Control circuit for rotary rectifier and brushless self-starting synchronous motor

Abstract

A control circuit for a rotary rectifier according to an embodiment of the present invention detects the instantaneous voltage of a field coil, computes the frequency from the instantaneous voltage, and causes a current to be supplied from the rotary rectifier to the field coil within a prescribed phase range that includes a zero-crossing point where the instantaneous voltage changes from positive to negative. Thus, the control circuit is highly versatile with a simple configuration, and can carry out phase-optimized excitation control in a reliable manner.

Description

Rotary rectifier control circuit and brushless self-starting synchronous motor

[0001] SUMMARY OF THE INVENTION Embodiments of the present invention relate to a control circuit for a rotary rectifier and a brushless self-starting synchronous motor.

[0002] Conventionally, brushless synchronous motors have been started by self-starting them as induction motors, using optimal phase excitation control, which starts energizing the field coil when the motor approaches synchronous speed. To achieve this, the shaft rotation speed of the brushless synchronous motor must be close enough to the synchronous speed, and the slip must be small enough to be below a certain value. Furthermore, to increase the rotor pull-in torque, it is necessary to appropriately select the timing for energizing the field coil with excitation current.

[0003] JP-A-59-053069, JP-A-59-117490, JP-A-60-070982, JP-A-60-160069

[0004] For this reason, optimal phase excitation control, when the negative pole (low potential side) of the rotary rectifier is used as the reference point, detects the zero-crossing point when the field coil voltage falls, i.e., treats the field coil voltage as a sine wave, and desirably passes current from the rotary rectifier to the field coil at a timing of phase 180 degrees. However, because the actual field voltage waveform contains noise, noise countermeasures are required to prevent chattering. One possible noise countermeasure method is to introduce hysteresis, but introducing hysteresis results in the detection of the zero-crossing point occurring when the hysteresis level is exceeded, which deviates from the timing when the ideal threshold level is exceeded, potentially preventing excitation at the optimal timing. Furthermore, if the circuit for detecting the zero-crossing point is configured using an analog circuit, it must be configured according to the specifications of the brushless synchronous motor, resulting in limited versatility and increased design and manufacturing costs.

[0005] The present invention has been made in view of the above, and aims to provide a control circuit for a rotary rectifier and a brushless self-starting synchronous motor that have a simple configuration, are highly versatile, and are capable of reliably performing appropriate phase excitation control.

[0006] The control circuit of the rotary rectifier of the embodiment detects the instantaneous voltage of the field coil, calculates the frequency from the instantaneous voltage, and supplies current from the rotary rectifier to the field coil within a predetermined phase range that includes the zero-crossing point where the instantaneous voltage changes from positive to negative.

[0007] FIG. 1 is a schematic diagram illustrating the configuration of a self-starting synchronous motor system. FIG. 2 is a functional block diagram of a rotary rectifier control circuit 24 according to a first embodiment of the present invention. FIG. 3 is a flowchart illustrating the initial setting process of the rotary rectifier control circuit 24 according to the first embodiment of the present invention. FIG. 4 is a flowchart (part 1) illustrating the operation of the self-starting synchronous motor system according to the first embodiment at startup. FIG. 5 is a flowchart (part 2) illustrating the operation of the self-starting synchronous motor system according to the first embodiment at startup. FIG. 6 is a diagram illustrating the operation of the first detection circuit according to the first embodiment of the present invention. FIG. 7 is a diagram illustrating the transition state of the binarized status according to the first embodiment of the present invention. FIG. 8 is a flowchart illustrating the operation when an overvoltage is detected during startup of the self-starting synchronous motor system. FIG. 9 is a flowchart illustrating the operation of the self-starting synchronous motor system during operation. FIG. 10 is a flowchart illustrating the operation of the self-starting synchronous motor system when it is stopped. FIG. 11 is a functional block diagram of a rotary rectifier control circuit 24A according to a second embodiment of the present invention. FIG. 12 is a flowchart illustrating the initial setting process of the rotary rectifier control circuit 24A according to the second embodiment of the present invention. FIG. 13 is a flowchart showing the operation at the start of the self-starting synchronous motor system according to the second embodiment.

[0008] [1] First embodiment Fig. 1 is a schematic diagram illustrating the configuration of a self-starting synchronous motor system 10. The self-starting synchronous motor system 10 includes a self-starting synchronous motor 11, an excitation circuit AC power supply 12, a fixed-side excitation circuit rectifier 13, a circuit breaker unit 14, and a three-phase AC main power supply 15.

[0009] The self-starting synchronous motor 11 includes an exciter fixed-side coil 21, an exciter rotating-side coil 22, a bridge rectifier 23, a rotary rectifier control circuit 24, a field coil 25, a field protection circuit 26, and an armature coil 27 of the motor. The exciter rotating-side coil 22, the bridge rectifier 23, the rotary rectifier control circuit 24, the field coil 25, and the field protection circuit 26 are fixed to the rotating shaft of the self-starting synchronous motor 11 and rotate together with the rotating shaft. The exciter fixed-side coil 21 and the exciter rotating-side coil 22 constitute an AC exciter 21 / 22.

[0010] The exciter fixed-side coil 21 is connected to a fixed-side excitation circuit rectifier 13, and is electromagnetically coupled to the exciter rotating-side coil 22 to supply power using DC power obtained by rectifying three-phase AC power from the excitation circuit AC power supply 12 via the fixed-side excitation circuit rectifier 13.

[0011] The exciter rotating side coil 22 has a star-connected (Y-connected) coil and is electromagnetically coupled to the fixed side coil 21 to convert the supplied DC power into three-phase AC power and output it to the bridge rectifier 23 and the rotary rectifier control circuit 24. The three-phase AC outputs (A, B, C) of the exciter rotating side coil 22 are connected to the AC inputs of the bridge rectifier 23 and also to terminals S1, S2, S3, which are power supply inputs of the rotary rectifier control circuit 24, respectively.

[0012] 1, the bridge rectifier 23 is configured as a mixed bridge rectifier and includes thyristors TR1 to TR3, each having a cathode connected to the high-potential side power supply line P, a diode D1 having a cathode connected to the anode of the thyristor TR1 and an anode connected to the low-potential side power supply line N, a diode D2 having a cathode connected to the anode of the thyristor TR2 and an anode connected to the low-potential side power supply line N, and a diode D3 having a cathode connected to the anode of the thyristor TR3 and an anode connected to the low-potential side power supply line N. The gates of the thyristors TR1, TR2, and TR3 are connected to terminals G1, G2, and G3 of the rotary rectifier control circuit 24, respectively.

