CN202798515U - Magnetic bearing system switch power amplifier - Google Patents
Magnetic bearing system switch power amplifier Download PDFInfo
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- CN202798515U CN202798515U CN 201220396979 CN201220396979U CN202798515U CN 202798515 U CN202798515 U CN 202798515U CN 201220396979 CN201220396979 CN 201220396979 CN 201220396979 U CN201220396979 U CN 201220396979U CN 202798515 U CN202798515 U CN 202798515U
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Abstract
The utility model relates to a magnetic bearing system switch power amplifier, which is a device used for an active control of current of a magnetic bearing coil. The power amplifier mainly comprises a controller, an isolation driving circuit, a four-legged power main circuit, a current feedback detection circuit, a signal conditioning circuit, and a signal filter circuit. By using the digital switch power amplifier, an error between a current sampling value and a current desired value can be calculated by the controller and the dead zone correction can be carried out by a controller, and a PWM modulation can be carried out based on a three-dimensional space vector, and the modulated PWM signal can be used by the isolation driving circuit to control the switching on/off of a power switch tube of the four-legged power main circuit, therefore the object of controlling the current of the magnetic bearing coil can be achieved. The utility model provides the digital switch power amplifier suitable for the magnetic bearing control system, the quantity of the power switch tubes and the amplitude of the output ripple current can be reduced, and the loss of the electromagnetic bearing can be reduced.
Description
Technical field
The utility model relates to a kind of switch power amplifier, is used for the output current of magnetic bearing coil is carried out ACTIVE CONTROL, is widely used in the magnetic bearings control of the systems such as magnetic levitaion motor, magnetically levitated flywheel, magnetic suspension control torque gyroscope.
Background technology
The high-speed magnetic levitation motor has the rotating speed height, has broad application prospects without advantages such as rubbing, need not to lubricate, energy density is high, size is little owing to adopt magnetic suspension bearing to replace traditional mechanical bearing.Power amplifier is as the actuator of high-speed magnetic levitation motor magnetic bearing control system, and its energy consumes maximum, and the energy loss, raising integrated level, the increase reliability that reduce power amplifier are one of main purposes of Designing power amplifier.
In order to improve the efficient of power amplifier, high-speed magnetic levitation motor magnetic bearing control system generally adopts switch power amplifier.The implementation that produces circuit according to pulse width modulating signal is different, and magnetic bearing is divided into switch power amplifier that analogue device is realized and two kinds of Digital Implementation.The many employings of existing magnetic bearing control system power amplifier full bridge structure shown in Figure 1 adopts two traditional level PWM pulse duration modulation method output current ripples very large, produces larger iron loss and copper loss in electromagnetic bearing.
At Chinese patent " ZL200510012131.2 " disclosed " a kind of low-ripple switch power amplifier for permanent magnet biased electromagnetic-bearing ", adopt analogue device to realize the function of three-level pwm pulse-width modulation, reduced the ripple loss; But the power amplifier loss of adopting analogue device to build is large, volume is larger, must carry out hardware adjustment if will change the PWM modulation system simultaneously, uses inconvenient.
At Chinese patent " 200610114390.0 " disclosed " a kind of switch power amplifier for magnetic suspension flywheel magnetic bearing system ", employing FPGA+DSP is controller, adopts ternary PWM modulation system, and data-handling capacity is strong, and current ripples is little; But it need to be connected in series respectively noninductive power resistor at two power switch pipe source electrodes of lower bridge with between with reference to ground, when being controlled at the loop afterflow by FPGA current signal is sampled, and control mode is complicated, and programming realizes difficulty.
Above-mentioned two patents all adopt full bridge structure, and controlling a coil all needs 4 power switch pipes, realize the magnetic bearings control of 5 coils, need 20 power tubes, cause volume and loss all to increase to some extent.
Chinese patent " 200710120705.7 " disclosed " a kind of for the switch power amplifier of magnetic bearing system based on space vector ", adopt three bridge arm structures shown in Figure 2 as main circuit, adopt FPGA+DSP as controller, utilize the two-dimensional space vector modulation method, greatly reduce the current ripples loss, and middle brachium pontis is public by two magnetic bearing coil institutes, has reduced the quantity of power switch pipe, has reduced the volume of power amplifier; But its switching tube quantity is still more, the power amplifier volume is still larger, if further reduce the quantity of switching tube and the volume of power amplifier, the method will be restricted, and the method can only realize the vector adjustment in the two-dimensional space, and it utilizes sampling resistor to carry out current sample simultaneously, isolates when supply power voltage is higher a little less than the effect, fail safe is not high, and anti-interference is also not strong.
Simultaneously above-mentioned several patents are not all considered the impact that cause magnetic bearing voltage in the PWM dead band, and when Dead Time is larger, when modulating frequency is higher, the voltage difference accumulation that cause in the dead band will can not be ignored.
