CN108181071B

CN108181071B - Power amplifier, power control system and method of electric vibration table

Info

Publication number: CN108181071B
Application number: CN201810138887.9A
Authority: CN
Inventors: 韩金刚; 杨义; 陈安迪; 杨振涛
Original assignee: Shanghai Qianli Electric Technology Co ltd
Current assignee: Shanghai Qianli Electric Technology Co ltd
Priority date: 2018-01-09
Filing date: 2018-02-07
Publication date: 2024-04-05
Anticipated expiration: 2038-02-07
Also published as: CN108181071A

Abstract

The invention discloses a power amplifier of an electric vibrating table, which comprises: the first power supply circuit, the PWM rectifying circuit, the second power supply circuit, the PWM inverter circuit and the filter circuit are electrically connected in sequence; the power amplifier of the electrodynamic vibration shaker further includes: the control circuit, and the sampling circuit and the driving circuit are respectively and electrically connected with the control circuit; the control circuit is also electrically connected with the first power supply circuit; the driving circuit is respectively and electrically connected with the PWM inverter circuit and the PWM rectifying circuit; the sampling circuit is respectively and electrically connected with the PWM rectifying circuit and the PWM inverting circuit. The PWM rectifying circuit and the PWM inverter circuit can adopt SiC power devices, so that each power device has real-time short-circuit protection and is not enabled in the bus voltage establishment process, the defects of low reliability and short service life of the traditional power amplifier are avoided, and the power amplifier has high reliability.

Description

Power amplifier, power control system and method of electric vibration table

Technical Field

The present invention relates to the field of power amplification, and in particular, to a power amplifier, a power control system and a power control method for an electric vibration table.

Background

With the rapid development of the aerospace and automotive electronics industries, various test devices for simulating the operating conditions of the devices are increasingly required. The vibration table test has been widely used in the performance and strength identification of equipment as an effective means for simulating the vibration test environment, verifying the reliability of the equipment and the strength of the components. The traditional electric test bench uses MOSFET made of Si material as a power device, and has the defects of high power consumption, low efficiency, serious heating of the device, low reliability and the like. The reliability of a new generation of power amplifier of an electric vibration table based on IGBT as a power device is greatly improved, but the output cut-off frequency of the power amplifier is low due to the low switching frequency of the device, and the high-frequency waveform distortion is serious. Meanwhile, aiming at vibration tables with different powers, power amplifiers with various power levels are needed, so that the design period is long. There is therefore a need for a power amplifier for an electrodynamic vibrating table that is highly reliable, efficient, and modular.

Disclosure of Invention

In order to solve the technical defects, the invention provides a power amplifier of an electric vibration table, a power control system and a power control method. Specifically, the technical scheme of the invention is as follows:

In a first aspect, the present invention discloses a power amplifier for an electrodynamic vibration shaker, comprising: the first power supply circuit, the PWM rectifying circuit, the second power supply circuit, the PWM inverter circuit and the filter circuit are electrically connected in sequence; the power amplifier of the electrodynamic vibration shaker further includes: the control circuit, and the sampling circuit and the driving circuit are respectively and electrically connected with the control circuit; the control circuit is also electrically connected with the first power supply circuit; the driving circuit is respectively and electrically connected with the PWM inverter circuit and the PWM rectifying circuit; the sampling circuit is respectively and electrically connected with the PWM rectifying circuit and the PWM inverter circuit; wherein: the three-phase alternating current is subjected to filtering treatment through the first power supply circuit, and the PWM rectification circuit outputs stable direct current bus voltage to the second power supply circuit after rectification treatment; the second power supply circuit provides the stable direct current bus voltage for the PWM inverter circuit, the PWM inverter circuit inverts the stable direct current bus voltage into stable alternating current, and the stable alternating current is provided for the electric vibration table after high-frequency filtering treatment by the filtering circuit; the control circuit controls the on-off of a switching tube of the PWM rectifying circuit through the driving circuit according to the bus voltage output by the PWM rectifying circuit and acquired by the sampling circuit, so that the PWM rectifying circuit outputs stable direct current bus voltage; the control circuit is further used for controlling the on-off of a switching tube of the PWM inverter circuit through the driving circuit according to the alternating current which is acquired by the sampling circuit and is output by the PWM inverter circuit, so that the PWM inverter circuit outputs stable alternating current.

Preferably, the first power supply circuit includes: the device comprises an EMC filter, three alternating current inductors and two groups of selection circuits, wherein the selection circuits are formed by connecting a current limiting resistor and an alternating current contactor in parallel; among three-phase alternating current output ends of the EMC filter, an alternating current output end is electrically connected with an alternating current inductor and then connected into the PWM rectifying circuit; each alternating current output end of the remaining two-phase alternating current output ends is connected with an alternating current inductor and a group of selection circuits in sequence and then connected with the PWM rectifying circuit; the second power supply circuit at least comprises a group of capacitors, and provides stable direct current power for the PWM inverter circuit.

Preferably, the PWM rectifying circuit is a SiC rectifier, and the SiC rectifier includes three half-bridge units, each half-bridge unit includes a first MOS transistor and a second MOS transistor, and each first MOS transistor and each second MOS transistor are reversely connected to a diode; the source electrode of the first MOS tube is connected with the drain electrode of the second MOS tube and is connected with one phase of three-phase current output by the first power supply circuit; drains of the first MOS tubes of the three half-bridge units are connected with each other to serve as an anode output end of the SiC rectifier, and sources of the second MOS tubes of the three half-bridge units are connected with each other to serve as a cathode output end of the SiC rectifier.

Preferably, the PWM inverter circuit is a SiC inverter, and the SiC inverter includes two inverter units, each of which includes a third MOS transistor and a fourth MOS transistor; each third MOS tube and each fourth MOS tube are reversely connected with a diode; the source electrode of the third MOS tube is connected with the drain electrode of the fourth MOS tube and is used as an output end of the SiC inverter; the drains of the third MOS tubes of the two inversion units are connected with each other and are electrically connected with the positive output end of the second power supply circuit; sources of the fourth MOS tubes of the two inversion units are connected with each other and are electrically connected with the negative electrode output end of the second power supply circuit.

Preferably, the sampling circuit includes: the first sampling sub-circuit is used for collecting three-phase alternating current output by the first power supply circuit to the PWM rectifying circuit; the second sampling sub-circuit is used for collecting the direct current bus voltage at the output end of the PWM rectifying circuit; the third sampling sub-circuit is used for collecting the alternating current output by the PWM inverter circuit; and the fourth sampling sub-circuit is used for collecting the direct current bus current output by the PWM rectifying circuit.