[0013] The rotary rectifier control circuit 24 is configured as a circuit including, for example, a so-called MPU or FPGA, and performs appropriate phase excitation control based on the voltage of the field coil 25, as well as protective control to protect the field coil 25 from overvoltage. The field coil 25 is electromagnetically coupled to the armature coil 27 of the motor, and obtains rotational driving force from the magnetic field formed by the armature coil 27 of the motor.

[0014] When an overvoltage occurs in field coil 25, field protection circuit 26 passes the energy induced in field coil 25 through a resistor in the field protection circuit, thereby reducing the voltage between the terminals of field coil 25 (the voltage between the high-potential side power supply line P and the low-potential side power supply line N) and protecting field coil 25 and bridge rectifier 23. The high-potential side power supply line P is connected to terminal SP of rotary rectifier control circuit 24, and the low-potential side power supply line N is connected to terminal SN of rotary rectifier control circuit 24.

[0015] More specifically, the field protection circuit 26 includes a thyristor TR having an anode connected to the high-potential side power supply line P, a discharge resistor R connected between the anode of the thyristor TR and the low-potential side power supply line N, and a diode DR having a cathode connected to the high-potential side power supply line P and an anode connected to the junction of the thyristor TR and the discharge resistor R. The gate of the thyristor TR is connected to a terminal GR of the rotary rectifier control circuit 24, and the junction of the thyristor TR and the discharge resistor R is connected to a terminal SR of the rotary rectifier control circuit 24 for detecting the voltage of the discharge resistor.

[0016] Here, discharge resistor R is provided to protect field coil 25 by suppressing the voltage of field coil 25 to a predetermined voltage (e.g., 600 V). Note that reverse voltage applied to field coil 25 is discharged by diode DR. When self-starting synchronous motor 11 starts, voltage VL of field coil 25 is approximately sinusoidal, and its frequency is the slip frequency when self-starting synchronous motor 11 operates as an induction motor, and the induced voltage decreases as the slip frequency decreases.

[0017] The armature coil 27 of the motor generates a rotating magnetic field by the three-phase AC power supplied from the three-phase AC main power supply 15 .

[0018] The excitation circuit AC power supply 12 supplies three-phase AC power for exciting the self-starting synchronous motor 11. The fixed-side excitation circuit rectifier 13 rectifies the three-phase AC power supplied from the excitation circuit AC power supply 12 and supplies it to the exciter fixed-side coil 21 as DC power.

[0019] The circuit breaker unit 14 includes a circuit breaker corresponding to each phase of the three-phase AC power, and is capable of interrupting the supply of three-phase AC power from the three-phase AC main power supply 15 to the armature coil 27 of the motor. The three-phase AC main power supply 15 supplies three-phase AC power for driving the self-starting synchronous motor to the armature coil 27 of the motor.

[0020] Next, the configuration of the rotary rectifier control circuit 24 will be described. Figure 2 is a functional block diagram of the rotary rectifier control circuit 24 of the first embodiment. The rotary rectifier control circuit 24 includes a rectifier circuit 31, a DC-DC conversion circuit 32, a level detection circuit 33, a first amplifier unit 34, a second amplifier unit 35, a first detection circuit 36, an input / output interface (IF) circuit 37, a set value holding circuit 38, a first determination circuit 39, a second determination circuit 40, a first photocoupler 41, a rotary rectifier thyristor control circuit 42, a second photocoupler 43, a field coil protection thyristor control circuit 44, and a waveform recording circuit 45.

[0021] The rotary rectifier thyristor control circuit 42 includes diodes DD1, DD2, DD3, thyristor THG, and resistors RG1, RG2, RG3, RG4, RG5, and RG6. The anodes of diodes DD1, DD2, and DD3 are connected to terminals S1, S2, and S3, respectively. The cathodes of diodes DD1, DD2, and DD3 are connected to the anode of thyristor THG and one end of resistor RG6.

[0022] The other end of resistor RG6 is connected to one end of resistor RG5 and the collector side (high potential side) of the phototransistor on the output side of the first photocoupler 41, and the other end of resistor RG5, the gate of thyristor THG, and one end of resistor RG4 are connected to the emitter side (low potential side) of the phototransistor on the output side of the first photocoupler 41. The other end of resistor RG4 is connected to the cathode of thyristor THG and one end of resistors RG1, RG2, and RG3. The other ends of resistors RG1, RG2, and RG3 are connected to terminals G1, G2, and G2, respectively. In other words, when the first photocoupler 41 is driven, thyristor THG is turned on, and thyristors TR1, TR2, and TR3 are also turned on.

[0023] The field coil protection thyristor control circuit 44 includes a thyristor THR, resistors RR1, RR2, and RR3, and a Zener diode ZD. The terminal SP is connected to the anode of the thyristor THR and one end of the resistor RR1.

[0024] The other end of resistor RR1 is connected to the cathode of Zener diode ZD and the collector side (high potential side) of the phototransistor on the output side of second photocoupler 43, and the anode of Zener diode ZD, the gate of thyristor THR, and one end of resistor RR2 are connected to the emitter side (low potential side) of the phototransistor on the output side of second photocoupler 43. The other end of resistor RR2 is connected to the cathode of thyristor THR and one end of resistor RR3. The other end of resistor RR3 is connected to terminal GR.

[0025] That is, when the second photocoupler 43 is activated or a voltage equal to or greater than the limiting voltage is applied to the Zener diode ZD, the thyristor THR turns on, and then the thyristor TR turns on. Here, the voltage value of the field coil 25 when a voltage equal to the limiting voltage is applied to the Zener diode ZD is defined as the breakover protection voltage VLZD.

[0026] The rectifier circuit 31 rectifies the three-phase AC input power input via the exciter rotating coil 22 and the power supply input terminals S 1 to S 3 , and outputs the rectified power to the DC-DC conversion circuit 32 .

[0027] The DC-DC conversion circuit 32 converts the voltage of the input DC power to a predetermined voltage (e.g., 3.3 V) and supplies it as an operating power source for each circuit that makes up the rotary rectifier control circuit 24, and also outputs it to the level detection circuit 33.

[0028] The level detection circuit 33 detects the voltage of the DC power output by the DC-DC conversion circuit 32, and when the voltage reaches a predetermined voltage level, generates a trigger signal TRG for controlling the waveform recording timing of the waveform recording circuit 45 and outputs the signal to the waveform recording circuit 45. Here, the predetermined voltage level is a voltage at which the first amplifier unit 34, the second amplifier unit 35, the first detection circuit 36, the input / output interface circuit 37, the set value holding circuit 38, the first determination circuit 39, the second determination circuit 40, etc. operate normally.

