CN110235352B - Multi-speed multi-power motor control method and control system - Google Patents
Multi-speed multi-power motor control method and control system Download PDFInfo
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- CN110235352B CN110235352B CN201780085289.3A CN201780085289A CN110235352B CN 110235352 B CN110235352 B CN 110235352B CN 201780085289 A CN201780085289 A CN 201780085289A CN 110235352 B CN110235352 B CN 110235352B
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- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
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Abstract
A control method and a control system for a multi-speed multi-power motor are provided, wherein the control method comprises the following steps: closing the first contactor, driving the first winding, detecting that the rotating speed of the first winding reaches a preset rotating speed, stopping the output of the frequency converter, and then disconnecting the first contactor; when the first contactor is completely disconnected, the second contactor is attracted, so that the frequency converter is conducted with the second winding through the second contactor; when the second contactor is completely closed, the frequency converter drives the second winding and tracks the phase current and the phase voltage of the second winding to obtain the motor rotating speed and the phase of the second winding; the frequency converter smoothly controls the second winding; when the rotating speed of the second winding reaches the power frequency, phase locking is carried out on the input voltage and the output voltage of the frequency converter, the frequency converter stops outputting after the phase locking, and then the second contactor is disconnected; and after the second contactor is completely disconnected, the third contactor is closed, and the second winding is switched to power frequency operation smoothly. And a large impact current can not be generated in the switching process.
Description
[ technical field ] A method for producing a semiconductor device
The invention relates to the technical field of electronics, in particular to a control method and a control system for a multi-speed multi-power motor.
[ background of the invention ]
In many devices, such as a head knock machine in oilfield equipment, the friction resistance of the equipment is high when the equipment is started, and enough starting torque needs to be provided to enable the equipment to operate. After the system is started, the equipment can run by means of inertia, the sliding friction force of the equipment is small, and the equipment can be kept running only by providing small moment. For a common motor, the output torque corresponds to the output power, so that the selection of a motor with large torque means that the power of the motor is also amplified, but after the equipment is started, the operation can be maintained only by the motor with smaller power, and the selection of the motor with large power means the increase of energy consumption.
In order to solve the problems, a motor manufacturer designs a multi-winding motor which can realize multi-speed and multi-power operation. When starting, a low-speed high-torque winding is selected, and the starting torque is increased. After starting, the winding is switched to a high-speed low-torque winding, and after power frequency is achieved, the winding is switched to power frequency operation.
In the past, the switching of each winding was directly performed by using a contactor for such a new motor. However, since the current surge is large when the contactor is switched, a contactor having a capacity much larger than a normal use capacity has to be selected. But even then the contactor failure rate is still high.
[ summary of the invention ]
In view of the above, there is a need for a control method and system for a multi-speed multi-power motor with a lower contactor failure rate.
A method of controlling a multi-speed, multi-power motor including at least a first winding, a second winding, a first contactor, a second contactor, and a third contactor, the method comprising:
attracting the first contactor to enable the frequency converter to be conducted with the first winding through the first contactor;
the frequency converter drives the first winding and detects the rotating speed of the first winding, when the rotating speed of the first winding reaches a preset rotating speed, the frequency converter stops outputting, and then the first contactor is disconnected;
when the first contactor is detected to be completely disconnected, the second contactor is attracted, and the frequency converter is conducted with the second winding through the second contactor;
when the second contactor is detected to be completely closed, the frequency converter drives the second winding and tracks the phase current and the phase voltage of the second winding, and the motor rotating speed and the phase of the second winding are obtained according to the phase current and the phase voltage of the second winding;
smoothly controlling the second winding according to the motor rotating speed of the second winding and the phase frequency converter;
detecting the working frequency of the second winding, performing phase locking on the input voltage and the output voltage of the frequency converter when the working frequency of the second winding reaches the power frequency, stopping the output of the frequency converter after the phase locking, and then disconnecting the second contactor;
and after the second contactor is detected to be completely disconnected, attracting the third contactor, and smoothly switching the second winding to power frequency operation.
A control system for a multi-speed, multi-power motor, the multi-speed, multi-power motor including at least a first winding and a second winding, the control system comprising:
one end of the first contactor is connected with the output end of the frequency converter, and the other end of the first contactor is connected with the first winding;
one end of the second contactor is connected with the output end of the frequency converter, and the other end of the second contactor is connected with the second winding;
one end of the third contactor is connected with the three-phase voltage input end, and the other end of the third contactor is connected with the second winding;
the frequency converter is used for attracting the first contactor to enable the frequency converter to be conducted with the first winding through the first contactor; driving the first winding and detecting the rotating speed of the first winding, stopping the output of the frequency converter when the rotating speed of the first winding reaches a preset rotating speed, and then disconnecting the first contactor; when the first contactor is detected to be completely disconnected, the second contactor is attracted, and the frequency converter is conducted with the second winding through the second contactor; when the second contactor is detected to be completely closed, driving a second winding and tracking phase current and phase voltage of the second winding, and acquiring the motor rotating speed and phase corresponding to the second winding according to the phase current and phase voltage of the second winding; according to the motor speed and the phase of the second winding, enabling the frequency converter to smoothly control the second winding; detecting the working frequency of the second winding, performing phase locking on the input voltage and the output voltage of the frequency converter when the working frequency of the second winding reaches the power frequency, stopping the output of the frequency converter after the phase locking, and then disconnecting the second contactor; and after the second contactor is detected to be completely disconnected, the third contactor is closed, and the second winding is switched to power frequency operation smoothly.