Preferably, the control circuit includes: the first control module is connected with the second control module through the CAN bus; wherein:

The first control module is electrically connected with the first sampling sub-circuit, the second sampling sub-circuit and the first power supply circuit respectively; the controller is used for receiving a reference bus voltage value required to be output by the given PWM rectifying circuit and a reference alternating current value required to be output by the PWM inverter circuit through the CAN bus; the first control module transmits the alternating current value required to be output by the PWM inverter circuit to the second control module through the CAN bus, and: the first control module judges whether the voltage and the current phase of the three-phase alternating current are consistent according to the three-phase alternating current collected by the first sampling circuit; when the voltage and current phases of the three-phase alternating current are not consistent, the first control module controls the first power supply circuit to output the three-phase alternating current with consistent phases; when the direct current bus voltage at the output end of the PWM rectifying circuit acquired by the second sampling circuit reaches a first preset voltage value, the first control module controls the alternating current contactor of the selection circuit in the first power supply circuit to be attracted, and the driving circuit drives the PWM rectifying circuit to carry out rectifying work; when the voltage value of the direct current bus acquired by the second sampling circuit reaches a second preset voltage value, the first control module sends an inversion starting instruction to the second control module so that the second control module drives the PWM inverter circuit to start working through the driving circuit; the first control module is further used for driving the on-off of a switching tube of the PWM rectifying circuit through the driving circuit according to the direct current bus voltage acquired by the second sampling circuit and the reference bus voltage value required to be output by the PWM rectifying circuit, and controlling the PWM rectifying circuit to output stable reference bus voltage;

The second control module is respectively and electrically connected with the third sampling sub-circuit and the fourth sampling sub-circuit; wherein: the second control module receives a reference alternating current value which is transmitted by the first control module and is required to be output by the PWM inverter circuit; after receiving the inversion starting instruction of the first control module, the second control module drives the PWM inversion circuit to start working through the driving circuit; the second control module judges whether the direct current bus current is greater than a preset direct current protection threshold value according to the direct current bus current output by the PWM rectifying circuit and collected by the fourth sampling sub-circuit, and if so, the driving circuit controls the PWM inverter circuit to stop working; the second control module is further configured to control the PWM inverter circuit to output a stable reference ac current according to the reference ac current value required to be output by the PWM inverter circuit, in combination with the ac current value output by the PWM inverter circuit and collected by the third sampling sub-circuit, by driving the on-off of the switching tube of the PWM inverter circuit by the driving circuit; the second control module is further configured to determine whether the ac current value output by the PWM inverter circuit collected by the third sampling sub-circuit is greater than a preset ac current protection threshold, and if yes, control the PWM inverter circuit to stop working through the driving circuit.

Preferably, each MOS transistor in the PWM rectifying circuit or the PWM inverting circuit is configured with a driving sub-circuit; the driving sub-circuit includes: the first driving chip, the second driving chip and a trigger chip, wherein: an input pin IN+ of the first driving chip receives a PWM control signal of the control circuit; the fault signal output by the control circuit is electrically connected with the base electrode of a triode through a resistor, the emitting electrode of the triode is grounded, and the collecting electrode of the triode is electrically connected with the input pin IN+ of the first driving chip; the input pin A of the trigger chip is electrically connected with the fault output end/RDY of the first driving chip; the output pin Y of the trigger chip is electrically connected with the negative electrode end of a diode, and the positive electrode end of the diode is electrically connected with a 5V power supply through a resistor; the input end IN of the second driving chip is electrically connected with the output end OUT of the first driving chip and is used for amplifying the driving current output by the second driving chip, and the driving signal output by the output end OUT of the second driving chip is used for driving the MOS tube corresponding to the driving sub-circuit.

In a second aspect, the invention also discloses a power control system of the electric vibration table, which comprises a plurality of power amplifiers, vibration table controllers and a master control chip of the electric vibration table which are connected in parallel; wherein: the vibration table controller obtains the vibration power required by the electric vibration table and transmits the vibration power required by the electric vibration table to the master control chip through the CAN bus; after receiving the vibration power required by the electric vibration tables, the master control chip calculates a reference alternating current value and a reference bus voltage value of the power amplifier of each electric vibration table according to the number of the power amplifiers of the parallel electric vibration tables; the master control chip gives a reference alternating current value of the power amplifier of the electric vibration table to the power amplifier of each electric vibration table through a CAN bus and the reference bus voltage value; so that the parallel-connected vibrating table power amplifiers provide the stable alternating current required by the electric vibrating table.

In a third aspect, the present invention also discloses a power control method of an electric vibration table applied to the power control system of an electric vibration table, including: s100, the vibration table controller obtains the vibration power required by the electric vibration table and transmits the vibration power to the master control chip through a CAN bus; s200, the master control chip calculates a reference alternating current value and a reference bus voltage value of the power amplifiers of each electric vibration table according to the vibration power required by the electric vibration table and the number of the power amplifiers of the parallel electric vibration tables, and transmits the reference alternating current value and the reference bus voltage value to the power amplifiers of each electric vibration table through a CAN bus; and S300, controlling and outputting alternating current required by each electric vibration table by a power amplifier of each electric vibration table according to the received reference alternating current value and the reference bus voltage value.

Preferably, the step S300 includes: s310, a control circuit of a power amplifier of the electric vibration table judges whether the voltage value of the polar capacitor of the second power supply circuit acquired by the sampling circuit reaches a preset first voltage value or not; if yes, entering the next step; s320, the control circuit controls the three-phase alternating current filtered by the first power supply circuit to be directly output to the PWM rectifying circuit, and the PWM rectifying circuit starts rectifying work under the control of the control circuit; s330, the control circuit receives the reference alternating current value and the reference bus voltage value issued by the master control chip through a CAN bus; s340, the control circuit controls the PWM rectifying circuit to output stable direct-current bus voltage consistent with the reference alternating-current voltage value through the driving circuit according to the reference bus voltage value; and S350, the control circuit controls the PWM inverter circuit to output stable alternating current consistent with the reference alternating current value through the driving circuit according to the reference alternating current bus current value.

Preferably, the step S340 includes: s341, the control circuit judges whether the direct current bus current exceeds a preset current protection value according to the direct current bus current output by the PWM rectifying circuit and collected by the sampling circuit, if so, the step S342 is carried out, otherwise, the step S343 is carried out; s342, the control circuit outputs a fault feedback signal, and the driving circuit controls the electric vibration table to stop working; and S343, the control circuit controls the PWM rectifying circuit to output stable direct current bus voltage consistent with the reference bus voltage through the driving circuit according to the direct current bus voltage output by the PWM rectifying circuit and the reference bus voltage value acquired by the sampling circuit.

Preferably, the step S350 includes: s351, when the PWM rectifying circuit outputs stable direct current bus voltage consistent with the reference bus voltage, the control circuit starts the PWM inverter circuit to start working; and S352, the control circuit controls the PWM inverter circuit to output stable alternating current consistent with the reference alternating current value according to the alternating current output by the PWM inverter circuit and the reference alternating current value acquired by the sampling circuit.

