CN110797844A - Magnetic suspension centrifuge, storage medium, high-power frequency converter and control method thereof - Google Patents
Magnetic suspension centrifuge, storage medium, high-power frequency converter and control method thereof Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/1216—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for AC-AC converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/125—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for rectifiers
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/36—Means for starting or stopping converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
- H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
- H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
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Abstract
The invention discloses a magnetic suspension centrifuge, a storage medium, a high-power frequency converter and a control method thereof, wherein the frequency converter comprises a main loop: the power supply device is connected with a load and supplies power to the load, and comprises a rectifying module and a bus capacitor; the control circuit: the main loop and the load are connected, power is supplied through the main loop, and the load is controlled to start; a charging circuit: the main loop is connected and used for protecting the main loop when being electrified; the voltage acquisition circuit: the control circuit is connected with the charging circuit and the control circuit and used for collecting a voltage signal Vr of the charging circuit and feeding the voltage signal Vr back to the control circuit, and the control circuit controls the rectification module according to the voltage signal Vr. The magnetic suspension centrifuge, the storage medium, the high-power frequency converter and the control method thereof effectively solve the phenomenon of IGBT misoperation caused by interference at the moment of electrifying the frequency converter and avoid safety accidents caused by heating of the charging resistor.
Description
Technical Field
The invention relates to the technical field of high-power frequency converters, in particular to a magnetic suspension centrifugal machine, a storage medium, a high-power frequency converter and a control method thereof.
Background
In a high-power frequency converter, in order to limit the impact on a bus capacitor in the power-on process, a charging circuit is added outside a main loop, wherein the charging circuit consists of three ripple resistors and a breaker, the power-on method is to close the breaker in a soft start loop first, charge a bus of the frequency converter through the charging resistor, when the bus voltage is greater than 400V, a DC-DC power supply can work, so that 24V voltage is output to supply power to a control circuit, the bus voltage is detected after the control circuit is powered on, when the bus voltage is greater than 450V, a control instruction is sent to the breaker in the main loop, at the moment, the breaker 1 has a closing condition, and the frequency converter enters a starting state to be closed.
In the process of powering on the frequency converter, for a power device of the frequency converter, firstly, strong current is powered on, and then, weak current is powered on (control current). Therefore, in the interval time between the strong current electrification and the weak current electrification, the IGBT has the problem of probability of generating misconduction when the control signal of the IGBT is in a state easy to be interfered. Then, the charging resistor will have a probabilistic over-current phenomenon, and if the main loop circuit is not closed in time, the charging resistor will generate heat seriously, which results in hidden danger.
Patent No. CN105871191A discloses an apparatus and method for suppressing the power surge current on a three-phase power source type PWM module rectifier. The controllable damping circuit design is provided for power-on impact. However, the detection circuit is complicated in design and has low reliability in an environment with strong electromagnetic interference.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a magnetic suspension centrifuge, a storage medium, a high-power frequency converter and a control method thereof.
In a first aspect, the present invention provides a high power frequency converter, including:
a main loop: the power supply device is connected with a load and supplies power to the load, and comprises a rectifying module and a bus capacitor;
the control circuit: the main loop and the load are connected, power is supplied through the main loop, and the load is controlled to start;
a charging circuit: the main loop is connected and used for protecting the main loop when being electrified;
the voltage acquisition circuit: the control circuit is connected with the charging circuit and the control circuit and used for collecting a voltage signal Vr of the charging circuit and feeding the voltage signal Vr back to the control circuit, and the control circuit controls the rectification module according to the voltage signal Vr.
Preferably, the main circuit further comprises a first circuit breaker, and the charging circuit comprises a second circuit breaker and a charging resistor.
Preferably, the converter still includes busbar voltage acquisition circuit, first circuit breaker control circuit and second circuit breaker control circuit, busbar voltage acquisition circuit connection generating line and control circuit, first circuit breaker control circuit connect control circuit with first circuit breaker, second circuit breaker control circuit connects the controller with the second circuit breaker.
Preferably, the control circuit comprises a rectification main control board, a DC-DC power supply and an inversion main control board, and the rectification main control board comprises a plurality of IGBT modules and drive boards corresponding to the IGBT modules.