According to the control method and the control system for the multi-speed multi-power motor, after the frequency converter sends a contactor pull-in or break-out signal, the contactor feedback signal is detected in real time. If the feedback signal indicates that the contactor has not been engaged or disengaged at this time, the next control action is temporarily stopped. When the feedback signal of the contactor is detected to indicate that the contactor is reliably attracted or disconnected, the next step of driving the motor or switching the contactor is carried out, so that large impact current cannot be generated, and the frequency converter is not easy to damage or trip protection is carried out. The frequency converter is smoothly switched to the second winding through the rotating speed tracking module, the second winding is smoothly switched to power frequency operation from the frequency converter through phase locking of input voltage and output voltage of the frequency converter, and current impact is small in switching engineering.
[ description of the drawings ]
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings of the embodiments can be obtained according to the drawings without creative efforts.
FIG. 1 is a flow diagram of a method of controlling a multi-speed, multi-power motor in one embodiment;
FIG. 2 is a diagram illustrating an embodiment of shaping an original sine wave signal into a square wave signal;
FIG. 3 is a current waveform for directly starting a rotating motor in one embodiment;
FIG. 4 is a graph of current voltage waveforms when a rotating motor is started using a speed tracking function in one embodiment;
FIG. 5 is a time-varying frequency-cutting power frequency waveform without phase detection in an embodiment;
FIG. 6 is a frequency waveform of an embodiment of adding phase detection and frequency conversion cutting;
FIG. 7 is a flow chart of a method of controlling a multi-speed multi-power motor in another embodiment;
FIG. 8 is a block diagram of a control system for a multi-speed, multi-power motor in one embodiment;
FIG. 9 is a partial circuit diagram of a speed tracking module in one embodiment;
FIG. 10 is another block diagram of a multi-speed multi-power motor control system in accordance with an embodiment.
[ detailed description ] embodiments
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Referring to fig. 1, a flowchart of a control method of a multi-speed multi-power motor including at least a first winding, a second winding, a first contactor, a second contactor, and a third contactor includes the following steps S110 to S170.
Step S110: and attracting the first contactor to enable the frequency converter to be conducted with the first winding through the first contactor.
The frequency converter firstly controls the action of the first relay, controls the first contactor to attract and conduct, and connects the output end of the frequency converter with the first winding.
Step S120: the frequency converter drives the first winding and detects the rotating speed of the first winding, when the rotating speed of the first winding reaches a preset rotating speed, the frequency converter stops outputting, and then the first contactor is disconnected.
The frequency converter detects the rotating speed of the first winding through the rotating speed detection module, when the rotating speed reaches a preset rotating speed, switching of the second winding of the first winding is started, the frequency converter stops outputting in the switching process, and then the first contactor is disconnected. The nameplate parameters of the multi-speed multi-power motor can be input into a motor parameter module of the frequency converter, and can be input through an operation panel of the frequency converter; and parameters such as stator resistance, rotor resistance, leakage inductance, mutual inductance, no-load current and the like corresponding to each rotating speed power of the motor are respectively obtained through a parameter self-tuning function built in the frequency converter. Simply referred to as the first set of parameters, the second set of parameters. Wherein the first set of parameters corresponds to the first winding and the second set of parameters corresponds to the second winding. And acquiring the rated rotating speed of the first winding according to the first group of parameters. The predetermined speed may be equal to or less than the rated speed of the first winding, as desired. Step S130: and when the first contactor is detected to be completely disconnected, the second contactor is attracted, so that the frequency converter is conducted with the second winding through the second contactor.
The frequency converter controls the second relay to act, controls the second contactor to be closed and conducted, and connects the output end of the frequency converter with the second winding.
Step S140: and when the second contactor is detected to be completely closed, the frequency converter drives the second winding and tracks the phase current and the phase voltage of the second winding, and the motor rotating speed and the phase of the second winding are obtained according to the phase current and the phase voltage of the second winding.
And the rotating speed tracking module is started when the frequency converter drives the second winding and tracks the phase current and the phase voltage of the second winding. Specifically, the rotating speed tracking module calculates a first phase voltage and a second phase voltage in the three-phase voltage of the second winding to obtain a first judgment voltage, and the rotating speed tracking module calculates a second phase voltage and a third phase voltage in the three-phase voltage of the second winding to obtain a second judgment voltage.
And shaping the first judgment voltage and the second judgment voltage into square waves, wherein when the square waves shaped by the first judgment voltage rise, if the square wave voltage shaped by the second judgment voltage is at a low level at the moment, the rotation direction of the motor is a first direction, otherwise, the rotation direction of the motor is a second direction opposite to the first direction. The first direction may be a counterclockwise direction, and the second direction may be a clockwise direction, or the first direction may be a clockwise direction and the second direction may be a counterclockwise direction.
A first phase voltage and a second phase voltage in the three-phase voltage in the second winding form a first group of phase voltages, a second phase voltage and a third phase voltage form a second group of phase voltages, and the first group of phase voltages or the second group of phase voltages are subjected to two groups of differential proportion operation to obtain two unequal first basic voltages and second basic voltages, wherein the first basic voltage is smaller than the second basic voltage; and sampling the first basic voltage and acquiring the maximum value of the sampling value, wherein if the maximum value of the sampling value is smaller than a preset threshold value, the second basic voltage is a first judgment voltage or a second judgment voltage, and otherwise, the first basic voltage is the first judgment voltage or the second judgment voltage. The preset threshold is a voltage value, and can be obtained according to the rated voltage of the driver 1/3-1/4 mainly for distinguishing the large voltage from the small voltage, and of course, other values can be set for distinguishing the large voltage from the small voltage.