The invention has at least one of the following advantages:

(1) The power amplifier is a closed loop, and voltage and current at corresponding positions are obtained through sampling, so that the regulation and control of the PWM rectifying circuit and the PWM inverter circuit are respectively realized, the control precision is high, various protection functions are complete, and the power amplifier has high reliability and high precision.

(2) Compared with the traditional power amplifier of the electric vibration table, the power amplifier of the electric vibration table adopts a power device of SiC, and the traditional power amplifier adopts a MOSFET or IGBT of Si material.

(3) The power amplifier is a power amplifier of a modularized high-efficiency broadband electric vibrating table based on SiC devices, wherein a driving circuit part of the power amplifier also adopts the latest SiC driving design technology, so that each power device can realize real-time short circuit protection, each power device has hardware overcurrent protection, and the thermal reliability of the device is ensured. Meanwhile, the power device is not enabled in the bus voltage establishment process, so that the defects of low reliability and short service life of the traditional power amplifier are avoided, and the power amplifier has high reliability.

(4) The single power amplifier adopts a method of staggered control of a plurality of SiC devices, and can improve the output frequency bandwidth of the power amplifier, so that the power amplifier has the characteristic of broadband output.

(5) The power control system of the electric vibration table can realize the parallel connection of a plurality of power amplifiers, and can improve the equivalent switching frequency to N times of the original frequency (N is equal to the number of the power amplifiers) under the action of the master control chip, so that the high-power electric vibration table has better performance. And moreover, the current equalization and the output phase between the power amplifiers connected in parallel can be controlled through the master control chip, and the power amplifiers can jointly output, so that the high-power output requirement is met.

(6) The power amplifier, the vibrating table controller and the master control chip of the invention use the CAN bus to transmit the current reference instruction, thereby improving the control stability and reliability.

(7) The power amplifier can be integrated into each single module (such as a PWM rectifying circuit, a PWM inverter circuit and a driving sub-circuit can be realized by integrating SiC power devices), and can be independently integrated into a power amplifying module (integrated into the SiC power amplifier), and when larger vibration power is required to be provided, the power amplifier can be realized by adopting a plurality of power amplifying modules connected in parallel, so that the power amplifier is convenient and quick.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, it will be apparent that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a block diagram of an embodiment of a power amplifier of an electrodynamic vibration table of the present invention;

FIG. 2 is a circuit diagram of a first power supply circuit according to the present invention;

FIG. 3 is a schematic diagram of another embodiment of a power amplifier of the electrodynamic vibration shaker of the present invention;

FIG. 4 is a schematic diagram of circuit connections of a driving sub-circuit according to the present invention;

FIG. 5 is a schematic diagram of the connection of another embodiment of the power amplifier of the electrodynamic vibration table of the present invention;

FIG. 6 is a schematic diagram of an embodiment of a power control system of an electrodynamic vibration table of the present invention;

FIG. 7 is a flow chart of an embodiment of a method of power control of an electrodynamic vibration table of the present invention;

FIG. 8 is a flow chart of another embodiment of a method of power control of an electrodynamic vibration table of the present invention;

fig. 9 is a flowchart of another embodiment of the power control method of the electrodynamic vibration shaker of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The invention discloses a power amplifier of an electric vibrating table, an embodiment of which is shown in fig. 1, comprising: the first power supply circuit 100, the PWM rectifying circuit 200, the second power supply circuit 300, the PWM inverter circuit 400, and the filter circuit 500 are electrically connected in this order; the power amplifier 1000 of the electrodynamic vibration table further includes: a control circuit 600, a sampling circuit 700 and a driving circuit 800 electrically connected to the control circuit 600, respectively; the control circuit 600 is further electrically connected to the first power supply circuit 100; the driving circuit 800 is electrically connected to the PWM inverter circuit 400 and the PWM rectifier circuit 200, respectively; the sampling circuit 700 is electrically connected to the PWM rectifying circuit 200 and the PWM inverter circuit 400, respectively; wherein:

The three-phase alternating current is filtered by the first power supply circuit 100, and the PWM rectifying circuit 200 outputs a stable dc bus voltage to the second power supply circuit 300 after rectifying; the second power supply circuit 300 supplies the stabilized dc bus voltage to the PWM inverter circuit 400, and the PWM inverter circuit 400 inverts the stabilized dc bus voltage into a stabilized ac current, and supplies the stabilized ac current to the electric vibration table 2000 after performing high-frequency filtering processing on the stabilized ac current by the filter circuit 500; the control circuit 600 controls the on-off of the switching tube of the PWM rectifying circuit 200 through the driving circuit 800 according to the bus voltage output by the PWM rectifying circuit 200 and collected by the sampling circuit 700, so that the PWM rectifying circuit 200 outputs a stable dc bus voltage; the control circuit 600 further controls the on-off of the switching tube of the PWM inverter circuit 400 through the driving circuit 800 according to the ac current output by the PWM inverter circuit 400 collected by the sampling circuit 700, so that the PWM inverter circuit 400 outputs a stable ac current.

The power amplifier 1000 of the electric vibration table in the above embodiment is a modularized high-power high-efficiency broadband power amplifier composed of the first power supply circuit 100, the PWM rectifying circuit 200, the second power supply circuit 300, the PWM inverter circuit 400, the filter circuit 500, the sampling circuit 700, the control circuit 600 and the driving circuit 800.

The following we specifically say the circuit portions:

(1) A first power supply circuit, as shown in fig. 2, the first power supply circuit includes: the device comprises an EMC filter, three alternating current inductors and two groups of selection circuits, wherein the selection circuits are formed by connecting a current limiting resistor and an alternating current contactor in parallel; among three-phase alternating current output ends of the EMC filter, an alternating current output end is electrically connected with an alternating current inductor and then connected into the PWM rectifying circuit; and among the remaining two-phase alternating current output ends, each alternating current output end is connected with one alternating current inductor and one group of selection circuits in sequence and then connected into the PWM rectifying circuit.

After the first power supply circuit is started, three-phase alternating current is input to an EMC filter of the first power supply circuit for filtering, then the three-phase alternating current is further filtered through an alternating current inductor, then the current is limited through a current limiting resistor (an alternating current contactor is opened), the current is output to a PWM rectifying circuit, and then the second power supply circuit is charged, until the charging voltage of the second power supply circuit reaches a first preset value (such as 450V), the control circuit controls the alternating current contactor in the first power supply circuit to be closed, at the moment, three-phase alternating current is not filtered through the current limiting resistor any more, the filtered three-phase current is directly input to the PWM rectifying circuit, and the control circuit controls the rectifying circuit to start rectifying, so that the rectifying circuit outputs stable direct current bus voltage.

(2) The second power supply circuit, as shown in fig. 3, the second power supply circuit 300 includes at least one set of capacitors to provide a stable dc power supply for the PWM inverter circuit 400. The group of capacitors comprises a plurality of capacitors connected in series.

