Winding field type rotating electric machine

Abstract

This invention provides a wound-field type rotating electric machine that can accurately estimate the power supplied to the field winding using a rotary transformer, thereby improving controllability. [Solution] The wound-field rotating electric machine device 1 comprises a wound-field rotating electric machine body M having a rotor 12 and a stator 14, a rotary transformer T having a rotating part Tb that can rotate integrally with the rotor 12, a first circuit 31 on the primary side and a second circuit 32 on the secondary side of the rotary transformer T, and a rotor control unit 4 that controls the power supply to the field winding 11 of the rotor 12. The rotor control unit 4 supplies the primary side transformer current I to the primary side of the rotary transformer T. T And the rotor current I flowing through the field winding 11 L Based on the relationship, rotor current I L It has a rotor current estimation unit 41 that estimates the primary side transformer current I T The detection timing is set to the point when the excitation current Ie becomes negligibly large.

Description

[Technical Field]

[0001] This invention relates to a wound-field type rotating electric machine. [Background technology]

[0002] Conventionally, rotating electric machines used in electric vehicles and the like have widely adopted permanent magnet field structures, which have permanent magnets in the rotor. In recent years, however, there has been consideration to adopt wound field structures, which have windings in the rotor, as an alternative to the permanent magnet type that uses rare earth elements. Wound field type rotating electric machines allow for adjustment of the field flux by controlling the field current flowing through the rotor windings, and are expected to operate more efficiently. In such cases, power to the rotor windings can be supplied, for example, using a rotary transformer in a brushless manner.

[0003] On the other hand, Patent Document 1 discloses a power conversion device used to supply power to loads such as in-vehicle equipment and auxiliary batteries. This power conversion device is configured as a DC-DC converter including a transformer, with an input current detection circuit using a current transformer placed between the inverter device connected to the primary side of the transformer and the DC power supply, and an output voltage detection circuit placed on the secondary side in parallel with the load. The control unit is configured to estimate the input current and output current from a predetermined calculation formula and power conversion efficiency map data, using the AD conversion value obtained by converting the detected current on the primary side into a current-voltage, and the detected values ​​of the input voltage from the battery and the output voltage to the external load. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 6906566 [Overview of the project] [Problems that the invention aims to solve]

[0005] In a wound-field rotating electric machine, to supply power to the rotor's field windings in a brushless manner, it is desirable to accurately estimate the rotor current flowing through the field windings in order to control the power supplied to the field windings, for example, via a rotary transformer. However, when using a rotary transformer, it is difficult to directly detect the output voltage by providing a detection circuit on the secondary side, which is integrally provided with the rotating rotor. Therefore, the method of estimating the input and output currents of the power converter by performing calculations based on the detected value of the output voltage, as in Patent Document 1, cannot be adopted, and there is a need for a new method that can estimate the rotor current without using the detected value on the secondary side.

[0006] The present invention has been made in view of the above problems, and provides a wound-field rotating electric machine device that uses a rotary transformer to supply power to a wound-field rotating electric machine, and that can accurately estimate the power supplied to the field winding and improve controllability. [Means for solving the problem]

[0007] One aspect of the present invention is, A wound-field rotating electric machine body (M) comprises a rotor (12) having a field winding (11) and a stator (14) having an armature winding (13), A rotary transformer (T) comprising a fixed part (Ta) having a primary winding (21) and a rotating part (Tb) having a secondary winding (22), wherein the rotating part is provided to be rotatable integrally with the rotor, A first circuit (31) converts DC power to AC power and outputs it to the primary winding, and a second circuit (32) converts AC power from the secondary winding to DC power and outputs it to the field winding, The first circuit comprises a rotor control unit (4) that controls the power supply to the field winding by controlling the on / off operation of a plurality of switching elements (Q1 to Q4) constituting the first circuit, The rotor control unit supplies primary side transformer current (I T ) and the rotor current (I) flowing through the field winding. L It has a rotor current estimation unit (41) that estimates the rotor current based on the relationship with ), The rotor current estimation unit determines the detection timing of the primary side transformer current based on the excitation inductance (L) of the rotary transformer. M The winding field rotating electric machine (1) is configured such that the excitation current (Ie) flowing through the rotor is negligible in relation to the magnitude of the rotor current. [Effects of the Invention]

[0008] In the wound-field rotating electric machine with the above configuration, the AC voltage output from the first circuit to the primary side of the rotary transformer is transformed according to the turns ratio of the primary and secondary windings, converted to DC in the second circuit on the secondary side, and supplied to the field winding. During this power transmission, the primary transformer current detected on the primary side of the rotary transformer has a predetermined relationship with the excitation current flowing through the excitation inductance and the rotor current flowing through the field winding. Furthermore, the excitation current increases or decreases around the zero point as the output voltage of the first circuit reverses between positive and negative. Therefore, by detecting the primary transformer current at the timing when the excitation current is almost zero and becomes negligible, the rotor current can be accurately estimated from the relationship between the primary transformer current and the rotor current.