Further, the maximum value of the sampling value may be obtained by the following method: the first base voltage is changed from negative to positive, the size of the first base voltage is judged every time, and the larger first base voltage in each comparison is set as the maximum value of the sampling value until the first base voltage is changed from negative to positive.
Further, the first determination voltage may be low-pass filtered and/or zero-offset processed to be an AD voltage with a smaller amplification factor. The second decision voltage may be low-pass filtered and/or zero-offset processed to obtain an AD voltage with a larger amplification factor.
Referring to fig. 2, the line voltage of the second winding is shaped into a square wave, and the frequency of the square wave is calculated to obtain the rotation frequency of the motor at the moment. Acquiring the rotation frequency of the motor at the moment also acquires the rotation speed of the motor at the moment. The line voltage can be a first judgment voltage or a second judgment voltage.
Step S150: and smoothly controlling the second winding according to the motor rotating speed of the second winding and the phase frequency converter.
The motor speed and the phase of the second winding are obtained, and then the frequency converter is smoothly controlled to the second winding, so that the current impact can be effectively reduced, see fig. 3, wherein an L3 curve is the current waveform of the motor in direct starting rotation, and it can be seen that there is obvious fluctuation in the switching process, see fig. 4, the current voltage waveform when the motor in rotation is started by using the speed tracking function, wherein L1 is the line voltage waveform, and L2 is the current waveform of the motor, and it can be obviously seen that the current fluctuation in the switching process is greatly reduced compared with fig. 3.
Step S160: and detecting the working frequency of the second winding, performing phase locking on the input voltage and the output voltage of the frequency converter when the working frequency of the second winding reaches the power frequency, stopping the output of the frequency converter after the phase locking, and then disconnecting the second contactor.
The rotational speed and operating frequency of the second winding may be calculated based on the second set of parameters. Furthermore, when the frequency converter stops outputting after the phase locking, the working frequency of the second winding can be slightly larger than the power frequency, so that the working frequency of the second winding is reduced a little after the frequency converter stops outputting and is matched with the power frequency.
Wherein phase locking the converter input voltage and output voltage comprises: acquiring input voltages Ur, Us and Ut of the frequency converter; projecting three-phase input voltages Ur, Us and Ut to a two-phase static coordinate system through coordinate change to obtain Ud and Uq; acquiring an included angle theta 1 of the synthetic voltage vector relative to a coordinate system calculated according to Uq and Ud; acquiring output voltages Ur ', Us ' and Ut ' of the frequency converter; projecting the three-phase output voltages Ur ', Us ' and Ut ' to a two-phase static coordinate system through coordinate change to obtain Ud ' and Uq '; obtaining an included angle theta 2 of the synthetic voltage vector relative to the coordinate system calculated according to Uq 'and Ud'; and performing phase locking according to the difference value of the included angle theta 1 and the included angle theta 2, wherein the phase locking comprises substituting the included angle theta 1 of the input voltage and the included angle theta 2 of the output voltage into a phase-locked loop module, and controlling the output PWM wave of the frequency converter through the phase-locked loop module so that the included angle theta 2 of the output voltage approaches to the included angle theta 1 of the input voltage. Phase lock is considered if angle θ 1 is equal or nearly equal to angle θ 2.
Step S170: and after the second contactor is detected to be completely disconnected, the third contactor is closed, and the second winding is switched to power frequency operation smoothly.
Because the frequency converter adopts a PWM wave output mode, higher harmonics and high-frequency noise exist in output voltage. The frequency converter drives the motor, and when a load has a power generation state, a braking unit and a braking resistor are required to be arranged outside the frequency converter. This is not the case for a grid-connected direct machine. However, the motor driven by the frequency converter is switched to the power grid, and in order to avoid current impact during switching, the frequency and the phase of the output voltage of the frequency converter during switching need to be controlled.
Referring to fig. 5, a frequency-varying power frequency-switching waveform without phase detection is added, where L7 is a motor current waveform, L8 is a grid voltage waveform, and L9 is a motor line voltage waveform, so that it can be seen that the motor current has great fluctuation when the power frequency is switched. Referring to fig. 6, a phase detection time-varying frequency-switching power frequency waveform is added, wherein L4 is a motor current waveform, L5 is a grid voltage waveform, and L6 is a motor line voltage waveform, so that it can be seen that the motor current fluctuation is obviously small when the power frequency is switched.