The capacitor in the second power supply circuit can be a polar capacitor or a nonpolar capacitor, preferably, two thin film capacitors are connected in series to serve as a group of capacitors of the second power supply circuit, and the thin film capacitors have the advantages of no polarity, high insulation impedance, excellent frequency characteristic (wide frequency response) and small dielectric loss.

(3) As shown in fig. 3, the PWM rectifying circuit 200 is a SiC rectifier, and the SiC rectifier includes three half-bridge units, each of the half-bridge units includes a first MOS transistor (Q1, Q3, and Q5 are all first MOS transistors) and a second MOS transistor (Q2, Q4, and Q6 are all second MOS transistors), and each of the first MOS transistor and each of the second MOS transistors are reversely connected to a diode; the source electrode of the first MOS tube is connected with the drain electrode of the second MOS tube and is connected with one phase of three-phase current output by the first power supply circuit; the anode end of the diode is electrically connected with the source electrode of the MOS tube, and the cathode end of the diode is electrically connected with the drain electrode of the MOS tube; drains of the first MOS tubes of the three half-bridge units are connected with each other to serve as an anode output end of the SiC rectifier, and sources of the second MOS tubes of the three half-bridge units are connected with each other to serve as a cathode output end of the SiC rectifier.

In this embodiment, compared with the conventional MOSFET or IGBT made of Si material, the SiC device has a higher switching frequency, lower loss, and better conduction breaking characteristics, so that the efficiency of the power amplifier is higher. The PWM rectifier of SiC can be a packaged rectifying module or an unpackaged PWM rectifier, and specifically, each component in the PWM rectifier of SiC is made of SiC materials.

(4) As shown in fig. 3, the PWM inverter circuit 400 is a SiC inverter, and the SiC inverter includes two inverter units, each of which includes a third MOS transistor (Q7 and Q9 are both third MOS transistors) and a fourth MOS transistor (Q8 and Q10 are both fourth MOS transistors); each third MOS tube and each fourth MOS tube are reversely connected with a diode; the source electrode of the third MOS tube is connected with the drain electrode of the fourth MOS tube and is used as an output end of the SiC inverter; the drains of the third MOS tubes of the two inversion units are connected with each other and are electrically connected with the positive output end, namely the P end, of the second power supply circuit; sources of the fourth MOS tubes of the two inversion units are connected with each other and are electrically connected with a negative electrode output end, namely an N end, of the second power supply circuit.

In the above embodiments, siC power devices (SiC rectifiers, siC inverters) are adopted, and preferably, the latest SiC power module of germany english femtoin is adopted, so that the power amplifier has the characteristics of high efficiency and high power density. And the SiC rectifier and the SiC inverter adopt a method of staggered control of a plurality of SiC MOS tube components, so that the output frequency bandwidth of the power amplifier can be improved, and the power amplifier has the characteristic of broadband output.

(5) A sampling circuit, the sampling circuit comprising: a first sampling sub-circuit, i.e. the input current sampling in fig. 3; the first power supply circuit is used for collecting three-phase alternating current output to the PWM rectifying circuit by the first power supply circuit; the second sampling sub-circuit is used for collecting the direct current bus voltage at the output end of the PWM rectifying circuit, namely, sampling the bus voltage in the figure; the third sampling sub-circuit is used for collecting alternating current output by the PWM inverter circuit, namely sampling output current in the figure; and the fourth sampling sub-circuit is used for collecting the direct current bus current output by the PWM rectifying circuit, namely bus current sampling in the figure.

The sampling circuit collects voltage and current at corresponding positions and provides the voltage and current for the control circuit, so that the control circuit can conveniently control the PWM rectifying circuit and the PWM inverter circuit according to the voltage and current collected by the sampling circuit, and closed-loop control is realized.

(6) A control circuit, as shown in fig. 3, the control circuit comprising: the first control module 610 and the second control module 620 connected through the CAN bus; wherein: the first control module is electrically connected with the first sampling sub-circuit (namely input current sampling), the second sampling sub-circuit (namely bus voltage sampling) and the first power supply circuit respectively; the first control module is used for receiving a reference bus voltage value required to be output by the vibration table controller for transmitting a given PWM rectifying circuit and a reference alternating current value required to be output by the PWM inverter circuit through a CAN bus; the first control module transmits the alternating current value required to be output by the PWM inverter circuit to the second control module through the CAN bus, and:

a first control module:

the first control module judges whether the voltage and the current phase of the three-phase alternating current are consistent according to the three-phase alternating current collected by the first sampling circuit; when the voltage and current phases of the three-phase alternating current are not consistent, the first control module controls the first power supply circuit to output the three-phase alternating current with consistent phases;

when the direct current bus voltage at the output end of the PWM rectifying circuit acquired by the second sampling circuit reaches a first preset voltage value, the first control module controls the alternating current contactor of the selection circuit in the first power supply circuit to be attracted, and the driving circuit drives the PWM rectifying circuit to carry out rectifying work; when the voltage value of the direct current bus acquired by the second sampling circuit reaches a second preset voltage value, the first control module sends an inversion starting instruction to the second control module so that the second control module drives the PWM inverter circuit to start working through the driving circuit;

The first control module is further used for controlling the PWM rectifying circuit to output stable reference bus voltage according to the direct current bus voltage acquired by the second sampling circuit and the reference bus voltage value required to be output by the PWM rectifying circuit through the driving circuit driving the on-off of the switching tube of the PWM rectifying circuit.

And a second control module:

the second control module is respectively and electrically connected with the third sampling sub-circuit (namely output current sampling) and the fourth sampling sub-circuit (namely bus current sampling); wherein: the second control module receives a reference alternating current value which is transmitted by the first control module and is required to be output by the PWM inverter circuit; after receiving the inversion starting instruction of the first control module, the second control module drives the PWM inversion circuit to start working through the driving circuit;

the second control module judges whether the direct current bus current is greater than a preset direct current protection threshold value according to the direct current bus current output by the PWM rectifying circuit and collected by the fourth sampling sub-circuit, and if so, the driving circuit controls the PWM inverter circuit to stop working;

The second control module is further configured to control the PWM inverter circuit to output a stable reference ac current according to the reference ac current value required to be output by the PWM inverter circuit, in combination with the ac current value output by the PWM inverter circuit and collected by the third sampling sub-circuit, by driving the on-off of the switching tube of the PWM inverter circuit by the driving circuit;

the second control module is further configured to determine whether the ac current value output by the PWM inverter circuit collected by the third sampling sub-circuit is greater than a preset ac current protection threshold, and if yes, control the PWM inverter circuit to stop working through the driving circuit.