[0009] This allows, for example, the rotor control unit to perform switching control based on the rotor current estimated by the rotor estimation unit, so that a rotor current corresponding to the output demand of the rotating electric machine is obtained, thereby improving the controllability of the rotating electric machine.

[0010] As described above, according to the above embodiment, in a device that supplies power to a wound-field type rotating electric machine using a rotary transformer, it is possible to provide a wound-field type rotating electric machine device that can accurately estimate the power supplied to the field winding and improve controllability. The symbols in parentheses in the claims and the means for solving the problem indicate the correspondence with the specific means described in the embodiments later, and do not limit the technical scope of the present invention. [Brief explanation of the drawing]

[0011] [Figure 1] A circuit diagram showing the overall configuration of a wound-field type rotating electric machine in Embodiment 1. [Figure 2] A circuit diagram showing the main components of a wound-field type rotating electric machine in Embodiment 1. [Figure 3] A time chart diagram showing the operation of the first circuit of the wound-field type rotating electric machine in Embodiment 1. [Figure 4] A block diagram showing an example of control by the rotor control unit of a wound-field type rotating electric machine in Embodiment 1. [Figure 5] A time chart diagram showing the changes in current in each part due to the operation of the first circuit in Embodiment 1. [Figure 6] A block diagram showing an example of control by the rotor control unit in Embodiment 2. [Figure 7] A time chart diagram showing the operation and delay time of each part of a wound-field type rotating electric machine in Embodiment 2. [Figure 8] A block diagram showing an example of control by the rotor control unit in Embodiment 3. [Figure 9] A time chart diagram showing the operation and delay time of each part of a wound-field type rotating electric machine in Embodiment 3. [Figure 10] A circuit diagram showing the main components of a wound-field type rotating electric machine in Embodiment 4. [Figure 11] A time chart diagram showing the operation and delay time of each part of a wound-field type rotating electric machine in Embodiment 4. [Figure 12] A circuit diagram showing the main components of a wound-field type rotating electric machine in Embodiment 4. [Figure 13] A time chart diagram showing an example of setting the detection timing by the rotor current estimation unit in Embodiment 4. [Figure 14] A circuit diagram showing the overall configuration of a wound-field type rotating electric machine in Embodiment 5. [Figure 15] A time chart diagram showing the operation and delay time of each part of a wound-field type rotating electric machine in Embodiment 5. [Figure 16]A time chart diagram showing the simulation results of rotor current estimation by the rotor current estimation unit in Embodiment 5. [Modes for carrying out the invention]

[0012] (Embodiment 1) Hereinafter, Embodiment 1 of a wound-field type rotating electric machine will be described with reference to the drawings. The wound-field type rotating electric machine of this embodiment is configured, for example, as a wound-field type rotating electric machine applied to a drive motor of an electric vehicle and a device for controlling its power supply.

[0013] As shown in Figure 1, in this embodiment, the wound-field rotating electric machine device 1 includes a brushless wound-field rotating electric machine body M, a rotary transformer T, a first circuit 31 and a second circuit 32, and a rotor control unit 4 including a rotor current estimation unit 41. The wound-field rotating electric machine body M comprises a rotor 12 having field windings 11 and a stator 14 having armature windings 13. The wound-field rotating electric machine device 1 is configured to provide contactless power to the rotor 12 of the wound-field rotating electric machine body M using a field circuit 30 with a rotary transformer T, and the field current applied to the rotor 12 can be controlled by the rotor control unit 4.

[0014] The rotary transformer T consists of a stationary part Ta having a primary winding 21 and a rotating part Tb having a secondary winding 22. The rotating part Tb is mounted coaxially with the rotor 12 and configured to rotate integrally with it, while the stationary part Ta is positioned with a gap between it and the rotating part Tb. The field circuit 30 is configured as a DC-DC converter and includes a first circuit 31 on the stationary part Ta side of the rotary transformer T that converts DC power to AC power and outputs it to the primary winding 21. The field circuit 30 also includes a second circuit 32 on the rotating part Tb side of the rotary transformer T that converts AC power from the secondary winding 22 to DC power and outputs it to the field winding 11.

[0015] The rotor control unit 4 controls power supply to the field winding 11 by controlling the on / off operations of the plurality of switching elements Q1 to Q4 constituting the first circuit 31. Specifically, the rotor control unit 4 controls the rotor current I flowing through the field winding 11 L and includes a rotor current estimation unit 41 for estimating, and based on the result, for example, the first circuit 31 can be phase-shift driven.

[0016] As the main configuration is shown in Figure 2, the rotor control unit 4 outputs control signals (gate signals Q1in to Q4in) to the first circuit 31, and accordingly, detects the primary-side transformer current I supplied to the primary side of the rotary transformer T T . The rotor current estimation unit 41 detects the primary-side transformer current I at a predetermined detection timing based on the relationship between the primary-side transformer current I T and the rotor current I flowing through the field winding 11 L T , and estimates the rotor current I L . Specifically, since the exciting current Ie flowing through the exciting inductance L of the rotary transformer T M has a predetermined relationship with the primary-side transformer current I T and the rotor current I L , the timing can be set such that the exciting current Ie has a magnitude that is negligible relative to the magnitude of the rotor current I L .

