Thrust compensation system of dual-winding voice coil motor
09621084 ยท 2017-04-11
Assignee
Inventors
- Liyi Li (Harbin, CN)
- Donghua PAN (Harbin, CN)
- Qingbo Guo (Harbin, CN)
- Chengming Zhang (Harbin, CN)
- Jiwei Cao (Harbin, CN)
Cpc classification
H02P7/025
ELECTRICITY
H02K2213/03
ELECTRICITY
International classification
H02K41/00
ELECTRICITY
H02P7/025
ELECTRICITY
Abstract
A thrust compensation system of a dual-winding voice coil motor, which is used for driving the voice coil motor having main windings (100) and secondary windings (200), wherein the secondary windings (200) of the voice coil motor are between each pair of the main windings (100). The system includes a switch drive circuit of the main windings (800) which is powered by a first controlled voltage source to drive the main windings (100) adopted as the main working windings of the voice coil motor and used for providing the output electromagnetic force required by the driving system of the voice coil motor in work; a switch drive circuit of the secondary windings (900) which is powered by a second voltage source to drive the secondary windings (200) adopted as compensation windings, and used for providing the thrust ripple opposite to the main windings (100) so as to compensate the thrust ripple of the main windings (100) and keep the resultant force of the output of the main windings (100) and the secondary windings (200) of the voice coil motor in constant; wherein the voltages U.sub.dc1 and U.sub.dc2 of the first and second controlled voltage sources of the main windings (100) and the second windings (200) are configured as meeting a certain relationship.
Claims
1. A thrust compensation system comprising: a switch drive circuit of main windings of a voice coil motor that is powered by a first controlled voltage source to drive the main windings adopted as the main working windings of the voice coil motor and used for providing the output electromagnetic force required by a driving system of the voice coil motor in work; a switch drive circuit of secondary windings of the voice coil motor that is powered by a second voltage source to drive the secondary windings adopted as compensation windings and used for providing the thrust ripple opposite to the main windings to compensate the thrust ripple of the main windings and keep the resultant force of the output of the main windings and the secondary windings of the voice coil motor constant; wherein the voltages U.sub.dc1 and U.sub.dc2 of the first and second controlled voltage sources of the main windings and the second windings are configured as
2. The thrust compensation system as claimed in claim 1, wherein R.sub.2 is adjustable.
3. The thrust compensation system as claimed in claim 2, wherein the thrust ripple of the system can be reduced while the average thrust can be kept at the same time.
4. The thrust compensation system as claimed in claim 1, wherein R.sub.2 is proportional to R.sub.1.
5. The thrust compensation system as claimed in claim 1, wherein the ratio of R.sub.2 of the secondary windings to R.sub.1 of the main windings is proportional to the ratio of L.sub.2 to L.sub.1.
6. The thrust compensation system as claimed in claim 5, wherein the proportion of the ratio of R.sub.2 to R.sub.1 to the ratio of L.sub.2 to L.sub.1 is larger than 1.
7. The thrust compensation system as claimed in claim 1, wherein the drive circuits of the main windings and the secondary windings are H-shaped full-bridge drive circuits.
8. The thrust compensation system as claimed in claim 1, wherein the system is for a dual-winding voice coil motor, which is used for driving the voice coil motor having the main windings and secondary windings, wherein the secondary windings of the voice coil motor are between each pair of the main windings.
9. A thrust compensation system of a dual-winding voice coil motor, including a voice coil motor, wherein the voice coil motor includes main windings, a magnetic steel and a permanent magnet, and further includes secondary windings arranged between a pair of main windings of the voice coil motor; wherein the main windings are the main working windings of the voice coil motor, driven by a switch drive circuit of the main windings which is powered by an independent controlled voltage source, and used for providing the electromagnetic force required by the driving system of the voice coil motor in work; the secondary windings are compensation windings, driven by a switch drive circuit of the secondary windings which is powered by another independent controlled voltage source, and used for providing the thrust ripple opposite to the main windings so as to compensate the thrust ripple of the main windings and then keep the resultant force of the output of the main windings and the secondary windings of the voice coil motor in constant; wherein the voltages U.sub.dc1 and U.sub.dc2 of the controlled voltage sources of the main windings and the second windings are configured as
10. The thrust compensation system of the dual-winding voice coil motor as claimed in claim 9, wherein the main windings and the secondary windings of the voice coil motor are shaped of layered type or joint filling type.
11. The thrust compensation system of the dual-winding voice coil motor as claimed in claim 10, wherein the secondary windings are enclosed between the two layers of the main windings, and the main windings at the internal side are enclosed on the external layer of the winding pillar.
12. The thrust compensation system of the dual-winding voice coil motor as claimed in claim 10, wherein the secondary windings are clamped between the upper main winding and the lower main winding, and the winding pillar passes through the upper main winding, the secondary winding and the lower main winding from upside to downside.