The first control module and the second control module both comprise a control chip, and the first control module is used for controlling the work of the PWM rectifying circuit and other modules; the second control chip is mainly used for controlling the work of the PWM inverter circuit. Specific: after three-phase alternating current is input to a first power supply circuit, the first power supply circuit is subjected to filtering through an EMC filter and an alternating current inductor, then is subjected to current limiting through a current limiting resistor (an alternating current contactor is opened and not closed) in a selection circuit, and then the three-phase alternating current after current limiting is respectively subjected to charging through a group of capacitors of a second power supply circuit after passing through diodes of a corresponding half-bridge unit in a PWM rectifying circuit; the second sampling sub-circuit samples the voltage at the output end of the PWM rectifying circuit, namely samples the charging voltage of the capacitor bank of the second power supply circuit, when the charging voltage of the capacitor bank of the second power supply circuit is collected to reach 450V, the first control module controls the AC contactor in the first power supply circuit to be closed, the current filtered by the EMC filter and the AC induction is directly output to the PWM rectifying circuit, in addition, the first control module drives the PWM rectifying circuit to start rectifying through the driving circuit, and meanwhile, the first control module also controls the PWM rectifying circuit to output stable DC bus voltage through the driving circuit according to the DC bus voltage collected by the second sampling sub-circuit; when the second sampling sub-circuit collects the voltage stabilizing output 650V of the direct current bus output by the PWM rectifying circuit, the first control module informs the second control module to start the PWM inverter circuit to perform inversion work. The PWM inverter circuit inverts 650V direct-current voltage to output sinusoidal alternating current required by the electric vibration table.

(7) The driving circuit comprises a plurality of driving sub-circuits; each MOS tube in the PWM rectifying circuit or the PWM inverting circuit is provided with a driving sub-circuit; the driving sub-circuit, as shown in fig. 4, includes: the first driving chip U1, the second driving chip U2 and a trigger chip U13, wherein:

an input pin IN+ of the first driving chip U1 receives a PWM control signal of the control circuit; the fault signal output by the control circuit is electrically connected with the base electrode of a triode through a resistor, the emitting electrode of the triode is grounded, and the collecting electrode of the triode is electrically connected with the input pin IN+ of the first driving chip U1; the input pin A of the trigger chip U13 is electrically connected with the fault output end/RDY of the first driving chip U1; the output pin Y of the trigger chip U13 is electrically connected with the negative electrode end of a diode, and the positive electrode end of the diode is electrically connected with a 5V power supply through a resistor; the input end IN of the second driving chip U2 is electrically connected with the output end OUT of the first driving chip U1, and is used for amplifying the driving current output by the second driving chip U2, and the driving signal output by the output end OUT of the second driving chip U2 is used for driving the MOS tube corresponding to the driving sub-circuit. The drain electrode of each MOS tube in the PWM rectifying circuit or the PWM inverting circuit is electrically connected with the output end VCC_UP_A in the corresponding driving sub-circuit, the grid electrode of the MOS tube is electrically connected with the output end G_UP_A in the driving sub-circuit, and the source electrode of the MOS tube is electrically connected with the output end VE_UP_A of the driving sub-circuit. The driving sub-circuit controls the on-off of the corresponding MOS tube according to the PWM control signal issued by the control circuit. Specifically, among the pins of the first driving chip U1, pin Vcc2: the output stage of the chip is connected with the positive power supply end; pin GND2: an output pole reference ground; pin DESAT: a short circuit detection end; pin OUT: driving the output end of the chip; pin IN+, IN-: a PWM signal input terminal; pin/FLT,/RDY: a chip fault state output; pin/RST: the reset end of the driving chip: logic input enables the control end, at low level, the PWM control signal of the single-chip microcomputer input IN+, IN-is invalid; pin Vcc1: a +5v power supply terminal of the input stage; pin GND1: and signal ground of the input stage.

(8) The input end of the filter circuit 500 is electrically connected with the output end of the PWM inverter circuit 400, and is used for filtering the ac circuit output by the PWM inverter circuit 400, and the output end of the filter circuit 500 is electrically connected with the electric vibration table, and is used for providing the filtered ac current to the electric vibration table. The filtering circuit may also be implemented by an EMC filter or other filtering methods, which is not limited in this embodiment.

Preferably, each driving sub-circuit in the driving circuit of the embodiment adopts SiC driving, the SiC driving is used as a novel digital driving, an FPGA is used as a PWM driving chip, a SHUNT resistor (for current sampling) is utilized to sample and output chip current in real time, and a current signal is fed back to the FPGA through an AD chip to realize dynamic output current protection.

Another embodiment of the power amplifier of the electric vibration table of the present invention, as shown in fig. 5, is a power amplifier of a modularized high-efficiency broadband electric vibration table based on SiC devices, and comprises a first power supply circuit, a PWM rectifier, a second power supply circuit, a PWM inverter (full-bridge inverter circuit), a filter circuit, a sampling circuit, a driving circuit (not shown in the figure, and described in the previous embodiment section for the driving circuit), rectification and multi-module parallel control (i.e., a first control module), and inversion control (i.e., a second control module). Wherein the PWM rectifier and the PWM inverter are SiC power devices adopting the latest technology.

The three-phase alternating current of AC380V is connected into an alternating current precharge circuit, the precharge circuit is connected with PWM rectification current, and when a bus capacitor is charged to 450V by a current limiting resistor with a large resistance value in the precharge circuit, an alternating current contactor is attracted, and the PWM rectification circuit starts to work. The PWM rectifier is composed of three-phase half-bridge, and bus voltage control and power control are realized by controlling inductance current and bus capacitance voltage. The PWM rectifying circuit is connected with a full-bridge inverter circuit, and the full-bridge inverter circuit inverts 650V direct-current voltage to output sinusoidal alternating current required by vibration of the electric vibration table. Because the electric vibration table consists of a direct-current excitation coil and an alternating-current ampere force moving coil, the magnetic induction intensity is as follows:

where u is magnetic permeability, N is the number of turns of the coil, I is excitation current, and Le is the effective flux linkage length. The ampere force expression of the moving coil is:

f=bil 2

Wherein I is coil energizing current, and L is moving coil flux linkage length. The acceleration equation of the moving coil can be obtained as follows:

m is the weight of the moving coil and the measured substance, g is the gravitational acceleration. Because the working condition of the electric vibration table is that the neutral point vibrates up and down, the electric vibration table has bias current:

the working condition of the electric vibration table is closely related to the output current of the power amplifier, and if the acceleration of the electric vibration table is a sine signal, the electric vibration table is provided with:

a=asinwt type 5

Wherein A is the acceleration amplitude, and w is the angular velocity of the signal change. The power amplifier output current at this time is:

in order to ensure high reliability, the current of the power amplifier is given to a single-module output amplitude frequency controller by an electric vibration table controller through a CAN bus, and then the current of the power amplifier is sampled through an output current sampling circuit, so that closed-loop control is formed.