[0017] Preferably, the detection timing is set to a timing at which the exciting current Ie is substantially zero (0A), and the primary-side transformer current I can be sampled at a timing that has substantially no influence on the estimation of the rotor current I L T . At this time, the magnitude of the exciting current Ie may be within a range that is sufficiently small relative to the rotor current I L and can be regarded as not affecting the estimation of the rotor current I L . Specifically, it can be appropriately set according to the magnitude of the rotor current I L and the required estimation accuracy, and for example, can be within ±2A, preferably within ±1A.

[0018] ​​ As a result, the primary side transformer current I T Based on the detected value, the rotor current I L This allows for accurate estimation and improves the controllability of the rotor control unit 4. Details of the control by the rotor control unit 4 will be described later.

[0019] The configuration of the wound-field type rotating electric machine 1 of this embodiment will be described in detail below. In Figure 1, the rotor 12 and stator 14 of the wound-field rotating electric machine body M are arranged coaxially around a rotation axis (not shown) such that, for example, the field winding 11 wound around the rotor core and the armature winding 13 wound around the stator core face each other with a predetermined gap. A DC power source B, such as an on-board battery, is used as the power source for driving the wound-field rotating electric machine body M.

[0020] The operation of the entire system, including the wound-field rotating electric machine body M and the circuits for driving it, is controlled by the control device 40. The control device 40 can be configured to include a microcomputer equipped with a processor, memory, and other peripheral circuits.

[0021] The first circuit 31 of the field circuit 30 is specifically configured as a full-bridge inverter circuit in which four switching elements Q1 to Q4 are connected in a full-bridge configuration. The full-bridge inverter circuit has two sets of legs connected in parallel between the high-potential side wiring 101 and the low-potential side wiring 102, and each leg consists of a series connection of two switching elements Q1, Q2 (or switching elements Q3, Q4). The midpoint of one set of legs is connected to one end of the primary winding 21, and the midpoint of the other set of legs is connected to the other end of the primary winding 21.

[0022] In this embodiment, unless otherwise specified, "connection" refers to an electrical connection.

[0023] The high-potential wiring 101 and the low-potential wiring 102 are connected to the positive and negative terminals of the DC power supply B, respectively. As a result, the first circuit 31 can convert the DC power of the DC power supply B into AC power by switching the on and off of multiple switching elements Q1 to Q4, and supply it to the primary side of the rotary transformer T. The primary winding 21 and the secondary winding 22 of the rotary transformer T are magnetically coupled, and when current is supplied to the primary winding 21, an induced electromotive force is generated in the secondary winding 22.

[0024] On the rotating part Tb side of the rotary transformer T, the secondary winding 22 is electrically connected to the field winding 11 of the rotor 12 via a second circuit 32. The second circuit 32 is configured as a full-wave rectifier circuit with four diodes D1 to D4 connected in a full bridge configuration. Specifically, the second circuit 32 consists of two sets of legs, each made up of two diodes D1 and D2 (or diodes D3 and D4) connected in series, which are connected in parallel to the field winding 11. The midpoint of one set of legs is connected to one end of the secondary winding 22, and the midpoint of the other set of legs is connected to the other end of the secondary winding 22. As a result, the AC output from the secondary winding 22 is converted to DC power and can be output to the field winding 11.

[0025] The stator 14 is connected to a DC power supply B via a known three-phase inverter circuit 51. Generally, the three-phase inverter circuit 51 consists of six switching elements connected in a three-phase full bridge configuration, with three sets of legs corresponding to each phase connected in parallel between the high-potential side wiring 101 and the low-potential side wiring 102. The armature winding 13 is, for example, connected to the stator core in a three-phase Y configuration, so that DC power from the DC power supply B is converted to three-phase AC power in the three-phase inverter circuit 51 and supplied to the armature winding 13.

[0026] The switching elements Q1 to Q4 constituting the first circuit 31 of the field circuit 30 are composed of gate voltage controlled semiconductor switching elements. The gate voltage controlled semiconductor switching elements are, for example, MOSFETs (field-effect transistors), and each switching element Q1 to Q4 has a freewheeling diode connected in reverse between the drain and source of the MOSFET. The MOSFET is switched on or off by controlling the gate drive voltage to an on voltage or off voltage according to the gate signals Q1in to Q4in.

[0027] The switching elements constituting the three-phase inverter circuit 51 can also be configured in a similar manner. In addition to MOSFETs, for example, IGBTs (isolated-gate bipolar transistors) can also be used. The gate signals Q1in to Q4in are control signals for switching the on and off states of each switching element Q1 to Q4, and serve as reference signals for commanding the start of the voltage output period T1 in the rotor current estimation unit 41, which will be described later.