[0029] The first amplifier unit 34 is configured as an isolation amplifier, and detects the output voltage of the bridge rectifier 23, i.e., the voltage VL of the field coil 25, as the voltage between the terminals SP and SN, isolates it, performs AD conversion, detects it in an isolated state as a numerical signal, and outputs it to the first detection circuit 36 ​​and the second judgment circuit 40.

[0030] The second amplifier unit 35 is configured as an isolation amplifier and an AD converter, and detects a discharge resistor voltage VR, which is the voltage of a discharge resistor R (described below) that constitutes the field protection circuit 26, and outputs it to the first judgment circuit 39 and the waveform recording circuit 45.

[0031] The waveform recording circuit 45 receives and records the first positive voltage threshold Ht1, the second positive voltage threshold Ht2, the first negative voltage threshold Lt1, the second negative voltage threshold Lt2, the field coil frequency set value fsref, the first reference discharge resistor voltage VRref1, the second reference discharge resistor voltage VRref2, and the field coil voltage set value VLref from the input / output interface circuit 37. The waveform recording circuit 45 receives and records the field coil voltage VL from the first amplifier unit 34, the discharge resistor voltage VR from the second amplifier unit 35, the output signal DR1 from the first determination circuit 39A, and the output signal DR2 from the second determination circuit 40.

[0032] Here, the breakover protection voltage VLZD is greater than the field coil voltage set value VLref. The field coil voltage set value VLref is greater than the first reference discharge resistor voltage VRref1, which is greater than the second reference discharge resistor voltage VRref2.

[0033] The first detection circuit 36 ​​converts the voltage VL of the field coil 25 output by the first amplifier unit 34 into a binary voltage level LV of the voltage VL of the field coil 25 based on the first positive voltage threshold Ht1, the second positive voltage threshold Ht2, the first negative voltage threshold Lt1, and the second negative voltage threshold Lt2 held in the set value holding circuit 38, and outputs the binary voltage level LV.

[0034] The input / output interface (IF) circuit 37 is connected to the terminals SIF-IN / OUT of an external personal computer or tablet terminal, and performs input / output interface operations when writing setting values ​​to the setting value holding circuit 38, reading setting values ​​from the setting value holding circuit 38, and reading waveform data recorded in the waveform recording circuit 45. While this diagram illustrates a wired connection, an interface using short-range wireless communication such as Wi-Fi or Bluetooth (registered trademark) may also be used. In the following description, the external personal computer or tablet terminal will be collectively referred to simply as a personal computer.

[0035] The set value holding circuit 38 stores the first positive voltage threshold Ht1, the second positive voltage threshold Ht2, the second negative voltage threshold Lt2, and the first negative voltage threshold Lt1 in a nonvolatile manner. Note that the set value holding circuit 38 is configured to update only when the self-starting synchronous motor 11 is stopped. In this case, the magnitude relationship is set as follows: second positive voltage threshold Ht2 > first positive voltage threshold Ht1 > first negative voltage threshold Lt1 > second negative voltage threshold Lt2. Note that the relationship may also be first positive voltage threshold Ht1 > 0 > first negative voltage threshold Lt1.

[0036] When the frequency of the induced voltage waveform of the input field coil 25 is less than the frequency corresponding to the field coil frequency setting value fsref, for example, when the rotation speed of the motor becomes 97 to 98% of the rotation speed at synchronization and the phase exceeds 180 degrees, for example, when the voltage of the field coil changes from positive to negative, the first judgment circuit 39 outputs first judgment result output data DR1="H" level and outputs a gate signal GG via the first photocoupler 41.

[0037] This puts the bridge rectifier 23 into an operating state, rectifies the AC power sent from the AC exciter 2122, and supplies a drive current to the field coil 25. This causes the self-starting synchronous motor 11 to operate as a brushless synchronous motor.

[0038] The second determination circuit 40 compares the voltage VL of the field coil 25 with the field coil voltage set value VLref, and when the voltage VL of the field coil 25 exceeds the field coil voltage set value VLref, in order to protect the field coil 25, applies an “H” level gate signal GR to the gate of the thyristor THR via a photocoupler 43, turns on the thyristor THR, turns off the bridge rectifier 23, cuts off the power supply to the field coil 25, and performs control to protect the field coil 25.

[0039] When the first determination result output data DR1 becomes "H" level, the first photocoupler 41 outputs an "H" level gate signal GG for turning on a thyristor THG (described later) to the thyristor THG of the rotary rectifier thyristor control circuit 42 (described later). As a result, the thyristor THG, which has been turned on, outputs an "H" level gate signal from the gate output terminals G1 to G3 that turns on the thyristors TR1 to TR3 of the bridge rectifier 23.

[0040] When the rotary rectifier thyristor control circuit 42 receives an "H" level gate signal GG from the first photocoupler 41, the thyristor THG turns on, the DC power supplied from the bridge rectifier 23 is limited by resistors RG1 to RG3, and "H" level gate signals that turn on the thyristors TR1 to TR3 of the bridge rectifier 23 are output from gate output terminals G1 to G3. The "H" level gate signals that turn on the thyristors TR1 to TR3 cause the bridge rectifier 23 to transition to rectification operation.

[0041] When the second judgment result output data DR2 becomes "H" level, the second photocoupler 43 outputs a gate signal GR of "H" level that turns on the thyristor THR of the field coil protection thyristor control circuit 44 described later.

[0042] When the field coil protection thyristor control circuit 44 receives an "H" level gate signal GR from the second photocoupler 43, the thyristor THR turns on, the DC power supplied from the field coil 25 is limited by the resistor RR3, and an "H" level gate signal that turns on the thyristor TR of the field protection circuit 26 is output from the gate output terminal GR. This "H" level gate signal that turns on the thyristor TR of the field protection circuit 26 causes the field protection circuit 26 to transition to protection operation.

[0043] In this case, if the control power supply for the rotary rectifier control circuit 24 is established, the field coil protection thyristor control circuit 44 will transition to protection operation by turning on the thyristor TR as described above, but if the control power supply is not established, the second judgment circuit 40 cannot operate, and therefore such protection operation cannot be performed.

[0044] Therefore, when the control power supply for the rotary rectifier control circuit 24 is not established, the field coil protection thyristor control circuit 44 connects a Zener diode ZD in parallel with the phototransistor on the output side of the second photocoupler 43, and uses the nonlinear characteristics of the Zener diode ZD as an alternative, so that when the divided voltage of the forward field coil voltage VL exceeds the limiting voltage of the Zener diode ZD, a gate signal GR is sent to the thyristor THR, which turns on the thyristor TR and enters protection operation. Protection of the field coil using the nonlinear characteristics of the Zener diode ZD is an example of protection thyristor operation using a nonlinear element.