The driving circuit of the SiC power module adopts intelligent driving, and uses an FPGA chip to manage the whole driving circuit, wherein the driving circuit has dead time adjustment, short-circuit protection, over-temperature protection, fault latching, PWM control signal immunity and power blocking of the driving in the system voltage establishment process, and the driving chip adopts a high-performance driving chip of Germany English femtocells, so that the on and off of the driving are more reasonable, rapid and reliable, and the loss of the SiC device is further reduced. The whole driving circuit adopts digital processing, so that the damage of a power device caused by the unstable state of an analog chip is avoided.

According to the loss comparison of IGBT and SiC devices provided by the English Underschet company, the loss of the whole machine is 1/3 of that of the IGBT used in the previous generation, the switching frequency is increased to 80KHz, the inductance volume and loss are reduced to 1/4 of that of the product in the previous generation, the radiator volume is reduced to 1/2 of that of the product in the previous generation, and the power density is greatly increased.

As shown in fig. 5, the specific working procedure of the present embodiment includes: the first power supply circuit is connected with a 3-phase 380V alternating current input, the alternating current contactor is in an off state, current charges a direct current bus capacitor of the second power supply circuit through a current limiting resistor and an anti-parallel diode of the PWM rectifier circuit, and when the bus voltage sampling circuit detects that the bus voltage is higher than 450V, the rectifier and the multi-module parallel controller control the alternating current contactor in the first power supply circuit to be attracted, and meanwhile, the PWM rectifier starts to work. The rectification and multi-module parallel controller samples three-phase alternating current inductance current and bus voltage in real time through a sampling circuit, and closed-loop control is achieved. The control of the PWM rectifier adopts a control strategy of an inner loop, an outer loop and a voltage loop of current, so as to ensure that the bus voltage is stable and the response is rapid. The current inner loop is regulated by a PID current loop, and the voltage outer loop is controlled by PI. The PWM rectifier performs bus voltage control and power control. After the PWM rectifier outputs stable direct current bus voltage (650V), the PWM inverter starts to work, inverts the 650V direct current bus voltage into stable alternating current, and then provides the stable alternating current for the electric vibration table after filtering by the filter circuit. Similarly, the inversion control can realize the control and adjustment of the PWM inverter by the alternating current output by the PWM inversion circuit collected by the sampling circuit, and the PID current loop adjustment can be adopted specifically. Specifically, the main function of the voltage outer ring of the PWM rectifier is to control the rectifier to output the dc side voltage, while the function of the current inner ring is to perform current control according to the current command output by the voltage outer ring. The voltage control is to compare the given voltage with the direct current voltage, the error value is input into a PI controller, the PI control realizes the no-static-difference control, meanwhile, the stability and rapidness of the output current command can be ensured, the current command output by the voltage outer loop control is compared with the three-phase alternating current by the current inner loop control, the formed error value is sent into a current PID, the PID output signal is subjected to dq inverse transformation to form an SVPWM duty ratio signal, and the SIC power device is controlled to realize the no-static-difference control of the current. The current control of the PWM inverter circuit is realized by comparing the output current with a given current error value and controlling the duty ratio of the inversion side SIC power device through a PID controller so as to achieve the purpose of controlling the output current.

In this embodiment, the power device (such as PWM rectifying circuit, PWM inverter circuit, driving chip, etc.) adopts the german intel latest SiC power module, so that the power amplifier has the characteristics of high efficiency and high power density. In the second aspect, the driving circuit of the SiC device adopts the latest technology, so that each power device has real-time short-circuit protection and power-on power devices are not enabled at the same time, the defects of low reliability and short service life of the traditional power amplifier are avoided, and the power amplifier has high reliability. In addition, the single power amplifier adopts a method of staggered control of a plurality of SiC devices, so that the output frequency bandwidth of the power amplifier can be improved, and the power amplifier has the characteristic of wide-band output.

Based on the same technical conception, the invention also discloses a power control system of the electric vibrating table, as shown in fig. 6, which comprises a plurality of power amplifiers, vibrating table controllers and master control chips of the electric vibrating table which are connected in parallel and are described in any embodiment; wherein: the vibration table controller obtains the vibration power required by the electric vibration table and transmits the vibration power required by the electric vibration table to the master control chip through the CAN bus; after receiving the vibration power required by the electric vibration tables, the master control chip calculates a reference alternating current value and a reference bus voltage value of the power amplifier of each electric vibration table according to the number of the power amplifiers of the parallel electric vibration tables; the master control chip gives a reference alternating current value of the power amplifier of the electric vibration table to the power amplifier of each electric vibration table through a CAN bus and the reference bus voltage value; so that the parallel-connected vibrating table power amplifiers provide the stable alternating current required by the electric vibrating table.

On the basis of the power amplifier of the electric vibration table, if the vibration power required by the electric vibration table is large, the electric vibration table can be realized by connecting a plurality of power amplifiers of the electric vibration table in parallel. Specifically, the power control system of the modularized high-efficiency broadband electric vibration table based on the SiC device can realize parallel use of a plurality of power amplifiers, and can enable equivalent switching frequency to be improved to N times of the original frequency (N is equal to the number of modules) under the action of the master control chip, so that the high-power electric vibration table has better performance.

After receiving vibration power (or alternating current value required by the electric vibration table) required by the electric vibration table, the electric vibration table controller transmits the vibration power (or alternating current value required by the electric vibration table) to a general control chip CPU through a CAN bus, and after obtaining the vibration power (or alternating current value required by the electric vibration table) required by the electric vibration table, the CPU evenly distributes output reference alternating current and reference direct current bus voltage of each power amplifier according to the number of power amplifiers of the electric vibration table connected in parallel, and distributes the output reference alternating current and the reference direct current bus voltage to a control circuit of each power amplifier so as to facilitate the work of each power amplifier according to the vibration power, thereby providing alternating current required by the electric vibration table. Further, the CPU simultaneously allocates the start phase angles of the respective power amplifiers. For example, when 3 power amplifiers are output in parallel, the operating frequency and the output current frequency of each power amplifier are the same in amplitude, the starting phase angles are different by 120 degrees, and module staggered output is formed, so that the output bandwidth of the power amplifier can be better.

The power amplifiers connected in parallel in the system are all provided with independent control circuits, the driving chip is a high-speed FPGA, and the frequency and amplitude adjustment of the output current is realized through PWM pulse width control. In order to stably control the output current, the control of the power amplifier samples the output current, and forms closed-loop control with the given current, so that the control accuracy is ensured.

The power control system of the electric vibration table is provided with a total control chip, so that current equalization and output phase control of each power amplifier can be realized, and a plurality of parallel power amplifiers can jointly output to meet the requirement of high-power output.