[0028] A current sensor S1, which serves as a primary side current detection unit, is provided on the fixed part Ta side of the rotary transformer T, and the primary side transformer current I supplied to the primary side is detected. T The primary transformer current I is now detectable. T This is detected at a predetermined timing in the rotor control unit 4 provided in the control device 40 and used to control the energization of the field winding 11 of the rotor 12 via the rotary transformer T.

[0029] The rotor control unit 4 switches the on and off of the switching elements Q1 to Q4 that constitute the first circuit 31, thereby controlling the rotor current I flowing through the field winding 11 connected to the second circuit 32. L The rotor control unit 4 has a rotor current estimation unit 41, and controls the primary side transformer current I T And the rotor current I flowing through the field winding 11 L Based on the relationship, rotor current I L This is estimated. The details of the control by the rotor control unit 4 will be explained next.

[0030] As shown in Figure 3, the switching elements Q1 to Q4 of the first circuit 31 are driven, for example, by phase shift control. In phase shift control, the two switching elements Q1 and Q2 (or switching elements Q3 and Q4) of each leg are turned ON (or OFF) in a complementary manner, and the operation of one leg is controlled to have a predetermined phase difference with respect to the operation of the other leg.

[0031] Each switching element Q1 to Q4 operates either on or off in response to the gate signals Q1in to Q4in output from the rotor control unit 4. Here, the on time Ton (i.e., Ton = Ts / 2) is half the switching period Ts. At this time, the time during which diagonally opposite switching elements Q1 and Q4 (or switching elements Q2 and Q3) are simultaneously on is the period (hereinafter referred to as the voltage output period) T1 during which a positive or negative voltage is actually output from the first circuit 31, and is equal to the phase shift amount P (i.e., P = T1 [seconds]).

[0032] In other words, the voltage output period T1 is the time during which the output voltage Vinv of the first circuit 31 is applied to the primary side of the rotary transformer T, and the duty cycle D, which is expressed as the ratio of the application time of the output voltage Vinv to the on time Ton, is given by the following equation 1. Equation 1: D = T1 / Ton = T1 / (Ts / 2)[-] Therefore, in phase shift control, the energization of the rotor 12 to the field winding 11 can be controlled by varying the voltage output period T1, i.e., the phase shift amount P, with respect to the switching period Ts.

[0033] In that case, the rotor control unit 4 is provided with a rotor current estimation unit 41 and a phase shift amount calculation unit 42, and the rotor current I LControl can be performed based on the estimated value of I. Specifically, in the control example shown in Figure 4, the rotor control unit 4 receives a rotor current command value corresponding to the desired motor torque from a vehicle ECU (electronic control unit) (not shown). The rotor control unit 4 receives the rotor current estimated value I estimated by the rotor current estimation unit 41. L_EST The difference between the rotor current command value and ΔI L The duty cycle D is calculated, and proportional-integral control (PI control) is performed by the PI controller 43 using the duty cycle D as the controlled variable. Furthermore, the phase shift amount P is calculated.

[0034] As a result, the switching elements Q1 to Q4 of the first circuit 31 are switched on and off based on the calculated phase shift amount P (see Figure 3). In Figure 1, a smoothing capacitor 33 is connected in parallel between the first circuit 31 and the DC power supply B, and a smoothed positive power supply voltage (Vin) or negative power supply voltage (-Vin) is input from the DC power supply B to the primary side of the rotary transformer T for the on-time Ton of the switching elements Q1 to Q4. The rotary transformer T is designed so that the coupling coefficient between the primary and secondary sides is approximately 1 (about 0.99). At this time, the voltage (Vo) output to the secondary side is the value obtained by multiplying the primary side voltage (Vin) by the turns ratio (N2 / N1) of the secondary side winding 22 to the primary side winding 21 and the duty cycle D, as shown in Equation 2 below. Equation 2: Vo = Vin × (N2 / N1) × D[V]

[0035] Here, in order to perform torque control based on the phase shift amount P shown in Figure 4 with good controllability, the rotor current I in the rotor current estimation unit 41 is L To improve the estimation accuracy, the rotor current estimation unit 41 acquires the detected value of the current sensor S1 at a predetermined timing, and the acquired primary side transformer current I T Based on this, rotor current estimate I L_EST Calculate.

[0036] Specifically, in the equivalent circuit example of the rotary transformer T shown in Figure 2, the excitation inductance L is on the primary side. MAn excitation current Ie flows due to this, and this excitation current Ie is the primary transformer current I T and rotor current I L We note that the following relationships exist between equations 3 and 5. That is, as shown in equation 3, the primary side transformer current I T These are the excitation current Ie and the rotor current I L It is expressed as the sum of the value obtained by multiplying by the turns ratio (N2 / N1). Equation 3:I T =Ie+I L ×(N2 / N1)[A]

[0037] Therefore, at the timing when the excitation current Ie becomes zero (0A), the primary side transformer current I T If this is detected, equation 3 is transformed into equation 4 and then equation 5, and the rotor current I L The primary side transformer current I T It can be calculated based on the detected values. Equation 4:I T =I L (N2 / N1)[A] (where Ie=0A) Equation 5:I L =I T ×(N1 / N2)[A] In the equivalent circuit shown in Figure 2, the coupling coefficient of the rotary transformer T is assumed to be approximately 1, and the leakage inductance is assumed to be sufficiently small, thus simplifying the magnetic circuit.

