Rotary electric machine control device

Abstract

To obtain a rotary electric machine control device capable of appropriately determining off-timing of a switching element, thereby improving the efficiency of synchronous rectification.SOLUTION: A control device 100 for controlling a rotary electric machine 1 equipped with an x-phase armature coil determines off-timing of a switching element Sw(i) on the basis of a time at which a synchronous rectification permitting signal corresponding to a switching element Sw(i-1) is switched from off to on when switching elements corresponding to synchronous rectification permitting signals Swp11, Swp12, etc. which sequentially become an on state are defined as switching elements Sw(0), Sw(1), Sw(2)...Sw(2x-1), upon performing synchronous rectification on AC power supplied from the rotary electric machine.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present disclosure relates to a control device for a rotating electric machine. [Background technology]

[0002] In a control device for a rotating electric machine that operates as a motor or a generator, synchronous rectification is one method for rectifying AC power output from the rotating electric machine into DC power. Synchronous rectification converts AC power into DC power by controlling the on / off of switching elements in synchronization with the waveform of AC power input to a bridge circuit of the switching elements. One specific method for implementing synchronous rectification is to determine the timing at which a specific switching element performs synchronous rectification (the timing at which the switching element is turned on and off) based on the conduction time of a parasitic diode one cycle before (see, for example, Patent Document 1). Here, when determining the on-period of the switching element, a certain margin time is subtracted from the conduction time. This margin time is determined taking into account factors such as control delays and rotational fluctuations of the rotating electric machine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-284564 Summary of the Invention [Problem to be solved by the invention]

[0004] In the method described in Patent Document 1, the on / off timing of a switching element is determined based on information from one electrical cycle to half a cycle before. In such a case, particularly when the rotation speed of a rotating electric machine is increasing, it is necessary to secure an extra margin time to prevent the margin time from becoming too small. On the other hand, from the perspective of synchronous rectification efficiency, it is required to minimize the margin time and maximize the synchronous rectification execution time. Therefore, it is difficult to set an appropriate margin time based on outdated information from one electrical cycle to half a cycle before, while there are changes such as rotation fluctuations. In particular, the off timing must be considered when the synchronous rectification enable signal has not yet been turned off (i.e., the off timing of the synchronous rectification enable signal has not yet been determined), making it even more difficult to set an appropriate off timing. Therefore, it is necessary to secure the extra margin time, which may reduce the efficiency of synchronous rectification. The present disclosure discloses a technology for solving the above-mentioned problems, and aims to provide a control device for a rotating electric machine that can appropriately determine the off timing of switching elements and improve the efficiency of synchronous rectification. [Means for solving the problem]

[0005] The control device for a rotating electric machine disclosed herein controls a rotating electric machine having an x-phase (x is an integer of 3 or more) armature winding, and when AC power is supplied from the rotating electric machine, converts this AC power into DC power by synchronous rectification. The control device for a rotating electric machine includes a power conversion unit connected between the armature winding and a DC power source and having a series connection of high-potential side switching elements and low-potential side switching elements corresponding to each phase of the armature winding, and a plurality of diodes connected in anti-parallel to each switching element; a synchronous rectification enable signal generation unit that detects the conduction state of each diode or the armature current corresponding to each switching element and generates a synchronous rectification enable signal corresponding to each switching element based on the conduction state or the armature current; and an on / off control unit that switches on and off each switching element. and an on / off signal generation unit that generates an on / off signal, the on / off signal generation unit determines the off timing of each switching element based on the time when the off reference signal switches from off to on, and 2x synchronous rectification enable signals are periodically turned on in sequence while the rotating electric machine rotates a certain amount, and the switching elements corresponding to the synchronous rectification enable signals that are turned on in sequence are defined as switching elements Sw(0), Sw(1), Sw(2), ... Sw(2x-1), where i is an integer between 0 and (2x-1) inclusive, and for a positive integer j, switching element Sw(-j) represents switching element Sw(2x-j) in the previous cycle, and the on / off signal generation unit sets the off reference signal of switching element Sw(i) to the synchronous rectification enable signal corresponding to switching element Sw(i-1).

[0006] Another control device for a rotating electric machine disclosed herein controls a rotating electric machine having an armature winding of x phases (x is an integer of 3 or more), and when AC power is supplied from the rotating electric machine, converts the AC power into DC power by synchronous rectification. The control device for a rotating electric machine includes: a power conversion unit connected between the armature winding and a DC power source, and having a series connection of high-potential side switching elements and low-potential side switching elements corresponding to each phase of the armature winding, and a plurality of diodes connected in anti-parallel to each switching element; a synchronous rectification enable signal generation unit that detects the conduction state of each diode or the armature current corresponding to each switching element and generates a synchronous rectification enable signal corresponding to each switching element based on the conduction state or the armature current; a synchronous rectification enable time calculation unit that calculates a synchronous rectification enable time which is the length of an on-time of the synchronous rectification enable signal; and an on-off signal generation unit that generates on-off signals that switch each switching element on and off. The on / off signal generation unit acquires the latest value of the synchronous rectification permission time, which is the latest synchronous rectification permission time at the time of generation of the on / off signal, determines the off-timing of each switching element based on the latest value of the synchronous rectification permission time, and updates the off-timing of each switching element based on the time when the off-reference signal switches from on to off. 2x synchronous rectification permission signals are periodically turned on in sequence while the rotating electric machine rotates a certain amount, and the switching elements corresponding to the synchronous rectification permission signals that are turned on in sequence are designated as switching elements Sw(0), Sw(1), Sw(2), ... Sw(2x-1), where i is an integer greater than or equal to 0 and less than or equal to (2x-1), and for a positive integer j, switching element Sw(-j) represents switching element Sw(2x-j) in the previous cycle. The on / off signal generation unit sets the off-reference signal of switching element Sw(i) to the synchronous rectification permission signal corresponding to switching element Sw(i-1). [Effects of the Invention]

[0007] According to the control device for a rotating electric machine of the present disclosure, it is possible to appropriately determine the off timing of the switching elements, thereby improving the efficiency of synchronous rectification. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram showing a control device for a rotating electric machine according to a first embodiment. [Figure 2] FIG. 3 is a diagram showing voltage vectors according to the first embodiment. [Figure 3] 1 is a schematic configuration diagram showing a converter according to a first embodiment. [Figure 4] 1 is a schematic configuration diagram showing a first inverter according to a first embodiment. [Figure 5] 4 is a diagram showing an example of a current path when all switching elements of the first inverter according to the first embodiment are turned off. FIG. [Figure 6] FIG. 2 is a schematic configuration diagram showing a second inverter according to the first embodiment. [Figure 7] FIG. 2 is a schematic block diagram showing a control unit according to the first embodiment. [Figure 8] 5 is a diagram illustrating a method for generating a field switching signal according to the first embodiment. FIG. [Figure 9] 3 is a block diagram showing an on / off signal generating unit according to the first embodiment. FIG. [Figure 10] 3A and 3B are diagrams illustrating a method for generating an on / off signal according to the first embodiment. [Figure 11] 5 is a diagram showing the relationship between the rotation speed and the on-margin time of the rotary electric machine according to the first embodiment. FIG. [Figure 12] 5 is a diagram showing the relationship between the rotation speed and the off-margin time of the rotary electric machine according to the first embodiment. FIG. [Figure 13] 11 is a diagram showing the correspondence between time and the phase of the electrical angle in the example shown in FIG. 10. FIG. [Figure 14] FIG. 10 is a diagram showing a comparison between the difference between the actual value and the expected value of the synchronous rectification permission time according to the first embodiment, and the difference in each comparative example and the difference in the first embodiment. [Figure 15] 5 is a diagram showing a synchronous rectification enable signal of each switching element according to the first embodiment. FIG. [Figure 16]10 is a diagram showing an example of timings for determining the on counters and off counters of the switching elements according to the first embodiment, and is a diagram showing an example of timings for determining the on counters and off counters of the switching elements when the rotating electric machine rotates in the forward direction. FIG. [Figure 17] 10 is a diagram showing an example of the timing for determining the on counters and off counters of the switching elements according to the first embodiment, and is a diagram showing an example of the timing for determining the on counters and off counters of the switching elements when the rotating electric machine rotates in the reverse direction. FIG. [Figure 18] FIG. 10 is a diagram showing the timings for determining the on counter and off counter of synchronous rectification in the first embodiment, and is a diagram showing the relationship between the switching elements arranged in order of the on timing of the corresponding synchronous rectification enable signals and the timings for determining the on counter and off counter of each switching element. [Figure 19] 5 is a diagram showing the relationship between the rotation speed of the rotary electric machine according to the first embodiment and an offset value p that determines a synchronous rectification permission signal used to determine the off timing of synchronous rectification. FIG. [Figure 20] 1 is a schematic configuration diagram showing an example in which the rotating electric machine according to the first embodiment is used as a vehicle generator motor. [Figure 21] 3 is a diagram illustrating an example of a hardware configuration of a control unit according to the first embodiment. FIG. [Figure 22] FIG. 10 is a schematic configuration diagram showing a control device for a rotating electric machine according to a second embodiment. [Figure 23] FIG. 10 is a schematic block diagram showing a control unit according to a second embodiment. [Figure 24] FIG. 10 is a diagram showing a synchronous rectification enable signal of each switching element according to the second embodiment. [Figure 25] FIG. 10 is a block diagram showing an on / off signal generating unit according to a second embodiment. [Figure 26] 10 is a diagram illustrating a method for generating an on / off signal according to the second embodiment. FIG. [Figure 27] 10 is a diagram illustrating timings for determining an on counter and an off counter of synchronous rectification and timings for updating the off counter according to the second embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiment 1 A first embodiment will be described below with reference to FIGS. 1 to 21. In each drawing, the same or corresponding members and parts are denoted by the same reference numerals. FIG. 1 is a schematic diagram showing a control device for a rotating electric machine according to the first embodiment. The control device 100, i.e., the control device for a rotating electric machine, controls a dual three-phase rotating electric machine 1. The control device 100 includes a converter 3, a first inverter 4A, and a second inverter 4B connected in parallel between a DC power supply 2 and the rotating electric machine 1, and a control unit 5 that controls the converter 3, the first inverter 4A, and the second inverter 4B. As will be described in detail later, the control unit 5 receives a control command C from a higher-level control device (not shown) and acquires data related to the DC voltage Vdc from the DC power supply 2. Based on this, the control unit 5 generates field switching signals Qlp, Qrp, Qln, and Qrn and outputs them to the converter 3. The control unit 5 also receives synchronous rectification enable signals Swp11, Swp12, Swp13, Swn11, Swn12, and Swn13 from the synchronous rectification enable signal generation unit of the first inverter 4A, acquires data related to the rotation speed ω from the rotating electric machine 1, and generates on / off signals Qp11, Qp12, Qp13, Qn11, Qn12, and Qn13 from these signals and outputs them to the first inverter 4A. Similarly, the control unit 5 receives synchronous rectification enable signals Swp21, Swp22, Swp23, Swn21, Swn22, and Swn23 from the synchronous rectification enable signal generation unit of the second inverter 4B, and generates on / off signals Qp21, Qp22, Qp23, Qn21, Qn22, and Qn23 from these signals and the data related to the rotation speed ω and outputs them to the second inverter 4B. Although the first embodiment controls a dual three-phase rotating electric machine, the invention is not limited to this and any rotating electric machine with three or more phases may be controlled.

[0010] The rotating electric machine 1 has two sets of armature windings: first three-phase armature windings L11, L12, and L13, each having one end connected to a neutral point; and second three-phase armature windings L21, L22, and L23, each having one end connected to a neutral point; and a field winding Lf. The first three-phase armature windings L11-L13 and the second three-phase armature windings L21-L23 are housed in a stator (not shown) of the rotating electric machine 1 without being electrically connected to each other and insulated from each other. Hereinafter, the i-th set of j-phase three-phase armature windings may be referred to as the three-phase armature winding Lij. The voltage vectors of the first three-phase armature windings L11-L1 and the second three-phase armature windings L21-L23 are set as shown in FIG. 2. In FIG. 2, the voltage vector of the ith group's jth-phase three-phase armature winding Lij is indicated as L(i, j). For example, the voltage vector of the first three-phase armature winding L11 is L(1, 1), and the voltage vector of the second three-phase armature winding L23 is L(2, 3), and so on. As can be seen from FIG. 2, the first three-phase armature windings L11-L13, which are the first group of three-phase armature windings, and the second three-phase armature windings L21-L23, which are the second group of three-phase armature windings, differ in phase by π / 6 electrical angle, and the phase of the second three-phase armature windings L21-L23 lags behind the phase of the first three-phase armature windings L11-L13 by π / 6. The phase difference between the armature windings will be described in detail later.