In a second aspect, the present invention further provides a control method for a high power frequency converter, where the control method is implemented by the high power frequency converter of the first aspect.
Preferably, the first embodiment of the control method of the high-power frequency converter comprises:
acquiring a voltage value Vr of the charging resistor;
and when the voltage value Vr of the charging resistor is greater than the preset threshold voltage Vr', the rectification main control board sends out pulses to sequentially close the IGBT modules.
Preferably, the step of sending pulses by the rectification main control board to sequentially turn off the IGBT modules specifically comprises:
when the voltage value Vr of the charging resistor is larger than a preset threshold voltage Vr', the PWM module is set to be in an independent mode;
after delaying n seconds, the rectification main control board sends out pulses to sequentially close the IGBT modules.
Preferably, the first embodiment of the control method of the high-power frequency converter further comprises the following steps:
setting the PWM module to be in a complementary mode;
starting normally;
and the frequency converter enters a starting state to be switched on.
Preferably, the rectification main control board sends out pulses after delaying for n seconds to sequentially close the IGBT modules, and the delay time is specifically 5 seconds.
Preferably, the second embodiment of the control method of the high-power frequency converter comprises:
electrifying the frequency converter, and starting charging the bus capacitor;
the control circuit is powered on and initialized;
and the rectification main control board initializes all the IGBT modules at the same time.
Preferably, the second embodiment of the control method of the high-power frequency converter further includes:
after all the IGBT modules are initialized, all the IGBT modules are stably turned off, and the normal operation of a rectifier module is ensured;
and the frequency converter enters a starting state to be switched on.
Preferably, the third embodiment of the control method of the high-power frequency converter comprises:
electrifying the frequency converter, and starting charging the bus capacitor;
starting an internal timer after the rectification main control board is powered on;
when the timing time reaches a preset time t, the rectification main control board controls the second circuit breaker to be switched off and controls the first circuit breaker to be switched on;
and the frequency converter enters a state to be started.
Preferably, a fourth embodiment of the control method of the high-power frequency converter comprises:
electrifying the frequency converter, and starting charging the bus capacitor;
after the rectification main control board is electrified, acquiring a voltage signal Vc at two ends of the bus capacitor;
when a voltage signal Vc at two ends of the bus capacitor is stable, the rectification main control board controls the second circuit breaker to be switched off, and controls the first circuit breaker to be switched on;
and the frequency converter enters a state to be started.
In a third aspect, the present invention further provides a magnetic suspension centrifuge, wherein the magnetic suspension centrifuge comprises the high-power frequency converter of the first aspect.
In a fourth aspect, the present invention is a computer readable storage medium that stores one or more programs, the one or more programs being executable by one or more processors to implement the control method according to any one of the embodiments of the second aspect.
The invention has the beneficial effects that: the invention provides a high-power frequency converter, a control method, a compressor and a storage medium, wherein the phenomenon of IGBT misoperation is judged by detecting the voltage drop at two ends of a charging resistor, if the voltage U is detected to be larger than a comparison voltage, a rectification main control board forcibly sends out a PWM narrow pulse signal to turn off the IGBT, so that the heating caused by the fact that the resistor flows through a large current for a long time is avoided; the phenomenon of IGBT misoperation caused by interference at the moment of electrifying the frequency converter is effectively solved, and safety accidents caused by heating of the charging resistor are avoided.
Drawings
The invention is further illustrated by means of the attached drawings, but the embodiments in the drawings do not constitute any limitation to the invention, and for a person skilled in the art, other drawings can be derived on the basis of the following drawings without inventive effort.
Fig. 1 is an electrical topology structural diagram of a high-power frequency converter of an embodiment of the present invention.
Fig. 2 is a schematic circuit diagram of a rectifying module in a power-on circuit of a high-power frequency converter according to an embodiment of the present invention.
Fig. 3 is a schematic circuit structure diagram of a driving board of a rectifying module in a power-on circuit of a high-power frequency converter according to an embodiment of the invention.
Fig. 4 is a flowchart illustrating a control method of a power-on circuit of a high-power frequency converter according to embodiment 1 of the present invention.
