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

Abstract

The control circuit for a rotary rectifier according to the embodiment detects an instantaneous voltage of the field coil, calculates a frequency from the instantaneous voltage, and causes the rotary rectifier to supply a current to the field coil within a predetermined phase range including a zero-crossing point at which the instantaneous voltage changes from positive to negative, and thus, a general optimum phase excitation control can be performed with a simple configuration.

Description

Technical Field

[0001] The embodiments of the present invention relate to the control circuit of a rotating rectifier and a brushless self-starting synchronous motor. Background Technology

[0002] Traditional brushless synchronous motors have a starting configuration in which the brushless synchronous motor performs self-starting as an induction motor and performs optimal phase excitation control at a speed close to synchronous speed to initiate current flow in the excitation coil.

[0003] In optimal phase excitation control, the brushless synchronous motor needs to have a shaft speed sufficiently close to the synchronous speed for excitation, and the slip needs to have a specific value or a smaller value. Additionally, to increase the rotor's pull-in torque, the timing for allowing the excitation current to flow through the excitation coil needs to be appropriately selected.

[0004] References Patent documents Patent Document 1: JPS59-053069A Patent Document 2: JPS59-117490A Patent Document 3: JPS60-070982A Patent Document 4: JPS60-160069U Invention Summary The problem that the invention aims to solve Therefore, in optimal phase excitation control, when the negative electrode side (low potential side) of the rotating rectifier is used as the reference point, it is desirable for the current from the rotating rectifier to flow through the excitation coil at the zero-crossing point detected when the voltage of the excitation coil drops. That is, when the voltage of the excitation coil is regarded as a sine wave, it flows through the excitation coil at a phase of 180 degrees. However, the actual excitation voltage waveform contains noise, so it is necessary to measure the noise to prevent chattering.

[0005] As a countermeasure against noise, hysteresis can be considered. However, due to hysteresis, zero-crossing points are detected at timings exceeding the hysteresis level, and timing deviations occur from the ideal threshold level, which may prevent the excitation from being performed at the optimal timing.

[0006] Furthermore, when the circuit used to detect zero crossing points is composed of analog circuits, it is necessary to construct the circuit according to the specifications of the brushless synchronous motor, which leads to low versatility and increased design and manufacturing costs.

[0007] The present invention was made in view of the above circumstances, and the object of the present invention is to provide a control circuit for a rotating rectifier and a brushless self-starting synchronous motor, which can reliably perform general optimal phase excitation control with a simple configuration.

[0008] Methods for solving problems According to the embodiment, the control circuit for the rotating rectifier detects the instantaneous voltage of the excitation coil, calculates the frequency based on the instantaneous voltage, and causes the rotating rectifier to supply current to the excitation coil within a predetermined phase range including the zero-crossing point where the instantaneous voltage changes from positive to negative. Attached Figure Description

[0009] Figure 1 This is a schematic diagram illustrating the configuration of a self-starting synchronous motor system.

[0010] Figure 2 This is a functional block diagram of the rotating rectifier control circuit 24 according to the first embodiment.

[0011] Figure 3 This is a flowchart of the initial setting process in the rotating rectifier control circuit 24 according to the first embodiment of the present invention.

[0012] Figure 4 This is a flowchart (1) of the operation during startup of the self-starting synchronous motor system according to the first embodiment.

[0013] Figure 5 This is a flowchart (2) of the operation during startup of the self-starting synchronous motor system according to the first embodiment.

[0014] Figure 6 This is an explanatory diagram of the operation of the first detection circuit according to the first embodiment of the present invention.

[0015] Figure 7 This is an explanatory diagram of the transition state of the binarized state according to the first embodiment of the present invention.

[0016] Figure 8 This is a flowchart of the operations performed when an overvoltage is detected at the start-up point of a self-starting synchronous motor system.

[0017] Figure 9 This is a flowchart of the operations performed during the operation of a self-starting synchronous motor system.

[0018] Figure 10 This is a flowchart of the operations performed when stopping a self-starting synchronous motor system.

[0019] Figure 11 This is a functional block diagram of the rotating rectifier control circuit 24A according to the second embodiment of the present invention.

[0020] Figure 12 This is a flowchart of the initial setting process in the rotating rectifier control circuit 24A according to the second embodiment of the present invention.

[0021] Figure 13 This is a flowchart of the operation during startup of the self-starting synchronous motor system according to the second embodiment. Detailed Implementation

[0022] [1] First implementation method Figure 1 This is a schematic diagram illustrating the configuration of a self-starting synchronous motor system.

[0023] The self-starting synchronous motor system 10 includes a self-starting synchronous motor 11, an excitation circuit AC power supply 12, a fixed excitation circuit rectifier 13, a circuit breaker unit 14, and a three-phase AC main power supply 15.

[0024] The self-starting synchronous motor 11 includes a fixed excitation coil 21, a rotating excitation coil 22, a bridge rectifier 23, a rotating rectifier control circuit 24, an excitation coil 25, an excitation protection circuit 26, and a motor armature coil 27. Here, the rotating excitation coil 22, the bridge rectifier 23, the rotating rectifier control circuit 24, the excitation coil 25, and the excitation protection circuit 26 are fixed to the rotating shaft of the self-starting synchronous motor 11 and rotate together with the rotating shaft. Furthermore, the fixed excitation coil 21 and the rotating excitation coil 22 constitute an AC exciter 2122.

[0025] The fixed excitation circuit rectifier 13 is connected to the fixed excitation coil 21, which is electromagnetically coupled to the rotating excitation coil 22 by the DC power obtained by rectifying the three-phase AC power from the excitation circuit AC power supply 12 via the fixed excitation circuit rectifier 13.

[0026] The rotating excitation coil 22 includes a star-connected (Y-connected) coil, electromagnetically coupled to a fixed coil 21, and converts the supplied DC power into three-phase AC power, outputting the obtained three-phase AC power to a bridge rectifier 23 and a rotating rectifier control circuit 24. The three-phase AC outputs (A, B, and C) from the rotating excitation coil 22 are connected to the AC input of the bridge rectifier 23 and to terminals S1, S2, and S3, respectively, which serve as the power inputs to the rotating rectifier control circuit 24.