[0011] In the first embodiment, the rotating electric machine 1 is a field winding type rotating electric machine in which an induced voltage is controlled by a field current if (not shown) flowing through a field winding Lf. However, a permanent magnet type rotating electric machine may also be used as the rotating electric machine 1. In this case, the field winding Lf can be omitted, and a permanent magnet for the field can be provided in the rotor (not shown) of the rotating electric machine 1.

[0012] The DC power supply 2 outputs a preset DC voltage Vdc to the converter 3, the first inverter 4A, and the second inverter 4B. As described above, data on the DC voltage Vdc to be output to the converter 3 and the like (this data is also written as Vdc in FIG. 1 and the like) is output to the control unit 5. The DC power supply 2 is not particularly limited as long as it outputs a DC voltage, and may be a battery, a DC-DC converter, a diode rectifier, a PWM (Pulse Width Modulation) rectifier, or the like.

[0013] FIG. 3 is a schematic diagram showing a converter according to the first embodiment, illustrating only the configuration necessary for explaining the converter 3. The converter 3 is connected between the DC power supply 2 and the field winding Lf and converts the DC voltage Vdc supplied from the DC power supply 2. The converter 3 applies the converted DC voltage Vdc to the field winding Lf, causing a field current if to flow through the field winding Lf. The converter 3 includes high-side switching elements Slp and Srp connected to a high-side line connected to the high-side of the DC power supply 2, and low-side switching elements Sln and Srn connected to a low-side line connected to the low-side of the DC power supply 2. The high-side switching elements Slp and Srp and the low-side switching elements Sln and Srn are connected in series to form two switching legs, i.e., a series-connected body. The junction between the high-side switching element Slp and the low-side switching element Sln that constitute one switching leg is connected to one end of the field winding Lf, and the junction between the high-side switching element Srp and the low-side switching element Srn that constitute the other switching leg is connected to the other end of the field winding Lf. In addition, a diode is connected in anti-parallel to each of the switching elements of the converter 3.

[0014] The switching elements Slp, Sln, Srp, and Srn of the converter 3 are turned on and off by field switching signals Qlp, Qln, Qrp, and Qrn input from the control unit 5, and the converter 3 converts the DC voltage Vdc into a desired voltage based on the field switching signals Qlp, Qln, Qrp, and Qrn and applies the desired voltage to the field winding Lf. This causes a field current if of a desired magnitude and direction to flow through the field winding Lf, generating a desired induced voltage. As described above, the field winding Lf can be omitted when a permanent magnet type rotating electric machine is used as the rotating electric machine 1. When the field winding Lf is omitted, the converter 3 can also be omitted.

[0015] The switching elements Slp, Sln, Srp, and Srn can be semiconductor switching elements such as IGBTs (Insulated Gate Bipolar Transistors), bipolar transistors, and MOS (Metal Oxide Semiconductor) power transistors. If there is no need to change the direction of the field current if flowing through the field winding Lf, the switching element Srp may be kept off, or the switching element Srp may be omitted and configured as a diode only. The same applies to the switching element Sln; it may be kept off or configured as a diode only. However, because a semiconductor switching element has a lower resistance in the on state than a diode, a configuration combining a switching element and a diode, as shown in Figure 3, can suppress heat generation.

[0016] Each of the field switching signals Qlp, Qln, Qrp, and Qrn turns on the corresponding switching element if its value is 1, and turns off the corresponding switching element if its value is 0 (zero). The generation of the field switching signals Qlp, Qln, Qrp, and Qrn will be described later.

[0017] 4 is a schematic configuration diagram showing a first inverter according to embodiment 1, illustrating only the configuration necessary for explaining the first inverter 4A. The first inverter 4A is an inverter corresponding to the first three-phase armature windings L11, L12, and L13, which are a first set of armature windings, and includes a full-bridge circuit unit 41A, i.e., a power conversion unit, connected between the DC power supply 2 and the first three-phase armature windings L11, L12, and L13, and a synchronous rectification enable signal generation unit 42A that generates synchronous rectification enable signals Swp11, Swp12, Swp13, Swn11, Swn12, and Swn13 from forward voltages Vdf of diodes (described later) connected in anti-parallel to the switching elements of the full-bridge circuit unit 41A, and outputs the generated synchronous rectification enable signals to the control unit 5.

[0018] The full-bridge circuit unit 41A includes high-side switching elements Sp11, Sp12, and Sp13 connected to a high-side line connected to the high-side of the DC power supply 2, and low-side switching elements Sn11, Sn12, and Sn13 connected to a low-side line connected to the low-side of the DC power supply 2. The high-side switching elements Sp11, Sp12, and Sp13 and the low-side switching elements Sn11, Sn12, and Sn13 are connected in series to form three switching legs, i.e., a series-connected body. Diodes Dp11 to Dp13 and Dn11 to Dn13, which serve as parasitic diodes, are connected in antiparallel to the switching elements Sp11 to Sp13 and Sn11 to Sn13, respectively. The connection point between the high-side switching element Sp11 and the low-side switching element Sn11 is connected to the other end (the terminal opposite the neutral point) of the first three-phase armature winding L11. Similarly, the connection points between the high-potential side switching elements Sp12, Sp13 and the low-potential side switching elements Sn12, Sn13 are connected to the other ends of the first three-phase armature windings L12, L13, respectively.

[0019] As the switching elements Sp11 to Sp13 and Sn11 to Sn13, similar to the switching elements Slp, Sln, Srp, and Srn of the converter 3, semiconductor switching elements such as IGBTs, bipolar transistors, and MOS power transistors can be used.

[0020] The three switching legs are connected in parallel, and power conversion is performed between the DC power supply 2 and the first three-phase armature windings L11, L12, and L13 by controlling the on / off of each switching element constituting the three switching legs. More specifically, when the rotating electric machine 1 is operated as a motor, the DC voltage Vdc supplied from the DC power supply 2 is converted into a three-phase AC voltage and supplied to the first three-phase armature windings L11, L12, and L13. When the rotating electric machine 1 is operated as a generator, the AC power supplied from the first three-phase armature windings L11, L12, and L13 is converted into DC power by synchronous rectification. That is, when AC power is supplied from the rotating electric machine 1, the full-bridge circuit unit 41A, and therefore the first inverter 4A, converts the AC power into DC power by synchronous rectification. The three switching legs are series connections of high-potential side switching elements and low-potential side switching elements corresponding to the respective phases of the first three-phase armature windings L11, L12, L13.

[0021] The switching elements of the full-bridge circuit section 41A, i.e., the high-side switching elements Sp11-Sp13 and the low-side switching elements Sn11-Sn13, are turned on and off based on on-off signals Qp11-Qp13 and on-off signals Qn11-Qn13, respectively. When the on-off signals Qp11-Qp13 and on-off signals Qn11-Qn13 have a value of 1, they turn on the corresponding switching element, and when the value is 0 (zero), they turn off the corresponding switching element. The generation of the on-off signals Qp11-Qp13 and on-off signals Qn11-Qn13 will be described later.

[0022] The synchronous rectification enable signal generation unit 42A detects the conduction states of the diodes Dp11-Dp13 and Dn11-Dn13, and generates synchronous rectification enable signals Swp11-Swp13 and Swn11-Swn13 corresponding to the switching elements Sp11-Sp13 and Sn11-Sn13, respectively, based on the conduction states of the diodes Dp11-Dp13 and Dn11-Dn13. The synchronous rectification enable signal generation unit 42A detects the conduction states of the diodes Dp11-Dp13 and Dn11-Dn13 based on their respective forward voltages. In FIG. 4, the forward voltages of the diodes Dp11-Dp13 and Dn11-Dn13 are collectively referred to as forward voltage Vdf.

[0023] 5, when all of the switching elements Sp11-Sp13 and Sn11-Sn13 are in the off state and current flows as indicated by the arrows in the figure, current flows through the diodes Dp11, Dn12, and Dn13, which are parasitic diodes of the high-side switching element Sp11 and the low-side switching elements Sn12 and Sn13, and the conduction state of these diodes is detected. On the other hand, the conduction state of the other diodes Dn11, Dp12, and Dp13 is not detected. In this case, the synchronous rectification enable signal generator 42A can permit synchronous rectification for the switching elements Sp11, Sn12, and Sn13, and determines that the switching elements Sp11, Sn12, and Sn13 may be turned on, thereby turning on the corresponding synchronous rectification enable signals Swp11, Swn12, and Swn13. On the other hand, for the other switching elements Sn11, Sp12, and Sp13, synchronous rectification cannot be permitted, and the corresponding synchronous rectification enable signals Swn11, Swp12, and Swp13 are turned off. Although not shown, a known technique may be used as a voltage detection means for detecting the forward voltage Vdf.

[0024] Each synchronous rectification enable signal may be a positive logic signal where on is 1 and off is 0, or a negative logic signal where on is 0 and off is 1. Here, however, a positive logic signal is used. Also, although each synchronous rectification enable signal is generated based on the conduction state of the corresponding diode, the synchronous rectification enable signal may be generated by detecting the armature current corresponding to each switching element and based on the amount of current flowing through it.

[0025] 6 is a schematic diagram showing the second inverter according to the first embodiment, illustrating only the configuration necessary for explaining the second inverter 4B. The second inverter 4B is an inverter corresponding to the second three-phase armature windings L21, L22, and L23, which are the second set of armature windings, but is similar in detail to the first inverter 4A. Specifically, the second inverter 4B includes a full-bridge circuit unit 41B and a synchronous rectification enable signal generating unit 42B. The full-bridge circuit unit 41B configures three switching legs, each of which includes high-side switching elements Sp21, Sp22, and Sp23 and low-side switching elements Sn21, Sn22, and Sn23 connected in series. The switching elements Sp21-Sp23 and Sn21-Sn23 are turned on and off based on on-off signals Qp21-Qp23 and on-off signals Qn21-Qn23. Diodes Dp21-Dp23 and Dn21-Dn23 are connected in anti-parallel to the switching elements Sp21-Sp23 and Sn21-Sn23, respectively, as parasitic diodes. A synchronous rectification enable signal generator 42B generates synchronous rectification enable signals Swp21-Swp23 and Swn21-Swn23 based on the conduction states of the diodes Dp21-Dp23 and Dn21-Dn23. The conduction states of each diode are detected based on its forward voltage Vdf.

[0026] 7 is a schematic block diagram showing a control unit according to embodiment 1. As described above, the control unit 5 controls the on / off of each switching element of the converter 3, the first inverter 4A, and the second inverter 4B, and includes a field voltage command calculation unit 51, a field switching signal generation unit 52, a synchronous rectification permission signal reception unit 53, and an on / off signal generation unit 54.

[0027] The field voltage command calculation unit 51 calculates a field voltage command Vf for controlling the field current if flowing through the field winding Lf based on the control command C and the DC voltage Vdc. In the control unit 5 of the first embodiment, it is assumed that the field voltage command Vf is calculated by feedforward control, but feedback control may also be used. When feedback control is used, a current detector (not shown) is provided in the circuit of the converter 3 or between the converter 3 and the field winding Lf, and the current detected by this current detector is fed back to calculate the field voltage command Vf by a known method. The field voltage command Vf is, for example, a signal that takes a constant value between Vdc and −Vdc for each carrier cycle. The field voltage command calculation unit 51 outputs the calculated field voltage command Vf to the field switching signal generation unit 52.

[0028] The field switching signal generation unit 52 generates field switching signals Qlp, Qln, Qrp, and Qrn based on the field voltage command Vf and outputs them to the converter 3. FIG. 8 is a diagram illustrating a method for generating a field switching signal according to the first embodiment. In FIG. 8, the carrier signal Cf is a triangular wave with a period Tf (carrier period, tf1 to tf5), reaches a maximum value Vdc at times tf1 and tf5, and reaches a minimum value -Vdc at time tf3, which is midway between times tf1 and tf5. The field switching signal generation unit 52 compares the carrier signal Cf with the field voltage command Vf, and outputs "Qlp=1 and Qln=0" and "Qrp=0 and Qrn=1" when the field voltage command Vf is greater than the carrier signal Cf (tf2 to tf4). When the field voltage command Vf is smaller than the carrier signal Cf (tf1 to tf2, tf4 to tf5), "Qlp=0 and Qln=1" and "Qrp=1 and Qrn=0" are output. Note that to reduce the number of switching elements, "Qrp=0 and Qrn=1" may be always set.