The utility model content
Technology of the present utility model is dealt with problems: overcome the deficiency that prior art exists, a kind of magnetic bearing system switch power amplifier is provided, employing is based on the modulation system of three-dimensional space vectors, the quantity of power tube and the volume of power amplifier have been reduced, reduced the amplitude of ripple, reduced the loss of magnetic bearing system, had simultaneously fast response time, the characteristics of flexible in programming; Adopt the method for PWM dead band real-Time Compensation to improve control precision; Adopt high-precision current transformer as the current feedback testing circuit, control electricity (light current) and power electricity (forceful electric power) isolation effect are good, safe, and accuracy of detection is high, and strong interference immunity, responsive bandwidth height are easy to realize.
Technical solution of the present utility model: a kind of magnetic bearing system switch power amplifier based on three-dimensional space vectors, mainly comprise controller, isolated drive circuit, four brachium pontis power main circuits, current feedback testing circuit, signal conditioning circuit, signal filter circuit, wherein:
Controller: the displacement signal of displacement transducer and the current feedback signal of three coils of magnetic bearing are sampled by the inner AD translation interface of controller, it is poor that the displacement signal that utilization collects and magnetic bearing rotor reference bit shifting signal are done, the magnetic bearing position error signal is calculated according to control algolithm, generate the electric current expected signal value, it is poor that electric current expected signal value and current feedback signal value are done, obtain error size, calculate simultaneously magnetic bearing coil voltage rising value or drop-out value that the accumulation of PWM Dead Time causes, and convert this rising value or drop-out value to the electric current correction value, with this electric current correction value the error signal that obtains is revised, utilize PWM Algorithm to carry out the PWM modulation to the error signal after revising, output eight-path PWM signal (PWM1～PWM8), deliver to isolated drive circuit;
Isolated drive circuit: the PWM1 of input and controller output～PWM8 signal links to each other, and exports the gate drive signal S1～S8 of power switch pipe VT1～VT8 in the four brachium pontis power main circuits, directly links to each other with the grid of four brachium pontis power main circuit switch pipes;
Four brachium pontis power main circuits: by conducting and the shutoff of the gate drive signal S1 of isolated drive circuit output～upper brachium pontis of S8 control and eight power switch pipe VT1～VT8 of lower brachium pontis, thereby in three coils of magnetic bearing, generate and the proportional electric current of Current Control amount is exported;
The current feedback testing circuit: input directly is in series with four brachium pontis power main circuits, and output connects signal conditioning circuit, for detection of three coil current feedback signals of the magnetic bearing of four brachium pontis power main circuits;
Modulate circuit: join with signal filter circuit, be used for the current feedback signal of three current feedback testing circuit outputs is carried out level deviation, zooms in or out;
Signal filter circuit: be connected with the signal after the signal conditioning circuit conditioning, be used for the noise signal of filtering input signal, the AD conversion mouth that three current feedback signals of output are connected to controller gathers.
Described controller is comprised of DSP and FPGA, wherein DSP is as master controller, mainly be responsible for finishing magnetic bearing rotor-position signal control algolithm and three-dimensional space vectors algorithm, FPGA is as the interface chip of DSP periphery, as pilot controller, be mainly used to receive the order of DSP, produce the pwm signal that needs.
Described four brachium pontis power main circuits adopt eight power switch pipes independently to control the topological structure of three coils, and wherein VT1 and VT5 consist of the first brachium pontis; VT2 and VT6 consist of the second brachium pontis; VT3 and VT7 consist of the 3rd brachium pontis; VT4 and VT8 consist of the 4th brachium pontis, and magnetic bearing coil L1 is connected between the first brachium pontis and the second brachium pontis, and the coil two-end-point is respectively A and B, and the coil both end voltage is U
ABMagnetic bearing coil L2 is connected between the second brachium pontis and the 3rd brachium pontis, and the coil two-end-point is respectively B and C, and the coil both end voltage is U
BCMagnetic bearing coil L3 is connected between the 3rd brachium pontis and the 4th brachium pontis, and the coil two-end-point is respectively C and D, and the coil both end voltage is U
CDNamely the second brachium pontis and the 3rd brachium pontis are the public brachium pontis of two magnetic bearing coils, 2 of B and C are two public tie points of magnetic bearing coil, and the driving signal of upper brachium pontis power switch pipe (S1, S2, S3, S4) respectively and interpolation die-out logic anti-phase with the driving signal (S5, S6, S7, S8) of lower brachium pontis power switch pipe leads directly to prevent upper and lower bridge arm.
The utility model realizes with existing analogue device or the magnetic bearing of Digital Implementation is compared with switch power amplifier, and advantage is:
(1) the control permanent magnet biased magnetic bearing need to be controlled five degrees of freedom usually, need two radial direction magnetic bearings of control and axial magnetic bearing totally five road magnetic bearing coils, the utility model is by adopting the topological structure of four brachium pontis power main circuits, utilize eight power tubes independently to control three independently coil currents, the power tube that the magnetic bearing system of 5 coils of control is needed is reduced to 14 by 20, and (four brachium pontis power main circuits are controlled respectively a radial direction magnetic bearing x, y direction and axial magnetic bearing direction totally three coils, as shown in Figure 3, need 8 power tubes; Three brachium pontis power main circuits are controlled the two-way coil of another radial direction magnetic bearing x, y direction, as shown in Figure 2, need 6 power tubes, totally 14 power tubes), reduce power tube quantity and power amplifier volume, improved integrated level, reduced the amplitude of ripple and the loss of magnetic bearing system.