[0027] exist Figure 1In the example, bridge rectifier 23 is configured as a non-uniform bridge rectifier and includes thyristors TR1 to TR3. Each of thyristors TR1 to TR3 has a cathode connected to the high-potential power line P, a diode D1 having a cathode connected to the anode of thyristor TR1 and an anode connected to the low-potential power line N, a diode D2 having a cathode connected to the anode of thyristor TR2 and an anode connected to the anode of the low-potential power line N, and a diode D3 having a cathode connected to the anode of thyristor TR3 and an anode connected to the anode of the low-potential power line N. Note that the gates of thyristors TR1, TR2, and TR3 are respectively connected to terminals G1, G2, and G3 of the rotating rectifier control circuit 24.

[0028] The rotating rectifier control circuit 24 is configured, for example, to include a circuit called an MPU or field-programmable gate array, and performs optimal phase excitation control and protection control based on the voltage across the excitation coil 25 to protect the excitation coil 25 from overvoltage.

[0029] The excitation coil 25 is electromagnetically coupled to the motor armature coil 27 and obtains the rotational driving force generated by the magnetic field formed by the motor armature coil 27.

[0030] When an overvoltage occurs in the excitation coil 25, the excitation protection circuit 26 utilizes the energy induced in the excitation coil 25 to cause an electrical follower in the resistance of the excitation protection circuit, thereby reducing the voltage between the terminals of the excitation coil 25 (the voltage between the high potential power line P and the low potential power line N), and protecting the excitation coil 25 and the bridge rectifier 23. The high potential power line P is connected to the terminal SP of the rotating rectifier control circuit 24, and the low potential power line N is connected to the terminal SN of the rotating rectifier control circuit 24.

[0031] More specifically, the excitation protection circuit 26 includes a thyristor TR having an anode connected to the high-potential power supply line P, a discharge resistor R connected between the anode of the thyristor TR and the low-potential power supply line N, and a diode DR having a cathode connected to the high-potential power supply line P and an anode connected to the junction point between the thyristor TR and the discharge resistor R. The thyristor TR has a gate connected to the terminal GR of the rotating rectifier control circuit 24, and the terminal SR of the rotating rectifier control circuit 24 is connected to the junction point between the thyristor TR and the discharge resistor R for detecting the voltage across the discharge resistor.

[0032] Here, a discharge resistor R is provided to suppress the voltage across the excitation coil 25 to approximately a predetermined voltage (e.g., 600V) to protect the excitation coil 25. Note that the reverse voltage applied to the excitation coil 25 is discharged by the diode DR. The voltage VL across the excitation coil 25 is substantially sinusoidal at the start-up of the self-starting synchronous motor 11 and has a frequency that is the slip frequency during the operation of the self-starting synchronous motor 11 as an induction motor, and an induced voltage that decreases as the slip frequency decreases.

[0033] The armature coil 27 of the electric motor generates a rotating magnetic field by means of three-phase AC power supplied from the three-phase AC main power supply 15.

[0034] The excitation circuit AC power supply 12 supplies three-phase AC power for the excitation of the self-starting synchronous motor 11.

[0035] The fixed excitation circuit rectifier 13 rectifies the three-phase AC power supplied from the excitation circuit AC power supply 12 into DC power, and supplies the DC power to the fixed excitation coil 21.

[0036] Circuit breaker unit 14 includes circuit breakers corresponding to each phase of the three-phase AC power supply to interrupt the three-phase AC power supplied from the three-phase AC main power supply 15 to the motor armature coil 27.

[0037] The three-phase AC main power supply 15 supplies three-phase AC power to the motor armature coil 27 for driving the self-starting synchronous motor.

[0038] Next, the configuration of the rotating rectifier control circuit 24 will be described.

[0039] Figure 2 This is a functional block diagram of the rotating rectifier control circuit 24 according to the first embodiment.

[0040] The rotating 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 judgment circuit 39, a second judgment circuit 40, a first optocoupler 41, a rotating rectifier thyristor control circuit 42, a second optocoupler 43, an excitation coil protection thyristor control circuit 44, and a waveform recording circuit 45.

[0041] The rotating rectifier thyristor control circuit 42 internally includes diodes DD1, DD2, DD3, thyristor THG, resistors RG1, RG2, RG3, RG4, RG5, and RG6.

[0042] Diodes DD1, DD2, and DD3 have anodes connected to terminals S1, S2, and S3, respectively. Diodes DD1, DD2, and DD3 also have anodes connected to the anode of thyristor THG and a cathode connected to one end of resistor RG6.

[0043] The other end of resistor RG6 is connected to one end of resistor RG5 and the collector side (high potential side) of the phototransistor located on the output side of the first optocoupler 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 optocoupler 41.

[0044] The other end of resistor RG4 receives the connection between the cathode of thyristor THG and one end of each of resistors RG1, RG2, and RG3. The other ends of resistors RG1, RG2, and RG3 are connected to terminals G1, G2, and G3, respectively. In other words, when the first optocoupler 41 is driven, thyristor THG is turned on, and thyristors TR1, TR2, and TR3 are also turned on.

[0045] The excitation coil protection thyristor control circuit 44 internally includes a thyristor THR, resistors RR1, RR2, RR3, and a Zener diode ZD. Terminal SP is connected to the anode of the thyristor THR and one end of resistor RR1.

[0046] 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 located on the output side of the second optocoupler 43. 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 the second optocoupler 43. The other end of resistor RR2 receives the connection between the cathode of thyristor THR and one end of resistor RR3. The other end of resistor RR3 is connected to terminal GR.

[0047] In other words, when the second optocoupler 43 is driven or a voltage equal to or greater than the clamping voltage is applied to the Zener diode ZD, the thyristor THR turns on, and further, the thyristor TR turns on. Here, when the clamping voltage is applied to the Zener diode ZD, the voltage value of the excitation coil 25 is defined as the breakover protection voltage VLZD.

[0048] The rectifier circuit 31 rectifies the three-phase AC input power input through the rotating excitation coil 22 and terminals S1 to S3 for power input, and outputs the obtained three-phase AC input power to the DC-DC conversion circuit 32.

[0049] DC-DC conversion circuit 32 performs DC-DC conversion on the voltage of the input DC power to provide a predetermined voltage (e.g., 3.3V) as the operating power supply for each circuit constituting the rotating rectifier control circuit 24, and further outputs the predetermined voltage to level detection circuit 33.

[0050] The level detection circuit 33 detects the voltage of the DC power output from the DC-DC conversion circuit 32, and when the voltage has a predetermined voltage level, the level detection circuit 33 generates a trigger signal TRG for controlling the waveform recording timing in the waveform recording circuit 45, and outputs the obtained trigger signal TRG to the waveform recording circuit 45. Here, the predetermined voltage level is the 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 judgment circuit 39, and the second judgment circuit 40 operate normally.

