Single-coil dual-frequency channel wireless DC motor system

Abstract

The present invention provides a wireless DC motor system with a single coil and dual frequency channels, the system comprising: a transmitting end comprising: a power supply, a three-level inverter, a transmitting end dual resonance module, and a frequency signal synthesis module; the frequency signal synthesis module is used to provide a square wave control signal of a first frequency and a second frequency; the three-level inverter is used to output an AC drive voltage containing a first frequency signal and a second frequency signal; the transmitting end dual resonance module is used to transmit AC magnetic energy containing a first frequency component and a second frequency component; the receiving end comprises: a receiving end dual resonance module, a first rectifier bridge and a second rectifier bridge, and a DC motor; the receiving end dual resonance module is used to pick up AC power; the first rectifier bridge is used to rectify and filter the AC power of the first frequency component into the first DC power; the second rectifier bridge is used to rectify and filter the AC power of the second frequency component into the second DC power. The present invention can realize independent power transmission of dual frequency channels, and the system structure is simplified.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a single-coil dual-frequency channel wireless DC motor system. Background Art

[0002] In known wireless DC motors, in order to achieve independent control of the armature winding and the field winding, two pairs of coupling coils are required to wirelessly transmit electrical energy respectively, which results in a complex structure on the motor side, a large footprint of the coils, and they are bulky and inconvenient to install and use. Summary of the invention

[0003] The embodiment of the present invention provides a single-coil dual-frequency channel wireless DC motor system, which only requires a pair of dual-frequency channel coupling coils to realize independent power transmission of the dual-frequency channels, and the system structure is simplified. The system includes:

[0004] The transmitter and receiver, where

[0005] The transmitting end includes: a power supply, a three-level inverter respectively connected to the three terminals of the power supply, a transmitting end dual resonance module connected to the three-level inverter, and a frequency signal synthesis module; wherein the frequency signal synthesis module is used to provide a square wave control signal of a first frequency and a second frequency to the three-level inverter; the three-level inverter is used to output an AC driving voltage containing a first frequency signal and a second frequency signal to the transmitting end dual resonance module according to the square wave control signal of the first frequency and the second frequency; the transmitting end dual resonance module is used to generate a high-frequency magnetic field containing a first frequency component and a second frequency component under the drive of the AC driving voltage having the first frequency signal and the second frequency signal, and transmit the AC magnetic energy containing the first frequency component and the second frequency component to the receiving end;

[0006] The receiving end includes: a receiving end dual resonance module coupled with the transmitting end dual resonance module through a magnetic field, a first rectifier bridge and a second rectifier bridge respectively connected in series with two branches of the receiving end dual resonance module, and a DC motor respectively connected to the first rectifier bridge and the second rectifier bridge; wherein the receiving end dual resonance module is used to pick up AC power containing a first frequency component and a second frequency component from a high-frequency magnetic field; the first rectifier bridge is used to rectify and filter the AC power of the first frequency component into a first DC power, and the first DC power is used to supply the armature winding of the DC motor; the second rectifier bridge is used to rectify and filter the AC power of the second frequency component into a second DC power, and the second DC power is used to supply the excitation winding of the DC motor.

[0007] In an embodiment of the present invention, independent power transmission of dual-frequency channels can be achieved by using only a pair of coupled coils, namely, a transmitting-end dual-resonance module and a receiving-end dual-resonance module; in addition, since a power conversion and control unit is no longer required on the motor side, the system has better modular performance and a more streamlined system structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0009] Figure 1 A circuit diagram of a single-coil dual-frequency channel wireless DC motor system according to an embodiment of the present invention;

[0010] Figure 2 is a switch control signal processing logic diagram of a three-level inverter in an embodiment of the present invention;

[0011] Figure 3 is the output waveform of the three-level inverter in the embodiment of the present invention. DETAILED DESCRIPTION

[0012] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0013] In the description of this specification, the terms "include", "including", "have", "contain", etc. are all open terms, which mean including but not limited to. The descriptions with reference to the terms "one embodiment", "a specific embodiment", "some embodiments", "for example", etc. mean that the specific features, structures or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. The order of steps involved in each embodiment is used to schematically illustrate the implementation of the present application, and the order of steps is not limited and can be appropriately adjusted as needed.