(2) the utility model adopts the combination of high speed digital signal processor DSP and FPGA to carry out the three-dimensional space vectors modulation, with DSP as master controller, give full play to the advantage that its computing capability is strong and peripheral interface is abundant, has fast system responses, FPGA is as pilot controller, the double peripheral expansion of being DSP is given full play to the advantage of its flexible in programming.
(3) the utility model adopts PWM dead band real-Time Compensation, calculates the voltage compensation value △ U of each point according to the sense of current of 4 of A, B, C, D
A, △ U
B, △ U
C, △ U
DWherein flow through the electric current that electric current that A orders equals to flow through coil L1, flow through the electric current that electric current that electric current that B orders equals coil L2 deducts coil L1, flow through the electric current that electric current that C orders equals to flow through coil L3 and deduct the electric current that flows through coil L2, flow through the opposite number that electric current that D orders equals to flow through the electric current of coil L3.Obtaining the voltage compensation value that corresponding voltage compensation value calculates three coils according to the electric current of each point is respectively: △ U
L1=△ U
A-△ U
B, △ U
L2=△ U
B-△ U
C, △ U
L3=△ U
C-△ U
D, △ U
L1, △ U
L2, △ U
L3Represent respectively the voltage compensation value of three coils, three voltage compensation values are converted respectively to the electric current correction value △ I of three coils
1, △ I
2, △ I
3Larger when the supply power voltage of the coil of magnetic bearing, when Dead Time is larger, the dead band voltage influence is larger, by real-time dead area compensation, can reach the purpose that improves control precision.
Description of drawings
Fig. 1 is existing unicoil full bridge power main circuit diagram
Fig. 2 is existing three brachium pontis power main circuit diagrams;
Fig. 3 is hardware composition frame chart of the present utility model;
Fig. 4 is that controller of the present utility model forms and flow chart;
Fig. 5 is the schematic diagram that pwm signal produces and adds the dead band;
Fig. 6 is the basic vector figure of three-dimensional space vectors algorithm of the present utility model;
Fig. 7 is the equivalent exploded view of the 3rd interval vector in the three-dimensional space vectors algorithm of the present utility model;
Fig. 8 is three-dimensional space vectors algorithm flow chart of the present utility model;
Fig. 9 is current feedback testing circuit of the present utility model;
Figure 10 is signal conditioning circuit of the present utility model and signal filter circuit circuit.
Embodiment
As shown in Figure 3, the utility model mainly comprises: controller, isolated drive circuit, four brachium pontis power main circuits, the current feedback testing circuit, signal conditioning circuit, signal filter circuit, wherein: controller is sampled to the displacement signal of displacement transducer and the current feedback signal of three coils of magnetic bearing by inner AD translation interface, it is poor that the displacement signal that utilization collects and magnetic bearing rotor reference bit shifting signal are done, the magnetic bearing position error signal is calculated according to control algolithm, generate the electric current expected signal value, it is poor that electric current expected signal value and current feedback signal value are done, obtain error size, calculate simultaneously magnetic bearing coil voltage rising value or drop-out value that the accumulation of PWM Dead Time causes, and convert this rising value or drop-out value to the electric current correction value, with this electric current correction value the error signal that obtains is revised, utilize PWM Algorithm to carry out the PWM modulation to the error signal after revising, output eight-path PWM signal (PWM1～PWM8), deliver to isolated drive circuit; The PWM1 of the input of isolated drive circuit and controller output～PWM8 signal links to each other, and exports the gate drive signal S1～S8 of power switch pipe VT1～VT8 in the four brachium pontis power main circuits, directly links to each other with the grid of four brachium pontis power main circuit switch pipes; Conducting and the shutoff of brachium pontis and eight power switch pipe VT1～VT8 of lower brachium pontis in the gate drive signal S1 that four brachium pontis power main circuits are exported by isolated drive circuit～S8 control, thus in three coils of magnetic bearing, generate and the proportional electric current output of Current Control amount; The input of current feedback testing circuit directly is in series with four brachium pontis power main circuits, and output connects signal conditioning circuit, for detection of three coil current feedback signals of the magnetic bearing of four brachium pontis power main circuits; Modulate circuit and signal filter circuit join, and are used for the current feedback signal of three current feedback testing circuit outputs is carried out level deviation, zooms in or out; Signal filter circuit is connected with signal conditioning circuit conditioning signal afterwards, is used for the noise signal of filtering input signal, and the AD conversion mouth that three current feedback signals of output are connected to controller gathers.