[0029] As described above, when a permanent magnet type rotating electric machine is used as the rotating electric machine 1, the field winding Lf and the converter 3 can be omitted, and therefore the field voltage command calculation unit 51 and the field switching signal generation unit 52 can also be omitted.

[0030] The synchronous rectification enable signal receiving unit 53 receives the synchronous rectification enable signals Swp11 to Swp13, Swn11 to Swn13 and the synchronous rectification enable signals Swp21 to Swp23, Swn21 to Swn23 from the synchronous rectification enable signal generating unit 42A and the synchronous rectification enable signal generating unit 42B, respectively, and sequentially outputs the received synchronous rectification enable signals as synchronous rectification enable signals SwX to the ON / OFF signal generating unit 54. At this time, the synchronous rectification enable signal receiving unit 53 outputs the synchronous rectification enable signals SwX so that the order in which the synchronous rectification enable signals rose (switched from OFF to ON) can be determined. For example, it is conceivable to output the synchronous rectification enable signals in the order in which the rising edge was detected first. As a result, the synchronous rectification enable signal receiving unit 53 sequentially outputs the synchronous rectification enable signals SwX arranged in the order of their ON timing to the ON / OFF signal generating unit 54.

[0031] Here, each synchronous rectification enable signal has a corresponding switching element, for example, synchronous rectification enable signal Swp11 has switching element Sp11. In an inverter (first inverter 4A and second inverter 4B) that controls a dual three-phase rotating electric machine such as the rotating electric machine 1, each group has a high-potential side switching element and a low-potential side switching element for each phase, resulting in a total of 12 (= 2 × 3 × 2) switching elements and their corresponding synchronous rectification enable signals. If the switching elements for which synchronous rectification is sequentially enabled (the corresponding synchronous rectification enable signals rise sequentially) while the rotating electric machine 1 rotates a certain amount are designated as switching elements Sw(0), Sw(1), Sw(2), ... Sw(11), then the synchronous rectification enable signal SwX becomes the synchronous rectification enable signal corresponding to the switching elements Sw(0), Sw(1), ... Sw(11). Generalizing this, if we consider a case where a rotating electric machine having x-phase armature windings is controlled using an inverter having high-potential side switching elements and low-potential side switching elements for each phase, the synchronous rectification enable signal SwX will be a synchronous rectification enable signal corresponding to switching elements Sw(0), Sw(1), Sw(2), ... Sw(2x-1). Note that the rotating electric machine 1 of the first embodiment is a dual three-phase, and therefore this is an example where x = 6 (2 × 3).

[0032] 9 is a block diagram showing an on / off signal generation unit according to embodiment 1. The on / off signal generation unit 54 receives the synchronous rectification enable signal SwX and the rotation speed ω as input, and generates on / off signals Qp11-Qp13, Qn11-Qn13, Qp21-Qp23, and Qp21-Qp23 for the respective switching elements based on these signals. The on / off signal generation unit 54 includes an off reference signal acquisition unit 541 that receives the synchronous rectification enable signal SwX and acquires from the synchronous rectification enable signal SwX an off reference signal Swoff used to determine the off timing of synchronous rectification; an on counter determination unit 542 that receives the synchronous rectification enable signal SwX and the rotation speed ω and determines an on counter that determines the timing at which each on / off signal switches from off to on (on timing) based on the synchronous rectification enable signal SwX and the rotation speed ω; an off counter determination unit 543 that receives the off reference signal Swoff and the rotation speed ω and determines an off counter that determines the timing at which each on / off signal switches from on to off (off timing) based on the off reference signal Swoff and the rotation speed ω; and a signal generation unit 544 that generates each on / off signal by setting the on timing and off timing of each switching element based on each on counter and each off counter.

[0033] "On counters" correspond to the respective on / off signals, and as shown in the figure, there are on counters Con_p11 to Con_p13, Con_n11 to Con_n13, Con_p21 to Con_p23, and Con_n21 to Con_n23. The same is true for "off counters," and there are off counters Coff_p11 to Coff_p13, Coff_n11 to Coff_n13, Coff_p21 to Coff_p23, and Coff_n21 to Coff_n23.

[0034] FIG. 10 is a diagram illustrating a method for generating an on / off signal according to the first embodiment. While FIG. 10 illustrates an example in which the on / off signal Qp21 is generated, the same applies to other on / off signals. In an initial state, the synchronous rectification enable signals Swp11 and Swp21, the on counter Con_p21, the off counter Coff_p21, and the on / off signal Qp21 are all off or zero. First, at time tc1, the synchronous rectification enable signal Swp11 switches from off to on. Next, at time tc2, the synchronous rectification enable signal Swp21 switches from off to on. When the synchronous rectification enable signal Swp21 switches on, the on / off signal generator 54 of the controller 5 performs start trigger processing. Here, the "start trigger processing" refers to processing that starts generating an on / off signal. Hereinafter, the start trigger processing that determines the on timing of the on / off signal Qp21 may be referred to as the "start trigger processing of the on / off signal Qp21."

[0035] In the start trigger process, the off-reference signal acquisition unit 541 acquires the off-reference signal Swoff from the synchronous rectification enable signal SwX. In the example shown in Fig. 10, when generating the on / off signal Qp21 of the switching element Sp21, the synchronous rectification enable signal Swp11 is used as the off-reference signal Swoff. A method for determining the off-reference signal Swoff will be described later in detail.

[0036] The ON counter determination unit 542 determines the ON counter Con_p21. The ON counter Con_p21 is determined so that the ON timing of the ON / OFF signal Qp21 is delayed from time tc2 by an ON margin time determined based on the rotation speed ω. After time tc2, the signal generation unit 544 decrements (reduces) the ON counter Con_p21 as time passes. The signal generation unit 544 switches the ON / OFF signal Qp21 from OFF to ON at the timing (time tc3) when the ON counter Con_p21 becomes zero. In this case, the ON margin time is (time tc3 - time tc2).

[0037] That is, the on / off signal generation unit 54 starts generating an on / off signal Qp21 for the switching element Sp21 at the timing (time tc2) when the synchronous rectification enable signal Swp21 corresponding to the switching element to be controlled (the switching element for which the on / off signal is generated, the switching element Sp21 in the example of FIG. 10) switches from off to on, thereby determining the on-timing of the switching element Sp21. The on / off signal generation unit 54 also determines the on-timing of the switching element Sp21 based on the time (time tc2) when the synchronous rectification enable signal Swp21 corresponding to the switching element Sp21 switches from off to on. The on / off signal generation unit 54 also determines an on-margin time based on the rotational speed ω of the rotating electric machine, and determines the on-timing of the switching element Sp21 based on the time that is the on-margin time after the time (time tc2) when the synchronous rectification enable signal Swp21 switches from off to on.

[0038] At time tc4, the synchronous rectification enable signal Swp11 switches from on to off. When the synchronous rectification enable signal Swp11 switches to off, the on / off signal generation unit 54 of the control unit 5 performs end trigger processing. Here, the "end trigger processing" is processing that determines the off timing of the on / off signal Qp21, and hereinafter, the end trigger processing that determines the off timing of the on / off signal Qp21 may be referred to as the "end trigger processing of the on / off signal Qp21."

[0039] In the end trigger process, the off counter determination unit 543 determines the off counter Coff_p21. The off counter determination unit 543 calculates the time required for the phase to change by π / 6 (the phase difference between the pairs) minus an off margin time determined based on the rotation speed ω, and determines the off counter Coff_p21 so that the off timing of the on / off signal Qp21 is delayed from time tc4 by this time. After time tc4, the signal generation unit 544 decrements (decreases) the off counter Coff_p21 as time passes. The signal generation unit 544 switches the on / off signal Qp21 from on to off at the timing (time tc5) when the off counter Coff_p21 becomes zero. Thereafter, at time tc6, the synchronous rectification enable signal Swp21 switches from on to off. In this case, the off margin time is (time tc5 - time tc4).

[0040] That is, the on / off signal generation unit 54 determines the off-timing of the switching element Sp21 at the timing (time tc4) when the synchronous rectification enable signal Swp11, which is the off-reference signal Swoff of the switching element Sp21, switches from on to off. The on / off signal generation unit 54 also determines the off-timing of the switching element Sp21 based on the time (time tc4) when the synchronous rectification enable signal Swp11, which is the off-reference signal Swoff of the switching element Sp21, switches from off to on. The on / off signal generation unit 54 also determines the off-margin time based on the rotational speed ω of the rotating electric machine 1, and determines the off-timing of the switching element Sp21 based on a time that is later than the time (time tc4) when the synchronous rectification enable signal Swp11 switches from off to on by a time determined based on the off-margin time.

[0041] In the example shown in Fig. 10, the above-mentioned "on margin time" corresponds to (time t3 - time t2). Furthermore, the phase difference between the synchronous rectification enable signal Swp11 and the synchronous rectification enable signal Swp21 is π / 6, and the off counter Coff_p21 is determined to reach zero at a time (time tc5) that is delayed from time tc4 by the time required for the phase to change by π / 6 (time tc6 - time tc4) minus the off margin time. Therefore, the "off margin time" is (time tc6 - time tc5). The on margin time and the off margin time may be set to be monotonically decreasing functions of the rotation speed ω, as shown in Figs. 11 and 12, respectively. 11 and 12, the slope is large in the low rotation speed region, and the on margin time and off margin time are set to change more rapidly as the rotation speed ω decreases, but the slope in the low rotation speed region may be made gentler so that the on margin time and off margin time in the low rotation speed region are shorter than in the example shown in Figures 11 and 12. By setting the on margin time and off margin time based on the rotation speed ω from the relationship between the on margin time and off margin time and the rotation speed as shown in Figures 11 and 12, the on margin time and off margin time can be optimized.

[0042] Although the off-margin time is calculated based on the rotation speed ω here, a configuration for acquiring the on-time of the synchronous rectification enable signal may be added to the control unit 5, and the off-margin time may be calculated by multiplying this on-time by a predetermined coefficient that is greater than zero and less than 1. In this case, the control unit 5 does not need to acquire the rotation speed ω to generate the on-off signal.

[0043] In the first embodiment, as described in FIG. 10 , start trigger processing is performed at the on timing of a synchronous rectification enable signal (Swp21) corresponding to a switching element (e.g., Sp21) that generates an on / off signal, and generation of an on / off signal (Qp21) is started. Conventionally, on / off signals have sometimes been generated periodically. However, considering the relationship between the synchronous rectification enable signal and the on / off signal, generating the on / off signal when the synchronous rectification enable signal switches on and off can reduce delays associated with the generation of the on / off signal, rather than generating the on / off signal through periodic processing. In this case, the margin time (on margin time and off margin time) for the synchronous rectification enable signal can be reduced, enabling more efficient synchronous rectification.

[0044] Furthermore, in the first embodiment, the end trigger process is performed at the off timing (time tc4 in FIG. 10 ) of the synchronous rectification enable signal, which is an off reference signal, to determine the off timing of the switching element. When rotational acceleration occurs, the rotation speed ω changes over time, which can result in a discrepancy between the expected synchronous rectification enable time and the actual synchronous rectification enable time. Here, the synchronous rectification enable time is the on time of the synchronous rectification enable signal, and the phase of the electrical angle that advances during the synchronous rectification enable time is the synchronous rectification enable phase θena. If the expected synchronous rectification enable time differs from the actual time, the off timing of the synchronous rectification enable signal also deviates from the expected timing. Therefore, even if an optimal off counter is determined based on past information, the off margin time may not be optimal due to subsequent changes in the rotation speed ω. This will be explained below by comparing the first embodiment with a conventional technique (comparison example). First, in the example of FIG. 10 , the phase at time tc2 will be used as a reference. In this case, the relationship between each time and phase in FIG. 10 is as shown in FIG. 13 . 13, θon is the phase that advances during the on-margin time, and θoff is the phase that advances during the off-margin time. In reality, the synchronous rectification permission phase θena may change, but here it is assumed that the synchronous rectification permission phase θena is constant (θena for both the synchronous rectification permission signal Swp11 and the synchronous rectification permission signal Swp21).

[0045] In general, if the rotational speed at a reference time (where the phase of the electrical angle at this time is considered to be zero [rad]) is N0 [rad / s], the phase θ of the electrical angle at time T (the time elapsed from the reference time) and the rotational speed are Nt [rad / s], the rotational acceleration from the reference time to time T is a [rad / s / s], and the number of pole pairs of the rotating electric machine 1 is Pm, then the following equation (1) holds, and equation (2) can be derived from equation (1).