Because the contactor has on-off time and the on-off time of the contactor of different loads is different, if the on-off time of the contactor is not considered, large current impact can be caused when the contactor is turned on and off, the frequency converter or the motor can be damaged, and tripping protection can also be caused. If the frequency converter has voltage and frequency output in the process of conducting the contactor, the frequency converter is equivalently directly connected with the motor when running, and if the frequency converter already sends out larger output voltage and frequency at the moment, great impact current can be generated, so that the frequency converter can be damaged or trip protection can be carried out on the frequency converter. If the contactor is switched in the process of contactor turn-off, for example, during the processes of KM2 disconnection and KM3 pull-in, and if KM2 is not reliably disconnected yet, KM3 is pulled-in, which is equivalent to directly connecting the input network voltage to the output side of the frequency converter, the frequency converter may be damaged. In this embodiment, after the frequency converter sends out the contactor pull-in/off signal, the contactor feedback signal is detected in real time, so that the current state of the contactor can be accurately known. If the feedback signal indicates that the contactor has not been engaged/disengaged at this time, the next control action is temporarily stopped. And when the fact that the feedback signal of the contactor indicates that the contactor is reliably closed/disconnected is detected, the next step of driving the motor or switching the contactor is carried out.
In one embodiment, after the first contactor is disconnected, the timing module is started, and if the preset time of the timing module is up and the first contactor is not completely disconnected, a fault alarm is sent out; and after the second contactor is disconnected, starting the timing module, and if the preset time of the timing module is up and the second contactor is not completely disconnected, sending out a fault alarm.
Referring to fig. 7, a flow chart of another multi-speed multi-power motor control method.
And acquiring nameplate parameters of the multi-speed and multi-power motor.
And parameters such as stator resistance, rotor resistance, leakage inductance, mutual inductance, no-load current and the like corresponding to each rotating speed power of the motor are respectively obtained through a parameter self-tuning function built in the frequency converter. Simply referred to as the first set of parameters, the second set of parameters.
The frequency converter controls the action of the first relay, controls the first contactor to be closed and conducted, and connects the output end of the frequency converter with the first winding.
Judging whether the first contactor is completely attracted, and if the first contactor is completely attracted, starting the first winding; and if the first contactor is not completely attracted, starting a timing function, timing, if the first contactor is not completely attracted, prompting a fault alarm, and timing time does not reach to control the first contactor to be attracted.
Detecting the rotating speed of the first winding, and when the rotating speed of the first winding reaches a preset rotating speed, controlling the first relay to act by the frequency converter and controlling the first contactor to be disconnected; if not, the detection is continued.
Judging whether the first contactor is completely disconnected or not, and controlling the second contactor to pull in if the first contactor is completely disconnected; and if the first contactor is not completely disconnected, starting a timing function, timing to the end, prompting a fault alarm if the first contactor is not completely disconnected, and timing to the end to control the first contactor to be attracted.
Judging whether the second contactor is completely attracted, and if the second contactor is completely attracted, starting a second winding; and if the first contactor is not completely attracted, starting a timing function, timing, if the first contactor is not completely attracted, prompting a fault alarm, and timing time does not reach to control the first contactor to be attracted.
And detecting the working frequency of the second winding, controlling the second contactor to be disconnected when the working frequency reaches the power frequency, and continuing to detect when the working frequency does not reach the power frequency.
Judging whether the second contactor is completely disconnected, and if the second contactor is completely disconnected, controlling the third contactor to pull in, and smoothly switching the second winding to power frequency operation; and if the first contactor is not completely disconnected, starting a timing function, and if the first contactor is not completely disconnected, prompting a fault alarm, and controlling the second contactor to pull in the timing time.
The method in the above embodiment can control the double-speed double-power motor, and the specific steps are as described above, and similarly, the method can also control the multi-speed multi-power motor such as the three-speed three-power motor, the four-speed four-power motor, and the like.
Referring to fig. 8, a multi-speed multi-power motor control system in which a multi-speed multi-power motor includes at least a first winding 210 and a second winding 220, the control system includes:
one end of the first contactor KM1 is connected with the output end of the frequency converter 100, and the other end of the first contactor KM1 is connected with the first winding 210;
one end of the second contactor KM2 is connected with the output end of the frequency converter 100, and the other end of the second contactor KM2 is connected with the second winding 220;
one end of the third contactor KM3 is connected with the three-phase voltage input end, and the other end of the third contactor KM3 is connected with the second winding 220;
the frequency converter 100 is used for attracting the first contactor KM1 at a preset rotating speed, so that the frequency converter is conducted with the first winding 210 through the first contactor KM 1; driving the first winding 210 and detecting the rotating speed of the first winding 210, stopping the output of the frequency converter 100 when the rotating speed of the first winding 210 reaches a preset rotating speed, and then disconnecting the first contactor KM 1; when the first contactor KM1 is detected to be completely disconnected, the second contactor KM2 is attracted, so that the frequency converter 100 is conducted with the second winding 220 through the second contactor KM 2; when the second contactor KM2 is detected to be completely attracted, the second winding 220 is driven, the phase current and the phase voltage of the second winding 220 are tracked, and the motor rotating speed and the phase corresponding to the second winding 220 are obtained according to the phase current and the phase voltage of the second winding 220; according to the motor speed and the phase of the second winding 220, the frequency converter 100 smoothly controls the second winding 220; detecting the working frequency of the second winding 220, performing phase locking on the input voltage and the output voltage of the frequency converter 100 when the second winding 220 reaches the power frequency, stopping the output of the frequency converter 100 after the phase locking, and then disconnecting the second contactor KM 2; when the second contactor KM2 is detected to be completely disconnected, the third contactor KM3 is attracted, and the second winding 220 is smoothly switched to power frequency operation. The frequency converter is also used for acquiring three-phase input voltages Ur, Us and Ut of the frequency converter; projecting the three-phase input voltages Ur, Us and Ut to a two-phase static coordinate system through coordinate change to obtain two-phase voltages Ud and Uq; acquiring an included angle theta 1 of a synthetic voltage vector relative to a coordinate system calculated according to the two-phase voltages Uq and Ud; obtaining three-phase output voltages Ur ', Us ' and Ut ' of the frequency converter; projecting the three-phase output voltages Ur ', Us ' and Ut ' to a two-phase static coordinate system through coordinate change to obtain two-phase voltages Ud ' and Uq '; obtaining an included angle theta 2 of a synthetic voltage vector relative to a coordinate system calculated according to the two-phase voltages Uq 'and Ud'; and performing phase locking according to the difference value of the included angle theta 1 and the included angle theta 2, and if the difference value of the included angle theta 1 and the included angle theta 2 is smaller than a preset difference value, determining that the phase is locked.