Controller comprises master controller DSP and pilot controller FPGA.Master controller DSP utilizes built-in AD translation interface that the displacement signal of displacement transducer and the current feedback signal of three coils of magnetic bearing are sampled, it is poor that the displacement signal that utilization collects and magnetic bearing rotor reference bit shifting signal are done, the magnetic bearing position error signal is calculated according to control algolithm, generate the electric current expected signal value, and this electric current desired value and current feedback value done poor three current error signals that obtain, then DSP carries out the dead area compensation algorithm, namely calculate the rising of magnetic bearing coil voltage or decline that the accumulation of PWM Dead Time causes, and convert this rising value or drop-out value to the electric current correction value, with this electric current correction value three current error signals are revised, utilized three corrections error afterwards to carry out the voltage-regulation amount that the PID computing obtains the three-dimensional space vectors expectation.DSP is according to the size and Orientation of the voltage-regulation amount of the three-dimensional space vectors expectation that obtains, generate four road comparison values according to the three-dimensional space vectors algorithm, the count value of four road comparison values and triangular carrier is compared, obtain the PWM1 of four power switch pipes of brachium pontis～PWM4 signal, simultaneously four road pwm signals are added inverted logic and die-out logic, obtain the PWM5 of four pipes of lower brachium pontis～PWM8 signal; Generate the gate drive signal of the power switch pipe of four brachium pontis power amplifier main circuits 3: S1～S8 through isolated drive circuit 2, wherein S1 and S5, S2 and S6, S3 and S7, S4 and S8 distinguish anti-phase and add the dead band, conducting and shutoff by S1～eight power switch pipes of S8 control, current feedback testing circuit 4 obtains the current feedback signal of coil by the current value of magnetic bearing coil in the isolation detection four brachium pontis power main circuits 3.
Wherein VT1 and VT5 consist of the first brachium pontis; VT2 and VT6 consist of the second brachium pontis; VT3 and VT7 consist of the 3rd brachium pontis; VT4 and VT8 consist of the 4th brachium pontis, and magnetic bearing coil L1 is connected between the first brachium pontis and the second brachium pontis, and the coil two-end-point is respectively A and B, and the coil both end voltage is U
ABMagnetic bearing coil L2 is connected between the second brachium pontis and the 3rd brachium pontis, and the coil two-end-point is respectively B and C, and the coil both end voltage is U
BCMagnetic bearing coil L3 is connected between the 3rd brachium pontis and the 4th brachium pontis, and the coil two-end-point is respectively C and D, and the coil both end voltage is U
CDNamely the second brachium pontis and the 3rd brachium pontis are the public brachium pontis of two magnetic bearing coils, 2 of B and C are two public tie points of magnetic bearing coil, and the driving signal of upper brachium pontis power switch pipe (S1, S2, S3, S4) respectively and interpolation die-out logic anti-phase with the driving signal (S5, S6, S7, S8) of lower brachium pontis power switch pipe leads directly to prevent upper and lower bridge arm.The high precision electric current transducer of contacting respectively among magnetic bearing coil L1, magnetic bearing coil L2 and the magnetic bearing coil L3 effectively will be controlled electricity (light current) and power electric (forceful electric power) and isolate the electric current of magnetic test coil.
As shown in Figure 4, controller of the present utility model is comprised of master controller DSP and pilot controller FPGA.DSP mainly is responsible for finishing magnetic bearing rotor-position signal control algolithm and three-dimensional space vectors algorithm as master controller; FPGA as pilot controller, is mainly used to receive the order of DSP as the interface chip of DSP periphery, produces the pwm signal that needs; DSP utilizes built-in AD interface to carry out feedback current sampling and displacement sampling, it is poor that the displacement signal of the displacement signal that the DSP utilization collects and the expectation of magnetic bearing rotor is done, after the magnetic bearing position error signal carried out control algolithm, generate the electric current desired value, DSP does this expectation current value and the sampled value of current feedback signal before and obtains three current error values after poor, then DSP carries out the dead area compensation algorithm, namely calculate magnetic bearing coil voltage rising value or drop-out value that the accumulation of PWM Dead Time causes, and convert this rising value or drop-out value to the electric current correction value, with this electric current correction value three current error signals are revised, utilized three corrections error afterwards to carry out the voltage-regulation amount that the PID computing obtains the three-dimensional space vectors expectation.DSP is according to the voltage-regulation amount size and Orientation of the three-dimensional space vectors expectation that obtains, the applying three-dimensional means of space vector representation calculates the ON time of four power switch pipe expectations of brachium pontis on the four bridge main circuits, and utilize this ON time to calculate conducting and trigger constantly and turn-off and trigger constantly, and will turn-off to trigger and change into corresponding comparison value constantly and deliver to FPGA and be used for generating pwm signal, the FPGA generation cycle is the triangular carrier counting of T, accepting simultaneously four comparison values that DSP sends here compares with the triangular carrier count value respectively, if the comparison value of sending here carries count value greater than the triangle that generates, then export high level, otherwise output low level then, obtain thus the pwm signal PWM1～PWM4 of four power switch pipes of brachium pontis, the signal PWM5～PWM8 of four power switch pipes of lower brachium pontis is obtained after die-out logic that FPGA produces and inverted logic by PWM1～PWM4.