Fig. 5 is a flowchart illustrating a control method of a power-on circuit of a high-power frequency converter according to embodiment 2 of the present invention.
Fig. 6 is an abnormal waveform diagram of the power-on circuit of the high-power frequency converter according to embodiment 1 of the present invention.
Fig. 7 is an abnormal waveform diagram during the power-on process of the power-on circuit of the high-power frequency converter according to embodiment 1 of the present invention.
Fig. 8 is a waveform diagram illustrating the implementation effect of the power-on circuit of the high-power frequency converter in embodiment 1 of the present invention.
Wherein the reference numbers are as follows: 10. main loop, 20 charging circuit, 30 control circuit, 40 load.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, the high power frequency converter of the present embodiment includes:
main circuit 10: the power supply device is connected with a load 40 and supplies power to the load 40, and comprises a rectifying module, a bus capacitor, a first breaker and an inverting module;
the control circuit 30: the main loop 10 and the load 40 are connected, the load 40 is controlled to start by supplying power through the main loop 10, and the main loop comprises a rectification main control board, a DC-DC power supply, an inversion main control board and a bearing controller, wherein the rectification main control board comprises a main control chip DSP, a processor and a memory;
the charging circuit 20: the main circuit 10 is connected and used for protecting the main circuit 10 during power-on, and comprises a second circuit breaker and a charging resistor;
the voltage acquisition circuit: the control circuit 30 is connected to the charging circuit 20 and the control circuit 30, and configured to collect a voltage signal Vr of the charging circuit 20 and feed back the voltage signal Vr to the control circuit 30, and the control circuit 30 controls the rectifying module according to the voltage signal Vr.
The high-power frequency converter of the embodiment can be used for various high-power devices, such as a motor, a compressor, a large-cooling-ton magnetic suspension unit, a magnetic suspension centrifuge and the like, and the embodiment takes the magnetic suspension centrifuge as an example for explanation. In this embodiment, the load 40 is a motor and a magnetic bearing in a magnetic suspension centrifuge.
As shown in fig. 2, the rectifying module includes six IGBTs, six corresponding driving boards, six corresponding diodes, and a filter capacitor CY, the anodes of the six diodes are connected to the emitters of the six corresponding IGBTs, the cathodes of the six diodes are connected to the collectors of the six corresponding IGBTs, the first ports of the six driving boards are all connected to the rectifying main control board, the second ports of the six driving boards are all connected to the gates of the six corresponding IGBTs, the third ports of the six driving boards are all connected to the emitters of the corresponding IGBTs, the emitters of the first IGBT, the second IGBT, and the third IGBT are respectively connected to U, V, W phases of three-phase power, the common ends of the emitters are respectively connected to the collectors of the fourth IGBT, the fifth IGBT, and the sixth IGBT, the collectors of the first IGBT, the second IGBT, and the third IGBT are commonly connected to the positive output terminal DC +, the emitters of the fourth IGBT, the fifth IGBT and the sixth IGBT are commonly connected to a negative output terminal DC-of the rectification module, and two ends of the filter capacitor CY are respectively connected with a positive output terminal DC + and a negative output terminal DC-of the rectification module.
The first IGBT, the second IGBT and the third IGBT are upper bridge arms, and the fourth IGBT, the fifth IGBT and the sixth IGBT are lower bridge arms.
The IPM driving pulse transformer is driven by the driving board, the input end of the IPM driving pulse transformer is connected with the rectification main control board, the output end of the IPM driving pulse transformer is connected with the control end of the IGBT, the IPM pulse transformer outputs high level when detecting that the input end has the upward jumping edge change, and the level signal drives the IGBT to be switched on; when the IPM pulse transformer detects the change of the falling edge at the input end, the IPM pulse transformer outputs low level, and the level signal drives the IGBT to be switched off.
As can be seen from the rectifier modules, the driving grounds of the three-phase lower arms are the same ground, while the emitters of the three-phase upper arms are three-phase inputs U, V, W, so the driving grounds of the upper arms cannot be shared, are all virtual grounds, and are relatively susceptible to interference (as shown in fig. 6).