[0045] The waveform recording circuit 45 digitally records the waveform state of each part to manage the operating state of the rotary rectifier control circuit 24, and the recorded data can be read out by connecting an external personal computer and used for various management and maintenance purposes. The waveform recording circuit 45 records while the signal TRG from the level detection circuit 33 indicates that power has been established, and the record length is longer than the period from the establishment of power to the time the self-starting synchronous motor fully operates as a synchronous motor. Alternatively, the circuit may record continuously during operation, erasing old records and recording new data.

[0046] Next, the operation of the self-starting synchronous motor system of the first embodiment will be described. First, the initial setting process of the rotary rectifier control circuit 24 will be described. Figure 3 is a flowchart showing the initial setting process of the rotary rectifier control circuit 24 in the first embodiment of the present invention. First, in step S11, an operator connects a personal computer (PC) for initial setting to the serial input / output interface of the rotary rectifier control circuit 24.

[0047] Then, in step S12, the operator starts up the setting application, sets the first positive voltage threshold Ht1, the second positive voltage threshold Ht2, the first negative voltage threshold Lt1, the second negative voltage threshold Lt2, the field coil frequency setting value fsref, the first reference discharge resistor voltage VRref1, the second reference discharge resistor voltage VRref2, and the field coil voltage setting value VLref as setting values, and stores them in the setting value holding circuit 38.

[0048] When the process of setting the set values ​​is completed, the operator disconnects the personal computer (PC) used for initial setup from the serial input / output interface of the rotary rectifier control circuit 24 in step S13, thereby completing the initial setup of the rotary rectifier control circuit 24.

[0049] Next, the operation of the self-starting synchronous motor system at startup will be described. Fig. 4 is a flowchart (part 1) of the operation of the self-starting synchronous motor system of the first embodiment at startup. Fig. 5 is a flowchart (part 2) of the operation of the self-starting synchronous motor system of the first embodiment at startup. First, in step S21, the self-starting synchronous motor system 10 operates the fixed-side excitation circuit rectifier 13 to rectify the three-phase AC power from the excitation circuit AC power supply 12 into DC power, and energizes the exciter fixed-side coil 21 that constitutes the AC exciter 2122 of the self-starting synchronous motor 11.

[0050] As a result, when the exciter rotating side coil 22 rotates using DC power supplied from the excitation circuit AC power supply 12 via the fixed side excitation circuit rectifier 13, the exciter fixed side coil 21 can be supplied with power through electromagnetic induction.

[0051] Next, in step S22, the self-starting synchronous motor system 10 closes the circuit breaker that constitutes the circuit breaker unit 14, connects the three-phase AC main power supply 15 to the armature coil 27 of the motor, and supplies three-phase AC power from the three-phase AC main power supply 15 to the armature coil 27 of the motor.

[0052] As a result, in step S23, the self-starting synchronous motor 11 starts to operate as an induction motor, and the rotary shaft and the bridge rectifier 23 serving as a rotary rectifier start to rotate, gradually increasing the rotation speed.

[0053] A voltage is induced in the exciter rotating side coil 22, and as a result, in step S24, the exciter rotating side coil 22 converts the supplied DC power into three-phase AC power and outputs it to the bridge rectifier 23 and the rotary rectifier control circuit 24. Then, in step S25, the voltage of the exciter rotating side coil 22 increases, and the output voltage of the DC-DC conversion circuit 2 of the rotary rectifier control circuit 24 becomes a predetermined voltage.

[0054] The operation will now be described in more detail. In parallel with the above operation, a voltage is induced in the field coil 25 due to the interaction between the armature coil 22 and field coil 25 of the motor. The terminal voltage of this field coil 25, both in voltage and frequency, is higher the slower the rotational speed of the motor is at start-up, and the voltage and frequency decrease as the rotational speed of the motor approaches the rated speed (as slip as an induction motor decreases). The output voltage of the bridge rectifier 23, i.e., the voltage VL of the field coil 25, is detected in an insulated state by the first amplifier 34, which performs A / D conversion and outputs the detected voltage to the first detection circuit 36 ​​and the second determination circuit 40.

[0055] As a result, the first detection circuit 36 ​​outputs a binary voltage level LV of the voltage VL of the field coil 25 based on the voltage VL of the field coil 25 output by the first amplifier unit 34, and the first positive voltage threshold Ht1, the second positive voltage threshold Ht2, the first positive voltage threshold Lt1, and the second negative voltage threshold Lt2 held in the set value holding circuit 38.

[0056] Here, the calculation operation of the binarized voltage level LV in the first detection circuit will be described. Fig. 6 is a diagram illustrating the operation of the first detection circuit in the first embodiment of the present invention. As shown in Fig. 6, the waveform of the voltage VL of the field coil 25 contains noise and is significantly different from an ideal sine wave waveform.

[0057] Therefore, in the first embodiment, the concept of binarization status is used, using the first positive voltage threshold Ht1, the second positive voltage threshold Ht2, the first positive voltage threshold Lt1, and the second negative voltage threshold Lt2, and the binarization result, the binarized voltage level, is obtained according to the transition state of the binarization status. As a result, according to the first embodiment, appropriate phase excitation control can be reliably performed with a simple configuration and simple processing.

[0058] More specifically, excitation is performed based on the voltage VL of the field coil 25 at the zero crossing points where the voltage VL of the field coil 25 switches from a positive voltage to a negative voltage (the timing at which the binarization result in FIG. 5 switches from "H" to "L", i.e., the timing corresponding to times t4 and t8 in FIG. 5 at which the binarization status changes from status ST3, where "3", to status ST0, where "0"). This ensures that appropriate phase excitation control can be performed.

[0059] 7 is an explanatory diagram of transition states of the binarization status in the first embodiment of the present invention. For example, if the current status is status ST0, where binarization status="0", then as shown at time t5 in FIG. 6, if the voltage VL of field coil 25 exceeds the first positive voltage threshold Ht1 (VL>Ht1), the binarization status transitions to "1" and the binarization result becomes "H", and otherwise status ST0 is maintained.

[0060] Furthermore, if the current status is status ST1 with binarization status="1", then as shown at times t2 and t6 in FIG. 6, if the voltage VL of the field coil 25 exceeds the second positive voltage threshold Ht2 (VL>Ht2), the binarization status transitions to "2" and the binarization result is "H", and in any other cases the status ST1 is maintained.