As shown in Figure 5, described die-out logic adopts upper brachium pontis power switch pipe Delayed conducting, turn-offs on time, and lower brachium pontis power switch pipe turn-offs on time, delays time open-minded.The dead area compensation algorithm mainly is that the sense of current according to 4 of A, B, C, D calculates the voltage difference △ U of each point before not compensating with respect to each point
A, △ U
B, △ U
C, △ U
D, the electric current positive direction is located from left to right, and the amplitude of each point voltage offset is △ U=N * T
Dead_time* T/U, wherein N represent one modulation period intercarrier number, reduce T along with the increase of rotating speed
Dead_timeRepresent Dead Time, U represents the amplitude of supplying DC voltage, and T represents carrier cycle.When the sense of current is timing, voltage compensation value is being for just, when the sense of current when negative, voltage compensation value is for negative.The electric current that flows through A, B, C, D is respectively I
L1, I
L2-I
L1, I
L3-I
L2,-I
L3So the voltage compensation value that A, B, C, D are 4 is respectively sign (I
L1) * △ U, sign (I
L2-I
L1) * △ U, sign (I
L3-I
L2) * △ U, sign (I
L3) * △ U, wherein sign is sign function.The voltage compensation value that calculates three coils according to the voltage compensation value of each point is respectively: △ U
L1=△ U
A-△ U
B, △ U
L2=△ U
B-△ U
C, △ U
L3=△ U
C-△ U
D, △ U
L1, △ U
L2, △ U
L3Represent respectively the voltage compensation value of three coils, three voltage compensation values are converted respectively to the electric current correction value △ I of three coils
1, △ I
2, △ I
3
As shown in Figure 6, according to the state of S1, S2, S3 and S4 (S1 and S5, S2 and S6, S3 and S7, S4 and S8 add respectively dead band after anti-phase), four brachium pontis can be combined into 16 kinds of on off states, comprising two zero vectors and 14 non-zero vectors.The voltage U on the magnetic bearing coil that is connected between brachium pontis mid point A, B
ABThe voltage of being used as the X-axis on an end magnetic bearing XY plane is the voltage U on the magnetic bearing coil that is connected between brachium pontis mid point B, the C
BCThe voltage of being used as the Y-axis on an end magnetic bearing XY plane is the voltage U on the magnetic bearing coil that is connected between brachium pontis mid point C, the D
CDBe used as axial voltage, i.e. the voltage of Z axis.16 kinds of on off states (0000), (0001) ..., (1111) are corresponding six basic voltage vectors V0 of outputting ten respectively, V1 ..., V15.Wherein V0 and V15 are two these voltage vectors of zero-base, respectively corresponding 14 the non-zero basic voltage vectors of V1～V14, and these 16 basic voltage vectors are divided into 24 intervals to three dimensions XYZ.16 kinds of conducting states of three coils of 16 kinds of corresponding magnetic bearings of fundamental space vector.The space voltage vector that each on off state is corresponding is synthetic by three non-zero basic voltage vectors in each interval.
Adopt the three-dimensional space vectors algorithm to control four brachium pontis power amplifier main circuits, charging can appear in three coils of magnetic bearing in the course of the work, three kinds of different states of discharge and free afterflow, and these characteristics are so that four brachium pontis power amplifier main circuits of three-dimensional space vectors algorithm control have the advantage that ripple is little, loss is little that three level control methods have.But the utility model is when possessing above-mentioned advantage, and the 3rd brachium pontis that the second brachium pontis of forming of VT2 and VT5 and VT3 and VT6 form shared by two magnetic bearing coils, and the Simultaneous Switching loss that has reduced power switch pipe quantity also reduces greatly.
The utility model adopts nine symmetrical section space vector pulse width modulation modes, each basic vector is divided into nine sections in each switch periods, beginning and ending phase in each switch periods, it is zero vector V15 action time, and the interlude section of switch periods is 0 action time of this vector V of zero-base, zero vector V15 and V0 divide the ON time of zero vector equally, other three non-zero basic voltage vectors will be divided into the left and right sides that two parts are distributed in this vector V of zero-base 0 symmetrically, whole like this periodic symmetry is divided into nine sections, sequence of operation and the time of each basic vector in each switch periods is symmetrical, and each the road pulse-width signal that produces also is symmetrical.t
0Be the time of zero vector effect; t
1, t
2And t
3Be respectively interval three non-zero basic vectors of living in according to conducting order action time successively.In beginning and the ending phase of each switch periods, be the action time of zero vector V15: t
0/ 4, and the interlude section of switch periods is zero vector V0 action time: t
0/ 2, other three non-zero basic voltage vectors will be divided into the left and right sides that two parts are distributed in zero vector V0 symmetrically, the selection principle of the sequence of operation of basic voltage vectors guarantees that the conversion of each on off state all only has one to change, namely when eight power switch pipes are transformed into another kind of on off state from a kind of on off state, only have a brachium pontis to participate in the change of current, so not only on-off times can be reduced, and switching loss can be reduced.