[0051] The first amplifier unit 34, configured as an isolation amplifier, detects the output voltage from the bridge rectifier 23, that is, the voltage VL across the excitation coil 25 as the voltage between terminals SP and SN, and then detects the voltage VL in the isolation, AD conversion and isolation states of the numerical signal, and outputs the voltage VL to the first detection circuit 36 ​​and the second judgment circuit 40.

[0052] The second amplifier unit 35, configured as an isolation amplifier and an AD converter, detects the discharge resistor voltage VR, which is the voltage across the discharge resistor R, which constitutes the excitation protection circuit 26 and is described later, and outputs the discharge resistor voltage VR to the first judgment circuit 39 and the waveform recording circuit 45.

[0053] 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 excitation coil frequency setting value fsref, the first reference discharge resistor voltage VRref1, the second reference discharge resistor voltage VRref2, and the excitation coil voltage setting value VLref, which are input from the input / output interface circuit 37.

[0054] The waveform recording circuit 45 records the excitation coil voltage VL input from the first amplifier unit 34, the discharge resistor voltage VR input from the second amplifier unit 35, the output signal DR1 input from the first judgment circuit 39A, and the output signal DR2 input from the second judgment circuit 40.

[0055] Here, the transition protection voltage VLZD is greater than the excitation coil voltage setting value VLref. Furthermore, the excitation coil voltage setting value VLref is greater than the first reference discharge resistor voltage VRref1, and the first reference discharge resistor voltage VRref1 is greater than the second reference discharge resistor voltage VRref2.

[0056] The first detection circuit 36, 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, converts the voltage VL across the excitation coil 25 output by the first amplifier unit 34 into a binary voltage level LV of the voltage VL across the excitation coil 25, and outputs the obtained voltage level VL.

[0057] In the input / output interface (IF) circuit 37, an external personal computer or tablet terminal is connected to the SIF-input / output terminal for input / output interface operation when writing settings to the setpoint holding circuit 38, reading settings from the setpoint holding circuit 38, or reading waveform data recorded in the waveform recording circuit 45. In the accompanying drawings, the interface is shown as a wired connection, but it could be an interface using near-field communication such as Wi-Fi or Bluetooth (registered trademark). Note that in the following description, the external personal computer or tablet terminal is collectively referred to as a personal computer.

[0058] The setpoint 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 non-volatile manner. Note that the setpoint holding circuit 38 is configured to be updated only when the self-starting synchronous motor 11 stops.

[0059] In this configuration, the amplitude relationship is set such that the second positive voltage threshold Ht2 > the first positive voltage threshold Ht1 > the first negative voltage threshold Lt1 > the second negative voltage threshold Lt2. Note that the relationship of first positive voltage threshold Ht1 > 0 > first negative voltage threshold Lt1 can also be used.

[0060] In the first judgment circuit 39, when the frequency of the waveform of the input induced voltage across the excitation coil 25 is less than the frequency corresponding to the excitation coil frequency setting value fsref, for example, the motor speed is synchronously 97 to 98% of the speed, and when the phase of the waveform exceeds 180 degrees, for example, the voltage of the excitation coil changes from positive to negative, the first judgment result output data DR1 is output at the level of "H", and the gate signal GG is output via the first optocoupler 41.

[0061] This configuration puts the bridge rectifier 23 into operation, rectifying the AC power transmitted from the AC exciter 2122 and supplying drive current to the excitation coil 25. Therefore, the self-starting synchronous motor 11 operates as a brushless synchronous motor.

[0062] The second judgment circuit 40 compares the voltage VL across the excitation coil 25 with the excitation coil voltage setting value VLref. When the voltage VL across the excitation coil 25 exceeds the excitation coil voltage setting value VLref, the second judgment circuit 40 applies an "H" level gate signal GR to the gate of the thyristor THR via the optocoupler 43 to turn on the thyristor THR, turn off the bridge rectifier 23, and cut off the power supply to the excitation coil 25 to perform control for protecting the excitation coil 25.

[0063] When the first judgment result output data DR1 = "H" level, the first optocoupler 41 outputs an "H" level gate signal GG to the thyristor THG (described later) of the rotating rectifier thyristor control circuit 42 to the thyristor THG (described later). Therefore, the thyristor THG in the conducting state outputs an "H" level gate signal from the gate output terminals G1 to G3 to turn on the thyristors TR1 to TR3 of the bridge rectifier 23.

[0064] In the rotating rectifier thyristor control circuit 42, when an "H" level gate signal GG is input from the first optocoupler 41, thyristor THG is turned on. The DC power supplied from the bridge rectifier 23 is limited by resistors RG1 to RG3, and an "H" level gate signal is output from the gate output terminals G1 to G3 to turn on thyristors TR1 to TR3 of the bridge rectifier 23. The bridge rectifier 23 is shifted to rectification operation by the "H" level gate signal to turn on thyristors TR1 to TR3.

[0065] When the second judgment result output data DR2 = "H" level, the second optocoupler 43 outputs a "H" level gate signal GR to turn on the thyristor THR of the excitation coil protection thyristor control circuit 44, which will be described later.

[0066] In the excitation coil protection thyristor control circuit 44, when an "H" level gate signal GR is input from the second optocoupler 43, the thyristor THR is turned on. The DC power supplied from the excitation coil 25 is limited by the resistor RR3, and an "H" level gate signal for turning on the thyristor TR of the excitation protection circuit 26 is output from the gate output terminal GR. The excitation protection circuit 26 is shifted to protection operation by the "H" level gate signal to turn on the thyristor TR of the excitation protection circuit 26.

[0067] In this configuration, when a control power supply is established for the rotating rectifier control circuit 24, the excitation coil protection thyristor control circuit 44 is shifted to protection operation by turning on the thyristor TR as described above. However, when no control power supply is established, the second judgment circuit 40 cannot operate and therefore cannot perform the protection operation as described above.

[0068] Therefore, in the excitation coil protection thyristor control circuit 44, when no control power supply is established for the rotating rectifier control circuit 24, the Zener diode ZD is connected in parallel with the phototransistor on the output side of the second optocoupler 43. The nonlinear characteristics of the Zener diode ZD are used as an alternative to provide the gate signal GR to the thyristor THR when the voltage divided in the forward direction from the excitation coil voltage VL exceeds the clamping voltage of the Zener diode ZD, and the thyristor TR is turned on for protection operation. Using the nonlinear characteristics of the Zener diode ZD to protect the excitation coil is an example of protecting the thyristor through nonlinear element operation.