As shown in figure 7, at the moment of electrifying the frequency converter, the bus capacitor exists
i=C*（du/dt）
It is known that a current spike is caused and the varying current generates a varying magnetic field that generates an EMI signal that interferes with the driving of the upper bridge arm. And after detecting that the jump signal outputs a high level, the IPM pulse transformer in the driving board latches the high level signal and drives the upper bridge arm IGBT of the phase to be switched on. Because the interference signal has no jump signal of a falling edge, the IPM pulse transformer can not generate a low level signal, so that the IGBT can not be turned off. The continuous turn-on of the IGBT will break the original three-phase symmetrical operation timing sequence, causing a continuous large current (about 1.2A abnormal, about 0.2A normal charging current) to flow through the charging resistor in the phase charging circuit 20. By
Q=I^2 R
It can be known that the charging resistor has a large heat productivity under the condition of long-time abnormal charging, so that potential safety hazards exist, and safety accidents such as fire disasters can be caused under serious conditions.
In this embodiment, the voltage collecting circuit includes a comparator, one input terminal of the comparator is connected to the charging circuit 20, the other input terminal of the comparator is connected to a power supply, the voltage of the power supply is equal to the preset threshold voltage Vr', and the output terminal of the comparator is connected to the first I/O port of the rectification main control board.
The working principle and the beneficial effects of the embodiment are as follows: as shown in fig. 8, after the frequency converter is powered on, the bus capacitor starts to charge, when the voltage acquisition circuit detects that the charging circuit 20 is abnormal, a high-level overheat signal is output to the rectification main control board, the main control chip DSP of the rectification main control board sets the PWM module to be in an independent mode first, the main control chip delays for 5s to send out PWM module narrow pulse signals in sequence, the narrow pulse signals have complete up-skip edges and down-skip edges, the down-skip edges are input to the IGBT drive board to forcibly turn off the IGBT module, then the PWM module is set to be in a complementary mode, the frequency converter starts normally after entering the complementary mode, after the charging of the bus capacitor is completed, the frequency converter enters a start-up mode to be switched on, and the frequency converter enters a state that the charging resistor cannot cause potential safety hazards due to overheat.
Example 2.
As shown in fig. 4, this embodiment provides a control method for a high-power frequency converter, where the control method is implemented by the high-power frequency converter described in embodiment 1, and includes:
acquiring a voltage value Vr of the charging resistor;
and acquiring a real-time voltage value of the charging resistor through a voltage acquisition circuit.
When the voltage value Vr of the charging resistor is larger than the preset threshold voltage Vr', the PWM module is set to be in an independent mode;
the voltage acquisition circuit comprises a comparison circuit, when the voltage value Vr of the charging resistor is larger than the preset threshold voltage Vr', the voltage acquisition circuit outputs a high-level overheat signal to a main control chip DSP of the rectification main control board, and the main control chip DSP sets the PWM module to be in an independent mode after acquiring the overheat signal.
After delaying n seconds, the rectification main control board sends out pulses to sequentially close the IGBT modules;
specifically, the delay time n is 5 seconds;
through tests, the fault recurrence is generally that about 200ms after power-on, some margin is left, pulse signals can be sent after 1s,
however, the time interval cannot be too long, and if heat continues to be generated, a hidden trouble may be generated, so in this embodiment, the delay time n is 5 seconds. After a PWM module of a main control chip DSP is set to be in an independent mode, a pulse is sent to a control end of each IGBT after 5 seconds, and the pulse signal has a complete up-jumping edge and a complete down-jumping edge, so that all the IGBTs are closed.
Setting the PWM module to be in a complementary mode;
starting normally;
and the frequency converter enters a starting state to be switched on.
After all IGBTs are closed, setting the PWM module mode of the main control chip DSP to be a complementary mode again to enable the frequency converter to be started normally, after the frequency converter is started normally, continuously charging the bus capacitor, and after the bus capacitor is charged, enabling the frequency converter to enter a starting state to be switched on.