[0038] As shown in Figure 5, in this case, the excitation current Ie increases or decreases for a voltage output period T1 (=DTs / 2) corresponding to the phase shift amount P, with respect to the gate signal (only Q1in and Q2in are shown here). That is, the excitation current Ie shows a current waveform that increases or decreases at a nearly constant speed, with the current value at the start of application being the minimum or maximum, as the output voltage Vinv of the first circuit 31 is applied to the primary side of the rotating transformer T, and crosses zero at the midpoint. In other words, the excitation current Ie becomes almost zero (0A) in half the time of the voltage output period T1 (T1 / 2 = DTs / 4).

[0039] Therefore, if the leakage inductance of the rotary transformer T is sufficiently small and can be considered an ideal state where delays caused by circuits, etc., can be almost ignored, the point in time when the elapsed time from the output of the gate signals Q1in to Q4in, which serve as the reference signal, is T1 / 2 can be used as the reference detection timing. The reference signal is a signal that commands the start of the voltage output period T1, and the point in time when the elapsed time is T1 / 2 is the point in time when half the length of the voltage output period T1 has elapsed from the start of the voltage output period T1.

[0040] As a result, the primary transformer current I rises (or falls) rapidly along with the gate signals Q1in~Q4in. T This is detected at a timing unaffected by the excitation current Ie, and the rotor current I L Rotor current estimate I for (true value) L_EST This makes it possible to improve the estimation accuracy.

[0041] Thus, according to this embodiment, the rotor current I L This allows for accurate estimation. Furthermore, by controlling the power supply to the field winding 11 based on the estimation results, the controllability of the motor torque can be improved.

[0042] (Embodiment 2) Embodiment 2 relating to a wound-field type rotating electric machine will be described with reference to the drawings. In this embodiment of a wound-field rotating electric machine, the rotor control unit 4 of the control device 40 controls the rotor current I L Primary transformer current I for estimation T The setting of the detection timing differs from that of Embodiment 1 described above. The other basic configurations and basic controls are the same as those of Embodiment 1 described above, and will not be explained. In addition, among the reference numerals used in Embodiment 2 and later, those that are the same as those used in the previously described embodiments represent the same components, etc., as those in the previously described embodiments, unless otherwise specified.

[0043] If there is an output delay from the first circuit 31 relative to the output of the gate signals Q1in to Q4in, which serve as the reference signal, the delay time Δt can be considered when setting the detection timing. In that case, a correction is performed by adding the delay time Δt to the reference detection timing (i.e., T1 / 2 + Δt), and sampling is performed at the corrected timing, thereby reducing the rotor current I L This can improve the detection accuracy.

[0044] As shown in Figure 6, specifically, the output delay from the first circuit 31 occurs due to the timing difference of the output from the gate drivers (driver circuits) 44 corresponding to each switching element Q1 to Q4 in relation to the gate signals Q1in to Q4in output from the rotor control unit 4. As shown in the figure, each switching element Q1 to Q4 is individually provided with a gate driver 44, and is configured to output gate drive voltages Q1gs to Q4gs generated by an isolated power supply (not shown) in response to the input of gate signals Q1in to Q4in.

[0045] In this case, as shown in Figure 7, for example, with respect to the switching element Q1, a roughly constant first delay time Δt1 occurs between the rising edge of the gate signal Q1in, which serves as the reference signal, and the rising edge of the gate drive voltage Q1gs output from the gate driver 44. This delay is caused, for example, by the circuit configuration of the gate driver 44, and a similar first delay time Δt1 also occurs for the rising edges of the gate signals Q2in to Q4in of the switching elements Q2 to Q4.

[0046] Therefore, the first delay time Δt1 caused by the gate driver 44 can be determined in advance through testing, and control in the rotor control unit 4 can be performed using a detection timing that takes the first delay time Δt1 into consideration. This reduces the deviation in detection timing caused by the output delay of the first circuit 31 relative to the reference signal, and the rotor current I L This allows for further improvement in the estimation accuracy.

[0047] Thus, according to this embodiment, the rotor current IL This allows for more accurate estimation. Furthermore, by controlling the power supply to the field winding 11 based on the estimation results, the controllability of the motor torque can be further improved. Other effects and advantages similar to those of Embodiment 1 can also be obtained.

[0048] (Embodiment 3) Embodiment 3 of a wound-field type rotating electric machine will be described with reference to the drawings. In this embodiment of a wound-field rotating electric machine, the rotor control unit 4 of the control device 40 controls the rotor current I L Primary transformer current I for estimation T The setting of the detection timing differs from that of embodiments 1 and 2 described above. The other basic configurations and basic controls are the same as those of embodiment 1, and therefore will not be explained.