[0061] Similarly, if the current status is status ST2 with binarization status="2", then as shown at times t3 and t7 in FIG. 6, if the voltage VL of the field coil 25 becomes less than the first negative voltage threshold Lt1 (VL<Lt1), the binarization status transitions to "3", and the binarization result is "L", and in any other cases the status ST2 is maintained.

[0062] Furthermore, if the current status is status ST3 with binarization status="3", then as shown at times t4 and t8 in FIG. 6, if the voltage VL of the field coil 25 becomes less than the second negative voltage threshold Lt2 (VL<Lt2), the binarization status transitions to "0" and the binarization result is "L", and in any other cases the status ST3 is maintained.

[0063] As explained above, the voltage VL (instantaneous voltage) of the field coil 25 is simply compared with the first positive voltage threshold Ht1, the second positive voltage threshold Ht2, the first negative voltage threshold Lt1 or the second negative voltage threshold Lt2, so that the influence of noise can be eliminated with very simple processing, and a stable binary result ("H" or "L") can be obtained.

[0064] Furthermore, the first positive voltage threshold Ht1, the second positive voltage threshold Ht2, the first negative voltage threshold Lt1, and the second negative voltage threshold Lt2 can be easily determined according to the specifications of the self-starting synchronous motor 11 to be controlled, and the control processing can be made constant simply by rewriting the data in the set value holding circuit 38. Therefore, compared to when an analog circuit is configured to perform appropriate phase excitation control, this can be applied to motors of various specifications without requiring any changes to the circuit design.

[0065] Furthermore, it is possible to easily accommodate not only changes in the specifications of the self-starting synchronous motor 11 but also changes in the load at the time of startup.

[0066] 4 and 5, the operation of the self-starting synchronous motor system at startup will be described. As described above, excitation should be performed at times t3 and t7 corresponding to the transition from status ST2, where the binary status is "2," to status ST3, where the binary status is "3," in FIG. 6. The voltage VL of the field coil 25 is then binarized by a loop consisting of steps S27 to S35 and step S38. In addition, in step S26, the first detection circuit 36 ​​sets the binary voltage level LV to "L" as an initial value.

[0067] Next, in step S27, the first judgment circuit resets to "0" a half-cycle counter for detecting the frequency of the induced voltage generated in the field coil 25, and further resets to "0" a synchronization flag indicating that the frequency of the induced voltage has become less than a predetermined frequency (a frequency at which an excitation current can be passed through the field coil).

[0068] Next, in step S28, the first detection circuit 36 ​​determines whether the field coil voltage LV exceeds the first positive voltage threshold Ht1. If the field coil voltage LV exceeds the first positive voltage threshold Ht1 (Yes), it is determined that the binarized status has changed to "1" and the process proceeds to step S29. If not (No), it is determined that the binarized status remains "0" and the process returns to step S28.

[0069] Next, in step S29, the first detection circuit 36 ​​sets the binary voltage level LV to "H", and in response to the binary voltage level LV being "H", the first determination circuit 39 operates a half-cycle counter for detecting the frequency of the field coil voltage LV and starts measuring time.

[0070] Next, in step S30, the first detection circuit 36 ​​determines whether the field coil voltage LV exceeds the second positive voltage threshold Ht2. If the field coil voltage LV exceeds the second positive voltage threshold Ht2 (Yes), it is determined that the binarization status has changed to "2" and the process proceeds to step S31. If not (No), it is determined that the binarization status remains "1" and the process returns to step S30.

[0071] Next, in step S31, the first determination circuit 39 determines whether the frequency of the field coil voltage LV has become less than a predetermined field coil frequency set value fsref. Specifically, it determines whether the time counted by the half-cycle counter has exceeded half the period of the field coil frequency set value fsref. If it has exceeded this (Yes), the process proceeds to step S32, where the first determination circuit 39 sets the synchronization flag to "1," and the process proceeds to step S33. If it has not exceeded this (No) in step S31, the process proceeds directly to step S33.

[0072] In step S33, the first detection circuit 36 ​​determines whether the field coil voltage LV is less than the first negative voltage threshold Lt1. If the field coil voltage LV is less than the first negative voltage threshold Lt1 (Yes), it is determined that the binarization status has changed to "3," and the process proceeds to step S34. If not (No), it is determined that the binarization status remains "2," and the process returns to step S31.

[0073] In step S34, the first determination circuit 39 sets the binarized voltage level LV to "L", and the process proceeds to step S35.

[0074] Next, in step S35, the first determination circuit 39 determines whether the frequency of the field coil voltage VL is less than a predetermined field coil frequency set value fsref and has reached zero crossing (i.e., the phase is 180 degrees when the field coil voltage VL is considered to be a sine wave); specifically, it determines whether the synchronization flag is "1." Since the timing at which step S35 is reached is immediately after the binarized voltage level LV changes from "H" to "L," it is sufficient to determine whether the synchronization flag is "1." If the synchronization flag is "1" (Yes), the process proceeds to step S36; if not (No), the process proceeds to step S38.

[0075] In step S36, the output DR1 of the first determination circuit is set to "H" level. When the output DR1 of the first determination circuit becomes "H" level, the phototransistor on the output side of the first photocoupler 41 turns on, and current from terminals S1 to S3 passes through diodes DD1 and DD2 and resistor GR6 to output an "H" level gate signal GG to thyristor THG of the rotary rectifier thyristor control circuit 42 to turn on thyristor THG. As a result, thyristor THG, which has turned on, outputs an "H" level gate signal from gate output terminals G1 to G3 to turn on thyristors TR1 to TR3 of the bridge rectifier 23.

[0076] This puts the bridge rectifier 23 into an operating state, rectifies the AC power sent from the AC exciter 2122, and supplies a drive current to the field coil 25. As a result, in step S37, the self-starting synchronous motor 11 operates as a brushless synchronous motor.

[0077] In step S38, the first detection circuit 36 ​​determines whether the field coil voltage VL is less than the second negative voltage threshold Lt2. If the field coil voltage VL is less than the second negative voltage threshold Lt2 (Yes), it determines that the binarization status has changed to "0" and the process returns to step S27. If not (No), it determines that the binarization status remains "3" and the process returns to step S38.

[0078] In this way, if the synchronization flag is not "1," it is determined that the rotational speed is not sufficient for the self-starting synchronous motor 11 to rotate as a synchronous motor, and the process returns to step S27 via step S38 to continue processing. In the flow of FIG. 4, the period (frequency) is determined by timing (counting) half periods in which the binary voltage level is H. However, the period (frequency) may also be determined by timing one period taking into account both the L and H binary voltage levels. When counting one period, starting the period timing from the timing when the binary voltage level is L allows for earlier detection of the falling edge.