After the frequency converter is powered on, because the bus capacitor in the frequency converter needs to be charged through the charging circuit 20, a certain time is needed in the process, and the output voltage of the frequency converter is an unstable voltage which cannot work due to the driving motor. Only when the bus capacitor of converter charges and accomplishes the back, the output voltage of converter is stable, and at this moment, the output voltage of converter just can the work of direct drive motor, can close a floodgate with the circuit breaker of converter major loop 10 this moment, and converter voltage can directly start motor, consequently, when converter bus capacitor charges and accomplishes the back, the converter gets into and treats the start state of closing a floodgate.
The working principle and the beneficial effects of the embodiment are as follows: the charging resistor is additionally provided with voltage acquisition circuits at two ends, whether the charging resistor is abnormal or not is judged through the voltage acquisition circuits, when the charging resistor is abnormal, the main control chip DSP sets the PWM module to be in an independent mode firstly, the main control chip is delayed for 5s, narrow pulse signals of the PWM module are sequentially sent out, the narrow pulse signals have complete up-jumping edges and down-jumping edges, and the down-jumping edges are input to the IGBT drive board to forcibly turn off the IGBT module. Therefore, the IGBT module is effectively closed, and safety accidents caused by overlarge charging current for a long time are avoided.
Example 3.
As shown in fig. 5, this embodiment provides a control method for a high-power frequency converter, where the control method is implemented by the high-power frequency converter described in embodiment 1, and includes:
after three-phase input power is firstly connected into a frequency converter, a bus capacitor starts to charge;
after the frequency converter is normally powered on, the bus capacitor starts to charge, when the bus voltage reaches the lowest working threshold voltage of the DC/DC switching power supply, the DC/DC switching power supply supplies power to the rectification main control board and the motor inversion main control board, and the rectification main control board and the motor inversion main control board are connected into the frequency converter system.
The control circuit 30 is powered on and initialized;
after the rectification main control board is powered on, the main control chip DSP is initialized.
The rectification main control board initializes each IGBT;
after the IGBT initialization is completed, all the IGBTs are stably turned off, and the normal operation of the rectification module is ensured;
after the main control chip DSP completes initialization, the main control chip DSP sequentially initializes the IGBTs of each bridge arm, namely, narrow pulses are sequentially sent out to the IGBTs of each bridge arm. The narrow pulse signal has a complete up-jumping edge and a complete down-jumping edge, the down-jumping edge is input to the control end of the IGBT drive board, and when a pulse transformer electrified on the drive board detects a level rising edge, the rear end output level is high; when a level falling edge is detected, its back end output is low.
And then each IGBT is controlled to carry out complete turn-on and turn-off actions once, so that the IGBT mechanism is in a controllable and stable state no matter whether the charging resistor is overheated or not in the process that the frequency converter is charged to be switched into the main loop 10 is ensured.
And the frequency converter enters a starting state to be switched on.
The working principle and the beneficial effects of the embodiment are as follows: the three-phase input power is firstly connected into the frequency converter system, and when the bus voltage rises to the lowest working threshold value of the DC/DC switching power supply, the frequency converter rectification and inversion main control board controls the power to be connected into the frequency converter system again. After the main control board is electrified, each bridge arm is initialized in sequence, namely a stable on-off process is given to the IGBT of each bridge arm by sending narrow pulses. Even if interference in the power-on process of the frequency converter enables a certain bridge arm to be in a normally open state, after the PFC main control board initializes the IGBT, the abnormal IGBT can be stably turned off. Thereby restoring the rectifier module to a three-phase symmetrical normal operating state.
Example 4.
The embodiment provides a control method of a high-power frequency converter, and the difference between the high-power frequency converter implementing the control method of the embodiment and the frequency converter of embodiment 1 is that the high-power frequency converter of the embodiment further includes a first circuit breaker control circuit 30 and a second circuit breaker control circuit 30, the first circuit breaker control circuit 30 is connected to a second I/O port of the control circuit 30 and the first circuit breaker, and the second circuit breaker control circuit 30 is connected to a third I/O port of the controller and the second circuit breaker.
The first circuit breaker control circuit 30 controls the on/off of the first circuit breaker according to the input signal, and the second circuit breaker control circuit 30 controls the on/off of the second circuit breaker according to the input signal, for example, when the first circuit breaker control circuit 30 inputs a high level, the first circuit breaker control circuit 30 controls the first circuit breaker to be turned on; when the first breaker control circuit 30 inputs a low level, the first breaker control circuit 30 controls the first breaker to be opened, and the control logic of the second breaker control circuit 30 is the same as that of the first breaker control circuit 30. Wherein the level signals output by the first and second breaker control circuits 30 and 30 cannot be the same.