Similarly, based on the same technical concept, the invention also discloses a power control method of the electric vibration table applied to the power control system of the electric vibration table, and the embodiment shown in fig. 7 includes:

s100, the vibration table controller obtains the vibration power required by the electric vibration table and transmits the vibration power to the master control chip through a CAN bus;

s200, the master control chip calculates a reference alternating current value and a reference bus voltage value of the power amplifiers of each electric vibration table according to the vibration power required by the electric vibration table and the number of the power amplifiers of the parallel electric vibration tables, and transmits the reference alternating current value and the reference bus voltage value to the power amplifiers of each electric vibration table through a CAN bus;

And S300, controlling and outputting alternating current required by each electric vibration table by a power amplifier of each electric vibration table according to the received reference alternating current value and the reference bus voltage value.

Another embodiment of the method of the present invention, as shown in fig. 8, comprises:

s310, a control circuit of a power amplifier of the electric vibration table judges whether the voltage value of the polar capacitor of the second power supply circuit acquired by the sampling circuit reaches a preset first voltage value or not; if yes, entering the next step;

s320, the control circuit controls the three-phase alternating current filtered by the first power supply circuit to be directly output to the PWM rectifying circuit, and the PWM rectifying circuit starts rectifying work under the control of the control circuit;

S330, the control circuit receives the reference alternating current value and the reference bus voltage value issued by the master control chip through a CAN bus;

s340, the control circuit controls the PWM rectifying circuit to output stable direct-current bus voltage consistent with the reference alternating-current voltage value through the driving circuit according to the reference bus voltage value;

and S350, the control circuit controls the PWM inverter circuit to output stable alternating current consistent with the reference alternating current value through the driving circuit according to the reference alternating current bus current value.

Preferably, step S340 in the above embodiment includes:

s341, the control circuit judges whether the direct current bus current exceeds a preset current protection value according to the direct current bus current output by the PWM rectifying circuit and collected by the sampling circuit, if so, the step S342 is carried out, otherwise, the step S343 is carried out;

s342, the control circuit outputs a fault feedback signal, and the driving circuit controls the electric vibration table to stop working;

and S343, the control circuit controls the PWM rectifying circuit to output stable direct current bus voltage consistent with the reference bus voltage through the driving circuit according to the direct current bus voltage output by the PWM rectifying circuit and the reference bus voltage value acquired by the sampling circuit.

Preferably, step S350 in the above embodiment includes:

s351, when the PWM rectifying circuit outputs stable direct current bus voltage consistent with the reference bus voltage, the control circuit starts the PWM inverter circuit to start working;

and S352, the control circuit controls the PWM inverter circuit to output stable alternating current consistent with the reference alternating current value according to the alternating current output by the PWM inverter circuit and the reference alternating current value acquired by the sampling circuit.

Another embodiment of the method of the present invention is shown in fig. 9. After receiving the vibration power required by the vibration table, the vibration control table transmits the vibration power to the master control chip through the CAN bus, and the master control chip calculates the reference alternating current value and the reference direct current bus voltage required to be output by each power amplifier according to the number of the parallel power amplifiers after inquiring the CAN signal, and distributes the reference alternating current value and the reference direct current bus voltage to each power amplifier in parallel through the CAN bus. After receiving a given reference alternating current value and a given reference direct current bus voltage, the power amplifier sets an output direct current bus voltage for the PWM rectifying circuit and sets an output alternating current for the PWM inverting circuit; meanwhile, the input three-phase voltage and current of the PWM rectifying circuit and the output direct current bus voltage are sampled; once the over-current or over-voltage phenomenon is found, a fault signal is fed back, and then the power amplifier stops working through the driving circuit. In addition, if the phase of the three-phase voltage and the phase of the current input by the PWM rectifying circuit are not consistent, the first power supply circuit is controlled to output the voltage and the current with the consistent phases through the PLL phase lock. And the direct current bus voltage output by the PWM rectifying circuit is collected and used for realizing closed-loop control of the PWM rectifying circuit, and the direct current bus voltage is output stably by PID current inner-loop voltage outer-loop regulation. After the PWM rectifying circuit outputs stable direct current bus voltage, the PWM inverter circuit is started again, and the output current of the inverter circuit is collected; and judging whether the current exceeds a protection value, and if so, feeding back a fault signal to the driving circuit to control the power amplifier to stop working. In addition, the power amplifier can also carry out PID current loop adjustment on the PWM inverter circuit according to the collected PWM inverter circuit output current, so that the PWM inverter circuit is ensured to output stable alternating current.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. A power amplifier for an electrodynamic vibration shaker, comprising: the first power supply circuit, the PWM rectifying circuit, the second power supply circuit, the PWM inverter circuit and the filter circuit are electrically connected in sequence; the power amplifier of the electrodynamic vibration shaker further includes: the control circuit, and sampling circuit and driving circuit which are respectively connected with the control circuit; the control circuit is also electrically connected with the first power supply circuit; the driving circuit is respectively and electrically connected with the PWM inverter circuit and the PWM rectifying circuit; the sampling circuit is respectively and electrically connected with the PWM rectifying circuit and the PWM inverter circuit; wherein:

The three-phase alternating current is subjected to filtering treatment through the first power supply circuit, and the PWM rectification circuit outputs stable direct current bus voltage to the second power supply circuit after rectification treatment; the second power supply circuit provides the stable direct current bus voltage for the PWM inverter circuit, the PWM inverter circuit inverts the stable direct current bus voltage into stable alternating current, and the stable alternating current is provided for the electric vibration table after high-frequency filtering treatment by the filtering circuit; the control circuit controls the on-off of a switching tube of the PWM rectifying circuit through the driving circuit according to the bus voltage output by the PWM rectifying circuit and acquired by the sampling circuit, so that the PWM rectifying circuit outputs stable direct current bus voltage; the control circuit is used for controlling the on-off of a switching tube of the PWM inverter circuit through the driving circuit according to the alternating current which is acquired by the sampling circuit and is output by the PWM inverter circuit, so that the PWM inverter circuit outputs stable alternating current;

the first power supply circuit includes: the device comprises an EMC filter, three alternating current inductors and two groups of selection circuits, wherein the selection circuits are formed by connecting a current limiting resistor and an alternating current contactor in parallel; among three-phase alternating current output ends of the EMC filter, an alternating current output end is electrically connected with an alternating current inductor and then connected into the PWM rectifying circuit; each alternating current output end of the remaining two-phase alternating current output ends is connected with an alternating current inductor and a group of selection circuits in sequence and then connected with the PWM rectifying circuit;

After the first power supply circuit is started, the current limiting resistor is used for limiting current input, and when the charging voltage of the second power supply circuit reaches a first preset value, the alternating current contactor is closed, and the current limiting resistor is short-circuited;

the second power supply circuit at least comprises a group of capacitors, and provides stable direct current power for the PWM inverter circuit.

2. The power amplifier of an electrodynamic vibration shaker of claim 1, wherein the PWM rectifying circuit is a SiC rectifier, the SiC rectifier comprising three half-bridge units, each half-bridge unit comprising a first MOS transistor and a second MOS transistor, each of the first MOS transistor and each of the second MOS transistors being connected in reverse with a diode; the source electrode of the first MOS tube is connected with the drain electrode of the second MOS tube and is connected with one phase of three-phase current output by the first power supply circuit; drains of the first MOS tubes of the three half-bridge units are connected with each other to serve as an anode output end of the SiC rectifier, and sources of the second MOS tubes of the three half-bridge units are connected with each other to serve as a cathode output end of the SiC rectifier.