[0069] To manage the operating state of the rotating rectifier control circuit 24, the waveform recording circuit 45 digitally records the waveform state of the components, reads data recorded via a connected external personal computer, and uses the data for various management and maintenance purposes. The waveform recording circuit 45 performs recording when the signal TRG from the level detection circuit 33 indicates power establishment, and has a recording length longer than the period from power establishment until the self-starting synchronous motor fully operates as a synchronous motor. Furthermore, recording can be performed continuously during operation to first erase older records and record new data.

[0070] Next, the operation of the self-starting synchronous motor system of the first embodiment will be described.

[0071] First, the initial setup process in the rotating rectifier control circuit 24 will be described.

[0072] Figure 3 This is a flowchart of the initial setting process in the rotating rectifier control circuit 24 according to the first embodiment of the present invention.

[0073] First, in step S11, the operator connects a personal computer (PC) for initial setup to the serial input / output interface of the rotating rectifier control circuit 24.

[0074] Then, in step S12, the operator starts 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 excitation coil frequency setting value fsref, the first reference discharge resistor voltage VRref1, the second reference discharge resistor voltage VRref2, and the excitation coil voltage setting value VLref as the set value, and stores the set value in the set value holding circuit 38.

[0075] When the setting of the set value is completed, in step S13, the operator disconnects the personal computer (PC) used for initial setting from the serial input / output interface of the rotating rectifier control circuit 24 and completes the initial setting of the rotating rectifier control circuit 24.

[0076] Next, the startup process of the self-starting synchronous motor system will be described.

[0077] Figure 4 This is a flowchart (1) of the operation during startup of the self-starting synchronous motor system according to the first embodiment.

[0078] Figure 5 This is a flowchart (2) of the operation during startup of the self-starting synchronous motor system according to the first embodiment.

[0079] First, in step S21, the self-starting synchronous motor system 10 operates the fixed excitation circuit rectifier 13 to rectify the three-phase AC power from the excitation circuit AC power supply 12 into DC power, and excite the fixed excitation coil 21 of the AC exciter 2122 constituting the self-starting synchronous motor 11.

[0080] As a result, when the rotating excitation coil 22 is rotated by the DC power supplied from the excitation circuit AC power supply 12 through the fixed excitation circuit rectifier 13, the fixed excitation coil 21 is allowed to be powered by electromagnetic induction.

[0081] Subsequently, in step S22, the self-starting synchronous motor system 10 turns on the circuit breaker constituting the circuit breaker unit 14, connects the three-phase AC main power supply 15 to the motor armature coil 27, and supplies three-phase AC power from the three-phase AC main power supply 15 to the motor armature coil 27.

[0082] As a result, in step S23, the self-starting synchronous motor 11 starts to operate as an induction motor, and the bridge rectifier 23 starts to rotate as a rotating shaft rectifier, and the speed gradually increases.

[0083] A voltage is induced in the rotating excitation coil 22. Therefore, in step S24, the rotating excitation coil 22 converts the supplied DC power into three-phase AC power and outputs the three-phase AC power to the bridge rectifier 23 and the rotating rectifier control circuit 24.

[0084] Then, in step S25, the voltage across the rotating excitation coil 22 increases, and the output voltage of the DC-DC conversion circuit 2 from the rotating rectifier control circuit 24 reaches a predetermined voltage.

[0085] The operation will be described in more detail here.

[0086] In parallel with the above operation, the interaction between the motor armature coil 22 and the excitation coil 25 induces a voltage in the excitation coil 25. The terminal voltage of the excitation coil 25 is relatively high in both voltage and frequency because the motor speed is relatively slow at startup, and the voltage decreases as the motor speed approaches the rated speed (as the slip of the induction motor decreases), and the frequency also decreases.

[0087] Then, the first amplifier unit 34 detects the output voltage from the bridge rectifier 23, i.e., the voltage VL across the excitation coil 25, in an isolated state to perform A / D conversion and outputs the voltage VL to the first detection circuit 36 ​​and the second judgment circuit 40.

[0088] Therefore, the first detection circuit 36 ​​outputs the binarized voltage level LV of the voltage VL across the excitation coil 25 based on the voltage VL across the excitation coil 25 output from the first amplifier unit 34, 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.

[0089] Here, the operation for calculating the binarized voltage level LV in the first detection circuit will be described.

[0090] Figure 6 This is an explanatory diagram of the operation of the first detection circuit according to the first embodiment of the present invention.

[0091] like Figure 6 As shown, the waveform of the voltage VL across the excitation coil 25 contains noise and is significantly different from an ideal sine wave.

[0092] Therefore, in the first embodiment, by using 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, and by using the concept of a binary state, a binary voltage level is obtained as a binary result which is a transition state according to the binary state. As a result, according to this first embodiment, optimal phase excitation control can be reliably performed with a simple configuration and simple processing.

[0093] More specifically, optimal phase excitation control can be reliably performed by performing excitation at a zero crossing point where the voltage VL across the excitation coil 25 is switched from a positive voltage to a negative voltage based on the voltage VL across the excitation coil 25 (the timing when the binary result switches from “H” to “L” in Figure 5 , that is, the timing corresponding to the time t4 and the time t8 when the state ST3 with the binary state = “3” becomes Figure 5 the state ST0 with the binary state = “0” in

[0094] Figure 7 is an explanatory diagram of the transition state of the binary state according to the first embodiment of the present invention.

[0095] For example, if the current state is the state ST0 where the binary state = “0”, then when the voltage VL across the excitation coil 25 exceeds the first positive voltage threshold Ht1 (when VL > Ht1, the current state changes to the binary state = “1” with a binary result of “H”, as shown by the time t5 in Figure 6 , otherwise, the state ST0 is maintained.

[0096] Furthermore, if the current state is the state ST1 where the binary state = “1”, then when the voltage VL across the excitation coil 25 exceeds the second positive voltage threshold Ht2 (when VL > Ht2, the current state changes to the binary state = “2” with a binary result of “H”, as shown by the time t2 and the time t6 in Figure 6 , otherwise, the state ST1 is maintained.

[0097] Similarly, if the current state is the state ST2 where the binary state = “2”, then when the voltage VL across the excitation coil 25 is less than the first negative voltage threshold Lt1 (when VL < Lt1, the current state changes to the binary state = “3” with a binary result of “L”, as shown by the time t3 and the time t7 in Figure 6 , otherwise, the state ST2 is maintained.