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[0046] Here, if C is placed as a function of the rotation speed N0 and the phase θ as in equation (3), Nt and T in equation (2) become as shown in equations (4) and (5).

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[0047] If the time tc2, which is the ON timing of the synchronous rectification enable signal Swp21, is used as a reference and the rotation speed at this time is Ntc2 [rad / s], the rotation speed Ntc6 [rad / s] and the synchronous rectification enable time Tena [s] at the time tc6, which is the OFF timing of the synchronous rectification enable signal Swp21, are respectively expressed by equations (6) and (7). Furthermore, equations (6) and (7) can be transformed into the form of equation (2) to obtain equation (8). Tena in equations (7) and (8) is the synchronous rectification enable time of the synchronous rectification enable signal Swp21.

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[0048] When using the previous synchronous rectification permission time of the switching element as in Patent Document 1, information from one electrical angle period before is used. This is the same as calculating the time required for the electrical angle phase to change from -2π to (θena-2π) with time tc2 as the reference time. If the rotation speed when the electrical angle phase is -2π is Ntc2_old and the time required for the electrical angle phase to change from -2π to (θena-2π) is Tena_old, Tena_old is expressed as shown in equations (9) and (10). Furthermore, rearranging equations (9) and (10) into the form of equation (2) results in equation (11).

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[0049] Therefore, the difference ΔT1 between Tena and Tena_old is as shown in equation (12).

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[0050] Therefore, when the rotation speed ω changes with the rotation acceleration a, even if the off timing of synchronous rectification is determined using the previous synchronous rectification permitted time of the switching element in question, the estimated synchronous rectification permitted time Tena_old will have a difference of ΔT1 from the synchronous rectification permitted time Tena. If Tena_old is smaller than Tena, the estimated time will be shorter by -ΔT1. ΔT1 represents the difference between the actual synchronous rectification permitted time and the synchronous rectification permitted time one cycle ago, when the synchronous rectification permitted time of the previous cycle is taken as the estimated value of the current synchronous rectification permitted time.

[0051] Furthermore, when using the synchronous rectification permitted time of the switching element on the arm opposite to the switching element itself, i.e., if the switching element itself is on the high potential side (low potential side), and the arm on the low potential side (high potential side) is used, information from half an electrical cycle ago is used. If the assumed synchronous rectification permitted time in this case is synchronous rectification permitted time Tena_old2, the synchronous rectification permitted time Tena_old2 and the difference ΔT2 between this and the synchronous rectification permitted time Tena are as shown in equations (13) and (14). ΔT2 refers to the difference between the actual synchronous rectification permitted time and the assumed value of the current synchronous rectification permitted time when the synchronous rectification permitted time half a cycle ago is used.

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[0052] In the first embodiment, the off counter Coff_p21 is determined at time tc4. When time tc2 is used as a reference, the phase corresponding to time tc4 is (θena-π / 6), and therefore the rotation speed Ntc4 at time tc4 is as shown in equation (15).

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[0053] Here, if we use time tc4 as the reference instead of time tc2 and assume that the rotational speed ω of the rotating motor 1 is constant until the off timing (time tc6) of the synchronous rectification enable signal Swp21, the predicted time Ttc46_exp from time tc4 to the off timing of the synchronous rectification enable signal Swp21 is as shown in equation (16).

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[0054] On the other hand, since there is actually a rotational acceleration a, the rotational speed Ntc6 at time tc6 is as shown in equation (17), and the actual time Ttc46_act from time tc4 to time tc6 is as shown in equation (18).

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[0055] Therefore, for the time period from time tc4 to time t6, the difference ΔT3 between the predicted time Ttc46_exp and the actual time Ttc46_act is as shown in equation (19). ΔT3 means the difference between the estimated value for the remaining synchronous rectification allowed time at time tc4, assuming a constant rotation speed, and the actual value.

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[0056] FIG. 14 compares ΔT1, ΔT2, and ΔT3. FIG. 14 compares the difference between the actual and estimated synchronous rectification permitted time values ​​according to the first embodiment, comparing the difference between each comparative example and the difference between the first embodiment. The vertical axis represents time, and the horizontal axis represents rotation speed. As shown in FIG. 14, ΔT2 is smaller than ΔT1, approximately half the magnitude. As described above, both ΔT1 and ΔT2 use the past synchronous rectification permitted time as the estimated value for the current synchronous rectification permitted time. However, the results show that ΔT2, which represents the difference when a more recent synchronous rectification permitted time is used as the estimated value, is smaller. However, because ΔT2 also has a certain magnitude, it can be seen that some difference occurs when the past synchronous rectification permitted time is used as the estimated value. On the other hand, ΔT3 is significantly smaller than ΔT2. This is because ΔT3 is the difference between the estimated value based on current data and the actual value, and the phase change in the time being estimated is small, at π / 6. 14, ΔT1, ΔT2, and ΔT3 monotonically decrease while maintaining their relative magnitude relationships as the rotation speed increases. This corresponds to the fact that when the rotation speed (Ntc2 or Ntc4) is high, the right-hand sides of equations (12), (14), and (19) approach zero.

[0057] Although Ttc46_exp is a predicted value that ignores rotational acceleration, the error from the actual time Ttc46_act is still small. The reason for this is that time tc4 is used as the reference, and the time from the reference to the off-timing of the synchronous rectification enable signal Swp21 is set to be short. In other words, if the synchronous rectification enable phase θena is estimated to be π, a calculation using time tc4 as the reference only needs to consider a time change that is about 1 / 6 of that when using time tc2 as the reference. Since the error caused by the influence of rotational acceleration is thought to be smaller the smaller the time change from the reference, even if the off-timing of the synchronous rectification enable signal Swp21 is estimated using only the rotational speed Ntc4 at the reference point (time tc4), the error from the actual value can be significantly reduced.

[0058] Furthermore, as can be seen by comparing Tena in equation (8) with Ttc46_act in equation (18), when time tc4 is used as the reference, the phase change up to time tc6 is the phase difference (π / 6) between the groups, and calculations can be performed based on this. When time tc2 is used as the reference, each calculation is performed using the synchronous rectification permission phase θena, but the value of the synchronous rectification permission phase θena may also vary depending on the operating state of the rotating electric machine 1. Furthermore, fluctuations in the synchronous rectification permission phase θena cause an error between the calculated synchronous rectification permission time Tena and the actual synchronous rectification permission time Tena. On the other hand, when time tc4 is used as the reference, calculations are performed based on a fixed phase change (phase difference between the groups) as described above, and are therefore not affected by fluctuations in the synchronous rectification permission phase θena.

[0059] For the above reasons, by using a configuration in which the off counter Coff_p21 is determined at time tc4 as in the first embodiment, even if the off timing of the synchronous rectification enable signal Swp21 is estimated based on the rotation speed ω at the reference time point, the error from the actual timing can be reduced. In addition, the occurrence of errors can be further suppressed without being affected by fluctuations in the synchronous rectification enable phase θena. By more accurately estimating the off timing of the synchronous rectification enable signal Swp21, it is also possible to set a small off margin time, and the off timing of the switching element Sp21 can also be more appropriately determined. This makes it possible to improve the efficiency of synchronous rectification.

[0060] Next, a description will be given of which synchronous rectification enable signal is used to determine the off counter, i.e., which synchronous rectification enable signal is used as the off reference signal Swoff. In the example shown in Fig. 10, when determining the off timing of the on / off signal Qp21 of the switching element Sp21, the synchronous rectification enable signal Swp11 of the switching element Sp11 is used as the off reference signal Swoff, and the end trigger process of the on / off signal Qp21 is performed at the off timing of the synchronous rectification enable signal Swp11. However, in reality, the synchronous rectification enable signals of the switching elements of each phase are periodically turned on and off in a fixed order, so how to determine the off reference signal Swoff becomes an issue.

[0061] 15 is a diagram showing the synchronous rectification enable signals of each switching element according to the first embodiment, illustrating changes in each of the synchronous rectification enable signals Swp11 to Swp13, Swp21 to Swp23, Swn11 to Swn13, and Swn21 to Swn23 over approximately one electrical angle cycle. Similar to the voltage vectors shown in FIG. 2, one of the synchronous rectification enable signals rises every time the phase changes by π / 6. Therefore, the on counters and off counters that determine the on timing and off timing of each switching element can be set in accordance with the changes in the synchronous rectification enable signals shown in FIG. 15.

[0062] 16 is a diagram showing an example of the timing for determining the on counter and the off counter of each switching element according to the first embodiment, when the rotating electric machine 1 rotates in the forward direction. For example, the on counter Con_p11 of the switching element Sp11 is determined using the switching of the synchronous rectification enable signal Swp11 from off to on as a trigger. That is, the on counter Con_p11 is determined by the on timing of the synchronous rectification enable signal Swp11. The other on counters are determined similarly by the on timing of the corresponding synchronous rectification enable signal.

[0063] The off counter Coff_p11 of the switching element Sp11 is determined using the switching of the synchronous rectification enable signal Swn22 from on to off as a trigger. That is, the off reference signal Swoff of the on / off signal Qp11 is the synchronous rectification enable signal Swn22, and the off counter Coff_p11 is determined by the off timing of the synchronous rectification enable signal Swn22. In FIG. 15 , the synchronous rectification enable signal Swp11 corresponding to the switching element Sp11 switches from off to on at time ts1, and is the first of the synchronous rectification enable signals to switch from off to on. On the other hand, the synchronous rectification enable signal Swn22 switches from off to on at time ts23, and is the last of the synchronous rectification enable signals to switch from off to on. That is, while the rotating electric machine 1 rotates by an amount corresponding to one electrical angle cycle, 12 synchronous rectification enable signals Swp11-Swp13, Swp21-Swp23, Swn11-Swn13, and Swn21-Swn23 are switched from off to on in this order, and the off-timing of the switching element Sp11 corresponding to the synchronous rectification enable signal Swp11 that turns on first is determined by the off-timing of the synchronous rectification enable signal Swn22 that turns on last. Note that when the time between two on-timings (or off-timings) of a certain synchronous rectification enable signal is considered to be one cycle, the synchronous rectification enable signal Swn22 here is the synchronous rectification enable signal Swn22 of the previous cycle.

[0064] With regard to other off counters (off counters of switching elements whose corresponding synchronous rectification enable signals are turned on second or later), for example, the off counter Coff_p21 of the switching element Sp21 is determined by the off timing of the synchronous rectification enable signal Swp11. In FIG. 15 , the synchronous rectification enable signal Swp21 corresponding to the switching element Sp21 switches from off to on at time ts3. On the other hand, the synchronous rectification enable signal Swp11 switches from off to on at time ts1. Furthermore, no other synchronous rectification enable signals switch from off to on between time ts1 and time ts3. In other words, the off timing of a switching element whose corresponding synchronous rectification enable signal is turned on second or later is determined by the off timing of the synchronous rectification enable signal that is turned on one before the synchronous rectification enable signal corresponding to that switching element.

[0065] An example of the determination timing when the rotating electric machine rotates in the reverse direction is as shown in FIG. 17. In this case, the order in which the synchronous rectification enable signals are turned on is reversed, and it can be seen that the determination timing of the off counter also changes accordingly. For example, the off counter Coff_p11 of the switching element Sp11 is determined by the off timing of the synchronous rectification enable signal Swp21. The determination of the on counter is the same as in the case of the forward direction.

[0066] As can be seen from Figures 16 and 17, the order of the on-timings of the synchronous rectification enable signals matters when determining the off counters. Figure 18 shows the relationship between the on-timings of the switching elements and the timings for determining the on-counters and off-counters. In the example shown in Figure 18, the rotating electric machine has x-phase armature windings. In this case, the inverter that controls the rotating electric machine has high-potential and low-potential side switching elements for each phase, resulting in 2x switching elements. Furthermore, each switching element has a corresponding synchronous rectification enable signal, so the number of synchronous rectification enable signals is also 2x. Let Sw(0), Sw(1), Sw(2), ... Sw(2x-1) be the switching elements in order of the on-timing of the corresponding synchronous rectification enable signals. For i, an integer between 0 and 2x-1, the on-counter for Sw(i) is determined based on the on-timing of the synchronous rectification enable signal corresponding to the switching element Sw(i), and the off-counter for Sw(i) is determined based on the off-timing of the synchronous rectification enable signal corresponding to the switching element Sw(i-1). That is, the off-reference signal Swoff for the switching element Sw(i) is the synchronous rectification enable signal corresponding to the switching element Sw(i-1). Here, for a positive integer j, the switching element Sw(-j) represents the switching element Sw(2x-j) in the previous cycle. Note that x may be any integer greater than or equal to 3.