[0079] FIG. 8 is an operation flowchart when an overvoltage is detected during startup of the self-starting synchronous motor system. The operation of the second determination circuit 40 will now be described using the flowchart of FIG. 8. The operation flowchart of FIG. 8 is processed in parallel with the operation flowcharts of FIGS. 4 and 5. In step S71, the second determination circuit 40 compares the voltage VL of the field coil 25 with the field coil voltage set value VLref, and determines whether the voltage VL of the field coil 25 is equal to or greater than the field coil voltage set value VLref. If the determination in step S71 shows that the voltage VL of the field coil 25 is not equal to or greater than the field coil voltage set value VLref (No), the process proceeds to step S72; if the determination is equal to or greater than the field coil voltage set value VLref (Yes), the process proceeds to step S73.

[0080] In step S73, the second determination circuit 40 sets its output, that is, the second determination result output data DR2, to "H" in order to protect the field coil 25.

[0081] As a result, when the second judgment result output data DR2 becomes "H" level, the second photocoupler 43 turns on and outputs an "H" level gate signal GR that turns on thyristor THR of the field coil protection thyristor control circuit 44 from terminal SP via resistor RR1, turning thyristor THR on, and the process proceeds to step S71, where it continues. By turning thyristor THR on, a gate signal is provided to thyristor TR, which turns on thyristor TR and current flows through discharge resistor R, protecting the field coil.

[0082] If it is determined in step S71 that the voltage VL of the field coil 25 is equal to or lower than the field coil voltage set value VLref (No), the process proceeds to step S72 and continues.

[0083] In step S72, the second determination circuit 40 sets its output, the second determination result output data DR2, to "L" to turn off the thyristor TR. This causes the second photocoupler 43 to stop the gate signal GR of the thyristor THR. As a result, when the voltage VL of the field coil 25 becomes negative, the thyristor THR is turned off and the gate of the thyristor TR is also stopped, so that the thyristor TR is also turned off.

[0084] Next, the protective operation of the discharge resistor R when the self-starting synchronous motor system is operating with the self-starting synchronous motor 11 as a synchronous motor will be described. Figure 9 is a flowchart of the operation of the self-starting synchronous motor system during operation. The flowchart of Figure 9 does not apply when the system is operating according to the flowcharts of Figures 4 and 5.

[0085] While the self-starting synchronous motor system 10 is operating, the second determination circuit 40 compares the voltage VL of the field coil 25 with the field coil voltage set value VLref, and determines whether the voltage VL of the field coil 25 is equal to or greater than the field coil voltage set value VLref (step S41).

[0086] If it is determined in step S41 that the voltage VL of the field coil 25 is equal to or greater than the field coil voltage setting value VLref (Yes), the process proceeds to step S42, and if not (No), the process proceeds to step S47.

[0087] In step S42, to protect the field coil 25 from overvoltage, the second detection circuit 40 sets its output DR2 to "H". When DR2 becomes "H", the second photocoupler 43 turns on and outputs an "H" level gate signal GR to turn on thyristor THR of the field coil protection thyristor control circuit 44 from terminal SP via resistor RR1 of the field protection circuit 26, turning on thyristor THR. By turning thyristor THR on, a gate signal is given to thyristor TR, which turns on thyristor TR and current flows through discharge resistor R, protecting the field coil 25. Then, the process proceeds to step S43.

[0088] Next, in step S43, the first determination circuit 39 determines whether the voltage VR of the discharge resistor R is equal to or greater than the first reference discharge resistor voltage VRref1. If it is determined in step S43 that the voltage VR of the discharge resistor R is less than the first reference discharge resistor voltage VRref1 (No), it is determined that no current flows into the discharge resistor R from the thyristor TR, and the process proceeds to step S45.

[0089] If it is determined in step S43 that the voltage VR of the discharge resistor R is equal to or higher than the first reference discharge resistor voltage VRref1 (Yes), the process proceeds to step S44.

[0090] In step S44, the first determination circuit 39 sets its output DR1 to the "L" level. When the output DR1 of the first photocoupler 41 goes to the "L" level, the phototransistor on the output side of the first photocoupler 41 turns off, so that the gate signal GG of the thyristor THG of the rotary rectifier thyristor control circuit 42 goes to the L level, turning off the thyristor THG. As a result, the gate signals of the thyristors TR1 to TR3 of the bridge rectifier 23 from the gate output terminals G1 to G3 stop, and the thyristors TR1 to TR3 turn off.

[0091] As a result, the current supply from the bridge rectifier 23 is cut off, so that the thyristor TR is turned off, cutting off the current supply to the discharge resistor R and preventing burnout of the discharge resistor R. Then, the process proceeds to step S45.

[0092] In step S45, the first determination circuit 39 determines whether the voltage VR of the discharge resistor R is equal to or lower than the second reference discharge resistor voltage VRref2.

[0093] In the judgment of step S45, if it is judged that the voltage VR of the discharge resistor R is equal to or lower than the second reference discharge resistor voltage VRref1 (Yes), the process proceeds to step S46. If it is judged that the voltage VR of the discharge resistor R is not equal to or lower than the second reference discharge resistor voltage VRref1 (No), the process ends.

[0094] In step S46, if the voltage of the discharge resistor R is equal to or lower than the second reference discharge resistor voltage VRref1, the current supply from the bridge rectifier 23 has been cut off, and the following operation is performed to cause the bridge rectifier 23 to again supply current to the field coil 25. The output DR1 of the first determination circuit 39 is set to "H" level. When the signal DR1 becomes "H" level, the phototransistor on the output side of the first photocoupler 41 turns on, and the current from the terminals S1 to S3 passes through the diodes DD1 and DD2 and the resistor GR6, and outputs an "H" level gate signal GG to the thyristor THG of the rotary rectifier thyristor control circuit 42 to turn on the thyristor THG.

[0095] As a result, thyristor THG, which is now in the ON state, outputs an "H" level gate signal from gate output terminals G1 to G3 that turns on thyristors TR1 to TR3 of bridge rectifier 23. Therefore, thyristors TR1 to TR3 turn on, and current supply from bridge rectifier 23 to field coil 25 begins again, allowing self-starting synchronous motor 11 to operate as a synchronous motor.

[0096] In step S47, the second decision circuit 40 sets its output DR2 to "L". When DR2 becomes "L", the second photocoupler 43 turns off, and the gate signal GR that turns on the thyristor THR of the field coil protection thyristor control circuit 44 from the terminal SP via the resistor RR1 of the field protection circuit 26 becomes "L", and the thyristor THR is turned off.