[0014] Figure 1 is a circuit diagram of a single-coil dual-frequency channel wireless DC motor system in an embodiment of the present invention, such as Figure 1 As shown, the system includes:

[0015] The transmitter and receiver, where

[0016] The transmitting end includes: a power supply 1, a three-level inverter 2 respectively connected to the three terminals of the power supply 1, a transmitting end dual resonance module 4 connected to the three-level inverter 2, and a frequency signal synthesis module 3; wherein the frequency signal synthesis module 3 is used to provide a square wave control signal of a first frequency and a second frequency to the three-level inverter 2; the three-level inverter 2 is used to output an AC driving voltage containing a first frequency signal and a second frequency signal to the transmitting end dual resonance module 4 according to the square wave control signal of the first frequency and the second frequency; the transmitting end dual resonance module 4 is used to generate a high-frequency magnetic field containing a first frequency component and a second frequency component under the drive of the AC driving voltage having the first frequency signal and the second frequency signal, and transmit AC magnetic energy containing the first frequency component and the second frequency component to the receiving end;

[0017] The receiving end includes: a receiving end dual resonance module 5 coupled with the transmitting end dual resonance module 4 through a magnetic field, a first rectifier bridge 6 and a second rectifier bridge 7 connected in series with the two branches of the receiving end dual resonance module 5, and a DC motor 8 connected to the first rectifier bridge 6 and the second rectifier bridge 7 respectively; wherein the receiving end dual resonance module 5 is used to pick up AC power containing a first frequency component and a second frequency component from a high-frequency magnetic field; the first rectifier bridge 6 is used to rectify and filter the AC power of the first frequency component into a first DC power, and the first DC power is used to supply the armature winding of the DC motor 8; the second rectifier bridge 7 is used to rectify and filter the AC power of the second frequency component into a second DC power, and the second DC power is used to supply the excitation winding of the DC motor 8.

[0018] In an embodiment of the present invention, independent power transmission of dual-frequency channels can be achieved by using only a pair of coupled coils, namely, a transmitting-end dual-resonance module and a receiving-end dual-resonance module; in addition, since a power conversion and control unit is no longer required on the motor side, the system has better modular performance and a more streamlined system structure.

[0019] In one embodiment, the power supply 1 includes a DC power supply V connected to each other. DC , a first voltage-dividing capacitor C1 and a second voltage-dividing capacitor C2;

[0020] The first voltage-dividing capacitor C1 and the second voltage-dividing capacitor divide the DC power supply V DC It is divided into two equal voltage sources and connected to the midpoints of the four switching tubes of the three-level inverter 2 .

[0021] In one embodiment, the difference between the first frequency and the second frequency is greater than a preset threshold. The preset threshold is set relatively large, so that the difference between the first frequency and the second frequency can be large, so that the mutual influence between them can be ignored.

[0022] In one embodiment, the transmitting end dual resonance module 4 adopts an LCC compensation topology, and the two peak points of the current-frequency response curve of the LCC compensation topology are the first frequency and the second frequency, respectively, so that two independent frequency channels can be provided for energy transmission.

[0023] In one embodiment, the three-level inverter 2 can output an AC driving voltage containing a first frequency signal and a second frequency signal to the transmitting-end dual resonance module 4. The square wave control signals of the four switches of the three-level inverter are generated by the frequency signal synthesis module 3.