13. The thrust compensation system of the dual-winding voice coil motor as claimed in claim 9, wherein the main windings, the secondary windings and the winding pillar are encapsulated in a primary winding support plate through epoxy glue; wherein the primary winding support plate is supported through a primary support pedestal; and wherein a secondary magnetic steel is connected with a secondary support structure through a yoke plate.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DESCRIPTION OF THE PREFERRED EMBODIMENT
(25) To overcome the influence of the servo performance of the system caused by the thrust ripple produced when the servo drive control system of the voice coil motor in the current ultra-high precision servo control field adopts the PWM power converter scheme, the invention provides a new voice coil motor structure and a drive control scheme of the corresponding servo drive control system. In the scheme, the thrust ripple of the servo system of the voice coil motor is greatly reduced, the ultra-high precision control of the servo drive control system of the voice coil motor when the system is in the low switching frequency, the stability of the system is improved, the system loss is reduced, and the cost of the drive controller is greatly reduced.
(26) In the invention, the technical scheme for solving the technical problems thereof is as follows: an auxiliary secondary compensation winding at the other side of the main winding of the voice coil motor, and then the secondary winding produces the thrust ripple completely opposite to the main winding, so that the thrust ripples produced by the main windings and the secondary windings of the voice coil motor can be canceled each other out through the secondary windings. In the PWM power converter scheme, the synthetic output thrust produced by the main windings and the secondary windings of the servo system of the voice coil motor is constant, so that the ultra-high precision servo control of the voice coil motor in the low switching frequency is realized, the flexibility of the system control is enhanced, the control system can use multiple complex intelligent control strategies, the control performance of the system is effectively improved, the stability of the drive control system is improved, and the cost of the drive controller is reduced.
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(28) The distribution and the design of the main and secondary windings 100, 200 are related to the electrical time constant of each set of the windings required by the drive control system and the distribution of the air-gap field of the motor.
(29) The winding method of the windings 100, 200 is divided into the layered type or the joint filling type. For example,
(30) As shown in
(31) As shown in
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(35) In the scheme of the invention, the secondary windings 200 are electrified after introduced to the voice coil motor so as to produce the thrust ripple opposite to the main windings 100, therefore the thrust ripple of the main windings can be compensated. The wavelength theory of the thrust ripple applied on the main windings 100 by the secondary windings 200 is shown in
(36) Next, embodiments implementing the drive circuit of the first dual-winding voice coil motor are described in details.
(37) As shown in
(38) Based on the guarantee that the output thrust of the main windings and the output thrust of the second windings are ascended and descended synchronously, to completely compensate the thrust ripple of the main windings applied by the secondary windings, the secondary windings need to produce the thrust ripple of which the size is the same as the main windings and the direction is opposite at any time. Because the output thrust of the main winding is proportional to the current of the main windings, the proportion factor is the thrust coefficient K.sub.f1 of the main windings; because the output thrust of the secondary windings is proportional to the current of the secondary windings, the proportion factor is the thrust coefficient K.sub.f2 of the main windings. To compensate the thrust ripple of the main windings by the thrust ripple of the secondary windings a any time, the current ripple of the main windings is effectively compensated by adjusting the current ripple of the secondary windings. After the differential equations of the main windings and the secondary windings in different states are analyzed, in the condition that the inductances L1, L2 of the main windings and the secondary windings of the voice coil motor are definite, the voltage values U.sub.dc1 and U.sub.dc2 of the DC voltage sources of the main-winding drive circuit 800 and the secondary-winding drive circuit 900 mainly influence peak-to-peak value of the current ripple of the windings within the switching-on or off period of the drive circuit, and the resistances R.sub.1, R.sub.2 of the windings mainly influence the current change trend of the windings within the switching-on or off period of the drive circuit.
(39) To ensure that the secondary windings 200 can completely compensate the thrust ripple of the main windings 100 at any time, in accordance with the solution of the differential equations of the main windings 100 and the secondary windings 200, the resistance R.sub.2 of the secondary windings 200 can be obtained, and the voltage U.sub.dc2 of the DC voltage source of the drive circuit of the secondary windings shall meet the conditions below.
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in the formula,
U.sub.dc1 stands for the voltage value of the power supply of the drive circuit of the main windings;
U.sub.dc2 stands for the voltage value of the power supply of the drive circuit of the secondary windings;
R.sub.1 stands for the resistance value of the main windings;
R.sub.2 stands for the resistance value of the secondary windings;
L.sub.1 stands for the self-inductance value of the main windings;
L.sub.2 stands for the self-inductance value of the secondary windings;
M stands for the mutual inductance value of the main windings and the secondary windings;
K.sub.f1 stands for the thrust coefficient of the main windings;
K.sub.f2 stands for the thrust coefficient of the secondary windings;
(41) The secondary windings and the drive circuit thereof can be designed according to formulae (1.1) and formula (1.2), so that the dual-winding thrust compensation system can eliminate the ripple of the output thrust, realize the design target that the output resultant force of the main windings and the secondary windings is kept in constant, and improve the servo working performance of the system.