[0097] Therefore, the gate signal is no longer applied to the thyristor TR, the thyristor TR is turned off, and no current flows through the discharge resistor R. Then, the process proceeds to step S43, and the above-described process is carried out thereafter.

[0098] Next, the operation of the self-starting synchronous motor system when it is stopped will be described. Fig. 10 is a flowchart showing the operation when the self-starting synchronous motor system is stopped. When the self-starting synchronous motor system 10 is stopped, the circuit breaker 14 constituting the circuit breaking unit is opened to disconnect the three-phase AC main power supply 15 from the armature coil 27 of the motor, thereby stopping the supply of three-phase AC power from the three-phase AC main power supply 15 (step S51).

[0099] Next, the fixed-side excitation circuit rectifier 13 is stopped, and the current to the fixed-side coil 21 of the AC exciter 2122 is stopped (step S52). As a result, the voltage of the rotating-side coil of the AC exciter 2122 drops, and the output voltage of the DC-DC conversion circuit 32 drops from the predetermined voltage (step S53).

[0100] Furthermore, the trigger signal of the level detection circuit 33 stops, recording by the waveform recording device 45 stops, the first judgment result output data DR1 of the first judgment circuit 39 and the second judgment result output data DR2 of the second judgment circuit 40 become "L" level, thyristors TR1 to TR3 and thyristor TR become OFF (step S54), and the self-starting synchronous motor system 10 transitions to a stopped state.

[0101] As described above, according to the first embodiment, it is possible to realize a rotary rectifier control circuit that has a simple configuration, is highly versatile, and can reliably perform appropriate phase excitation control, and ultimately, a self-starting synchronous motor system.

[0102] [2] Second Embodiment Next, a second embodiment of the present invention will be described. Figure 11 is a functional block diagram of a rotary rectifier control circuit 24A according to the second embodiment of the present invention. In the second embodiment, the rotary rectifier control circuit 24 in the first embodiment is replaced with a rotary rectifier control circuit 24A, with the remaining components remaining unchanged. Components that are the same as those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted. The rotary rectifier control circuit 24A according to the second embodiment includes a first detection circuit 36A instead of the first detection circuit 36, a setting hold circuit 38A instead of the setting hold circuit 38, and a waveform recording circuit 45A instead of the waveform recording circuit 45.

[0103] In the first embodiment, the first detection circuit 36 ​​outputs a binary voltage level LV of the voltage VL of the field coil 25 based on the first positive voltage threshold Ht1, the second positive voltage threshold Ht2, the first negative voltage threshold Lt1, and the second negative voltage threshold Lt2 held in the set value holding circuit 38, but in the second embodiment, the second detection circuit 36A outputs the phase θs and frequency fs of the fundamental wave of the voltage VL of the field coil 25 to the first determination circuit 39A. The second detection circuit 36A continuously performs phase comparison using a method such as a Hilbert transform or a PLL from the input voltage VL of the field coil 25, and calculates and outputs the phase θs and frequency fs of the fundamental wave of the voltage VL. The second detection circuit 36A may be configured using a dedicated IC or the like.

[0104] The set value holding circuit 38A receives and holds the field coil frequency set value fsref, the first field coil phase set value θsref1, the second field coil phase set value θsref2, the first reference discharge resistor voltage VRref1, the second reference discharge resistor voltage VRref2, and the field coil voltage set value VLref from the input / output interface circuit 37.

[0105] The waveform recording circuit 45A receives and records the field coil frequency setting value fsref, the first field coil phase setting value θsref1, the second field coil phase setting value θsref2, the first reference discharge resistor voltage VRref1, the second reference discharge resistor voltage VRref2, and the field coil voltage setting value VLref from the input / output interface circuit 37. The waveform recording circuit 45A receives and records the field coil voltage VL from the first amplifier unit 34, the discharge resistor voltage VR from the second amplifier unit 35, the output signal DR1 from the first judgment circuit 39A, and the output signal DR2 from the second judgment circuit 40.

[0106] Fig. 12 is a flowchart showing the initial setting process of the rotary rectifier control circuit 24A in the second embodiment of the present invention. Fig. 13 is a flowchart showing the operation of the self-starting synchronous motor system at the start of the second embodiment. In this second embodiment, the operation flowchart of the second determination circuit corresponding to Fig. 8, the operation flowchart of the self-starting synchronous motor system during operation corresponding to Fig. 9, and the operation flowchart of the self-starting synchronous motor system at the stop corresponding to Fig. 10 are similar, so their explanations will be omitted and will be used interchangeably.

[0107] In FIG. 12 , only the differences from FIG. 3 of the first embodiment will be described. Similar steps are assigned the same numbers and will not be described again. The difference from FIG. 3 is that step S12 is replaced with step S12A, and in step S12A, the operator launches a setting application and sets the field coil frequency setting value fsref, the first field coil phase setting value θsref1, the second field coil phase setting value θsref2, the first discharge resistor voltage setting value VRref1, the second discharge resistor voltage setting value VRref2, and the field coil voltage setting value VLref as setting values, which are then stored in the setting value holding circuit 38. Here, the second field coil phase setting value θsref2 is greater than the first field coil phase setting value θsref1, and it is desirable that both be values ​​close to 180 degrees. The other steps are the same as those in FIG. 3 .

[0108] In Fig. 13, only the differences from Fig. 4 or Fig. 5 of the first embodiment will be described. The same steps are given the same numbers, and their description will be omitted. Steps S21 to S25 are the same as those in Fig. 4 or Fig. 5. Steps S36 and S37 are also the same.

[0109] 13, the process proceeds to step S26A after step S25, where the first determination circuit 39A determines whether the frequency fs of the fundamental wave of the voltage VL received from the first detection circuit 36A is smaller than the field coil frequency set value fsref. If the frequency fs is smaller than the field coil frequency set value fsref (Yes), the process proceeds to step S27A, and if not, the process returns to step S26A.

[0110] In step S27A, the first determination circuit 39A determines whether the phase θs of the fundamental wave of the voltage VL received from the first detection circuit 36A is greater than the first field coil phase set value θsref1 and less than the second field coil phase set value θsref2. If the phase θs is greater than the first field coil phase set value θsref1 and less than the second field coil phase set value θsref2 (Yes), the process proceeds to step S36; if not, the process returns to step S26A. The other steps are the same as in FIG. 4, and therefore description thereof will be omitted.

[0111] As explained above, like the first embodiment, the second embodiment also makes it possible to realize a rotary rectifier control circuit that has a simple configuration, is highly versatile, and can reliably perform appropriate phase excitation control, and ultimately, a self-starting synchronous motor system.