[0067] That is, in a control device 100 that controls a rotating electric machine 1 having an x-phase (x is an integer greater than or equal to 3) armature winding and converts AC power supplied from the rotating electric machine 1 into DC power by synchronous rectification, an on / off signal generation unit 54 determines the off timing of each switching element based on the time at which the off reference signal switches from off to on, and 2x synchronous rectification enable signals are periodically turned on in sequence while the rotating electric machine 1 rotates a certain amount, and the switching elements corresponding to the synchronous rectification enable signals that are turned on in sequence are defined as Sw(0), Sw(1), Sw(2), ... Sw(2x-1), where i is an integer greater than or equal to 0 and less than or equal to (2x-1), and for a positive integer j, Sw(-j) represents Sw(2x-j) in the previous cycle, and the on / off signal generation unit 54 sets the off reference signal of Sw(i) to the synchronous rectification enable signal corresponding to Sw(i-1).

[0068] Note that, because a dual three-phase armature winding with a phase difference between the windings of π / 6 is assumed here, the on-timings of the synchronous rectification enable signals corresponding to the switching elements Sw(0) to Sw(2x-1) are all different. For this reason, the off-reference signal for switching element Sw(i) can be determined by the synchronous rectification enable signal corresponding to switching element Sw(i-1). However, when there is one armature winding set and an even number of phases, as in the case of a single six-phase configuration, there are combinations where the on-timings of the synchronous rectification enable signals corresponding to the switching elements Sw(0) to Sw(2x-1) overlap. Therefore, when the on-timings of the synchronous rectification enable signals of switching element Sw(i) and switching element Sw(i-1) are different, the off-reference signal of switching element Sw(i) is determined by the synchronous rectification enable signal corresponding to switching element Sw(i-1), and when the on-timings of the synchronous rectification enable signals are the same, the off-reference signal of switching element Sw(i) is determined by the synchronous rectification enable signal corresponding to switching element Sw(i-2).

[0069] As described above, in the first embodiment, the synchronous rectification enable signal whose on-timing precedes the corresponding synchronous rectification enable signal is set as the off-reference signal Swoff, and the off-timing of the switching element to be controlled is determined in the end trigger process performed at the off-timing of the synchronous rectification enable signal, which is the off-reference signal Swoff. This is based on the premise that the time required for the end trigger process is secured between the off-timing of the synchronous rectification enable signal, which is the off-reference signal Swoff, and the off-timing of the synchronous rectification enable signal corresponding to the switching element to be controlled. However, as the rotation speed ω of the rotating electric machine 1 increases, the interval between the off-timings of the synchronous rectification enable signals becomes shorter, which may make it impossible to secure the time required for the end trigger process. For example, in FIG. 10 , if the time from time tc4 to time tc6 becomes too short, the end trigger process of the on-off signal Qp21 performed at time tc4 may not be able to determine the off-timing of the switching element (determine the off counter) in time for time tc6. Furthermore, even if the off timing is determined in time, the determined off timing will already be at the off timing determination time at the earliest, so there is a risk that a sufficient off margin time cannot be secured.

[0070] Therefore, it is conceivable to perform the termination trigger process of the switching element to be controlled at the off timing of the previous synchronous rectification enable signal in accordance with the rotational speed ω of the rotating electric machine 1. For example, as shown in FIG. 19 , an offset value p, which is a natural number determined according to the rotational speed ω, is set, and the off counter of the switching element Sw(i) is determined based on the off timing of the synchronous rectification enable signal corresponding to the switching element Sw(ip). In FIG. 19 , when the rotational speed ω of the rotating electric machine 1 is equal to or less than Nth1, p=1; when it is greater than Nth1 and equal to or less than Nth2, p=2; and when it is greater than Nth2 and equal to or less than Nth3, p=3. In FIG. 19 , when the rotational speed ω of the rotating electric machine 1 is equal to or less than Nth1, p=1, which is the same as the example in FIG. 18 , and the synchronous rectification enable signal corresponding to the previous switching element is set as the off reference signal Swoff. On the other hand, if the rotational speed ω of the rotating electric machine 1 is even larger and is greater than Nth1, the offset value p becomes 2 or 3, and the off-timing of the switching element Sw(i) is determined based on the off-timing of a synchronous rectification enable signal (for example, a synchronous rectification enable signal corresponding to the switching element Sw(i-2) (referred to as the "second off-reference signal") that turns on earlier. Note that even in this case, the off-counter is determined in the same way, and the off-timing of the switching element Sw(i) is determined to be a time delayed from the off-timing of the synchronous rectification enable signal corresponding to Sw(ip) by the time required for the phase to change by π / 6×p minus the off-margin time determined based on the rotational speed ω.

[0071] That is, when the rotation speed ω of the rotating electric machine is greater than a predetermined value Nth1, the on / off signal generation unit 54 determines the off timing of the switching element Sw(i) by processing that is triggered by the switching from on to off of the second off reference signal, which is a synchronous rectification enable signal that turns on before the synchronous rectification enable signal corresponding to the switching element Sw(i-1), and the second off reference signal is determined based on the rotation speed ω of the rotating electric machine 1. Furthermore, the on / off signal generation unit 54 determines the off margin time based on the rotation speed ω of the rotating electric machine, and determines the off timing of the switching element Sw(i) based on the time that is later than the time at which the second off reference signal switches from off to on by a time determined based on the off margin time.

[0072] Next, the optimal phase difference between the windings will be described. In the first embodiment, if the phase difference between the first three-phase armature winding L11 and the second three-phase armature winding L21 is assumed to be δ, the phase change from the phase at which the synchronous rectification enable signal Swp11 switches from ON to OFF to the phase at which the synchronous rectification enable signal Swp21 switches from ON to OFF is also δ. Furthermore, the phase change from the phase at which the synchronous rectification enable signal Swp21 switches from ON to OFF to the phase at which the synchronous rectification enable signal Swn13 switches from ON to OFF is (π / 3-δ). Therefore, to obtain the same effect for all switching elements when performing synchronous rectification, the time from the end trigger process of one switching element to the earliest start trigger process of the other switching elements must be equal. That is, δ should satisfy the following equation (20).

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[0073] Furthermore, the above explanation is for the case of a dual three-phase motor. When the number of armature winding sets is y (an integer equal to or greater than 2) and the number of phases is z (an odd number equal to or greater than 3), the optimal phase difference δ between the sets should satisfy the following equation (21). By setting the phase difference between the sets to the value obtained by dividing π by the product of y and z, as in equation (21), it is possible to suppress the off-margin time. As a result, the efficiency of synchronous rectification can be maximized.

number

[0074] Next, a case where the control device for a rotating electric machine according to the first embodiment is used in a vehicle generator motor will be described. FIG. 20 is a schematic diagram showing an example in which the rotating electric machine according to the first embodiment is used as a vehicle generator motor. The rotating electric machine 1 is connected to an internal combustion engine 1000 via a belt and a pulley (both of which are not shown) and operates as an auxiliary machine for the internal combustion engine 1000. The rotating electric machine 1 provides driving force to wheels via drivetrain components and generates electricity using the rotation of the internal combustion engine 1000. Synchronous rectification control is performed as described above when generating electricity, and known PWM control is performed when driving or generating electricity at low rotation speeds. Note that PWM control is not essential when generating electricity at low rotation speeds, and synchronous rectification control may be performed only within an operating range in which electricity can be generated. Since the rotating electric machine 1 is connected to the internal combustion engine 1000, rotational fluctuations are gentle due to the inertia of the internal combustion engine 1000, so the effects of rotational fluctuations can be reduced during synchronous rectification.

[0075] Next, a hardware configuration for realizing each functional unit of the control unit 5 will be described. FIG. 21 is a diagram illustrating an example of the hardware configuration of the control unit according to the first embodiment. The control unit 5 is mainly composed of a processor 81, a memory 82 serving as a main storage device, and an auxiliary storage unit 83. The processor 81 may be, for example, a microcomputer, a central processing unit (CPU), an application-specific integrated circuit (ASIC), a digital signal processor (DSP), or a field programmable gate array (FPGA). The memory 82 may be a volatile storage device such as a random access memory (RAM) that updates and sequentially rewrites stored data. The auxiliary storage unit 83 may be a nonvolatile storage device such as a flash memory, a read-only memory (ROM), or a hard disk. The auxiliary storage unit 83 stores predetermined programs and data such as fixed value data to be executed by the processor 81. The processor 81 reads these programs and fixed value data as appropriate, executes the programs, and performs various arithmetic operations. At this time, the predetermined programs are temporarily stored in the memory 82 from the auxiliary storage unit 83, and the processor 81 reads the programs from the memory 82. The arithmetic processing by each functional unit of the control unit 5 is realized by the processor 81 executing a predetermined program as described above. The results of the arithmetic processing by the processor 81 are temporarily stored in the memory 82, and then stored in the auxiliary storage device 83 according to the purpose of the executed arithmetic processing.

[0076] The control unit 5 also includes an input circuit 84 that receives various inputs from the outside, an output circuit 85 that outputs various types of data to the outside, and a communication device 86 that realizes transmission and reception of various types of communication data.

[0077] According to the first embodiment, it is possible to appropriately determine the off timing of the switching elements, and to improve the efficiency of synchronous rectification. More specifically, a control device for a rotating electric machine that controls a rotating electric machine having an armature winding of x phases (x is an integer of 3 or more, x=6 in the first embodiment as described above) and converts AC power supplied from the rotating electric machine into DC power by synchronous rectification, includes: a first inverter and a second inverter that are connected between the armature winding and a DC power source and have a series connection of a high-potential side switching element and a low-potential side switching element corresponding to each phase of the armature winding, and a plurality of diodes connected in anti-parallel to each switching element; a synchronous rectification enable signal generation unit that detects the conduction state of each diode or the armature current corresponding to each switching element and generates a synchronous rectification enable signal corresponding to each switching element based on the conduction state of the diode or the armature current; and an on / off signal generating unit that generates on / off signals that switch on and off the switching elements, wherein the on / off signal generating unit determines the off timing of each switching element based on the time when the off reference signal switches from off to on, wherein 2x synchronous rectification enable signals are turned on sequentially in a cyclical manner while the rotating electric machine rotates a certain amount, and the switching elements corresponding to the synchronous rectification enable signals that are turned on sequentially are defined as switching elements Sw(0), Sw(1), Sw(2), ... Sw(2x-1), where i is an integer between 0 and (2x-1) inclusive, and for a positive integer j, switching element Sw(-j) represents switching element Sw(2x-j) in the previous cycle, and the on / off signal generating unit sets the off reference signal of switching element Sw(i) to the synchronous rectification enable signal corresponding to switching element Sw(i-1).

[0078] That is, the synchronous rectification enable signal immediately preceding the synchronous rectification enable signal corresponding to the switching element to be controlled is used as the off-reference signal for determining the off-timing of the on-off signal. Therefore, the off-timing of the on-off signal is determined using the latest information, and the off-margin time is prevented from becoming too short even when the rotation speed of the rotating electric machine is increasing. As a result, there is no need to secure an extra off-margin time. Furthermore, the risk of setting an excessively long off-margin time when the rotation speed of the rotating electric machine is decreasing is also reduced. As such, according to the first embodiment, by appropriately setting the off-margin time, it is possible to appropriately set the on-off signal of the switching element, thereby improving the efficiency of synchronous rectification.

[0079] Furthermore, the on / off signal generation unit determines the off timing of the switching element to be controlled by processing triggered by the switching from on to off of the synchronous rectification enable signal, which is the off reference signal for the switching element to be controlled. This allows the off timing of the switching element to be determined at a timing that corresponds to the state of the synchronous rectification enable signal. In conventional technology, the off timing of the switching element may be determined by periodic processing, but the synchronous rectification enable signal may also change. By determining the off timing of the switching element to be controlled by processing triggered by the switching from on to off of the off reference signal, the off timing of the switching element to be controlled can be determined based on the latest state of the synchronous rectification enable signal. This allows the off timing of the switching element to be set more appropriately than when the off timing is determined by periodic processing.

[0080] The on / off signal generator determines the off-margin time based on the rotational speed of the rotating electric machine, and determines the off-timing of the switching element to be controlled based on a time that is a time determined based on the off-margin time after the time when the synchronous rectification enable signal, which is the off-reference signal, switches from off to on. Therefore, the off-timing of the switching element to be controlled can be set according to the rotational speed.