The nameplate parameters of the multi-speed multi-power motor can be input into a motor parameter module of the frequency converter, and can be input through an operation panel of the frequency converter; and parameters such as stator resistance, rotor resistance, leakage inductance, mutual inductance, no-load current and the like corresponding to each rotating speed power of the motor are respectively obtained through a parameter self-tuning function built in the frequency converter. Simply referred to as the first set of parameters, the second set of parameters. Wherein the first set of parameters corresponds to the first winding and the second set of parameters corresponds to the second winding. And acquiring the rated rotating speed of the first winding according to the first group of parameters. The predetermined speed may be equal to or less than the rated speed of the first winding, as desired. The rotational speed and operating frequency of the second winding may also be calculated based on the second set of parameters. When the frequency converter stops outputting after the phase locking, the working frequency of the second winding is slightly larger than the power frequency, so that the working frequency of the second winding is reduced a little after the frequency converter stops outputting and is matched with the power frequency.
The frequency converter comprises a phase-locking module, wherein the phase-locking module is used for acquiring an input voltage included angle theta 1 and an output voltage included angle theta 2 and controlling an output PWM wave of the frequency converter to enable the output voltage included angle theta 2 to approach the input voltage included angle theta 1.
In one embodiment, the frequency converter further comprises a rotation speed tracking module, the rotation speed tracking module is used for tracking phase current and phase voltage of the second winding, and the rotation speed tracking module is started when the frequency converter drives the second winding.
Specifically, the rotating speed tracking module comprises a first rotating speed tracking unit and a second rotating speed tracking unit, a first input end and a second input end of the first rotating speed tracking unit are respectively connected with a first phase voltage of a three-phase voltage and a second phase voltage of the three-phase voltage, an output end of the first rotating speed tracking unit is connected with the digital signal processor, a third input end and a fourth input end of the second rotating speed tracking unit are respectively connected with a second phase voltage and a third phase voltage of the three-phase voltage, and an output end of the second rotating speed tracking unit is connected with the digital signal processor.
Referring to fig. 9, the first rotational speed tracking unit includes a first operational amplifier IC1 and a second operational amplifier IC 2;
the inverting input end of the first operational amplifier IC1 is connected with a first phase voltage of a three-phase voltage through a resistor R1, the non-inverting input end of the first operational amplifier IC1 is connected with a second phase voltage of the three-phase voltage through a resistor R2, the non-inverting input end of the first operational amplifier IC1 is grounded through a resistor R5, the output end of the first operational amplifier IC1 is connected with the inverting input end of the first operational amplifier IC1 through a resistor R4, the output end of the first operational amplifier IC1 is connected with one end of a resistor R11, the other end of the resistor R11 is connected with a power supply end through a resistor R12, and the other end of the resistor R11 is also connected with a digital signal processor;
the inverting input end of the second operational amplifier IC2 is connected with the inverting input end of the first operational amplifier IC1, the non-inverting input end of the second operational amplifier IC2 is connected with the non-inverting input end of the first operational amplifier IC1, the non-inverting input end of the second operational amplifier IC2 is grounded through a resistor R7, the output end of the second operational amplifier IC2 is connected with the inverting input end of the second operational amplifier IC2 through a resistor R6, the output end of the second operational amplifier IC2 is connected with one end of a resistor R13, the other end of the resistor R13 is connected with the power supply end through a resistor R14, and the other end of the resistor R13 is also connected with a digital signal processor;
the resistance of the resistor R6 is greater than the resistance of the resistor R4. The power supply terminal may be at 3.3V or 5V.
The resistance of the resistor R6 may be ten times the resistance of the resistor R4. Of course, the resistance of the resistor R6 may be set to five times, eight times, twenty times, etc. the resistance of the resistor R4 as needed.
The other end of the resistor R11 is connected with two clamping diodes D4 and then is connected with a digital signal processor; one diode of the two clamping diodes D4 is grounded at the anode and connected with the other end of the resistor R11 at the cathode, and the other diode is connected with the anode of the power supply end and connected with the other end of the resistor R11 at the cathode. The other end of the resistor R13 is connected with two clamping diodes D5 and then is connected with a digital signal processor; one diode of the two clamping diodes D5 is grounded at the anode and connected with the other end of the resistor R13 at the cathode, and the other diode is connected with the anode of the power supply end and connected with the other end of the resistor R13 at the cathode. The output of the first op-amp IC1 processes the output voltage to a positive voltage suitable for DSP processing through R11 and R12 and the supply terminal. The output voltage of the first operational amplifier IC2 is processed into a positive voltage suitable for the digital signal processor DSP through R13, R14 and a power supply terminal. The rear part of the signal is directly sent to an AD port UVad2 of a digital signal processor DSP after passing through two clamping diodes D5.