[0112] The control circuit of the rotary rectifier of each embodiment includes a control device such as an MPU, a storage device such as a ROM (Read Only Memory) or RAM, an external storage device configured as a semiconductor memory device such as an SSD or USB memory, a display device such as a display device, and an input device such as an operation panel or operation switches, and is configured as hardware using a normal computer.

[0113] The program executed by the control circuit of the rotary rectifier of this embodiment is provided as a file in an installable or executable format recorded on a semiconductor memory device such as an SSD or USB memory, or a computer-readable recording medium such as a DVD (Digital Versatile Disk).

[0114] The program executed by the control circuit of the rotary rectifier of this embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network.The program executed by the control circuit of the rotary rectifier of this embodiment may be provided or distributed via a network such as the Internet.

[0115] The program for the control circuit of the rotary rectifier of this embodiment may be provided in advance in a ROM or the like.

[0116] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0117] In the above description, the thyristor bridge rectifier is configured as a mixed thyristor bridge rectifier, but it can also be configured as a pure thyristor bridge rectifier.

[0118] In the above explanation, the first detection circuit 36 ​​is configured to perform A / D conversion of the voltage VL of the field coil 25 output by the first amplifier unit 34, and to output a binarized voltage level LV of the voltage VL of the field coil 25 based on the first positive voltage threshold Ht1, the second positive voltage threshold Ht2, the first negative voltage threshold Lt1, and the second negative voltage threshold Lt2 held in the set value holding circuit 38, but instead, it may be configured to perform binarization digitally with hysteresis characteristics.

[0119] Furthermore, instead of the first detection circuit 36, it may be configured as a continuous phase comparison circuit, for example, using a PLL, a digital phase detection circuit, or an IC for a phase frequency detector, or it may be configured to use a Hilbert transform circuit as disclosed in Japanese Patent Laid-Open No. 2003-143063.

[0120] In the above explanation, the first detection circuit 36 ​​is configured to perform A / D conversion of the voltage VL of the field coil 25 output by the first amplifier unit 34, and to output a binarized voltage level LV of the voltage VL of the field coil 25 based on the first positive voltage threshold Ht1, the second positive voltage threshold Ht2, the first negative voltage threshold Lt1, and the second negative voltage threshold Lt2 held in the set value holding circuit 38, but instead, it may be configured to perform binarization digitally with hysteresis characteristics.

[0121] 10 Self-starting synchronous motor system 11 Self-starting synchronous motor 12 Excitation circuit AC power supply 13 Fixed side excitation circuit rectifier 14 Circuit breaker unit 15 Three-phase AC main power supply 21 Exciter fixed side coil 22 Exciter rotating side coil 23 Bridge rectifier 24 Rotating rectifier control circuit 25 Field coil 26 Field protection circuit 27 Motor armature coil 31 Rectifier circuit 32 DC-DC conversion circuit 33 Level detection circuit 34 First amplifier unit 35 Second amplifier unit 36 ​​First detection circuit 37 Input / output interface circuit 38 Set value holding circuit 39 First judgment circuit 40 Second judgment circuit 41 First photocoupler 42 Rotating rectifier thyristor control circuit 43 Second photocoupler 44 Field coil protection thyristor control circuit 45 Waveform recording circuits DD1 to DD3 Diode DR1 First judgment result output data DR2 Second judgment result output data fs Frequency fsref Field coil frequency setting value fsref1 Field coil frequency setting value fsref2 Field coil frequency G1 Gate output terminal DR Diode GG Gate signal GR Gate signal Ht1 First positive voltage threshold Ht2 Second positive voltage threshold Lt1 First negative voltage threshold Lt2 Second negative voltage threshold IC For phase frequency detector LV Digitized voltage level N Low potential side power supply line P High potential side power supply line R Discharge resistor ST0 to ST3 Status THG Thyristor THR Thyristor TR Field coil protection thyristor TR1 to TR3 thyristor VL Field coil voltage VLref Field coil voltage setting value VR Discharge resistor voltage VRref1 First reference discharge resistor voltage VRref2 Second reference discharge resistor voltage ZD Zener diode θs Phase θsref1 Field coil phase setting value θsref2 Field coil phase setting value

Claims

1. detecting an instantaneous voltage of a field coil, calculating a frequency from the instantaneous voltage, and supplying a current from a rotary rectifier to the field coil within a predetermined phase range including a zero crossing point where the instantaneous voltage changes from positive to negative; a detection circuit that performs A / D conversion of the voltage of the field coil and outputs the voltage of the field coil as a binary voltage level based on a first positive voltage threshold, a second positive voltage threshold, a first negative voltage threshold, and a second negative voltage threshold that are stored in advance; Rotary rectifier control circuit.

2. (delete)

3. The rotary rectifier is configured as a circuit including a mixed thyristor bridge rectifier or a pure thyristor bridge rectifier.

2. The rotary rectifier control circuit of claim 1.

4. A circuit is provided in which a protection thyristor and a discharge resistor are connected in series in parallel with the field coil, the protection thyristor is provided with a protection diode connected in anti-parallel, the protection thyristor is provided with a protection circuit that energizes the protection thyristor to protect the field coil when the forward voltage of the field coil becomes equal to or greater than a predetermined coil voltage value, and further configured so that when the power supply of the control circuit is not established, the protection thyristor is operated by a non-linear element.

2. The rotary rectifier control circuit of claim 1.

5. a means for detecting a terminal voltage of the discharge resistor; When the terminal voltage becomes equal to or greater than a predetermined resistance voltage value, the thyristor constituting the rotary rectifier is turned off.

5. The rotary rectifier control circuit of claim 4.

6. a set value holding circuit that stores the predetermined phase range and the predetermined coil voltage value in a non-volatile manner as set values; the set value holding circuit is externally accessible when the brushless self-starting synchronous motor to be controlled is stopped; 5. The rotary rectifier control circuit of claim 4.

7. a set value holding circuit that stores the predetermined resistance voltage value as a set value in a nonvolatile manner; the set value holding circuit is externally accessible when the brushless self-starting synchronous motor to be controlled is stopped; 6. The rotary rectifier control circuit of claim 5.

8. A waveform recording circuit is provided to record waveform data of each part of the control circuit of the rotary rectifier.

2. The rotary rectifier control circuit of claim 1.

9. The power supply for the control circuit is obtained by being insulated in parallel from the AC input power supply for the rotary rectifier.

2. The rotary rectifier control circuit of claim 1.

10. a control circuit for the rotary rectifier of claim 1; a rotary rectifier; A brushless self-starting synchronous motor equipped with a