The control method of the high-power frequency converter comprises the following steps:
electrifying the frequency converter, and starting to charge the bus capacitor;
and after the frequency converter is normally electrified, the bus capacitor starts to be charged, and when the bus voltage reaches the lowest working threshold voltage of the DC/DC switching power supply, the DC/DC switching power supply supplies power to the rectification main control board and the motor inversion main control board.
Starting an internal timer after the rectification main control board is powered on;
after the power of the rectification main control board is on, the initialization operation is started first, and after the initialization is completed, an internal timer in the main control chip DSP is started to start timing.
When the timing time reaches the preset time t, the rectification main control board controls the second circuit breaker to be switched off and controls the first circuit breaker to be switched on simultaneously;
when the timing time reaches the preset time t, the main control chip DSP outputs a low level to the third I/O port to disconnect the second circuit breaker, and simultaneously outputs a high level to the second I/O port to close the first circuit breaker.
The frequency converter enters a state to be started;
the first circuit breaker is closed, the second circuit breaker is opened, the charging circuit 20 of the frequency converter is disconnected, the main loop 10 is conducted, and the frequency converter enters a state to be started.
The working principle and the beneficial effects of the embodiment are as follows: and after the rectification main control board is powered on, the charging time is timed through a timer in the main control chip DSP. And when the preset time t is reached, automatically disconnecting the second circuit breaker, closing the first circuit breaker and enabling the frequency converter to enter a state to be started. Therefore, the frequency converter is prevented from being in a charging state for a long time, and the problems of unbalanced three-phase rectification and overheating of a charging resistor caused by IGBT misconduction which possibly occur are avoided.
Example 5.
The embodiment provides a control method of a high-power frequency converter, and the difference between the high-power frequency converter implementing the control method of the embodiment and the frequency converter of the embodiment 1 is that the frequency converter of the embodiment further includes a bus voltage acquisition circuit, a first circuit breaker control circuit 30 and a second circuit breaker control circuit 30, the bus voltage acquisition circuit is connected with a bus and the control circuit 30, the first circuit breaker control circuit 30 is connected with the control circuit 30 and the first circuit breaker, and the second circuit breaker control circuit 30 is connected with the controller and the second circuit breaker.
The first circuit breaker control circuit 30 controls the on/off of the first circuit breaker according to the input signal, and the second circuit breaker control circuit 30 controls the on/off of the second circuit breaker according to the input signal, for example, when the first circuit breaker control circuit 30 inputs a high level, the first circuit breaker control circuit 30 controls the first circuit breaker to be turned on; when the first breaker control circuit 30 inputs a low level, the first breaker control circuit 30 controls the first breaker to be opened, and the control logic of the second breaker control circuit 30 is the same as that of the first breaker control circuit 30. Wherein the level signals output by the first and second breaker control circuits 30 and 30 cannot be the same.
The bus voltage acquisition circuit comprises a voltage sampling resistor and an A/D conversion chip, and the bus voltage acquisition circuit inputs a bus voltage signal into the main control chip DSP.
The control method of the high-power frequency converter comprises the following steps:
electrifying the frequency converter, and starting to charge the bus capacitor;
and after the frequency converter is normally electrified, the bus capacitor starts to be charged, and when the bus voltage reaches the lowest working threshold voltage of the DC/DC switching power supply, the DC/DC switching power supply supplies power to the rectification main control board and the motor inversion main control board.
Acquiring a voltage signal Vc at two ends of a bus capacitor after the rectification main control board is electrified;
the bus voltage acquisition circuit input is connected with the both ends of bus electric capacity, and bus voltage acquisition circuit obtains the bus voltage size through sampling resistance, and the bus voltage signal of analog quantity is converted digital signal input main control chip DSP through the AD conversion chip.