[0081] Furthermore, when the rotation speed of the rotating electric machine is higher than a predetermined value, the on / off signal generator determines the off timing of the switching element to be controlled by processing triggered by a switch from on to off of a second off reference signal, which turns on even earlier than the off reference signal, and determines the second off reference signal based on the rotation speed of the rotating electric machine. This makes it possible to ensure the time required for the end trigger processing and a sufficient off margin time even when the rotation speed of the rotating electric machine is high and the interval between off timings is short.

[0082] Furthermore, when the above-described second off reference signal is used, the on / off signal generator determines the off margin time based on the rotation speed of the rotating electric machine, and determines the off timing of the switching element to be controlled based on the time that is the time determined based on the off margin time after the time when the second off reference signal switches from off to on. Therefore, even when the second off reference signal is used, the off timing of the switching element to be controlled can be determined according to the rotation speed.

[0083] Furthermore, the on / off signal generator determines the on-timing of the switching element to be controlled based on the time when the synchronous rectification enable signal corresponding to the switching element to be controlled switches from off to on. Therefore, the on-timing of the switching element to be controlled can be set more appropriately than when the on-timing is determined by periodic processing.

[0084] Furthermore, the on / off signal generator starts generating the on / off signal for the switching element to be controlled by processing triggered by the switching of the synchronous rectification enable signal corresponding to the switching element from off to on, and determines the on-timing of the switching element to be controlled. Therefore, the on-timing of the switching element to be controlled can be set more appropriately than when the on-timing is determined by periodic processing.

[0085] The on / off signal generator determines the on-margin time based on the rotational speed of the rotating electric machine, and determines the on-timing of the switching element to be controlled based on the time that is the on-margin time after the time when the corresponding synchronous rectification enable signal switches from off to on. Therefore, the on-timing of the switching element to be controlled can be determined in accordance with the rotational speed.

[0086] In addition, the phase difference between the sets of armature windings is set to the value obtained by dividing π by the product of the number of sets and the number of phases. By setting the phase difference between the sets in this way, voltage vectors are set at equal intervals without overlap, making it possible to suppress the off-margin time. As a result, the efficiency of synchronous rectification can be maximized.

[0087] Also provided is a converter connected between the field winding provided in the rotary electric machine 1 and a DC power supply, which converts the DC voltage supplied from the DC power supply into power and applies the converted DC voltage to the field winding to conduct a field current through the field winding. Therefore, the amount of power generated by the rotary electric machine can be controlled by controlling the field current.

[0088] Furthermore, when the control device for a rotating electric machine according to the first embodiment is used for a vehicle generator motor, the inertia of the internal combustion engine makes the rotational fluctuations gentle, and the influence of the rotational fluctuations during synchronous rectification can be reduced, so that the margin time can be set with high precision. As a result, the on-time of the synchronous rectification enable signal can be maximized, and the efficiency of synchronous rectification can be further improved.

[0089] In the first embodiment, the number of phases x is set to 6, but for example, in the case of a single three-phase system, x may be an odd number equal to or greater than 3. Even in this case, voltage vectors are set at equal intervals without overlapping, making it possible to suppress the off-margin time.

[0090] Embodiment 2 Next, a second embodiment will be described with reference to FIGS. 22 to 27. Unless otherwise specified, the same or corresponding components as those in FIGS. 1 to 21 are denoted by the same reference numerals. In the first embodiment, an off-reference signal is determined from a synchronous rectification enable signal of another switching element, and the off-timing of synchronous rectification (off-timing of a switching element) is determined based on the off-timing of the off-reference signal. The off-timing of synchronous rectification is determined by end trigger processing performed at the off-timing of the off-reference signal. The second embodiment is also similar in that the off-timing of synchronous rectification is determined at the off-timing of the off-reference signal. Meanwhile, in the first embodiment, only the on-counter is determined at the on-timing of the synchronous rectification enable signal corresponding to the switching element to be controlled, and the off-counter is determined at the off-timing of the off-reference signal. In contrast, in the second embodiment, the off-counter is first determined at the on-timing of the synchronous rectification enable signal corresponding to the switching element to be controlled, and then the off-counter is updated at the off-timing of the off-reference signal to determine the off-timing of synchronous rectification. Furthermore, when determining the off counter at the on timing of the synchronous rectification enable signal, the latest synchronous rectification enable time at that time is used.

[0091] 22 is a schematic configuration diagram showing a control device for a rotating electric machine according to embodiment 2. A control device 100a differs from the control device 100 according to embodiment 1 in that the control unit 5 is replaced with a control unit 5a.

[0092] 23 is a schematic block diagram showing a control unit according to embodiment 2. Control unit 5a differs from control unit 5 of embodiment 1 in that it further includes a synchronous rectification permission time calculation unit 55 and that on / off signal generation unit 54 is replaced with on / off signal generation unit 54a.

[0093] The synchronous rectification permission time calculation unit 55 calculates synchronous rectification permission times Tp11-Tp13, Tn11-Tn13, Tp21-Tp23, and Tn21-Tn23 of the respective switching elements of the first inverter 4A and the second inverter 4B based on the synchronous rectification permission signals Swp11-Swp13, Swn11-Swn13 and the synchronous rectification permission signals Swp21-Swp23, Swn21-Swn23 input from the synchronous rectification permission signal generation unit 42A and the synchronous rectification permission signal generation unit 42B, respectively. The synchronous rectification permission time calculation unit 55 calculates the difference between the time of ON timing and the time of subsequent OFF timing for each synchronous rectification permission signal, thereby calculating the time during which the synchronous rectification permission signal was ON as the synchronous rectification permission time. The synchronous rectification permission time calculation unit 55 outputs the synchronous rectification permission times Tp11 to Tp13, Tn11 to Tn13, Tp21 to Tp23, and Tn21 to Tn23 to the on / off signal generation unit 54a. The relationship between each synchronous rectification permission time and the synchronous rectification permission signal is shown in FIG.

[0094] 25 is a block diagram showing an ON / OFF signal generation unit according to embodiment 2. Compared with ON / OFF signal generation unit 54 of embodiment 1, ON / OFF signal generation unit 54a further includes latest value acquisition unit 545 and OFF counter update unit 546, and OFF counter determination unit 543 and signal generation unit 544 are replaced with OFF counter determination unit 543a and signal generation unit 544a, respectively.

[0095] The latest value acquiring unit 545 acquires the latest synchronous rectification permission time from the synchronous rectification permission times Tp11 to Tp13, Tn11 to Tn13, Tp21 to Tp23, and Tn21 to Tn23 as the synchronous rectification permission time latest value Tnew, and outputs the synchronous rectification permission time latest value Tnew to the OFF counter determining unit 543a. The OFF counter determining unit 543a determines an OFF counter Coff_p11 or the like based on the synchronous rectification permission time latest value Tnew, and outputs the determined OFF counter to the OFF counter updating unit 546.

[0096] The off-counter update unit 546 acquires the off-reference signal Swoff from the off-reference signal acquisition unit 541, and updates the off-counter Coff_p11 etc. acquired from the off-counter determination unit 543a based on the off-timing of the off-reference signal Swoff. The off-counter update unit 546 outputs the updated off-counter Coff_p11 etc. as the off-counter Upd_Coff to the signal generation unit 544a. The signal generation unit 544a generates on-off signals Qp11 etc. based on the on-counter Con_p11 etc. respectively acquired from the on-counter determination unit 542 and the off-counter update unit 546, and the updated off-counter Upd_Coff.

[0097] FIG. 26 is a diagram for explaining a method of generating an on-off signal according to Embodiment 2. FIG. 26 is basically the same as FIG. 10 and is a diagram for explaining the generation of the on-off signal Qp21, but the same applies to other on-off signals. Also, in order to explain the update of the off-counter, it is assumed that the off-timing of the synchronous rectification permission signal Swp21 becomes earlier and varies from time tc6a to time tc6b. For example, when the rotational speed ω of the rotating electrical machine 1 is constant, even if the off-timing of the synchronous rectification permission signal Swp21 is at time tc6a, when the rotational speed ω increases and the time for one cycle of the electrical angle becomes shorter, the time for implementing synchronous rectification becomes shorter and the off-timing of the synchronous rectification permission signal Swp21 may advance to time tc6b. Also, when the field current if decreases, the induced voltage of the rotating electrical machine 1 decreases, so the time for implementing synchronous rectification becomes shorter and the off-timing of the synchronous rectification permission signal Swp21 may advance to time tc6b. In such a case, even if the off-timing of the on-off signal Qp21 is determined to be at time tc5a based on time tc6a, there may be problems such as the off-timing of the on-off signal Qp21 and the off-timing of the synchronous rectification permission signal Swp21 being close and the actual off-margin time (tc6b - tc5a) becoming insufficient, or the off-timing of the synchronous rectification permission signal Swp21 becoming earlier than the off-timing of the on-off signal Qp21 (tc6b < tc5a). Embodiment 2 addresses such a situation.

[0098] In the initial state, the synchronous rectification enable signals Swp11, Swp21, on counter Con_p21, off counter Coff_p21, and on / off signal Qp21 are all off or zero. First, at time tc1, the synchronous rectification enable signal Swp11 switches from off to on. Next, at time tc2, the synchronous rectification enable signal Swp21 switches from off to on. When the synchronous rectification enable signal Swp21 switches on, the on / off signal generation unit 54a of the control unit 5a performs start trigger processing for the on / off signal Qp21.

[0099] In the start trigger process of the on / off signal Qp21, the off reference signal acquirer 541 acquires the synchronous rectification enable signal Swp11 as the off reference signal Swoff. The off reference signal acquirer 541 outputs the acquired off reference signal Swoff to the off counter updater 546. The on counter determiner 542 determines the on counter Con_p21 in the same manner as in the first embodiment.

[0100] Furthermore, in the second embodiment, the off counter Coff_p21 is also determined in the start trigger process of the on / off signal Qp21. However, at time tc2, the synchronous rectification permission time Tp21 of the synchronous rectification permission signal Swp21 has not been determined, and the off timing of the synchronous rectification permission signal Swp21 has not been determined either. For this reason, the latest synchronous rectification permission time Tnew is used instead of the synchronous rectification permission signal Swp21. The latest value acquisition unit 545 acquires the latest synchronous rectification permission time, such as the synchronous rectification permission time Tp11, as of time tc2 as the latest synchronous rectification permission time Tnew, and outputs the acquired latest synchronous rectification permission time value Tnew to the off counter determination unit 543a. 24 as an example, the latest value Tnew of the synchronous rectification permission time at time tc2, i.e., the ON timing of the synchronous rectification permission signal Swp21, will be described. In FIG. 24, the ON timing of the synchronous rectification permission signal Swp21 is time ts3, and therefore the synchronous rectification permission time Tn21 of the synchronous rectification permission signal Swn21, which is OFF at time ts2, becomes the latest value Tnew of the synchronous rectification permission time. However, which synchronous rectification permission time becomes the latest value Tnew of the synchronous rectification permission time depends on the magnitude of the synchronous rectification permission phase, the number of armature windings of the rotating electric machine 1, and the set and phase of the target synchronous rectification permission signal (the second or first phase in the case of the synchronous rectification permission signal Swp21).

[0101] The OFF counter determiner 543a determines the OFF counter Coff_p21. The OFF counter Coff_p21 is determined so that the timing of the ON / OFF signal Qp21 is time tc5a. Time tc5a is the time obtained by subtracting an OFF margin time determined based on the rotation speed ω from time tc6a, and time tc6a is delayed from time tc2 by the latest synchronous rectification permission time value Tnew. In other words, tc5a = tc2 + Tnew - (OFF margin time). In this way, the ON / OFF signal generator 54a obtains the latest synchronous rectification permission time value Tnew, which is the latest synchronous rectification permission time at the time of generation of the ON / OFF signal Qp21, and determines the OFF timing of the ON / OFF signal Qp21 based on the latest synchronous rectification permission time value Tnew.

[0102] After time tc2, the signal generating unit 544a decrements (reduces) the on counter Con_p21 and the off counter Coff_p21 as time passes. At the timing (time tc3) when the on counter Con_p21 reaches zero, the on / off signal Qp21 is switched from off to on. Note that in the example shown in FIG. 26, the decrement of the off counter Coff_p21 starts at time tc2, but it is also possible to start decrementing the off counter Coff_p21 at time tc3 when the on counter Con_p21 reaches zero. As long as the desired on margin time and off margin time can be obtained, the timing to start decrementing the on counter Con_p21 and the off counter Coff_p21 is not particularly limited.