[0098] In addition, if the current state is the state ST3 in which the binarization state = "3", when the voltage VL across the excitation coil 25 is less than the second negative voltage threshold Lt2 (when VL < Lt2, the current state changes to the binarization state = "0" with the binarization result "L"), as Figure 6 shown by the time t4 and the time t8 in

[0099] Otherwise, the state ST3 is maintained. As described above, simply comparing the voltage VL (instantaneous voltage) across the excitation coil 25 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, it is possible to eliminate the influence of noise through extremely simple processing to obtain a stable binarization result ("H" or "L").

[0100] In addition, 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 stable control processing can be provided only by rewriting the data held by the set value holding circuit 38. Therefore, compared with the optimal phase excitation control that requires an analog circuit, the control processing can be applied to motors of various specifications without changing the circuit design.

[0101] In addition, it is possible not only to adapt to changes in the specifications of the self-starting synchronous motor 11 but also to adapt to changes in the load at activation.

[0102] Here, referring again to Figure 4 and Figure 5 the operation of the self-starting synchronous motor system at startup will be further described.

[0103] As described above, in Figure 6 preferably, excitation is performed at timings corresponding to the time t3 and the time t7, at which the state ST2 with the binarization state = "2" changes to the state ST3 with the binarization state = "3".

[0104] Then, the voltage VL across the excitation coil 25 is binarized in the cycle including steps S27 to 35 and step S38.

[0105] In addition, in step S26, the first detection circuit 36 sets the binarized voltage level LV to "L" as the initial value.

[0106] Next, in step S27, the first judgment circuit resets the half-cycle counter for detecting the frequency of the induced voltage generated in the excitation coil 25 to "0", and resets the synchronization flag indicating that the frequency of the induced voltage is less than the predetermined frequency (the frequency at which an excitation current can flow through the excitation coil) to "0".

[0107] Next, in step S28, the first detection circuit 36 ​​determines whether the excitation coil voltage LV exceeds the first positive voltage threshold Ht1. When the excitation coil voltage LV exceeds the first positive voltage threshold Ht1 (yes), it is determined that the binarization state has become "1", and the process proceeds to step S29. Otherwise (no), it is determined that the binarization state remains "0", and the process returns to step S28.

[0108] Next, in step S29, the first detection circuit 36 ​​sets the binarized voltage level LV to "H", and the first judgment circuit 39 operates a half-cycle counter for detecting the frequency of the excitation coil voltage LV based on the binarized voltage level LV set to "H" to start timing.

[0109] Next, in step S30, the first detection circuit 36 ​​determines whether the excitation coil voltage LV exceeds the second positive voltage threshold Ht2. When the excitation coil voltage LV exceeds the second positive voltage threshold Ht2 (yes), it is determined that the binarization state has changed to "2", and the process proceeds to step S31. Otherwise (no), it is determined that the binarization state remains "1", and the process returns to step S30.

[0110] Next, in step S31, the first determination circuit 39 determines whether the frequency of the excitation coil voltage LV is less than the predetermined excitation coil frequency setting value fsref. Specifically, it determines whether the time measured by the half-cycle counter exceeds 1 / 2 of the period of the excitation coil frequency setting value fsref. When it is determined that the time measured by the half-cycle counter exceeds 1 / 2 of the excitation coil frequency setting value fsref (Yes), the process proceeds to step S32, the first determination circuit 39 sets the synchronization flag to "1", and the process proceeds to step S33. When it is determined in step S31 (No) that the time measured by the half-cycle counter does not exceed 1 / 2 of the excitation coil frequency setting value fsref, the process proceeds to step S33.

[0111] In step S33, the first detection circuit 36 ​​determines whether the excitation coil voltage LV is less than the first negative voltage threshold Lt1. When the excitation coil voltage LV is less than the first negative voltage threshold Lt1 (yes), it is determined that the binarization state has changed to "3", and the process proceeds to step S34. Otherwise (no), it is determined that the binarization state remains "2", and the process returns to step S31.

[0112] In step S34, the first judgment circuit 39 sets the binarized voltage level LV to "L" and proceeds to step S35.

[0113] Next, in step S35, the first determination circuit 39 determines whether the frequency of the excitation coil voltage VL is less than the predetermined excitation coil frequency setting value fsref and, more specifically, determines whether the synchronization flag is "1" by zero crossing (i.e., when the excitation coil voltage VL is considered a sine wave with a phase of 180 degrees). The timing of reaching step S35 immediately follows the change of the binarized voltage level LV from "H" to "L", thus sufficient to determine whether the synchronization flag is "1". When the synchronization flag is "1" (yes), the process proceeds to step S36, and when the synchronization flag is not "1" (no), the process proceeds to step S38.

[0114] In step S36, the output DR1 from the first judgment circuit is set to an "H" level. Then, in the first optocoupler 41, when the output DR1 from the first judgment circuit is at an "H" level, the phototransistor on the output side is turned on, and the current from terminals S1 to S3 flows through diodes DD1 to DD2. The "H" level gate signal GG used to turn on thyristor THG is output through resistor GR6 to thyristor THG in the rotating rectifier thyristor control circuit 42. Therefore, thyristor THG in the turned-on state outputs "H" level gate signals from gate output terminals G1 to G3 to turn on thyristors TR1 to TR3 of the bridge rectifier 23.

[0115] This configuration puts the bridge rectifier 23 into operation, rectifying the AC power transmitted from the AC exciter 2122 and supplying drive current to the excitation coil 25.

[0116] Therefore, in step S37, the self-starting synchronous motor 11 operates as a brushless synchronous motor.

[0117] In step S38, the first detection circuit 36 ​​determines whether the excitation coil voltage VL is less than the second negative voltage threshold Lt2. When the excitation coil voltage VL is less than the second negative voltage threshold Lt2 (yes), it is determined that the binarization state has become "0", and the process returns to step S27. Otherwise (no), it is determined that the binarization state remains "3", and the process returns to step S38.

[0118] As described above, when the synchronization flag is not "1", it is determined that the self-starting synchronous motor 11 does not have the speed required to rotate as a synchronous motor, and the process returns to step S27 via step S38, and the process continues. Note that in Figure 4 During the process, the half-cycle of the binarized voltage level H is timed (counted) to determine the period (frequency).

[0119] However, considering a period of two binary voltage levels set to L and H, the period (frequency) can be determined by timing. When counting a period, if the counting of the period is started from a timing point where the binary voltage level is set to L, a drop can be detected earlier.

[0120] Figure 8 This is a flowchart of the operations performed when an overvoltage is detected at the start-up point of a self-starting synchronous motor system.

[0121] Here, we will use Figure 8 The flowchart is used to describe the operation of the second judgment circuit 40.

[0122] Figure 8 Operation flowchart and Figure 4 and Figure 5 The operation flowchart is executed in parallel.

[0123] In step S71, the second judgment circuit 40 compares the voltage VL across the excitation coil 25 with the excitation coil voltage setting value VLref, and determines whether the voltage VL across the excitation coil 25 is equal to or greater than the excitation coil voltage setting value VLref.

[0124] In step S71, if the voltage VL across the excitation coil 25 is not equal to or greater than the excitation coil voltage setting value VLref (No), the process proceeds to step S72, and if the voltage VL across the excitation coil 25 is equal to or greater than the excitation coil voltage setting value VLref (Yes), the process proceeds to step S73.

[0125] In step S73, the second judgment circuit 40 sets the output data DR2 of the second judgment result to "H" to protect the excitation coil 25.

[0126] As a result, in the second optocoupler 43, when the second judgment result output data DR2 is at the "H" level, the second optocoupler 43 is turned on. A "H" level gate signal GR is output from terminal SP via resistor R1 to turn on the thyristor THR in the excitation coil protection thyristor control circuit 44, thus turning on the thyristor THR. The process then proceeds to step S71 and continues. When the thyristor THR is turned on, the gate signal is provided to the thyristor TR, the thyristor TR is turned on, and current flows through the discharge resistor R. Therefore, the excitation coil is protected.

[0127] In the determination in step S71, if the voltage VL across the excitation coil 25 is equal to or less than the excitation coil voltage setting value VLref (No), the process proceeds to step S72, and the process continues.

[0128] In step S72, the second judgment circuit 40 sets the output data DR2 of the second judgment result to "L" to turn off the thyristor TR. Therefore, the second optocoupler 43 stops at the gate signal GR of the thyristor THR. As a result, when the voltage VL across the excitation coil 25 has a negative voltage, the thyristor THR is turned off, and the gate of the thyristor TR is also open, thus turning off the thyristor TR as well.

[0129] Next, the protection operation of the discharge resistor R when the self-starting synchronous motor 11 in the self-starting synchronous motor system is operated as a synchronous motor will be described.

[0130] Figure 9 This is a flowchart of the operations performed during the operation of a self-starting synchronous motor system.

[0131] When according to Figure 4 and Figure 5 When performing operations on the flowchart, do not apply Figure 9 The flowchart of the operation.

[0132] During the operation of the self-starting synchronous motor system 10, the second determination circuit 40 compares the voltage VL across the excitation coil 25 with the excitation coil voltage setting value VLref, and determines whether the voltage VL across the excitation coil 25 is equal to or greater than the excitation coil voltage setting value VLref (step S41).

[0133] In the determination in step S41, if the voltage VL across the excitation coil 25 is equal to or greater than the excitation coil voltage setting value VLref (yes), the process proceeds to step S42; otherwise (no), the process proceeds to step S47.

[0134] In step S42, the second judgment circuit 40 sets its output DR2 to "H" to protect the excitation coil 25 from overvoltage. When DR2 is at the "H" level, the second optocoupler 43 is turned on, and the "H" level gate signal GR of the thyristor THR of the excitation coil protection thyristor control circuit 44 is output from terminal SP through resistor RR1 of the excitation protection circuit 26 to turn on the thyristor THR. When the thyristor THR is turned on, the gate signal is given to the thyristor TR to turn on the thyristor TR, and current flows through the discharge resistor R, thus protecting the excitation coil 25. Then, the process proceeds to step S43.

[0135] Subsequently, in step S43, the first judgment circuit 39 determines whether the voltage VR across the discharge resistor R is equal to or greater than the voltage VRref1 of the first reference discharge resistor.

[0136] When it is determined in step S43 that the voltage VR across the discharge resistor R is less than the voltage VRref1 of the first reference discharge resistor (no), it is determined that no current flows from the thyristor TR into the discharge resistor R, and the process proceeds to step S45.

[0137] When it is determined in step S43 that the voltage VR across the discharge resistor R is equal to or greater than the voltage VRref1 of the first reference discharge resistor (yes), the process proceeds to step S44.

[0138] In step S44, the first judgment circuit 39 sets the output DR1 to the "L" level. Then, in the first optocoupler 41, when the output DR1 is at the "L" level, the phototransistor on the output side is turned off. Therefore, the gate signal GG of the thyristor THG in the rotating rectifier thyristor control circuit 42 changes to the L level, and the thyristor THG is turned off.

[0139] Therefore, the gate signals of the thyristors TR1 to TR3 used in the bridge rectifier 23 are not output from the gate output terminals G1 to G3, and thus the thyristors TR1 to TR3 are turned off.

[0140] As a result, no current is supplied from the bridge rectifier 23, and therefore, the thyristor TR is turned off, no current is supplied to the discharge resistor R, and the discharge resistor R is prevented from burning out. Then, the process proceeds to step S45.

[0141] In step S45, the first judgment circuit 39 determines whether the voltage VR across the discharge resistor R is equal to or less than the voltage VRref2 of the second reference discharge resistor.

[0142] When it is determined in step S45 that the voltage VR across the discharge resistor R is equal to or less than the second reference discharge resistor voltage VRref1 (yes), the process proceeds to step S46. When it is determined that the voltage VR across the discharge resistor R is not equal to or less than the second reference discharge resistor voltage VRref1 (no), the process ends.

[0143] In step S46, when the voltage across the discharge resistor R is equal to or less than the second reference discharge resistor voltage VRref1, no current is supplied from the bridge rectifier 23. Therefore, the following operation is performed to make the bridge rectifier 23 supply current to the excitation coil 25 again.

[0144] The output DR1 from the first judgment circuit 39 is set to the "H" level.

[0145] Then, in the first optocoupler 41, when the signal DR1 is at the “H” level, the phototransistor on the output side is turned on, and the current from terminals S1 to S3 passes through diodes DD1 to DD2, and the “H” level gate signal GG used to turn on the thyristor THG is output to the thyristor THG of the rotating rectifier thyristor control circuit 42 through resistor GR6.

[0146] Therefore, the thyristor THG in the conducting state outputs "H" level gate signals from the gate output terminals G1 to G3 to turn on the thyristors TR1 to TR3 of the bridge rectifier 23.

[0147] Therefore, thyristors TR1 to TR3 are turned on, restarting the current supply from bridge rectifier 23 to excitation coil 25, and the self-starting synchronous motor 11 can operate as a synchronous motor.