When the voltage signal Vc at two ends of the bus capacitor is stable, the rectification main control board controls the second circuit breaker to be switched off and controls the first circuit breaker to be switched on;
when the frequency converter is powered on, the frequency converter is in a charging state firstly, the voltage at two ends of the bus capacitor is changed continuously, when the main control chip DSP or the taken voltage signal is stable, the bus capacitor is indicated to be charged completely, after the bus charging is completed, the main control chip DSP outputs a low level to the third I/O port to disconnect the second circuit breaker, and simultaneously outputs a high level to the second I/O port to close the first circuit breaker.
And the frequency converter enters a state to be started.
The first circuit breaker is closed, the second circuit breaker is opened, the charging circuit 20 of the frequency converter is disconnected, the main loop 10 is conducted, and the frequency converter enters a state to be started.
The working principle and the beneficial effects of the embodiment are as follows: after the rectification main control board is electrified, the charging condition of the bus capacitor is detected through the main control chip DSP, when the bus voltage reaches stability, the second circuit breaker is automatically disconnected, the first circuit breaker is closed, and the frequency converter enters a state to be started. Therefore, the frequency converter is prevented from being in a charging state for a long time, and the problems of unbalanced three-phase rectification and overheating of a charging resistor caused by IGBT misconduction which possibly occur are avoided.
Example 6, a magnetic levitation centrifuge.
The present invention also provides a magnetic suspension centrifuge, which includes the high-power frequency converter of embodiment 1, and the high-power frequency converter is used to drive a motor and/or a magnetic suspension bearing in the magnetic suspension centrifuge, so that the magnetic suspension centrifuge has more reliable performance.
Embodiment 7, a computer-readable storage medium.
The present embodiment provides a computer-storable medium that stores one or more programs that can be executed by one or more processors to implement the control method of any of the above embodiments.
The rectification main control board comprises a main control chip DSP, a processor and a memory, wherein the processor is used for executing a control program stored in the memory so as to realize the control method of any one of the embodiments.
A storage medium for recording a program code of a software program that can realize the functions of the above-described embodiments is provided to the inverter in the above-described embodiments, and the program code stored in the storage medium is read and executed by the CPU or MPU in the inverter. In this case, the program code itself read out from the storage medium performs the functions of the above-described embodiments, and the storage medium storing the program code constitutes an embodiment of the present invention.
As a storage medium for supplying the program code, such as a floppy disk, a hard disk, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus drive, or a combination of two or more of these, in a specific embodiment, the memory includes a Read Only Memory (ROM); where appropriate, the ROM may be mask-programmed ROM, Programmable ROM (PROM), Erasable PROM (EPROM), Electrically Erasable PROM (EEPROM), electrically rewritable ROM (EAROM), or flash memory or a combination of two or more of these may be used.
The functions of the above-described embodiments may be realized not only by executing the readout program code by the computer, but also by some or all of actual processing operations executed by an OS (operating system) running on the computer according to instructions of the program code.
Further, the embodiments of the present invention also include a case where after the program code read out from the storage medium is written into a function expansion card inserted into the computer or into a memory provided in a function expansion unit connected to the computer, a CPU or the like included in the function expansion card or the function expansion unit performs a part of or the whole of the processing in accordance with the command of the program code, thereby realizing the functions of the above-described embodiments.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (15)
1. A high power frequency converter, characterized in that said frequency converter comprises:
a main loop: the power supply device is connected with a load and supplies power to the load, and comprises a rectifying module and a bus capacitor;
the control circuit: the main loop and the load are connected, power is supplied through the main loop, and the load is controlled to start;
a charging circuit: the main loop is connected and used for protecting the main loop when being electrified;
the voltage acquisition circuit: the control circuit is connected with the charging circuit and the control circuit and used for collecting a voltage signal Vr of the charging circuit and feeding the voltage signal Vr back to the control circuit, and the control circuit controls the rectification module according to the voltage signal Vr.
2. The high power inverter as claimed in claim 1, wherein the main circuit further comprises a first circuit breaker, and the charging circuit comprises a second circuit breaker and a charging resistor.
3. The high power inverter as claimed in claim 2, wherein the inverter further comprises a bus voltage acquisition circuit, a first circuit breaker control circuit and a second circuit breaker control circuit, the bus voltage acquisition circuit connects the bus and the control circuit, the first circuit breaker control circuit connects the control circuit and the first circuit breaker, and the second circuit breaker control circuit connects the controller and the second circuit breaker.