As shown in Figure 8, the software realization flow of three-dimensional space vectors algorithm of the present utility model.In the course of work of magnetic bearing, in the three-dimensional space vectors algorithm in each interval the switching signal of the sequence of operation of basic voltage vectors and power switch pipe become corresponding corresponding relation, so at first will calculate the current error signal of three coils of magnetic bearing in the middle of the working control; Then the Dead Time according to the pwm signal design carries out the dead band correction to three current error signals, utilizes the error after revising to carry out the voltage-regulation amount that the PID computing obtains the three-dimensional space vectors expectation, is positioned at which interval according to table 1 judgement voltage vector; Obtain t action time of three basic voltage vector according to range lookup table 2 of living in
1, t
2, t
3, then utilize formula t
0=T-t
1-t
2-t
3Calculate t
0, and then trigger constantly t according to the shutoff that table 2 obtains four power switch pipes
Trig_off_1, t
Trig_off_2, t
Trig_off_3, t
Trig_off_4The shutoff that obtains is triggered constantly as a comparison value deliver to FPGA, compare with the triangular carrier count value of FPGA, if the comparison value of sending here carries count value greater than the triangle that generates, then export high level, otherwise output low level then, obtain thus the pwm signal PWM1～PWM4 of four power switch pipes of brachium pontis, the signal PWM5～PWM8 of four power switch pipes of lower brachium pontis is obtained after die-out logic that FPGA produces and inverted logic by PWM1～PWM4.Ux in the table 1, Uy, Uz represent respectively the reference voltage regulated quantity of three coil expectations in the space vector, X in the table 2, Y, Z represent respectively reference voltage regulated quantity Ux, Uy, the Uz of three coil expectations in the space vector, T represents carrier cycle, and U represents the amplitude of supplying DC voltage.
The interval voltage sequence of operation of table 1 and interval judgement condition
Each interval ON time of table 2 and shutoff trigger timetable
The PWM carrier cycle that adopts in the utility model is 20KHz, the crystal oscillator of FPGA is 40MHZ in the present embodiment, because present embodiment adopts the symmetrical PWM ripple, so the triangular carrier that adopts is the symmetric triangular ripple, so maximum triangular carrier count value is 40M/20K/2=1000, direct voltage U correspondence 1000, the cycle T correspondence 2000 of symmetric triangular carrier wave.Calculate three error signal question blanks 1 after DSP revises according to the dead band and judge interval of living in, obtain t action time of three non-zero basic vectors according to interval query table 2 of living in
1, t
2And t
3, and then then utilize formula t
0=T-t
1-t
2-t
3Calculate t
0, according to t
0, t
1, t
2And t
3The turn-off time of four switching tubes of brachium pontis in the calculating is for example to being positioned at the reference vector Vref in the 3rd interval, the t that calculates among Fig. 7
Trig_off_1=t
0/ 4+t
3/ 2+t
2/ 2+t
1/ 2, t
Trig_off_2=t
0/ 4+t
1/ 2, t
Trig_off_3=t
0/ 4+t
1/ 2+t
2/ 2, t
Trig_off_4=t
0/ 4, t wherein
Trig_off_1, t
Trig_off_2, t
Trig_off_3, t
Trig_off_4The shutoff of corresponding upper four power switch pipes of brachium pontis constantly is assigned to respectively four comparison value CMP1, CMP2, CMP3 and CMP4 with above-mentioned four values and sends into FPGA for generation of the pwm signal of needs respectively.Below a example in the actual implementation process be the example explanation three-dimensional space vectors method course of work: suppose after the current signal collection of DSP with three coils of magnetic bearing, three current error values that obtain after the overcurrent dead band is revised are respectively: Ux=300, Uy=-100, Uz=200, because Ux+Uy 〉=0, Uy≤0, Uy+Uz 〉=0, question blank 1 as can be known this vector is positioned at the 3rd interval, because T=2000, U=1000 can get according to interval query table 2 of living in: the time of (S1S2S3S4) getting (1110) is t
1=200, the time of getting (1010) is t
2=200, the time of getting (1000) is t
3=400, remaining time t
0=2000-200-200-400=1200 is averagely allocated to V15 and V0.According to t
0, t
1, t
2And t
3Can obtain t
Trig_off_1=t
0/ 4+t
1/ 2+t
2/ 2+t
3/ 2=700, t
Trig_off_2=t
0/ 4+t
1/ 2=400, t
Trig_off_3=t
0/ 4+t
1/ 2+t
2/ 2=500, t
Trig_off_4=t
0/ 4=300 triggers constantly as a comparison value, i.e. CMP1=t with the shutoff that obtains
Trig_off_1=700, CMP2=t
Trig_off_2=400, CMP3=t
Trig_off_3=500, CMP4=t
Trig_off_4=300, and four comparison values are sent into the pwm signal that relatively can obtain four power switch pipes of upper brachium pontis among the FPGA with triangular carrier.
As shown in Figure 9, provided current feedback testing circuit of the present utility model.With the I among the figure+and I-be concatenated into respectively in the magnetic bearing coil of Fig. 2, I+connect electric current to flow into end, I-connect outflow of bus current end, respectively "+" and "-" of current sensor in the corresponding diagram 4, current sensor adopts multrirange current sensor LA28-NP, the range of selecting is 5A, be about to its 2 pin and 10 pin, 3 pin and 9 pin, 4 pin and 8 pin, 5 pin link to each other respectively with 7 pin, 1 pin and 6 pin are unsettled, turn ratio is selected 5:1000, during full scale, and the current signal of secondary side output 25mA, the resistance in external 360 Europe is converted into voltage signal with current signal, and at the resistance two ends and connect an electric capacity it is carried out simple filtering.Current sensor carries out electrical isolation with electric current primary side and secondary side, strong interference immunity, and fail safe is good, and its bandwidth reaches 150kHZ, and accuracy of detection reaches ± and 0.5%, and be easy to realize.