[0148] In step S47, the second judgment circuit 40 sets its output DR2 to "L". When DR2 is at the "L" level, the second optocoupler 43 is turned off, and the gate signal GR of the thyristor THR used to turn on the excitation coil protection thyristor control circuit 44 is output from terminal SP through the resistor RR1 of the excitation protection circuit 26, and is changed to the "L" level, and the thyristor THR is turned off.

[0149] Therefore, no gate signal is supplied 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 performs the same process steps as described above.

[0150] The following describes the operations performed when stopping a self-starting synchronous motor system.

[0151] Figure 10 This is a flowchart of the operations performed when stopping a self-starting synchronous motor system.

[0152] When the self-starting synchronous motor system 10 stops, the circuit breaker 14 constituting the circuit breaker unit opens, the three-phase AC main power supply 15 is disconnected from the motor armature coil 27, and the supply of three-phase AC power from the three-phase AC main power supply 15 stops (step S51).

[0153] Subsequently, the fixed excitation circuit rectifier 13 is stopped, and the current supply to the fixed coil 21 of the AC exciter 2122 is stopped (step S52).

[0154] As a result, the voltage across the rotating 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).

[0155] Furthermore, the trigger signal from the level detection circuit 33 is stopped, the recording of the waveform recording device 45 is stopped, the first judgment result output data DR1 from the first judgment circuit 39 and the second judgment result output data DR2 from the second judgment circuit 40 are changed to the "L" level, the thyristors TR1 to TR3 and the thyristor TR are turned off (step S54), and the self-starting synchronous motor system 10 is shifted to the stop state.

[0156] As described above, according to the first embodiment, a control circuit for a rotating rectifier and a self-starting synchronous motor system capable of reliably performing universal optimal phase excitation control with a simple configuration can be realized.

[0157] [2] Second implementation method Next, a second embodiment of the present invention will be described.

[0158] Figure 11 This is a functional block diagram of the rotating rectifier control circuit 24A according to the second embodiment of the present invention.

[0159] The second embodiment is an embodiment in which the rotating rectifier control circuit 24 in the first embodiment is replaced by a rotating rectifier control circuit 24A, and all other aspects remain unchanged. Identical components are indicated by the same reference numerals, and their descriptions will be omitted. The rotating rectifier control circuit 24A according to the second embodiment includes a first detection circuit 36A replacing the first detection circuit 36, a setting and holding circuit 38A replacing the setting and holding circuit 38, and a waveform recording circuit 45A replacing the waveform recording circuit 45.

[0160] In the first embodiment, the first detection circuit 36 ​​outputs the binarized voltage level LV of the voltage VL across the excitation 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. However, in the second embodiment, the second detection circuit 36A outputs the phase θs and frequency fs of the fundamental wave of the voltage VL across the excitation coil 25 to the first judgment circuit 39A. The second detection circuit 36A continuously performs phase comparisons using methods such as Hilbert transform or PLL, calculates the phase θs and frequency fs of the fundamental wave of the voltage VL from the input voltage VL across the excitation coil 25, and outputs the results. The second detection circuit 36A can be configured using a dedicated IC or the like.

[0161] The setpoint holding circuit 38A holds the excitation coil frequency setting value fsref, the first excitation coil phase setting value θsref1, the second excitation coil phase setting value θsref2, the first reference discharge resistor voltage VRref1, the second reference discharge resistor voltage VRref2, and the excitation coil voltage setting value VLref, which are input from the input / output interface circuit 37.

[0162] Waveform recording circuit 45A records the excitation coil frequency setting value fsref, the first excitation coil phase setting value θsref1, the second excitation coil phase setting value θsref2, the first reference discharge resistor voltage VRref1, the second reference discharge resistor voltage VRref2, and the excitation coil voltage setting value VLref, all input from the input / output interface circuit 37. Waveform recording circuit 45A also records the excitation coil voltage VL input from the first amplifier unit 34, the discharge resistor voltage VR input from the second amplifier unit 35, the output signal DR1 input from the first judgment circuit 39A, and the output signal DR2 input from the second judgment circuit 40.

[0163] Figure 12 This is a flowchart of the initial setting process in the rotating rectifier control circuit 24A according to the second embodiment of the present invention.

[0164] Figure 13 This is a flowchart of the operation during startup of the self-starting synchronous motor system according to the second embodiment.

[0165] In this second embodiment, the operation flowchart of the second determination circuit is configured to correspond to Figure 8 The operation flowchart executed during the operation of the self-starting synchronous motor system is configured to correspond to Figure 9 Furthermore, the operation flowchart executed when stopping the self-starting synchronous motor system is configured to correspond to... Figure 10 Therefore, its description will be used and will not be repeated.

[0166] refer to Figure 12 The description will only be related to the first embodiment. Figure 3 The differences are as follows. Similar steps are represented by the same numbers and their descriptions will not be repeated.

[0167] Due to Figure 3The difference in step S12 is replaced by step S12A, in which the operator activates the setting application to set the excitation coil frequency setting value fsref, the first excitation coil phase setting value θsref1, the second excitation coil phase setting value θsref2, the first discharge resistor voltage setting value VRref1, the second discharge resistor voltage setting value VRref2, and the excitation coil voltage setting value VLref as setting values, and stores the setting values ​​in the setting value holding circuit 38. Here, the second excitation coil phase setting value θsref2 is greater than the first excitation coil phase setting value θsref1, and both the second excitation coil phase setting value θsref2 and the first excitation coil phase setting value θsref1 are expected to have values ​​closer to 180 degrees. Other steps are the same as... Figure 3 The same as in [the previous sentence].

[0168] refer to Figure 13 The description will only be related to the first embodiment. Figure 4 or Figure 5 The differences are as follows. Similar steps are represented by the same numbers and their descriptions will not be repeated. Steps S21~S25 are the same as... Figure 4 or Figure 5 Same. Steps S36 and S37 are also the same.

[0169] exist Figure 13 In this process, after step S25, the process proceeds to step S26A. In step S26A, the first judgment circuit 39A determines whether the frequency fs of the fundamental wave of the voltage VL received from the first detection circuit 36A is less than the excitation coil frequency setting value fsref. When the frequency fs is less than the excitation coil frequency setting value fsref (yes), the process proceeds to step S27A; otherwise, the process returns to step S26A.

[0170] In step S27A, the first judgment 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 excitation coil phase setting value θsref1 and less than the second excitation coil phase setting value θsref2. When the phase θs is greater than the first excitation coil phase setting value θsref1 and less than the second excitation coil phase setting value θsref2 (yes), the process proceeds to step S36; otherwise, the process returns to step S26A.