The frequency converter 100 further comprises a first relay for controlling the first contactor KM1 to be switched on and off, a second relay for controlling the second contactor KM2 to be switched on and off, and a third relay for controlling the third contactor KM3 to be switched on and off. The frequency converter 100 further includes input terminals for obtaining feedback signals of the contactors, and the number of the input terminals is set according to the number of the contactors.
The motor in the system adopts a multi-speed multi-power motor, and parameters of a plurality of groups of motors such as three groups, four groups and the like can be input, so that the possibility is provided for switching motors with different rotating speeds and different powers; a high torque start can be provided; the load condition can be automatically judged, and the energy-saving mode is switched to when the load is light; the motor has a rotating speed tracking function, and can automatically identify the rotating speed of the motor; the power frequency conversion switching module is arranged, the phase and frequency of the phase voltage and the phase current of the motor can be detected, the phase angle and the phase of a power grid are detected, and equipment is switched to the power grid to run smoothly.
In the above embodiment, the first phase voltage of the three-phase voltages is a U-phase voltage, the second phase voltage is a V-phase voltage, and the third phase voltage is a W-phase voltage. Of course, it may be set as desired.
Referring to fig. 10, another multi-speed, multi-power motor control system. The main difference from the previous embodiment is that the motor is a three-speed three-power motor, and the third contactor KM3 is connected with the power grid at one end and the third winding 230 at the other end.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (20)
1. A method of controlling a multi-speed, multi-power motor comprising at least a first winding, a second winding, a first contactor, a second contactor, and a third contactor, the method comprising:
closing the first contactor in a pull-in mode at a preset rotating speed, and enabling the frequency converter to be conducted with the first winding through the first contactor;
the frequency converter drives the first winding and detects the rotating speed of the first winding, when the rotating speed of the first winding reaches a preset rotating speed, the frequency converter stops outputting, and then the first contactor is disconnected;
when the first contactor is detected to be completely disconnected, the second contactor is attracted, and the frequency converter is conducted with the second winding through the second contactor;
when the second contactor is detected to be completely closed, the frequency converter drives the second winding and tracks the phase current and the phase voltage of the second winding, and the motor rotating speed and the phase of the second winding are obtained according to the phase current and the phase voltage of the second winding;
smoothly controlling the second winding according to the motor rotating speed of the second winding and the phase frequency converter;
detecting the working frequency of the second winding, performing phase locking on the input voltage and the output voltage of the frequency converter when the working frequency of the second winding reaches the power frequency, stopping the output of the frequency converter after the phase locking, and then disconnecting the second contactor;
and after the second contactor is detected to be completely disconnected, closing the third contactor, and smoothly switching the second winding to power frequency operation.
2. The method of controlling a multi-speed, multi-power motor of claim 1, wherein said phase locking the inverter input voltage and the output voltage comprises:
acquiring three-phase input voltages Ur, Us and Ut of the frequency converter;
projecting the three-phase input voltages Ur, Us and Ut to a two-phase static coordinate system through coordinate change to obtain two-phase voltages Ud and Uq;
acquiring an included angle theta 1 of a synthetic voltage vector relative to a coordinate system calculated according to the two-phase voltages Uq and Ud;
acquiring three-phase output voltages Ur ', Us ' and Ut ' of the frequency converter;
projecting the three-phase output voltages Ur ', Us ' and Ut ' to a two-phase static coordinate system through coordinate change to obtain two-phase voltages Ud ' and Uq ';
obtaining an included angle theta 2 of a synthetic voltage vector relative to a coordinate system calculated according to the two-phase voltages Uq 'and Ud';
and performing phase locking according to the difference value of the included angle theta 1 and the included angle theta 2, and if the difference value of the included angle theta 1 and the included angle theta 2 is smaller than a preset difference value, determining that the phase is locked.
3. A method of controlling a multi-speed multi-power motor as recited in claim 2, wherein said phase locking based on a difference between said included angle θ 1 and said included angle θ 2 comprises:
substituting the input voltage included angle theta 1 and the output voltage included angle theta 2 into the phase-locked loop module, and controlling the output PWM wave of the frequency converter through the phase-locked loop module to enable the output voltage included angle theta 2 to approach the input voltage included angle theta 1.
4. A method for controlling a multi-speed multi-power motor according to claim 1, wherein a speed tracking module is activated when the inverter drives the second winding, the speed tracking module tracking phase current and phase voltage of the second winding.
5. The control method of the multi-speed multi-power motor according to claim 4, wherein the rotation speed tracking module calculates a first phase voltage and a second phase voltage of three-phase voltages of the second winding to obtain a first judgment voltage, and the rotation speed tracking module calculates a second phase voltage and a third phase voltage of three-phase voltages of the second winding to obtain a second judgment voltage; and shaping the first judgment voltage and the second judgment voltage into square waves, wherein when the square waves shaped by the first judgment voltage rise, if the square wave voltage shaped by the second judgment voltage is at a low level at the moment, the rotation direction of the motor is a first direction, otherwise, the rotation direction of the motor is a second direction opposite to the first direction.