[0024] Figure 2 The figure is a logic diagram of the switch control signal processing of the three-level inverter in the embodiment of the present invention. PWM-f1 and PWM-f2 are two square wave control signals, specifically square wave frequency signals, whose frequency values ​​correspond to the first frequency and the second frequency. After the "AND" operation of PWM-f1 and PWM-f2, the control signal of switch S1 is generated; after the control signal of switch S1 is inverted, the control signal of switch S3 is generated; after the "OR" operation of PWM-f1 and PWM-f2, the control signal of switch S2 is generated; after the control signal of switch S2 is inverted, the control signal of switch S4 is generated. Figure 3 is the output waveform of the three-level inverter in the embodiment of the present invention, which is the superposition of two sub-waveforms. One of the two sub-waveforms is a square wave with a frequency of the first frequency and an amplitude of VDC / 2, and the other is a square wave with a frequency of the second frequency and an amplitude of VDC / 2. The duty cycles of the two sub-waveforms are independently controlled by PWM-f1 and PWM-f2, respectively. In actual operation, the power regulation of the two energy channels can be achieved by independently adjusting the duty cycle or frequency of PWM-f1 and PWM-f2.

[0025] In one embodiment, the transmitting end dual resonance module 4 includes a first transmitting end inductor L p1 , the second transmitting end inductor L p2 , the first transmitting end capacitor C p1 and the second transmitting end capacitor C p2 ;in,

[0026] The first transmitting end inductor L p1 , the second transmitting end inductor L p2 and the second transmitting end capacitor C p2 The resonant frequency of the formed resonant circuit is the first frequency f1;

[0027] The first transmitting end inductor L p1 , the first transmitting end capacitor C p1 The resonant frequency of the resonant circuit is the second frequency f2, and the first transmitting end L p1 and the first transmitting end capacitor C p1Drive the second transmitting - end inductor L when resonating at the second frequency p2 and the second transmitting - end capacitor C p2 to generate a working current of a preset magnitude at the second frequency.

[0028] In the above - mentioned embodiment, the preset magnitude is generally a relatively large current. Assume f1 < f2. Therefore, when the output of the three - level inverter 3 includes two frequency components f1 and f2, the transmitting - end coupled - resonance module (4) will generate currents of two frequency components in the coupling coil L p2 to generate an alternating magnetic field of two frequency components.

[0029] In one embodiment, the receiving - end double - resonance module 5 includes a first receiving - end inductor L s1 , a first receiving - end capacitor C s1 , a second receiving - end capacitor C s2 ; where

[0030] the resonance frequency of the first series - resonance circuit formed by the first receiving - end inductor L s1 and the first receiving - end capacitor C s1 is the first frequency;

[0031] the resonance frequency of the second series - resonance circuit formed by the first receiving - end inductor L s1 , the first receiving - end capacitor C s1 , and the second receiving - end capacitor C s2 is the second frequency.

[0032] In one embodiment, the receiving - end double - resonance module 5 further includes a second receiving - end inductor L sf1 , a third receiving - end inductor L sf2 , a third receiving - end capacitor C sf1 and a fourth receiving - end capacitor C sf2 ; where

[0033] the second receiving - end inductor L sf1 and the third receiving - end capacitor C sf1 form a first band - stop filter through parallel resonance in the first parallel - resonance circuit, and the resonance frequency of the first band - stop filter is the second frequency;

[0034] the third receiving - end inductor L sf2 , and the fourth receiving - end capacitor C sf2 form a second band - stop filter through parallel resonance in the second parallel - resonance circuit, and the resonance frequency of the second band - stop filter is the first frequency;

[0035] In one embodiment, the first parallel - resonance circuit is connected in series with the input side of the first rectifier bridge 6;

[0036] The second parallel resonant circuit is connected in series with the input side of the second rectifier bridge 7 .

[0037] In the above embodiment, the first parallel resonant circuit and the second parallel resonant circuit are LC band-stop filters, which are used to eliminate the electric energy of the second frequency component and the first frequency component respectively. In this way, the independent control of the electric energy of the two frequency components can be achieved. Specifically: the resonant frequency of the first parallel resonant circuit is the second frequency, so it is in a high-impedance state for the second frequency; the resonant frequency of the second parallel resonant circuit is the first frequency, so it is in a high-impedance state for the first frequency. When the AC magnetic energy is picked up from the high-frequency magnetic field (alternating magnetic field), the AC electric energy of the first frequency passes through the first receiving end inductor L s1 and the first receiving end capacitor C s1 , the second receiving end inductor L sf1 The second frequency AC power is output to the first rectifier bridge 6, and the second frequency AC power is blocked by the first parallel resonant circuit; the second frequency AC power is transmitted through the first receiving end inductor L s1 , the first receiving end capacitor C s1 , the second receiving end capacitor C s2 , the third receiving end inductor L sf2 The first frequency AC power is output to the second rectifier bridge 7, while the first frequency AC power is blocked by the second parallel resonant circuit. Therefore, the first frequency AC power can only be output through the first rectifier bridge 6, and the second frequency AC power can only be output through the second rectifier bridge 7.

[0038] The transmitting coil L in the transmitting end dual resonance module 4 p2 The receiving coil L in the receiving end double resonance module 5 s1 Through magnetic field coupling, the mutual inductance between the two coils is M ps .

[0039] In one embodiment, the first rectifier bridge 6 and the second rectifier bridge 7 are full-bridge rectifier bridges. The DC output of the first rectifier bridge 6 is connected to the armature winding of the DC motor (8), and the DC output of the second rectifier bridge 7 is connected to the excitation winding of the DC motor.

[0040] In one embodiment, the first DC power and the second DC power are adjusted by adjusting the duty ratio or frequency value of the square wave control signals of the first frequency and the second frequency of the frequency signal synthesis module.

[0041] In summary, in an embodiment of the present invention, only a pair of coupled coils, namely, a transmitting end dual resonance module and a receiving end dual resonance module, can be used to realize independent power transmission of dual frequency channels; in addition, since the motor side no longer requires a power conversion and control unit, it has better modular performance and a more streamlined system structure. In particular, the power transmission of the two frequency channels is simultaneous and continuous, rather than time-sharing transmission. This feature reduces the fluctuation of current in the armature winding and the excitation winding, making the operation of the wireless motor more stable. In addition, control, drive and other units are no longer required on the motor side, and the entire motor can also be made into a fully enclosed form, so as to have better waterproof and explosion-proof performance. Therefore, it can be used in applications such as underwater sewage pumps and exhaust fans inside pipes. Furthermore, it can also be applied to hub motors in products such as balancing vehicles and electric bicycles, so that the power components in these products are more streamlined, reliable, and easier to modularize.

[0042] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A single-coil dual-frequency channel wireless DC motor system, characterized in that: include: The transmitter and receiver, where The transmitting end comprises: a power supply (1), a three-level inverter (2) connected to three terminals of the power supply (1), a transmitting end dual resonance module (4) connected to the three-level inverter (2), and a frequency signal synthesis module (3); wherein the frequency signal synthesis module (3) is used to provide a square wave control signal of a first frequency and a second frequency to the three-level inverter (2); the three-level inverter (2) is used to output an AC driving voltage containing a first frequency signal and a second frequency signal to the transmitting end dual resonance module (4) according to the square wave control signal of the first frequency and the second frequency; the transmitting end dual resonance module (4) is used to generate a high-frequency magnetic field containing a first frequency component and a second frequency component under the drive of the AC driving voltage containing the first frequency signal and the second frequency signal, and transmit the AC magnetic energy containing the first frequency component and the second frequency component to the receiving end; The receiving end comprises: a receiving end dual resonance module (5) coupled to a transmitting end dual resonance module (4) through a magnetic field, a first rectifier bridge (6) and a second rectifier bridge (7) respectively connected in series with two branches of the receiving end dual resonance module (5), and a DC motor (8) respectively connected to the first rectifier bridge (6) and the second rectifier bridge (7); wherein the receiving end dual resonance module (5) is used to pick up AC power containing a first frequency component and a second frequency component from a high-frequency magnetic field; the first rectifier bridge (6) is used to rectify and filter the AC power of the first frequency component into a first DC power, and the first DC power is used to supply the armature winding of the DC motor (8); and the second rectifier bridge (7) is used to rectify and filter the AC power of the second frequency component into a second DC power, and the second DC power is used to supply the excitation winding of the DC motor (8).

2. The single-coil dual-frequency channel wireless DC motor system as claimed in claim 1, characterized in that: The power supply (1) comprises a direct current power supply, a first voltage-dividing capacitor and a second voltage-dividing capacitor connected to each other; The first voltage-dividing capacitor and the second voltage-dividing capacitor divide the DC power supply into two equal voltage sources, and are connected to the midpoint positions of the four switch tubes of the three-level inverter (2).

3. The single-coil dual-frequency channel wireless DC motor system as claimed in claim 1, characterized in that: The difference between the first frequency and the second frequency is greater than a preset threshold.

4. The single-coil dual-frequency channel wireless DC motor system as claimed in claim 1, characterized in that: The transmitting end dual resonance module (4) adopts an LCC compensation topology, and the two peak points of the current-frequency response curve of the LCC compensation topology are respectively the first frequency and the second frequency.

5. The single-coil dual-frequency channel wireless DC motor system as claimed in claim 1, characterized in that: The transmitting end dual resonance module (4) comprises a first transmitting end inductor, a second transmitting end inductor, a first transmitting end capacitor and a second transmitting end capacitor; wherein: The resonant frequency of the resonant circuit formed by the first transmitting end inductor, the second transmitting end inductor and the second transmitting end capacitor is the first frequency; The resonant frequency of the resonant circuit formed by the first transmitting end inductor and the first transmitting end capacitor is the second frequency, and when the first transmitting end inductor and the first transmitting end capacitor resonate at the second frequency, the second transmitting end inductor and the second transmitting end capacitor are driven to generate a working current of a preset magnitude at the second frequency.

6. The single-coil dual-frequency channel wireless DC motor system as claimed in claim 1, characterized in that: The receiving end dual resonance module (5) comprises a first receiving end inductor, a first receiving end capacitor, and a second receiving end capacitor; wherein: The resonant frequency of the first series resonant circuit formed by the first receiving end inductor and the first receiving end capacitor is the first frequency; The resonant frequency of the second series resonant circuit formed by the first receiving end inductor, the first receiving end capacitor, and the second receiving end capacitor is the second frequency.

7. The single-coil dual-frequency channel wireless DC motor system as claimed in claim 6, characterized in that: The receiving end dual resonance module (5) further includes a second receiving end inductor, a third receiving end inductor, a third receiving end capacitor and a fourth receiving end capacitor; wherein: The second receiving end inductor and the third receiving end capacitor form a first band-stop filter in a first parallel resonant circuit through parallel resonance, and the resonant frequency of the first band-stop filter is the second frequency; The third receiving end inductor and the fourth receiving end capacitor form a second band-stop filter in the second parallel resonant circuit through parallel resonance, and the resonant frequency of the second band-stop filter is the first frequency.

8. The single-coil dual-frequency channel wireless DC motor system as claimed in claim 7, characterized in that: The first parallel resonant circuit is connected in series with the input side of the first rectifier bridge (6); The second parallel resonant circuit is connected in series with the input side of the second rectifier bridge (7).

9. The single-coil dual-frequency channel wireless DC motor system as claimed in claim 1, characterized in that: The first rectifier bridge (6) and the second rectifier bridge (7) are full-bridge rectifier bridges.

10. The single-coil dual-frequency channel wireless DC motor system as claimed in claim 1, characterized in that: The first DC power and the second DC power are adjusted by adjusting the duty ratio or frequency value of the square wave control signals of the first frequency and the second frequency of the frequency signal synthesis module.

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