[0171] Other steps are similar. Figure 4 The steps in the previous section will not be repeated here.

[0172] As described above, as in the first embodiment, according to this second embodiment, a control circuit for a rotating rectifier and a self-starting synchronous motor system capable of reliably performing universal optimal phase excitation control with a simple configuration can be realized.

[0173] Each embodiment of the control circuit for the rotating rectifier includes a control device such as an MPU, a storage device such as a read-only memory (ROM) 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 unit, and an input device such as an operation panel or operation switch, and has a hardware configuration that uses a common computer.

[0174] The program executed in the control circuit of the rotary rectifier in this embodiment is provided as an installable or executable file on a semiconductor memory device such as an SSD or USB memory device or a computer-readable recording medium such as a digital universal disc (DVD).

[0175] Furthermore, the program executed in the control circuit of the rotary rectifier in this embodiment can be provided by storing it on a computer connected to a network such as the Internet and downloading it via the network. Additionally, the program executed in the control circuit of the rotary rectifier in this embodiment can be provided or distributed via a network such as the Internet.

[0176] Furthermore, the program for the control circuit of the rotating rectifier used in this embodiment can be provided in advance by incorporating it into a ROM or the like.

[0177] While certain embodiments of the invention have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. The novel embodiments described herein may be embodied in various other forms, and various omissions, substitutions, and changes may be made without departing from the spirit of the invention. The appended claims and their equivalents are intended to cover these forms or modifications that fall within the scope and spirit of the invention.

[0178] In the above description, the thyristor bridge rectifier is configured as a hybrid thyristor bridge rectifier, but it can also be configured as a pure thyristor bridge rectifier.

[0179] In the above description, the first detection circuit 36 ​​is configured to perform A / D conversion of the voltage VL across the excitation coil 25 output by the first amplifier unit 34, and to output a binarized voltage level LV of the voltage VL across the excitation 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. Alternatively, binarization with digital hysteresis characteristics can be performed.

[0180] Alternatively, instead of the first detection circuit 36, a continuous phase comparison circuit can be configured using, for example, a PLL, a digital phase detection circuit, or a phase-frequency detector IC, or a Hilbert transform circuit disclosed in JP-A-2003-143063 can be used.

[0181] In the above description, the first detection circuit 36 ​​is configured to perform A / D conversion of the voltage VL across the excitation coil 25 output by the first amplifier unit 34, and to output a binarized voltage level LV of the voltage VL across the excitation 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. Alternatively, binarization with digital hysteresis characteristics can be performed.

[0182] Explanation of letters or numbers 10 self-starting synchronous motor system 11 self-starting synchronous motors 12 Excitation Circuit AC Current Power Supply 13 Fixed Excitation Circuit Rectifier 14 circuit breaker units 15-phase three-phase AC main power supply 21 Fixed excitation coil 22 Rotary excitation coil 23-bridge rectifier 24 Rotary Rectifier Control Circuit 25 Excitation Coil 26 Excitation 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 Setpoint Hold Circuit 39 First Judgment Circuit 40 Second Judgment Circuit 41 First optocoupler 42 Rotary Rectifier Thyristor Control Circuit 43 Second optocoupler 44 Excitation coil protection thyristor control circuit 45 waveform recording circuit DD1 to DD3 diodes DR1 first judgment result output data DR2 Second Judgment Result Output Data fs frequency fsref excitation coil frequency setting value fsref1 Excitation coil frequency setting value fsref2 Excitation 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 detectors LV binarized voltage level N low potential power line P high potential power line R discharge resistor ST0 to ST3 status THG thyristor THR thyristor TR excitation coil protects thyristor TR1 to TR3 thyristors VL excitation coil voltage VLref excitation 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 Excitation coil phase setting value θsref2 Excitation coil phase setting value

Claims

1. A control circuit for a rotating rectifier, wherein, The control circuit detects the instantaneous voltage of the excitation coil, calculates the frequency based on the instantaneous voltage, and causes the rotating rectifier to supply current to the excitation coil within a predetermined phase range, the predetermined phase range including the zero-crossing point where the instantaneous voltage changes from positive to negative.

2. The control circuit for a rotating rectifier according to claim 1, wherein the control circuit comprises: The detection circuit performs A / D conversion of the voltage of the excitation coil and outputs the voltage of the excitation coil as a binarized voltage level based on a pre-stored first positive voltage threshold, a second positive voltage threshold, a first negative voltage threshold, and a second negative voltage threshold.

3. The control circuit for a rotating rectifier according to claim 1, wherein, The rotating rectifier has a circuit that includes a pure thyristor bridge rectifier or a hybrid thyristor bridge rectifier.

4. The control circuit for a rotating rectifier according to claim 1, wherein the control circuit comprises: The circuit includes a protection thyristor and a discharge resistor connected in parallel and series with the excitation coil. The protection thyristor has a protection diode connected in reverse parallel. The protection thyristor has a protection circuit that protects the excitation coil by inducing current flow when the forward voltage of the excitation coil is equal to or greater than a predetermined coil voltage value. The protection thyristor is configured to operate by a nonlinear element when no power supply is established for the control circuit.

5. The control circuit for a rotating rectifier according to claim 4, wherein the control circuit comprises: A device for detecting the terminal voltage of the discharge resistor. When the terminal voltage is equal to or greater than the predetermined resistor voltage value, the thyristor constituting the rotating rectifier is turned off.

6. The control circuit for a rotating rectifier according to claim 4, wherein the control circuit comprises: A setpoint holding circuit stores the predetermined phase range and the predetermined coil voltage value as a setpoint in a non-volatile manner. When the brushless self-starting synchronous motor to be controlled stops, the setpoint holding circuit can be accessed from the outside.

7. The control circuit for a rotating rectifier according to claim 5, wherein the control circuit comprises: A setpoint holding circuit stores the predetermined resistor voltage value as a setpoint in a non-volatile manner. When the brushless self-starting synchronous motor to be controlled stops, the setpoint holding circuit can be accessed from the outside.

8. The control circuit for a rotating rectifier according to claim 1, wherein the control circuit comprises: A waveform recording circuit that records waveform data for a portion of the control circuit used in the rotating rectifier.

9. The control circuit for a rotating rectifier according to claim 1, wherein, The power supply for the control circuit is obtained in parallel from the AC input power supply for the rotating rectifier while being isolated.

10. A brushless self-starting synchronous motor, comprising: Control circuit for the rotary rectifier according to claim 1; as well as The rotary rectifier.

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