3. The power amplifier of an electrodynamic vibration shaker of claim 1, wherein the PWM inverter circuit is a SiC inverter comprising two inverter units, each inverter unit comprising a third MOS transistor and a fourth MOS transistor; each third MOS tube and each fourth MOS tube are reversely connected with a diode; the source electrode of the third MOS tube is connected with the drain electrode of the fourth MOS tube and is used as an output end of the SiC inverter; the drains of the third MOS tubes of the two inversion units are connected with each other and are electrically connected with the positive output end of the second power supply circuit; sources of the fourth MOS tubes of the two inversion units are connected with each other and are electrically connected with the negative electrode output end of the second power supply circuit.

4. A power amplifier for an electrodynamic vibration shaker as claimed in claim 2, wherein the sampling circuit comprises:

the first sampling sub-circuit is used for collecting three-phase alternating current output by the first power supply circuit to the PWM rectifying circuit;

the second sampling sub-circuit is used for collecting the direct current bus voltage at the output end of the PWM rectifying circuit;

the third sampling sub-circuit is used for collecting the alternating current output by the PWM inverter circuit;

and the fourth sampling sub-circuit is used for collecting the direct current bus current output by the PWM rectifying circuit.

5. The power amplifier of an electrodynamic vibration shaker of claim 4, wherein the control circuit comprises: the first control module is connected with the second control module through the CAN bus; wherein:

the first control module is electrically connected with the first sampling sub-circuit, the second sampling sub-circuit and the first power supply circuit respectively; the controller is used for receiving a reference bus voltage value required to be output by the given PWM rectifying circuit and a reference alternating current value required to be output by the PWM inverter circuit through the CAN bus; the first control module transmits the alternating current value required to be output by the PWM inverter circuit to the second control module through the CAN bus, and:

The first control module judges whether the voltage and the current phases of the three-phase alternating current are consistent according to the three-phase alternating current collected by the first sampling sub-circuit; when the voltage and current phases of the three-phase alternating current are not consistent, the first control module controls the first power supply circuit to output the three-phase alternating current with consistent phases;

when the direct current bus voltage at the output end of the PWM rectifying circuit acquired by the second sampling sub-circuit reaches a first preset voltage value, the first control module controls the alternating current contactor of the selection circuit in the first power supply circuit to be attracted, and the driving circuit drives the PWM rectifying circuit to carry out rectifying work; when the direct current bus voltage acquired by the second sampling sub-circuit reaches a second preset voltage value, the first control module sends an inversion starting instruction to the second control module so that the second control module drives the PWM inverter circuit to start working through the driving circuit;

the first control module is further used for driving the on-off of a switching tube of the PWM rectifying circuit through the driving circuit according to the direct current bus voltage acquired by the second sampling sub-circuit and the reference bus voltage value required to be output by the PWM rectifying circuit, and controlling the PWM rectifying circuit to output stable reference bus voltage;

The second control module is respectively and electrically connected with the third sampling sub-circuit and the fourth sampling sub-circuit; wherein: the second control module receives a reference alternating current value which is transmitted by the first control module and is required to be output by the PWM inverter circuit; after receiving the inversion starting instruction of the first control module, the second control module drives the PWM inversion circuit to start working through the driving circuit;

6. A power amplifier of an electrodynamic vibration shaker as claimed in claim 2 or 3, wherein each MOS transistor in the PWM rectifying circuit or the PWM inverting circuit is provided with a driving sub-circuit; the driving sub-circuit includes: the first driving chip, the second driving chip and a trigger chip, wherein:

an input pin IN+ of the first driving chip receives a PWM control signal of the control circuit; the fault signal output by the control circuit is electrically connected with the base electrode of a triode through a resistor, the emitting electrode of the triode is grounded, and the collecting electrode of the triode is electrically connected with the input pin IN+ of the first driving chip;

the input pin A of the trigger chip is electrically connected with the fault output end/RDY of the first driving chip; the output pin Y of the trigger chip is electrically connected with the negative electrode end of a diode, and the positive electrode end of the diode is electrically connected with a 5V power supply through a resistor;

the input end IN of the second driving chip is electrically connected with the output end OUT of the first driving chip and is used for amplifying the driving current output by the second driving chip, and the driving signal output by the output end OUT of the second driving chip is used for driving the MOS tube corresponding to the driving sub-circuit.

7. A power control system of an electric vibration table, which is characterized by comprising a plurality of power amplifiers of the electric vibration table, a vibration table controller and a master control chip which are connected in parallel; wherein:

the vibration table controller obtains the vibration power required by the electric vibration table and transmits the vibration power required by the electric vibration table to the master control chip through the CAN bus;

after receiving the vibration power required by the electric vibration tables, the master control chip calculates a reference alternating current value and a reference bus voltage value of the power amplifier of each electric vibration table according to the number of the power amplifiers of the parallel electric vibration tables;

the master control chip gives the reference alternating current value and the reference bus voltage value of the power amplifier of the electric vibration table to the power amplifier of each electric vibration table through a CAN bus; so that the parallel-connected vibrating table power amplifiers provide the stable alternating current required by the electric vibrating table.

8. A power control method of an electric vibrating table applied to the power control system of an electric vibrating table as claimed in claim 7, characterized by comprising:

s200, the master control chip calculates the reference alternating current value and the reference bus voltage value of the power amplifiers of each electric vibration table according to the vibration power required by the electric vibration table and the number of the power amplifiers of the parallel electric vibration tables, and transmits the reference alternating current value and the reference bus voltage value to the power amplifiers of each electric vibration table through a CAN bus;

9. The method of controlling power of an electrodynamic vibration shaker as claimed in claim 8, wherein the step S300 includes:

s310, a control circuit of a power amplifier of the electric vibration table judges whether a voltage value of a polar capacitor of a second power supply circuit acquired by a sampling circuit reaches a preset first voltage value or not; if yes, entering the next step;

s340, the control circuit controls the PWM rectifying circuit to output stable direct current bus voltage consistent with the reference bus voltage value through a driving circuit according to the reference bus voltage value;

and S350, the control circuit controls the PWM inverter circuit to output stable alternating current consistent with the reference alternating current value through the driving circuit according to the reference alternating current value.

10. The method of claim 9, wherein the step S340 includes:

and S343, the control circuit combines the reference bus voltage value according to the DC bus voltage output by the PWM rectifying circuit and acquired by the sampling circuit, and controls the PWM rectifying circuit to output stable DC bus voltage consistent with the reference bus voltage value through the driving circuit.

11. The method of claim 9, wherein the step S350 includes: