device for a rotating electric machine as described in Appendix 4, wherein the abnormality determination unit determines that an abnormality has occurred when the torque difference deviates from the determination range.

[0086] (Note 6) A control device for a rotating electric machine according to any one of the appendices 1 to 3, further comprising a torque estimation unit that calculates a torque estimate value based on the torque command value and the torque difference.

[0087] (Note 7) The control device for a rotating electric machine according to Appendix 6, further comprising an abnormality determination unit that determines whether or not there is an abnormality based on the torque command value and the torque estimate value.

[0088] (Note 8) The control device for a rotating electric machine as described in Appendix 7, wherein the abnormality determination unit determines that an abnormality has occurred when the difference between the torque command value and the estimated torque value deviates from the determination range.

[0089] (Note 9) The torque estimation unit is a control device for a rotating electric machine as described in Appendix 6, which calculates the estimated torque value based on the sum of the torque command value and the torque difference.

[0090] (Note 10) The control device for a rotating electric machine as described in Appendix 9, wherein the torque estimation unit calculates the sum of the torque command value and the torque difference as the torque estimate value.

[0091] (Note 11) The control device for a rotating electric machine as described in Appendix 9, wherein the torque estimation unit calculates the torque estimation value as the sum of the torque command value and the torque difference multiplied by a first coefficient.

[0092] (Note 12) The control device for a rotating electric machine as described in Appendix 11, wherein the torque estimation unit sets the first coefficient to a value between 0 and 1.

[0093] (Note 13) The control device for a rotating electric machine according to Appendix 11 or 12, wherein the torque estimation unit sets the first coefficient based on the detected value-corresponding torque.

[0094] (Note 14) The control device for a rotating electric machine as described in Appendix 13, wherein the torque estimation unit sets the first coefficient based on the current 0 corresponding torque, which is the torque when at least one current present in the armature winding or the field winding is 0, and the detected value corresponding torque.

[0095] (Note 15) The control device for a rotating electric machine as described in Appendix 14, wherein the torque estimation unit sets the first coefficient based on the difference between the torque corresponding to current 0 and the torque corresponding to the detected value.

[0096] (Note 16) The control device for a rotating electric machine as described in Appendix 15, wherein the torque estimation unit sets the first coefficient to 0 when the absolute value of the difference between the current 0 corresponding torque and the detected value corresponding torque is 0, increases the first coefficient from 0 to 1 as the absolute value increases from 0 to a boundary value, and sets the first coefficient to 1 when the absolute value is equal to or greater than the boundary value.

[0097] (Note 17) The control device for a rotating electric machine as described in Appendix 16, wherein the boundary value is set in advance to a value that is 10% or less of the maximum value within the range of possible absolute values.

[0098] (Note 18) The control device for a rotating electric machine according to any one of the appendices 1 to 17, wherein the current command value calculation unit uses a torque-current setting function in which the torque command value is set as an argument and the current command value is set as a return value, inputs the current torque command value as an argument, and calculates the return value of the current command value.

[0099] (Note 19) The current command value calculation unit calculates the current command value of the d axis and the current command value of the q axis as the current command values ​​of the armature winding. The control device for a rotating electric machine according to any one of the appendices 1 to 18, wherein the torque difference calculation unit uses a current torque characteristic function in which the current of the d axis and the current of the q axis are set as arguments and torque is set as the return value, and calculates the return value torque calculated by inputting the current command value of the d axis and the current command value of the q axis as the command value corresponding torque, and calculates the return value torque calculated by inputting the current detection value of the d axis and the current detection value of the q axis as the detection value corresponding torque.

[0100] (Note 20) The torque difference calculation unit uses map data as the current-torque characteristic function, with the current of the d axis and the current of the q axis as argument map axes and torque as return value map setting data, and each of the argument map axes of the current of the d axis and the argument map axis of the current of the q axis has a discretely set number of steps, and torque is set for each combination of the step of the argument map axis of the current of the d axis and the step of the argument map axis of the current of the q axis, as described in Appendix 19, for the control device of a rotating electric machine.

[0101] While this application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are envisioned within the scope of the art disclosed herein. For example, these include modifying, adding, or omitting at least one component, or even extracting at least one component and combining it with a component from another embodiment. [Explanation of Symbols]

[0102] 1: Rotating electric machine, 5: Inverter, 8: Current sensor, 12: Armature winding, 30: Control device for rotating electric machine, 32: Current detection unit, 33: Current command value calculation unit, 34: Switching control unit, 35: Torque difference calculation unit, 36: Torque estimation unit, 37: Anomaly determination unit, Iddet: Current detection value of the d axis, Idref: Current command value of the d axis, Iqdet: Current detection value of the q axis, Iqref: Current command value of the q axis, K1: First coefficient, Tdiff: Torque difference, Test: Torque estimation value, Ti0: Torque corresponding to current 0, Tidet: Torque corresponding to detected value, Tiref: Torque corresponding to command value, Tref: Torque command value, 4: Field winding, 6: Current sensor for field winding, 9: Converter, 38: Current detection unit for field winding, 39: Current command value calculation unit for field winding, 40: Converter control unit, Ifdet: Current detection value of field winding, Ifref: Current command value of field winding

Claims

1. A control device for a rotating electric machine that controls an armature winding and a field winding, or a rotating electric machine having an armature winding, via a converter, A current command value calculation unit calculates the current command value of the armature winding and the field winding, or the armature winding, based on the torque command value. A current detection unit that detects the current flowing through the armature winding and the field winding, or the armature winding, based on the output signal of the current sensor, At a minimum, a switching control unit that controls the on / off state of a plurality of switching elements in the converter based on the current command value, A torque difference calculation unit calculates the torque difference based on the command value and the torque difference, using a current-torque characteristic function in which the current of the armature winding and the field winding, or the current of the armature winding, is set as an argument and the torque of the rotating electric machine is set as the return value, inputting the current command value as an argument to calculate the return value torque as the command value corresponding torque, using the current-torque characteristic function and inputting the current detection value as an argument to calculate the return value torque as the detection value corresponding torque, and the torque difference is calculated based on the command value corresponding torque and the detection value corresponding torque. The system includes a torque estimation unit that calculates a torque estimate value based on the torque command value and the torque difference, The torque estimation unit calculates the torque estimation value by multiplying the sum of the torque command value and the torque difference by a first coefficient, and sets the first coefficient based on the detected value corresponding torque.

2. The control device for a rotating electric machine according to claim 1, wherein the torque difference calculation unit calculates the torque difference based on the difference between the detected value-corresponding torque and the command value-corresponding torque.

3. The control device for a rotating electric machine according to claim 1, wherein the torque difference calculation unit calculates the difference between the detected value-corresponding torque and the command value-corresponding torque as the torque difference.

4. A control device for a rotating electric machine according to any one of claims 1 to 3, further comprising an abnormality determination unit that determines whether or not there is an abnormality based on the torque difference.

5. The control device for a rotating electric machine according to claim 4, wherein the abnormality determination unit determines that an abnormality has occurred when the torque difference deviates from the determination range.

6. The control device for a rotating electric machine according to claim 1, further comprising an abnormality determination unit that determines whether or not there is an abnormality based on the torque command value and the torque estimate value.

7. The control device for a rotating electric machine according to claim 6, wherein the abnormality determination unit determines that an abnormality has occurred when the difference between the torque command value and the torque estimate value deviates from the determination range.

8. The control device for a rotating electric machine according to claim 1, wherein the torque estimation unit sets the first coefficient to a value of 0 or more and 1 or less.

9. The control device for a rotating electric machine according to claim 1, wherein the torque estimation unit sets the first coefficient based on the current 0 corresponding torque, which is the torque when at least one current present in the armature winding or the field winding is 0, and the detected value corresponding torque.

10. The control device for a rotating electric machine according to claim 9, wherein the torque estimation unit sets the first coefficient based on the difference between the current 0 corresponding torque and the detected value corresponding torque.

11. The control device for a rotating electric machine according to claim 10, wherein the torque estimation unit sets the first coefficient to 0 when the absolute value of the difference between the current 0 corresponding torque and the detected value corresponding torque is 0, increases the first coefficient from 0 to 1 as the absolute value increases from 0 to a boundary value, and sets the first coefficient to 1 when the absolute value is equal to or greater than the boundary value.

12. The control device for a rotating electric machine according to claim 11, wherein the boundary value is set in advance to a value that is 10% or less of the maximum value within the range of possible absolute values.

13. The control device for a rotating electric machine according to claim 1, wherein the current command value calculation unit uses a torque-current setting function in which the torque command value is set as an argument and the current command value is set as a return value, inputs the current torque command value as an argument, and calculates the return value of the current command value.

14. The current command value calculation unit calculates the current command value of the d axis and the current command value of the q axis as the current command values ​​of the armature winding. The control device for a rotating electric machine according to claim 1, wherein the torque difference calculation unit uses a current torque characteristic function in which the current of the d axis and the current of the q axis are set as arguments and torque is set as the return value, inputs the current command value of the d axis and the current command value of the q axis as arguments and calculates the return value torque as the command value corresponding torque, and inputs the current detection value of the d axis and the current detection value of the q axis as arguments and calculates the return value torque as the detection value corresponding torque.

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