[0103] At time tc4, the synchronous rectification enable signal Swp11 switches from ON to OFF. When the synchronous rectification enable signal Swp11 switches to OFF, the ON / OFF signal generating unit 54a of the control unit 5a performs end trigger processing.

[0104] In the end trigger process, the off counter update unit 546 updates the off counter Coff_p21. The off counter update unit 546 calculates the time required for the phase to change by π / 6 (the phase difference between the pairs) minus an off margin time determined based on the rotation speed ω, and updates the off counter Coff_p21 so that the time (time tc5b) is delayed from time tc4 by this time. After time tc4, the signal generation unit 544a decrements (reduces) the updated off counter Coff_p21 as time passes. The signal generation unit 544a switches the on / off signal Qp21 from on to off at the timing (time tc5b) when the updated off counter Coff_p21 becomes zero. Thereafter, at time tc6b, the synchronous rectification enable signal Swp21 switches from on to off.

[0105] Since the synchronous rectification permission time Tp11 is determined at time tc4, the latest value obtaining unit 545 updates the latest value Tnew of the synchronous rectification permission time to the synchronous rectification permission time Tp11. That is, the on / off signal generating unit 54a updates the latest value Tnew of the synchronous rectification permission time to the synchronous rectification permission time Tp11 of the synchronous rectification permission signal Swp11 in a process triggered by the switching from on to off of the synchronous rectification permission signal Swp11, which is the off-reference signal Swoff of the switching element Sp21.

[0106] 27 is a diagram showing the timings for determining the on counter and off counter of synchronous rectification and the timings for updating the off counter according to embodiment 2, and similarly to Fig. 18, it shows the relationship between each switching element arranged in the order of the on timings of the corresponding synchronous rectification enable signals and the timings for determining the on counter and off counter and the timings for updating the off counter. As shown in Fig. 27, if the switching elements are Sw(0), Sw(1), Sw(2), ... Sw(2x-1) in the order of the on timings of the corresponding synchronous rectification enable signals, where i is an integer between 0 and 2x-1, the on counter and off counter of Sw(i) are determined based on the on timing of the synchronous rectification enable signal corresponding to the switching element Sw(i), and the off counter of the switching element Sw(i) is updated based on the off timing of the synchronous rectification enable signal corresponding to the switching element Sw(i-1).

[0107] That is, in a control device 100 that controls a rotating electric machine 1 having an x-phase (x is an integer greater than or equal to 3) armature winding and converts AC power supplied from the rotating electric machine 1 into DC power by synchronous rectification, an on / off signal generation unit 54a updates the off timing of each switching element based on the time at which an off reference signal Swoff switches from off to on, and 2x synchronous rectification enable signals are periodically turned on in sequence while the rotating electric machine 1 rotates a certain amount, and the switching elements corresponding to the synchronous rectification enable signals that are turned on in sequence are defined as Sw(0), Sw(1), Sw(2), ... Sw(2x-1), where i is an integer greater than or equal to 0 and less than or equal to (2x-1), and for a positive integer j, Sw(-j) represents Sw(2x-j) in the previous cycle, and the on / off signal generation unit 54 sets the off reference signal for Sw(i) to the synchronous rectification enable signal corresponding to Sw(i-1). The rest is the same as in the first embodiment.

[0108] According to the second embodiment, the same effects as those of the first embodiment can be obtained. Furthermore, the on / off signal generator in the second embodiment acquires the latest synchronous rectification permission time value, which is the latest synchronous rectification permission time at the time of generating the on / off signal, determines the off-timing of each switching element based on the latest synchronous rectification permission time value, and updates the off-timing of each switching element based on the time when the off-reference signal switches from on to off. The latest synchronous rectification permission time value can be acquired relatively easily by simply selecting the latest synchronous rectification permission time from among previously calculated synchronous rectification permission times. Furthermore, since it is not necessary to wait until the off-timing of the off-reference signal, the off counter (off-timing) can be determined early. Even if the synchronous rectification permission time is shortened due to an increase in the rotational speed of the rotating electric machine or a decrease in the induced voltage, the off counter (off-timing) is updated based on the time when the off-reference signal switches from on to off. Therefore, an off-margin time can be secured even in response to a sudden change in the synchronous rectification permission time, and the off-timing of the switching element can be appropriately determined.

[0109] Furthermore, the on / off signal generator updates the latest value of the synchronous rectification permission time to the synchronous rectification permission time of the synchronous rectification permission signal, which is the off reference signal, in a process triggered by the switching of the off reference signal of the switching element to be controlled from on to off. This allows the latest synchronous rectification permission time to be acquired earlier than in the case of fixed-cycle processing. Therefore, the latest value of the synchronous rectification permission time can be more reliably set to the latest synchronous rectification permission time.

[0110] Although the present disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not exemplified are conceivable within the scope of the technology disclosed in this specification, including, for example, cases where at least one component is modified, added, or omitted, and cases where at least one component is extracted and combined with components of another embodiment.

[0111] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) A control device for a rotating electric machine that controls a rotating electric machine having an armature winding with x phases (x is an integer of 3 or more), and when AC power is supplied from the rotating electric machine, converts the AC power into DC power by synchronous rectification, a power conversion unit connected between the armature winding and a DC power source, the power conversion unit including a series connection of high-potential side switching elements and low-potential side switching elements corresponding to each phase of the armature winding, and a plurality of diodes connected in anti-parallel to each of the switching elements; a synchronous rectification enable signal generating unit that detects a conduction state of each of the diodes or an armature current corresponding to each of the switching elements, and generates a synchronous rectification enable signal corresponding to each of the switching elements based on the conduction state or the armature current; an on / off signal generating unit that generates on / off signals that switch on and off each of the switching elements, the on / off signal generation unit determines the off timing of each of the switching elements based on the time when an off reference signal switches from off to on, a control device for a rotating electric machine, characterized in that, while the rotating electric machine rotates a certain amount, 2x of the synchronous rectification enable signals are turned on sequentially in a repeated manner, and the switching elements corresponding to the synchronous rectification enable signals that are turned on sequentially are defined as switching elements Sw(0), Sw(1), Sw(2), ... Sw(2x-1), where i is an integer greater than or equal to 0 and less than or equal to (2x-1), and for a positive integer j, switching element Sw(-j) represents switching element Sw(2x-j) in the previous cycle, and the on / off signal generation unit sets the off-reference signal for switching element Sw(i) to the synchronous rectification enable signal corresponding to switching element Sw(i-1). (Appendix 2) 2. The control device for a rotating electric machine according to claim 1, wherein the on / off signal generation unit determines the off timing of the switching element by processing triggered by a change from on to off of the off reference signal of the switching element. (Appendix 3) 3. The control device for a rotating electric machine according to claim 1, wherein the on / off signal generation unit determines an off margin time based on a rotation speed of the rotating electric machine, and determines an off timing of the switching element based on a time that is a time determined based on the off margin time after a time at which the off reference signal of the switching element switches from on to off. (Appendix 4) 4. The control device for a rotating electric machine according to any one of appendices 1 to 3, wherein, when the rotation speed of the rotating electric machine is greater than a predetermined value, the on / off signal generation unit determines the off timing of the switching element by processing triggered by a switch from on to off of a second off reference signal of the switching element, the second off reference signal being turned on before the off reference signal of the switching element, and the second off reference signal being determined based on the rotation speed of the rotating electric machine. (Appendix 5) 5. The control device for a rotating electric machine according to claim 4, wherein, when the rotation speed of the rotating electric machine is greater than a predetermined value, the on / off signal generation unit determines an off margin time based on the rotation speed of the rotating electric machine, and determines the off timing of the switching element based on a time that is a time determined based on the off margin time after a time at which the second off reference signal of the switching element switches from on to off. (Appendix 6) 6. The control device for a rotating electric machine according to any one of claims 1 to 5, wherein the on / off signal generation unit determines the on timing of the switching element based on the time when the synchronous rectification enable signal corresponding to the switching element switches from off to on. (Appendix 7) The control device for a rotating electric machine according to claim 6, wherein the on / off signal generation unit determines the on timing of the switching element by processing triggered by the switching from off to on of the synchronous rectification enable signal corresponding to the switching element. (Appendix 8) 8. The control device for a rotating electric machine according to claim 6, wherein the on / off signal generation unit determines an on margin time based on a rotation speed of the rotating electric machine, and determines an on timing of the switching element based on a time that is the on margin time after a time at which the synchronous rectification enable signal corresponding to the switching element switches from off to on. (Appendix 9) A control device for a rotating electric machine that controls a rotating electric machine having an armature winding with x phases (x is an integer of 3 or more), and when AC power is supplied from the rotating electric machine, converts the AC power into DC power by synchronous rectification, a power conversion unit connected between the armature winding and a DC power source, the power conversion unit including a series connection of high-potential side switching elements and low-potential side switching elements corresponding to each phase of the armature winding, and a plurality of diodes connected in anti-parallel to each of the switching elements; a synchronous rectification enable signal generating unit that detects a conduction state of each of the diodes or an armature current corresponding to each of the switching elements, and generates a synchronous rectification enable signal corresponding to each of the switching elements based on the conduction state or the armature current; a synchronous rectification permission time calculation unit that calculates a synchronous rectification permission time, which is the length of an on-time of the synchronous rectification permission signal; an on / off signal generating unit that generates on / off signals that switch on and off each of the switching elements, the on / off signal generation unit acquires a latest value of synchronous rectification permission time, which is the latest synchronous rectification permission time at the time of generation of the on / off signal, determines an off-timing of each of the switching elements based on the latest value of synchronous rectification permission time, and updates the off-timing of each of the switching elements based on a time when an off-reference signal switches from on to off, a control device for a rotating electric machine, characterized in that, while the rotating electric machine rotates a certain amount, 2x of the synchronous rectification enable signals are turned on sequentially in a repeated manner, and the switching elements corresponding to the synchronous rectification enable signals that are turned on sequentially are defined as switching elements Sw(0), Sw(1), Sw(2), ... Sw(2x-1), where i is an integer greater than or equal to 0 and less than or equal to (2x-1), and for a positive integer j, switching element Sw(-j) represents switching element Sw(2x-j) in the previous cycle, and the on / off signal generation unit sets the off-reference signal for switching element Sw(i) to the synchronous rectification enable signal corresponding to switching element Sw(i-1). (Appendix 10) 10. The control device for a rotating electric machine according to claim 9, wherein the on / off signal generation unit determines the off-timing of the switching element by processing triggered by a change from off to on of the synchronous rectification permission signal corresponding to the switching element, and then updates the off-timing of the switching element by processing triggered by a change from on to off of the off reference signal for the switching element, and updates the latest value of the synchronous rectification permission time to the synchronous rectification permission time of the off reference signal. (Appendix 11) the on / off signal generation unit determines and updates an off margin time based on a rotation speed of the rotating electric machine, the on / off signal generation unit determines the off-timing of the switching element based on a time that is a length of time determined based on the off margin time after a time at which the synchronous rectification enable signal corresponding to the switching element switches from off to on, and then updates the off margin time in a process triggered by switching of the off reference signal of the switching element from on to off, and determines the off-timing of the switching element based on a time that is a length of time determined based on the updated off margin time. (Appendix 12) 12. The control device for a rotating electric machine according to any one of appendices 9 to 11, wherein, when the rotation speed of the rotating electric machine is higher than a predetermined value, the on / off signal generation unit determines the off timing of the switching element by processing triggered by a switch from off to on of the synchronous rectification enable signal corresponding to the switching element, and then updates the off timing of the switching element by processing triggered by a switch from on to off of a second off reference signal that turns on before the off reference signal of the switching element, and the second off reference signal is determined based on the rotation speed of the rotating electric machine. (Appendix 13) the on / off signal generation unit determines and updates an off margin time based on a rotational speed of the rotating electric machine, and when the rotational speed of the rotating electric machine is greater than a predetermined value, the on / off signal generation unit determines the off margin time based on the rotational speed of the rotating electric machine, determines the off-timing of the switching element based on a time that is a time determined based on the off margin time after a time at which the synchronous rectification enable signal corresponding to the switching element switches from off to on, and then updates the off margin time in a process triggered by switching of the second off reference signal of the switching element from on to off, and determines the off-timing of the switching element based on a time that is a time that is a time determined based on the off margin time after a time at which the second off reference signal of the switching element switches from on to off. (Appendix 14) 14. The control device for a rotating electric machine according to any one of claims 9 to 13, wherein the on / off signal generation unit determines the on timing of the switching element based on the time when the synchronous rectification enable signal corresponding to the switching element switches from off to on. (Appendix 15) The control device for a rotating electric machine according to claim 14, wherein the on / off signal generation unit determines the on timing of the switching element by processing triggered by the switching from off to on of the synchronous rectification enable signal corresponding to the switching element. (Appendix 16) 16. The control device for a rotating electric machine according to claim 14 or 15, wherein the on / off signal generation unit determines an on margin time based on a rotation speed of the rotating electric machine, and determines an on timing of the switching element based on a time that is the on margin time after a time at which the synchronous rectification enable signal corresponding to the switching element switches from off to on. (Appendix 17) 17. The control device for a rotating electric machine according to any one of appendixes 1 to 16, wherein the armature winding is configured by a plurality of sets of armature windings, each having an odd number of phases equal to or greater than three, and wherein, when the number of sets is y and the number of phases is z, x is equal to the product of y and z, and a phase difference between the sets of armature windings in the plurality of sets is set equal to a value obtained by dividing π by x. (Appendix 18) 18. The control device for a rotating electric machine according to any one of Supplementary notes 1 to 17, wherein x is an odd number. (Appendix 19) 19. The control device for a rotating electric machine according to any one of appendixes 1 to 18, further comprising a converter that converts a DC voltage supplied from the DC power supply into power and applies the converted DC voltage to a field winding provided in the rotating electric machine. (Appendix 20) 20. The control device for a rotating electric machine according to any one of appendices 1 to 19, wherein the rotating electric machine is a generator motor for a vehicle. [Explanation of symbols]