6. A multi-speed multi-power motor control method according to claim 5, wherein a first phase voltage and a second phase voltage of three phase voltages in the second winding form a first group of phase voltages, a second phase voltage and a third phase voltage form a second group of phase voltages, and the first group of phase voltages or the second group of phase voltages are subjected to two groups of differential proportional operations to obtain two unequal first base voltages and second base voltages, wherein the first base voltage is less than the second base voltage;
and sampling the first basic voltage and acquiring the maximum value of the sampling value, wherein if the maximum value of the sampling value is smaller than a preset threshold value, the second basic voltage is a first judgment voltage or a second judgment voltage, and otherwise, the first basic voltage is the first judgment voltage or the second judgment voltage.
7. A method of controlling a multi-speed, multi-power motor according to claim 6, wherein said obtaining a maximum of sampled values comprises:
the first base voltage is changed from negative to positive, the size of the first base voltage at each time is judged, and the larger first base voltage in each comparison is set as the maximum value of the sampling value until the first base voltage is changed from negative to positive.
8. A method of controlling a multi-speed multi-power motor according to claim 5, characterized in that the first and second decision voltages are low-pass filtered and/or zero-offset processed.
9. A method of controlling a multi-speed, multi-power motor according to claim 4, wherein the line voltage of the second winding is shaped into a square wave and the frequency of said square wave is calculated to obtain the rotational frequency of the motor at that time.
10. The method of claim 1, wherein after the first contactor is opened, a timing module is started, and if a preset time of the timing module is up and the first contactor is not completely opened, a fault alarm is issued;
and after the second contactor is disconnected, starting a timing module, and if the preset time of the timing module is up and the second contactor is not completely disconnected, sending out a fault alarm.
11. A control system for a multi-speed, multi-power motor including at least a first winding and a second winding, the control system comprising:
one end of the first contactor is connected with the output end of the frequency converter, and the other end of the first contactor is connected with the first winding;
one end of the second contactor is connected with the output end of the frequency converter, and the other end of the second contactor is connected with the second winding;
one end of the third contactor is connected with the three-phase voltage input end, and the other end of the third contactor is connected with the second winding;
the frequency converter is used for attracting the first contactor at a preset rotating speed so as to be conducted with the first winding through the first contactor; driving the first winding and detecting the rotating speed of the first winding, stopping the output of the frequency converter when the rotating speed of the first winding reaches a preset rotating speed, and then disconnecting the first contactor; when the first contactor is detected to be completely disconnected, the second contactor is attracted, and the frequency converter is conducted with the second winding through the second contactor; when the second contactor is detected to be completely closed, driving a second winding and tracking phase current and phase voltage of the second winding, and acquiring the motor rotating speed and phase corresponding to the second winding according to the phase current and phase voltage of the second winding; according to the motor speed and the phase of the second winding, enabling the frequency converter to smoothly control the second winding; detecting the working frequency of the second winding, performing phase locking on the input voltage and the output voltage of the frequency converter when the second winding reaches the power frequency, stopping the output of the frequency converter after the phase locking, and then disconnecting the second contactor; and after the second contactor is detected to be completely disconnected, the third contactor is closed, and the second winding is switched to power frequency operation smoothly.
12. A multi-speed multi-power motor control system according to claim 11, wherein said inverter is further adapted to derive inverter three-phase input voltages Ur, Us and Ut; projecting the three-phase input voltages Ur, Us and Ut to a two-phase static coordinate system through coordinate change to obtain two-phase voltages Ud and Uq; acquiring an included angle theta 1 of a synthetic voltage vector relative to a coordinate system calculated according to the two-phase voltages Uq and Ud; acquiring three-phase output voltages Ur ', Us ' and Ut ' of the frequency converter; projecting the three-phase output voltages Ur ', Us ' and Ut ' to a two-phase static coordinate system through coordinate change to obtain two-phase voltages Ud ' and Uq '; obtaining an included angle theta 2 of a synthetic voltage vector relative to a coordinate system calculated according to the two-phase voltages Uq 'and Ud'; and performing phase locking according to the difference value of the included angle theta 1 and the included angle theta 2, and if the difference value of the included angle theta 1 and the included angle theta 2 is smaller than a preset difference value, determining that the phase is locked.
13. The system of claim 12, wherein the frequency converter comprises a phase-locked module, and wherein the phase-locked module is configured to obtain an input voltage angle θ 1 and an output voltage angle θ 2, and to control an output PWM wave of the frequency converter such that the output voltage angle θ 2 approaches the input voltage angle θ 1.
14. A multi-speed multi-power motor control system according to claim 11, wherein the inverter further comprises a speed tracking module for tracking phase current and phase voltage of the second winding, the speed tracking module being activated simultaneously when the inverter drives the second winding.
15. A multi-speed multi-power motor control system according to claim 14, wherein the speed tracking module comprises a first speed tracking unit and a second speed tracking unit, a first input terminal and a second input terminal of the first speed tracking unit are respectively connected with a first phase voltage and a second phase voltage of the three-phase voltages, an output terminal of the first speed tracking unit is connected with the digital signal processor, a third input terminal and a fourth input terminal of the second speed tracking unit are respectively connected with the second phase voltage and the third phase voltage of the three-phase voltages, and an output terminal of the second speed tracking unit is connected with the digital signal processor.