(42) When adopting the dual-winding thrust compensation system designed in the embodiment 1, the drive circuit of the system adopts the 10 kHz switching frequency used by the conventional servo system, at the moment, the thrust simulation waveform of the system is shown in
(43) As shown in the simulation waveform diagrams, the secondary windings can effectively compensate the output thrust of the main windings, so that the output thrust ripple of the servo drive system of the voice coil motor is greatly reduced, and the resultant force of the output thrust of the main windings and the secondary windings can be kept in constant. As shown in the partial enlarged views
(44) But the embodiment still has some shortcomings. As shown in
(45) In this way, when the servo system of the voice coil motor is applied to the ultra-high precision servo field, because of the steep requirements of the output thrust ripple of the motor, the parameters of the driver must be precisely designed according to the driver parameter design formula (1.1) and (1.2) discussed in the embodiment, therefore, the servo system of the voice coil motor can obtain the smallest thrust ripple, which may cause large design workload.
(46) As the improvement of the scheme in the embodiment, the second embodiment is described in the invention.
(47) In the embodiment, when the requirements of the output thrust ripple of the voice coil motor required by the application fields and occasions of the servo system of the voice coil motor are not particularly harsh, if the parameter design of the secondary windings of the motor in the embodiment 1 is changed, the reduction of the average thrust of the main windings applied by the secondary windings is reduced while the compensation effect of the thrust ripple of the main windings applied by the secondary windings, so that a new balance point of the resultant force of the output thrust of the main windings and the secondary windings of the voice coil motor is obtained between the thrust ripple and the average thrust: the thrust ripple is perfectly reduced, and the large average thrust is remained.
(48) Seem from the analysis above, in the dual-winding motor system, the thrust ripple of the windings is proportional to the current ripple of the windings, and the average output thrust of the windings is proportional to the average current of the windings. In the dual-winding thrust compensation system shown in the embodiment, the voltage values of the DC voltage sources U.sub.dc1 and U.sub.dc2 of the drive circuits 800, 900 of the windings mainly influence the peak-to-peak value of the current ripple of the windings within the switching-on or off period of the drive circuit, and the resistances R.sub.1, R.sub.2 of the windings mainly influence the current change trend of the windings within the switching-on or off period of the drive circuit. So when the resistance R.sub.2 of the secondary windings 200 and the power supplies of the drive circuits are designed according to formulae (1.1) and (1.2), the secondary windings 200 can perfectly compensate the thrust ripple of the main windings at any time.
(49) But the result is that the average thrust is greatly reduced while the secondary windings greatly reduces the thrust ripple of the main windings. The reduction degree of the average thrust of the main windings applied by the secondary windings is greatly influenced by the resistance R.sub.2 of the secondary windings and the voltage U.sub.dc2 of the drive circuit of the secondary windings.
(50) So based on the applications that the requirements of the output thrust ripple of the voice coil motor required by the application fields and occasions of the servo system of the voice coil motor are not particularly harsh, in the embodiment, the embodiment 1 is improved by compromise, namely in the condition that the voltage U.sub.dc2 of the drive circuit of the secondary windings is not changed, by a manner of adjusting the resistance R.sub.2 of the secondary windings, the big average thrust can be remained in the system while the thrust ripple is reduced.
(51) At the moment, the schematic view of the output thrust of the main windings and the secondary windings is shown in
(52) As shown in
(53) After the state equations of the dual-winding system in the embodiment 1 are analyzed and solved, in the condition that the power supply U.sub.dc2 of the drive circuit of the secondary winding meets the formula (1.1), the resistance R.sub.2 of the secondary windings can be adjusted according to the method shown in the formula (1.3),
(54)
in the formula, A>1.
(55) At the moment, in the condition that the requirements of the output thrust ripple of the drive system of the voice coil motor are not strict, a proper average solution between the thrust ripple of the motor and the average thrust of the motor can be obtained in the system, which not only reduces the thrust ripple, but also remains the average thrust.
(56) The accuracy and rationality of the theoretical analysis are verified through the simulation test. For the same voice coil motor, when the scheme in the embodiment is adopted and A=9, the simulation waveform of the output thrust of the system is shown in
(57) As shown in
(58) It is observed that after the resistance R.sub.2 of the secondary windings 200 is adjusted, the compensation effect of the thrust ripple of the dual-winding thrust compensation system is reduced, but the average output thrust of the dual-winding thrust compensation system is obviously improved, which is 6.85 times larger than the average output thrust in the embodiment and then adapts to the servo application fields of which requirements on the thrust ripple are not strict.
(59) In conclusion, the embodiments are better ones in this invention only, and not used to limit the implementation scope of the invention. All changes and decorations done within the patent application scope belong to the technical field of the invention.
(60) Seen from the analysis of the embodiment 1 above, in the embodiment 1, the average output thrust of the motor is obviously reduced while the thrust ripple of the voice coil motor is precisely compensated. When the requirements of the thrust ripple required by the servo system of the voice coil motor are not strict, the embodiment 2 can be adopted, the average output thrust of the system can be improved by adjusting the resistance of the secondary windings, but the consequences are that the compensation effect of the thrust ripple applied by the secondary windings is reduced, and the thrust ripple of the servo system is increased.