[0112] REFERENCE SIGNS LIST 1 Rotating electric machine, 2 DC power supply, 3 Converter, 4A First inverter, 4B Second inverter, 5, 5a Control unit, 41A, 41B Full bridge circuit unit, 42A, 42B Synchronous rectification enable signal generation unit, 51 Field voltage command calculation unit, 52 Field switching signal generation unit, 53 Synchronous rectification enable signal reception unit, 54, 54a On / off signal generation unit, 55 Synchronous rectification enable time calculation unit, 100, 100a Control device, 541 Off reference signal acquisition unit, 542 On counter determination unit, 543, 543a Off counter determination unit, 545 Latest value acquisition unit, 546 Off counter update unit, 1000 Internal combustion engine, Coff_p11 to Coff_p13, Coff_n11 to Coff_n13, Coff_p21 to Coff_p23, Coff_n21 to Coff_n23 Off counter, Con_p11 to Con_p13, Con_n11 to Con_n13, Con_p21 to Con_p23, Con_n21 to Con_n23 On counter, Dp11 to Dp13, Dp21 to Dp23, Dn11 to Dn13, Dn21 to Dn23 Diode, L11 to L13 First three-phase armature winding, L21 to L23 Second three-phase armature winding, Lf Field winding, p Offset value, Qp11 to Qp13, Qp21 to Qp23, Qn11 to Qn13, Qn21 to Qn23 On / off signal, Sp11 to Sp13, Sp21 to Sp23, Sn11 to Sn13, Sn21 to Sn23 Switching elements, Swp11 to Swp13, Swp21 to Swp23, Swn11 to Swn13, Swn21 to Swn23, SwX synchronous rectification enable signal, Swoff off reference signal, Tp11 to Tp13, Tp21 to Tp23, Tn11 to Tn13, Tn21 to Tn23 synchronous rectification enable time, Tnew latest value of synchronous rectification enable time, Upd_Coff updated off counter, Vdf forward voltage, ω rotation speed

Claims

1. A control device for a rotating electric machine that controls a rotating electric machine having an x-phase (x is an integer of 3 or more) armature winding, and when AC power is supplied from the rotating electric machine, converts the AC power into DC power by synchronous rectification, a power conversion unit connected between the armature winding and a DC power source, the power conversion unit including a series connection of high-potential side switching elements and low-potential side switching elements corresponding to each phase of the armature winding, and a plurality of diodes connected in anti-parallel to each of the switching elements; a synchronous rectification enable signal generating unit that detects a conduction state of each of the diodes or an armature current corresponding to each of the switching elements, and generates a synchronous rectification enable signal corresponding to each of the switching elements based on the conduction state or the armature current; an on / off signal generating unit that generates on / off signals that switch on and off each of the switching elements, the on / off signal generation unit determines the off timing of each of the switching elements based on the time when an off reference signal switches from off to on, A control device for a rotating electric machine, characterized in that 2x of the synchronous rectification enable signals are turned on sequentially in a cyclical manner while the rotating electric machine rotates a certain amount, and the switching elements corresponding to the synchronous rectification enable signals that are turned on sequentially are switching elements Sw(0), Sw(1), Sw(2), ... Sw(2x-1), where i is an integer greater than or equal to 0 and less than or equal to (2x-1), and for a positive integer j, switching element Sw(-j) represents switching element Sw(2x-j) in the previous cycle, and the on / off signal generation unit sets the off reference signal for switching element Sw(i) to the synchronous rectification enable signal corresponding to switching element Sw(i-1).

2. 2. The control device for a rotating electric machine according to claim 1, wherein the on / off signal generating unit determines the off timing of the switching element by processing triggered by a change from on to off of the off reference signal of the switching element.

3. 3. The control device for a rotating electric machine according to claim 2, wherein the on / off signal generation unit determines an off margin time based on a rotation speed of the rotating electric machine, and determines an off timing of the switching element based on a time that is a time determined based on the off margin time after a time at which the off reference signal of the switching element switches from on to off.

4. 2. The control device for a rotating electric machine according to claim 1, wherein when the rotational speed of the rotating electric machine is greater than a predetermined value, the on / off signal generating unit determines the off timing of the switching element by processing triggered by the switching from on to off of a second off reference signal of the switching element, the second off reference signal being turned on before the off reference signal of the switching element, and the second off reference signal is determined based on the rotational speed of the rotating electric machine.

5. 5. The control device for a rotating electric machine according to claim 4, wherein, when the rotation speed of the rotating electric machine is greater than a predetermined value, the on / off signal generation unit determines an off margin time based on the rotation speed of the rotating electric machine, and determines the off timing of the switching element based on a time that is a time determined based on the off margin time after the time at which the second off reference signal of the switching element switches from on to off.

6. 2. The control device for a rotating electric machine according to claim 1, wherein the on / off signal generating unit determines the on timing of the switching element based on the time when the synchronous rectification enable signal corresponding to the switching element switches from off to on.

7. 7. The control device for a rotating electric machine according to claim 6, wherein the on / off signal generating unit determines the on timing of the switching element by processing triggered by a change from off to on of the synchronous rectification enable signal corresponding to the switching element.

8. 7. The control device for a rotating electric machine according to claim 6, wherein the on / off signal generating unit determines an on margin time based on a rotation speed of the rotating electric machine, and determines an on timing of the switching element based on a time that is the on margin time after a time at which the synchronous rectification enable signal corresponding to the switching element switches from off to on.

9. A control device for a rotating electric machine that controls a rotating electric machine having an x-phase (x is an integer of 3 or more) armature winding, and when AC power is supplied from the rotating electric machine, converts the AC power into DC power by synchronous rectification, a power conversion unit connected between the armature winding and a DC power source, the power conversion unit including a series connection of high-potential side switching elements and low-potential side switching elements corresponding to each phase of the armature winding, and a plurality of diodes connected in anti-parallel to each of the switching elements; a synchronous rectification enable signal generating unit that detects a conduction state of each of the diodes or an armature current corresponding to each of the switching elements, and generates a synchronous rectification enable signal corresponding to each of the switching elements based on the conduction state or the armature current; a synchronous rectification permission time calculation unit that calculates a synchronous rectification permission time, which is the length of an on-time of the synchronous rectification permission signal; an on / off signal generating unit that generates on / off signals that switch on and off each of the switching elements, the on / off signal generation unit acquires a latest value of synchronous rectification permission time, which is the latest synchronous rectification permission time at the time of generation of the on / off signal, determines an off-timing of each of the switching elements based on the latest value of synchronous rectification permission time, and updates the off-timing of each of the switching elements based on a time when an off-reference signal switches from on to off, A control device for a rotating electric machine, characterized in that 2x of the synchronous rectification enable signals are turned on sequentially in a cyclical manner while the rotating electric machine rotates a certain amount, and the switching elements corresponding to the synchronous rectification enable signals that are turned on sequentially are switching elements Sw(0), Sw(1), Sw(2), ... Sw(2x-1), where i is an integer greater than or equal to 0 and less than or equal to (2x-1), and for a positive integer j, switching element Sw(-j) represents switching element Sw(2x-j) in the previous cycle, and the on / off signal generation unit sets the off reference signal for switching element Sw(i) to the synchronous rectification enable signal corresponding to switching element Sw(i-1).

10. 10. The control device for a rotating electric machine according to claim 9, wherein the on / off signal generation unit determines the off-timing of the switching element by processing triggered by a switch from off to on of the synchronous rectification permission signal corresponding to the switching element, and then updates the off-timing of the switching element by processing triggered by a switch from on to off of the off-reference signal for the switching element, and updates the latest value of the synchronous rectification permission time to the synchronous rectification permission time of the off-reference signal.

11. 11. The control device for a rotating electric machine according to claim 10, wherein the on / off signal generation unit determines and updates an off margin time based on a rotation speed of the rotating electric machine, and the on / off signal generation unit determines the off timing of the switching element based on a time that is a length of time that is determined based on the off margin time from a time at which the synchronous rectification enable signal corresponding to the switching element switches from off to on, and then updates the off margin time in a process triggered by switching of the off reference signal of the switching element from on to off, and determines the off timing of the switching element based on a time that is a length of time that is determined based on the updated off margin time from a time at which the off reference signal of the switching element switches from on to off.

12. 10. The control device for a rotating electric machine according to claim 9, wherein, when the rotation speed of the rotating electric machine is greater than a predetermined value, the on / off signal generating unit determines the off timing of the switching element by processing triggered by the switching from off to on of the synchronous rectification enable signal corresponding to the switching element, and then updates the off timing of the switching element by processing triggered by the switching from on to off of a second off reference signal that turns on before the off reference signal of the switching element, and the second off reference signal is determined based on the rotation speed of the rotating electric machine.

13. 13. The control device for a rotating electric machine according to claim 12, wherein the on / off signal generation unit determines and updates the off margin time based on a rotational speed of the rotating electric machine, and when the rotational speed of the rotating electric machine is higher than a predetermined value, the on / off signal generation unit determines the off margin time based on the rotational speed of the rotating electric machine, determines the off-timing of the switching element based on a time that is a time determined based on the off margin time after a time at which the synchronous rectification enable signal corresponding to the switching element switches from off to on, and then updates the off margin time in a process triggered by switching of the second off reference signal of the switching element from on to off, and determines the off-timing of the switching element based on a time that is a time that is a time determined based on the off margin time after a time at which the second off reference signal of the switching element switches from on to off.

14. 10. The control device for a rotating electric machine according to claim 9, wherein the on / off signal generating unit determines the on timing of the switching element based on the time when the synchronous rectification enable signal corresponding to the switching element switches from off to on.

15. 15. The control device for a rotating electric machine according to claim 14, wherein the on / off signal generating unit determines the on timing of the switching element by processing triggered by switching of the synchronous rectification enable signal corresponding to the switching element from off to on.

16. 15. The control device for a rotating electric machine according to claim 14, wherein the on / off signal generating unit determines an on margin time based on a rotation speed of the rotating electric machine, and determines an on timing of the switching element based on a time that is the on margin time after a time at which the synchronous rectification permission signal corresponding to the switching element switches from off to on.

17. 17. The control device for a rotating electric machine according to claim 1, wherein the armature winding is configured by a plurality of sets of armature windings, each having an odd number of phases equal to or greater than three, and wherein, when the number of sets is y and the number of phases is z, x is equal to the product of y and z, and a phase difference between the sets of armature windings in the plurality of sets is set equal to a value obtained by dividing π by x.

18. The control device for a rotating electric machine according to any one of claims 1 to 16, wherein the x is an odd number.

19. 17. The control device for a rotating electric machine according to claim 1, further comprising a converter that converts a DC voltage supplied from the DC power supply into power and applies the converted DC voltage to a field winding provided in the rotating electric machine.

20. The control device for a rotating electric machine according to any one of claims 1 to 16, wherein the rotating electric machine is a generator motor for a vehicle.

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