16. A multi-speed multi-power motor control system as claimed in claim 15, wherein the first speed tracking unit comprises a first operational amplifier and a second operational amplifier;
the inverting input end of the first operational amplifier is connected with a three-phase voltage first phase voltage through a resistor R1, the non-inverting input end of the first operational amplifier is connected with a three-phase voltage second phase voltage through a resistor R2, the non-inverting input end of the first operational amplifier is grounded through a resistor R5, the output end of the first operational amplifier is connected with the inverting input end of the first operational amplifier through a resistor R4, the output end of the first operational amplifier is connected with one end of a resistor R11, the other end of the resistor R11 is connected with the power supply end through a resistor R12, and the other end of the resistor R11 is further connected with a digital signal processor;
the inverting input end of the second operational amplifier is connected with the inverting input end of the first operational amplifier, the non-inverting input end of the second operational amplifier is connected with the non-inverting input end of the first operational amplifier, the non-inverting input end of the second operational amplifier is grounded through a resistor R7, the output end of the second operational amplifier is connected with the inverting input end of the second operational amplifier through a resistor R6, the output end of the second operational amplifier is connected with one end of a resistor R13, the other end of the resistor R13 is connected with the power supply end through a resistor R14, and the other end of the resistor R13 is also connected with a digital signal processor;
the resistance value of the resistor R6 is larger than that of the resistor R4.
17. The multi-speed multi-power motor control system of claim 16, wherein the resistance of the resistor R6 is ten times the resistance of the resistor R4.
18. The control system of claim 16, wherein the other end of said resistor R11 is connected to two clamping diodes and then to a digital signal processor; one diode anode of the two clamping diodes is grounded, the cathode of the diode is connected with the other end of the resistor R11, and the cathode of the diode is connected with the anode of the power supply end and is connected with the other end of the resistor R11; the other end of the resistor R13 is connected with two clamping diodes and then is connected with a digital signal processor; one diode anode of the two clamping diodes is grounded, the cathode of the diode is connected with the other end of the resistor R13, and the cathode of the diode is connected with the anode of the power supply end and is connected with the other end of the resistor R13.
19. A multi-speed multi-power motor control system as claimed in claim 11, wherein the frequency converter further comprises:
the first timer is used for starting after the first contactor is disconnected;
the second timer is used for starting after the second contactor is disconnected;
the frequency converter is also used for sending out a fault alarm when the first timer is preset for time and the first contactor is not completely disconnected; and the device is also used for sending out a fault alarm when the preset time of the second timer is up and the second contactor is not completely opened.
20. The multi-speed multi-power motor control system of claim 11, wherein the frequency converter further comprises a first relay for controlling the first contactor to be turned on and off, a second relay for controlling the second contactor to be turned on and off, and a third relay for controlling the third contactor to be turned on and off.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| PCT/CN2017/080459 WO2018188027A1 (en) | 2017-04-13 | 2017-04-13 | Control method and control system for multi-speed multi-power electric motor |
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| CN110235352A CN110235352A (en) | 2019-09-13 |
| CN110235352B true CN110235352B (en) | 2022-08-09 |
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| CN113746399A (en) * | 2020-05-28 | 2021-12-03 | 福建宏讯电子有限公司 | Motor control system |
| CN116633234A (en) * | 2022-02-14 | 2023-08-22 | 深圳市蓝海华腾技术股份有限公司 | Control method and control device for double-winding motor and motor device |
| CN115333429B (en) * | 2022-08-02 | 2024-01-30 | 东莞叁壹半导体科技有限公司 | Method and device for detecting initial angle of brushless doubly-fed motor rotor and starting method |
| CN116651308B (en) * | 2023-07-31 | 2023-10-20 | 浙江汉信科技有限公司 | Control method of rotating speed self-setting stirring device and stirring device |
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| US4122919A (en) * | 1976-03-23 | 1978-10-31 | Mitsubishi Denki Kabushiki Kaisha | Speed control apparatus for AC elevator |
| CN101383590A (en) * | 2008-10-24 | 2009-03-11 | 哈尔滨理工大学 | Dragging device with high starting performance induction motor and frequency transformer cooperatively running |
| CN101911473A (en) * | 2007-12-27 | 2010-12-08 | 株式会社安川电机 | Winding change-over switch of three-phase AC motor |
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| DK174880B1 (en) * | 2001-11-23 | 2004-01-19 | Danfoss Drives As | Procedure for control of frequency converter for various line voltages and a frequency converter |
| EP2088669A2 (en) * | 2008-02-09 | 2009-08-12 | Karlheinz Gerster | Apparatus and method to operate machines at single phase alternating current or three phase alternating current for mortar processing |
| FI121130B (en) * | 2008-02-29 | 2010-07-15 | Vacon Oyj | Connecting the electric motor to the supply network |
| CN201717819U (en) * | 2010-02-09 | 2011-01-19 | 艾欧史密斯电气产品(常州)有限公司 | Circuit board for bipolar double-speed motor |
| CN103095211B (en) * | 2013-01-18 | 2014-12-17 | 景德镇市景德电机有限公司 | Multi-power frequency conversion energy-saving three-phase asynchronous motor special for oil field |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4122919A (en) * | 1976-03-23 | 1978-10-31 | Mitsubishi Denki Kabushiki Kaisha | Speed control apparatus for AC elevator |
| CN101911473A (en) * | 2007-12-27 | 2010-12-08 | 株式会社安川电机 | Winding change-over switch of three-phase AC motor |
| CN101383590A (en) * | 2008-10-24 | 2009-03-11 | 哈尔滨理工大学 | Dragging device with high starting performance induction motor and frequency transformer cooperatively running |
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