As shown in figure 10, signal conditioning circuit of the present utility model and signal filter circuit circuit have been provided.The output of the current feedback testing circuit shown in its input map interlinking 9, output connects the AD mouth of DSP.Because the voltage of current sensor output is of ac, the scope that can gather for the AD mouth that is translated into DSP, i.e. 0～3.3V, it need to be nursed one's health, dwindle after at first the current sensor output signal being added bias voltage, the operational amplifier that adopts is TL084, and the BIAS_ I among the figure is exactly bias voltage value, and resistance R 5 is carried out the adjusting of minification.Signal after will nursing one's health afterwards carries out filtering, eliminate the aliasing in spectra of digital system and the interference of high-frequency noise, employing be a second-order low-pass filter, that capacitor C 1, C2 select is 0.01uf, resistance R 6 and R7 select 3.3k, and the cut-off frequency of low pass is elected 3.1kHZ as.In order to guarantee that the signal after the filtering is strict controlled in 0～3.3V scope, so before advancing the AD mouth of DSP, added two back-to-back 3.3V voltage-stabiliser tubes, the AD mouth that the signal after the filtering is sent to DSP gathers.
The control permanent magnet biased magnetic bearing need to be controlled five degrees of freedom usually, need two radial direction magnetic bearings of control and axial magnetic bearing totally five road magnetic bearing coils, during working control, with x, y direction and the axial magnetic bearing of a radial direction magnetic bearing totally three coils, receive successively on the coil 1, coil 2, coil 3 of four brachium pontis power main circuits shown in Figure 3, adopt the three-dimensional space vectors algorithm shown in the utility model to control; The two-way magnetic bearing coil of the x of another radial direction magnetic bearing, y direction is received on coil 1 in the three brachium pontis power main circuits shown in Figure 2, the coil 2 successively, adopted the disclosed general spatial vector operation of Chinese patent " 200710120705.7 ".
The utility model is a kind of magnetic bearing system switch power amplifier, and the switch power amplifier that can be used as general magnetic bearing system is applied to the magnetic bearings control of the systems such as magnetic levitaion motor, magnetically levitated flywheel, magnetic suspension control torque gyroscope.
Claims (3)
1. magnetic bearing system switch power amplifier, it is characterized in that comprising: controller (1), isolated drive circuit (2), four brachium pontis power main circuits (3), current feedback testing circuit (4), signal conditioning circuit (5), signal filter circuit (6), wherein:
Controller (1): the displacement signal of displacement transducer and the current feedback signal of three coils of magnetic bearing are sampled by the inner AD translation interface of controller, it is poor that the displacement signal that utilization collects and magnetic bearing rotor reference bit shifting signal are done, the magnetic bearing position error signal is calculated according to control algolithm, generate the electric current expected signal value, it is poor that electric current expected signal value and current feedback signal value are done, obtain error size, calculate simultaneously magnetic bearing coil voltage rising value or drop-out value that the accumulation of PWM Dead Time causes, and convert this rising value or drop-out value to the electric current correction value, with this electric current correction value the error signal that obtains is revised, utilize PWM Algorithm to carry out the PWM modulation to the error signal after revising, output eight-path PWM signal (PWM1～PWM8), deliver to isolated drive circuit (2);
Isolated drive circuit (2): the PWM1 that input and controller (1) are exported～PWM8 signal links to each other, export the gate drive signal S1～S8 of power switch pipe VT1～VT8 in the four brachium pontis power main circuits (3), directly link to each other with the grid of four brachium pontis power main circuit (3) switching tubes;
Four brachium pontis power main circuits (3): by conducting and the shutoff of the gate drive signal S1 of isolated drive circuit (2) output～upper brachium pontis of S8 control and eight power switch pipe VT1～VT8 of lower brachium pontis, thereby in three coils of magnetic bearing, generate and the proportional electric current of Current Control amount is exported;
Current feedback testing circuit (4): input directly is in series with four brachium pontis power main circuits (3), and output connects signal conditioning circuit (5), for detection of three coil current feedback signals of the magnetic bearing of four brachium pontis power main circuits (3);
Modulate circuit (5): join with signal filter circuit (6), be used for the current feedback signal of three current feedback testing circuits (4) output is carried out level deviation, zooms in or out;
Signal filter circuit (6): be connected with the signal after signal conditioning circuit (5) conditioning, be used for the noise signal of filtering input signal, the AD conversion mouth that three current feedback signals of output are connected to controller (1) gathers.