[0049] In the above embodiment 2, the detection timing was set considering the output delay of the first circuit 31 with respect to the gate signals Q1in to Q4in which serve as the reference signal, but the primary side transformer current I T It is also possible to set the parameters to take into account the detection delay. In that case as well, by applying a correction to the detection timing in the ideal state described above by adding the delay time Δt caused by the detection delay, the rotor current I L This can improve the detection accuracy.

[0050] As shown in Figure 8, specifically, the primary side transformer current I detected by the current sensor S1 T The current is input to the AD port of the rotor control unit 4 via the filter circuit 15 and the subsequent buffer circuit 16, where it is converted from analog to digital. The current sensor S1 can be, for example, a highly responsive coreless current sensor. The filter circuit 15 has, for example, a resistor R connected in series between the current sensor S1 and the buffer circuit 16. f Capacitor C connected in parallel with it f This is a low-pass filter consisting of [a specific component] and [another component].

[0051] At this time, as shown in Figure 9, the first detected value iv is output from the current sensor S1.OUT This is the actual primary side transformer current I T There is a slight delay time (second delay time Δt2) relative to the (true value). Preferably, it is desirable to select the current sensor S1 such that the delay time is about 1 / 100 of the switching period (for example, if the switching period is 10 μs, the delay is about 100 ns). Also, the second detected value i_ input to the AD port is obtained by passing through the filter circuit 15 and the buffer circuit 16. AN It has a further delay time (third delay time Δt3).

[0052] Here, the filter circuit 15 has a resistor R f and capacitor C f This removes a predetermined frequency determined by the primary side transformer current I T It is configured to handle the ringing current (e.g., several MHz) that occurs. This ringing current is caused by the recovery current of diodes D1 to D4 in the second circuit 32 that constitutes the rectifier circuit being commutated to its junction capacitance (not shown), and the ringing current due to the series resonance between the junction capacitance and the transformer leakage inductance flowing to the primary side of the rotating transformer T. Therefore, a more accurate rotor current I L For estimation purposes, a filter circuit 15 is used to remove high-frequency ringing that does not affect the switching frequency.

[0053] In that case, the filter circuit 15 should be configured to allow the switching frequency to pass through and remove high-frequency ringing. For example, when the switching frequency is 100 kHz and the ringing frequency is about 3 MHz, it is desirable to set the cutoff frequency to a range of about 200 kHz to 300 Hz. As a result, as shown in the figure, the first detected value iv OUT For the second detected value i_ AN While the ringing current is removed, the primary side transformer current I T A phase lag occurs.

[0054] Therefore, depending on the current sensor S1 and the circuit configuration for its detection, it is preferable to adjust the detection timing from the current sensor S1 by taking into account the known second and third delay times Δt2 and Δt3. For example, if the filter circuit 15 is a first-order CR filter and the cutoff frequency is approximately 300 kHz, the third delay time Δt3 is approximately 530 ns.

[0055] Thus, according to this embodiment, the rotor current I L This allows for more accurate estimation. Furthermore, by controlling the power supply to the field winding 11 based on the estimation results, the controllability of the motor torque can be further improved. Other effects and advantages similar to those of Embodiment 1 can also be obtained.

[0056] (Embodiment 4) Embodiment 4 relating to a wound-field type rotating electric machine will be described with reference to the drawings. In this embodiment of a wound-field rotating electric machine, the rotor current estimation unit 41 of the rotor control unit 4 estimates the rotor current I L Primary transformer current I for estimation T The setting of the detection timing differs from that of embodiments 1 to 3 described above. The other basic configurations and basic controls are the same as those of embodiment 1, and therefore will not be explained.

[0057] Specifically, as shown in Figure 10, an equivalent circuit example, the delay time Δt due to the output delay is defined as the leakage inductance L present in the rotating transformer T. I Considering the primary transformer current I T The detection timing can also be set. Here, the equivalent circuit is calculated by converting the leakage inductance of the primary winding 21 and the leakage inductance of the secondary winding 22 to the primary side. In the rotary transformer T, a gap necessary for rotation is formed between the rotor 12 and the stator 14, so there is a small leakage inductance L l It exists.

[0058] As shown in Figure 11, the leakage inductance L lIf present, the output voltage Vinv generated in the first circuit 31 will have leakage inductance L l A period occurs during which the leakage inductance L is applied, causing a delay in the rise of the excitation current Ie. l The fourth delay time Δt4, caused by the voltage application time Δt0, represents a timing shift in when the excitation current Ie becomes zero (0A). Therefore, current sampling can be performed by setting a detection timing that takes the fourth delay time Δt4 into consideration in advance.

[0059] Here, the leakage inductance L l The voltage application time Δt0 corresponds to the diode commutation section of the second circuit 32, and since both diodes D1 and D3 are turned on, the equivalent circuit can be considered as a state where the secondary side of the rotary transformer T is short-circuited, as shown in Figure 12. In that case, the leakage inductance L l The current value Δt0(t) of the voltage application time Δt0 during which the output voltage Vinv of the first circuit 31 is applied is calculated using the leakage inductance (primary side equivalent value), input voltage Vin, turns ratio (N2 / N1), and estimated rotor current values ​​from the previous value I L_EST Using (t-1), it can be approximated by the following equation 6.

[0060]

number

[0061] And the leakage inductance L l The voltage obtained by subtracting the time during which the output voltage Vinv of the first circuit 31 is applied is equal to the excitation inductance L. M Assuming that it is applied to the circuit, the time when the voltage output period T1 is halved (T1 / 2) is delayed by Δt0 / 4. Therefore, with respect to the reference detection timing (T1 / 2), the leakage inductance L l The detection timing can be set by taking into account the fourth delay time Δt4 (=Δt0 / 4) caused by the above.

[0062] Thus, the leakage inductance L is defined as the delay time Δt relative to the reference detection timing (T1 / 2). lBy taking the fourth delay time Δt4 caused by the above into account, more accurate estimation can be performed. Furthermore, as the delay time Δt, the detection timing can be set by appropriately combining the first to third delay times Δt1 to Δt3 shown in the above Embodiments 2 to 3 with the fourth delay time Δt4.

[0063] As shown in FIG. 13, it is preferable to perform current sampling that takes magnetic bias into consideration. Here, a case is illustrated where interrupt processing by the rotor current estimation unit 41 is performed with the time point at which a predetermined delay time Δt has elapsed relative to the rising edges of the gate signals Q1in and Q2in to the switching elements Q1 and Q2 output from the rotor control unit 4 taken as the detection timing. The detection timing can be, for example, a timing obtained by adding the first delay time Δt1 to the fourth delay time Δt4 (=Δt0 / 4) as the delay time Δt to the reference detection timing (T1 / 2=DTs / 4).

[0064] At this time, along with the rising edges of the gate signals Q1in and Q2in, the primary-side transformer current I is detected by the current sensor S1 T , and the second detection value i_ that has passed through the filter circuit 15 in the above Embodiment 3 is AN input to the rotor current estimation unit 41. The rotor current estimation unit 41 detects the positive-side detection value I1 corresponding to the gate signal Q1in and the negative-side detection value I2 corresponding to the gate signal Q2in at a predetermined detection timing including the delay time Δt, respectively, and can calculate the rotor current estimated value I by the following Equation 7. L_EST Equation 7: I L_EST =[(I1-I2) / 2]·(N1 / N2)

[0065] In this way, by performing current sampling on both the positive side and the negative side and using the averaged value thereof, the error occurring when the rotary transformer T is subjected to DC magnetic bias can be canceled out.

[0066] ​The delay times Δt (Δt1 to Δt4) shown in the above Embodiments 2 to 4 can be arbitrarily combined with one or two or more thereof, and depending on the configuration of the field circuit 30 of the applicable wound-field rotating electrical machine apparatus 1, the required rotor current I L can be appropriately selected so as to obtain the required estimation accuracy.

[0067] (Embodiment 5) Embodiment 5 relating to the wound-field rotating electrical machine apparatus will be described with reference to the drawings. The wound-field rotating electrical machine apparatus of the present embodiment differs from the above Embodiments 1 to 4 in the configuration of the field circuit 30 for supplying power to the rotor 12. The rest of the basic configuration and basic control are the same as those of the above Embodiment 1, and descriptions thereof are omitted.

[0068] As shown in FIG. 14, in the present embodiment, in the field circuit 30 using the rotary transformer T, an inductor 34 is connected in series between the first circuit 31 and the primary-side winding 21. Further, a voltage sensor S2 for detecting the both-end voltage Vla of the inductor 34 is provided, and the detection result thereof is input to the rotor control unit 4 of the control device 40.

[0069] The inductor 34 desirably has its inductance value (La) set to a value smaller than the leakage inductance value L of the rotary transformer T l (that is, La < L l ). This suppresses an increase in loss in the inductor 34 and a decrease in the induced voltage to the secondary side, enabling efficient operation.

[0070] As shown in FIG. 15, in the configuration of the present embodiment, when the field circuit 30 is in operation, along with the switching of the first circuit 31, during the voltage application time Δt0 to the leakage inductance L l , the voltage Vin of the DC power supply B is divided and applied across the added inductor 34. At this time, across the inductor 34 (La) and the leakage inductance L of the rotary transformer T lWith respect to the combined impedance, the voltage Vla across inductor 34 is expressed by the following equation 8. Equation 8: Vla = Vin·La / (L I +La) Therefore, the voltage application time Δt0 can be directly measured by the voltage Vla across the inductor 34 detected by the voltage sensor S2, and the fourth delay time Δt4 can be calculated.

[0071] Figure 16 shows the rotor current I calculated by the rotor current estimation unit 41 based on this embodiment. L This is the simulation result performed to verify the estimation accuracy. The figure shows the primary side transformer current I output in response to the reference signal. T Output voltage Vinv of the first circuit 31, leakage inductance L l This shows the change in the voltage Vla across the terminals and the excitation current Ie. At this time, as shown in the figure, the primary side transformer current I detected at a predetermined timing considering the delay time T Rotor current I based on L The estimated value (solid line) is the rotor current I L It was confirmed that this closely matches the true value (dotted line).

[0072] Thus, according to this embodiment, instead of using a mathematical formula that includes multiple parameters as in Embodiment 4 above, the leakage inductance L is obtained from the detection result of the voltage sensor S2. l By directly measuring the voltage application time Δt0, it becomes possible to correct the detection timing for current sampling. In addition, the same effects and advantages as in Embodiment 4 above can be obtained.

[0073] The present invention is not limited to the embodiments described above, and can be applied to various embodiments without departing from its spirit. [Explanation of Symbols]

[0074] 1. Wind-field rotating electric machine 11 Field winding 12 rotors 13. Armature winding 14 stata 21 Primary winding 22 Secondary winding 31 1st circuit 32 2nd circuit 34 Inductors 4. Rotor control unit 41 Rotor current estimation unit T Rotary Transformer S1 Current Sensor S2 Voltage Sensor

Claims

1. A wound-field rotating electric machine body (M) comprises a rotor (12) having a field winding (11) and a stator (14) having an armature winding (13), A rotary transformer (T) comprising a fixed part (Ta) having a primary winding (21) and a rotating part (Tb) having a secondary winding (22), wherein the rotating part is provided to be rotatable integrally with the rotor, A first circuit (31) converts DC power to AC power and outputs it to the primary winding, and a second circuit (32) converts AC power from the secondary winding to DC power and outputs it to the field winding, The first circuit comprises a rotor control unit (4) that controls the power supply to the field winding by controlling the on / off operation of a plurality of switching elements (Q1 to Q4) constituting the first circuit, The rotor control unit supplies primary side transformer current (I) to the primary side of the rotary transformer. Ｔ ) and the rotor current (I) flowing through the field winding. Ｌ It has a rotor current estimation unit (41) that estimates the rotor current based on the relationship with ), The rotor current estimation unit determines the detection timing of the primary side transformer current based on the excitation inductance (L) of the rotary transformer. Ｍ A wound-field rotating electric machine (1) wherein the timing of the excitation current (Ie) flowing through the rotor is such that it is negligible in relation to the magnitude of the rotor current.

2. The first circuit is a full-bridge inverter circuit, The rotor current estimation unit determines the voltage output period (T) during which a positive or negative voltage is output from the first circuit. 1 The winding field type rotating electric machine device according to claim 1, wherein the reference detection timing is set to the point when half of the voltage output period has elapsed from the start of the operation.

3. The rotor control unit controls the voltage output period T 1 The wound-field rotating electric machine according to claim 2, which outputs a control signal for switching the on / off state of a plurality of switching elements as a reference signal for commanding the start of the operation.

4. The wound-field rotating electric machine apparatus according to claim 3, wherein the rotor current estimation unit sets the detection timing by adding a delay time (Δt) based on one or both of the output delay from the first circuit with respect to the output of the reference signal and the detection delay of the primary side transformer current to the reference detection timing.

5. The system further includes a driver circuit (44) that outputs a drive voltage to the switching element upon input of the aforementioned control signal. The wound-field rotating electric machine apparatus according to claim 4, wherein the delay time includes a delay time (Δt1) from the input of the control signal to the output of the drive voltage.

6. Displaced between the first circuit and the rotary transformer, the primary side transformer current (I T It further includes a current sensor (S1) that detects the following: The winding field type rotating electric machine apparatus according to claim 4, wherein the delay time includes the delay time (Δt2 to Δt3) from the output of the current sensor to the detection of the primary side transformer current by the rotor current estimation unit.

7. The aforementioned delay time is determined by the leakage inductance (L) of the rotary transformer. １ The wound-field rotating electric machine apparatus according to claim 4, including a delay time (Δt4) caused by ).

8. The system further includes an inductor (34) connected in series between the first circuit and the rotary transformer, and a voltage sensor (S2) for detecting the voltage across the inductor. The rotor current estimation unit measures the delay time caused by the leakage inductance based on the output period of the voltage sensor, as described in claim 7.

9. The rotor current estimation unit calculates the estimated value I of the rotor current Ｌ_ＥＳＴ based on the positive-side detected value I of the primary transformer current detected at the detection timing １ and the negative-side detected value I ２ , and the number of turns N of the primary winding １ and the number of turns N of the secondary winding ２ , using the following formula, the wound-field rotating electrical machine apparatus according to any one of claims 1 to 8. Formula: I Ｌ_ＥＳＴ = [(I １ -I ２ ) / 2]・(N １ / N ２ )

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