4. The high-power frequency converter according to claim 1, wherein the control circuit comprises a rectification main control board, a DC-DC power supply and an inversion main control board, and the rectification main control board comprises a plurality of IGBT modules and driving boards corresponding to the IGBT modules.
5. A control method of a high-power frequency converter is characterized in that the control method is realized by the high-power frequency converter of any one of claims 1 to 4.
6. The method for controlling a high power inverter as claimed in claim 5, comprising:
acquiring a voltage value Vr of the charging resistor;
and when the voltage value Vr of the charging resistor is greater than the preset threshold voltage Vr', the rectification main control board sends out pulses to sequentially close the IGBT modules.
7. The method for controlling a high-power frequency converter according to claim 6, wherein the step of sending a pulse by the rectification main control board to sequentially turn off the IGBT modules comprises:
when the voltage value Vr of the charging resistor is larger than a preset threshold voltage Vr', the PWM module is set to be in an independent mode;
after delaying n seconds, the rectification main control board sends out pulses to sequentially close the IGBT modules.
8. The method for controlling a high power inverter as claimed in claim 7, further comprising the steps of:
setting the PWM module to be in a complementary mode;
starting normally;
and the frequency converter enters a starting state to be switched on.
9. The method as claimed in claim 7, wherein the rectification main control board sends out pulses after the delay of n seconds to turn off the IGBT module in sequence, and the delay time is 5 seconds.
10. The method for controlling a high power inverter as claimed in claim 5, comprising:
electrifying the frequency converter, and starting charging the bus capacitor;
the control circuit is powered on and initialized;
and the rectification main control board initializes all the IGBT modules at the same time.
11. The method for controlling a high power inverter as claimed in claim 10, further comprising:
after all the IGBT modules are initialized, all the IGBT modules are stably turned off, and the normal operation of the rectifier module is ensured;
and the frequency converter enters a starting state to be switched on.
12. The method for controlling a high power inverter as claimed in claim 5, comprising:
electrifying the frequency converter, and starting charging the bus capacitor;
starting an internal timer after the rectification main control board is powered on;
when the timing time reaches a preset time t, the rectification main control board controls the second circuit breaker to be switched off and controls the first circuit breaker to be switched on;
and the frequency converter enters a state to be started.
13. The method for controlling a high power inverter as claimed in claim 5, comprising:
electrifying the frequency converter, and starting charging the bus capacitor;
after the rectification main control board is electrified, acquiring a voltage signal Vc at two ends of the bus capacitor;
when a voltage signal Vc at two ends of the bus capacitor is stable, the rectification main control board controls the second circuit breaker to be switched off, and controls the first circuit breaker to be switched on;
and the frequency converter enters a state to be started.
14. A magnetic levitation centrifuge, characterized in that the magnetic levitation centrifuge comprises a high power frequency converter according to any one of claims 1 to 4.
15. A computer readable storage medium, characterized in that the computer storable medium stores one or more programs that are executable by one or more processors to implement the control method of any one of claims 5 to 13.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911025866.7A CN110797844A (en) | 2019-10-25 | 2019-10-25 | Magnetic suspension centrifuge, storage medium, high-power frequency converter and control method thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911025866.7A CN110797844A (en) | 2019-10-25 | 2019-10-25 | Magnetic suspension centrifuge, storage medium, high-power frequency converter and control method thereof |
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| CN110797844A true CN110797844A (en) | 2020-02-14 |
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| CN201911025866.7A Pending CN110797844A (en) | 2019-10-25 | 2019-10-25 | Magnetic suspension centrifuge, storage medium, high-power frequency converter and control method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111697810A (en) * | 2020-05-20 | 2020-09-22 | 惠州拓邦电气技术有限公司 | Slow start control device and method for high-power inverter |
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2019
- 2019-10-25 CN CN201911025866.7A patent/CN110797844A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111697810A (en) * | 2020-05-20 | 2020-09-22 | 惠州拓邦电气技术有限公司 | Slow start control device and method for high-power inverter |
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