2. a kind of magnetic bearing system switch power amplifier according to claim 1, it is characterized in that: described controller (1) is comprised of DSP and FPGA, wherein DSP is as master controller, mainly be responsible for finishing magnetic bearing rotor-position signal control algolithm and three-dimensional space vectors algorithm, FPGA is as the interface chip of DSP periphery, as pilot controller, be mainly used to receive the order of DSP, produce the pwm signal that needs.
3. a kind of magnetic bearing system switch power amplifier according to claim 1, it is characterized in that: described four brachium pontis power main circuits (3) adopt eight power switch pipes independently to control the topological structure of three coils, and wherein VT1 and VT5 consist of the first brachium pontis; VT2 and VT6 consist of the second brachium pontis; VT3 and VT7 consist of the 3rd brachium pontis; VT4 and VT8 consist of the 4th brachium pontis, and magnetic bearing coil L1 is connected between the first brachium pontis and the second brachium pontis, and the coil two-end-point is respectively A and B, and the coil both end voltage is U
ABMagnetic bearing coil L2 is connected between the second brachium pontis and the 3rd brachium pontis, and the coil two-end-point is respectively B and C, and the coil both end voltage is U
BCMagnetic bearing coil L3 is connected between the 3rd brachium pontis and the 4th brachium pontis, and the coil two-end-point is respectively C and D, and the coil both end voltage is U
CDNamely the second brachium pontis and the 3rd brachium pontis are the public brachium pontis of two magnetic bearing coils, 2 of B and C are two public tie points of magnetic bearing coil, and the driving signal of upper brachium pontis power switch pipe (S1, S2, S3, S4) respectively and interpolation die-out logic anti-phase with the driving signal (S5, S6, S7, S8) of lower brachium pontis power switch pipe leads directly to prevent upper and lower bridge arm.
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| CN 201220396979 CN202798515U (en) | 2012-08-10 | 2012-08-10 | Magnetic bearing system switch power amplifier |
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| CN 201220396979 CN202798515U (en) | 2012-08-10 | 2012-08-10 | Magnetic bearing system switch power amplifier |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105048838A (en) * | 2015-06-29 | 2015-11-11 | 浙江大学 | Single-side bridge arm frequency-doubling driving three-level switch power amplifier |
| CN106763185A (en) * | 2017-03-07 | 2017-05-31 | 华中科技大学 | A kind of power electronic controller for multiaxis magnetic suspension bearing |
| CN107387563A (en) * | 2017-09-09 | 2017-11-24 | 珠海格力电器股份有限公司 | A kind of magnetic suspension bearing control method and device |
| CN110061699A (en) * | 2019-05-10 | 2019-07-26 | 山东铂晶智能科技有限公司 | A kind of digital power amplifier modulator and method using FPGA control |
| CN110905920A (en) * | 2018-09-18 | 2020-03-24 | 北京亚之捷环保科技有限责任公司 | Magnetic bearing control device suitable for different offset combinations of each degree of freedom of magnetic bearing |
| CN112443575A (en) * | 2019-08-27 | 2021-03-05 | 株洲中车时代电气股份有限公司 | Control system of magnetic suspension bearing and magnetic suspension system |
| CN116827210A (en) * | 2023-08-24 | 2023-09-29 | 四川大学 | Three-dimensional space vector modulation method for open-winding motor |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105048838A (en) * | 2015-06-29 | 2015-11-11 | 浙江大学 | Single-side bridge arm frequency-doubling driving three-level switch power amplifier |
| CN105048838B (en) * | 2015-06-29 | 2017-12-15 | 浙江大学 | A kind of tri-level switch power amplifier of unilateral bridge arm frequency multiplication driving |
| CN106763185A (en) * | 2017-03-07 | 2017-05-31 | 华中科技大学 | A kind of power electronic controller for multiaxis magnetic suspension bearing |
| CN106763185B (en) * | 2017-03-07 | 2018-09-25 | 华中科技大学 | A kind of power electronic controller for multiaxis magnetic suspension bearing |
| CN107387563A (en) * | 2017-09-09 | 2017-11-24 | 珠海格力电器股份有限公司 | A kind of magnetic suspension bearing control method and device |
| CN110905920A (en) * | 2018-09-18 | 2020-03-24 | 北京亚之捷环保科技有限责任公司 | Magnetic bearing control device suitable for different offset combinations of each degree of freedom of magnetic bearing |
| CN110061699A (en) * | 2019-05-10 | 2019-07-26 | 山东铂晶智能科技有限公司 | A kind of digital power amplifier modulator and method using FPGA control |
| CN112443575A (en) * | 2019-08-27 | 2021-03-05 | 株洲中车时代电气股份有限公司 | Control system of magnetic suspension bearing and magnetic suspension system |
| CN112443575B (en) * | 2019-08-27 | 2022-01-21 | 株洲中车时代电气股份有限公司 | Control system of magnetic suspension bearing and magnetic suspension system |
| CN116827210A (en) * | 2023-08-24 | 2023-09-29 | 四川大学 | Three-dimensional space vector modulation method for open-winding motor |
| CN116827210B (en) * | 2023-08-24 | 2023-11-21 | 四川大学 | Three-dimensional space vector modulation method for open-winding motor |
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