Multi-channel independent inverter, motor driving device and direct current asynchronous motor

Abstract

The invention discloses a multi-channel independent inverter, a motor driving device and a direct current asynchronous motor, and relates to the technical field of motor driving, and the multi-channel independent inverter comprises a control circuit, N pre-driving circuits and an inverter circuit; the control circuit is used for generating N groups of pulse width modulation signals; the N pre-driving circuits are used for receiving N groups of pulse width modulation signals and outputting corresponding N groups of power driving signals; the power supply ends of the N inverter circuits are used for being connected with a direct-current power supply, the output ends of the N inverter circuits are used for being connected with the N stator windings in a one-to-one correspondence mode, and the controlled ends of the N inverter circuits are connected with the signal output ends of the N pre-driving circuits in a one-to-one correspondence mode; the N inverter circuits are used for converting an accessed direct-current power supply into N paths of mutually independent alternating voltages according to the N groups of power driving signals, and each path of alternating voltage is used for driving one stator winding; and a certain phase difference exists between every two adjacent alternating voltages. Therefore, the driving control of the motor is simplified.

Description

Technical Field

[0001] This application relates to the field of motor drive technology, and in particular to a multi-channel independent inverter, a motor drive device, and a DC asynchronous motor. Background Technology

[0002] In the existing technology, the drive control of DC asynchronous motors, especially poleless rotor motors, usually adopts a coupling architecture with star or delta connection of stator windings. This results in strong electrical coupling between each phase winding, making it difficult to achieve independent and precise adjustment of the current in each phase, thus increasing the complexity of the control algorithm. Summary of the Invention

[0003] The main objective of this application is to propose a multi-channel independent inverter, a motor drive device, and a DC asynchronous motor, which aims to simplify the drive control of the motor.

[0004] To achieve the above objectives, the multi-channel independent inverter proposed in this application is applied to a DC asynchronous motor, wherein the DC asynchronous motor includes a stator and a poleless rotor, the stator includes a stator core and N independently arranged stator windings, where N is greater than 1; the multi-channel independent inverter includes:

[0005] The control circuit is used to generate N sets of pulse width modulation signals; N pre-drive circuits are connected to the control circuit to receive N sets of pulse width modulation signals and output corresponding N sets of power drive signals. N inverter circuits, the power supply terminals of the N inverter circuits are used to connect to a DC power supply, the output terminals of the N inverter circuits are used to be connected to the N stator windings one by one, and the controlled terminals of the N inverter circuits are connected to the signal output terminals of the N pre-drive circuits one by one. The N inverter circuits are used to convert the input DC power supply into N independent alternating voltages according to the N sets of power drive signals, and each alternating voltage is used to drive a stator winding. The phase difference between the first and Xth paths of the N alternating voltages is within a preset phase difference range, and the minimum value of the preset phase difference range is: The maximum value of the preset phase difference interval is: The phase difference between the first path and the Xth path is greater than the phase difference between the first path and the (X-1)th path, where X is greater than 1 and not greater than N.

[0006] In one embodiment, the phase difference between any two adjacent alternating voltages in the N alternating voltages is 180 / N degrees.

[0007] The inverter circuit includes a first bridge arm and a second bridge arm. The first bridge arm includes a first switch and a second switch, and the second bridge arm includes a third switch and a fourth switch. The first terminal of the first switch is connected to a DC power supply, and the second terminal of the first switch is connected to the first terminal of the second switch. The second terminal of the second switch is grounded. The first terminal of the third switch is connected to a DC power supply, and the second terminal of the third switch is connected to the first terminal of the fourth switch. The second terminal of the fourth switch is grounded. The connection point between the first and second switches is the midpoint of the first bridge arm, and the connection point between the third and fourth switches is the midpoint of the second bridge arm. The midpoints of the first bridge arm and the second bridge arm are connected one-to-one to the two ends of the same stator winding.

[0008] In one embodiment, the first and third switching transistors are MOSFETs or IGBTs, the second and fourth switching transistors are transistors, and the control circuit includes N signal output ports. Each signal output port is used to output a set of pulse width modulation signals. The signal output ports include: a first output terminal, a second output terminal, a third output terminal, and a fourth output terminal. The pre-driving circuit includes: The first pre-drive unit has its input terminal connected to the first output terminal of the control circuit, and its output terminal connected to the controlled terminal of the first switching transistor. The second pre-drive unit has its input terminal connected to the second output terminal of the control circuit, and its output terminal connected to the controlled terminal of the third switching transistor. The controlled terminal of the second switching transistor is connected to the third output terminal of the control circuit, and the controlled terminal of the fourth switching transistor is connected to the fourth output terminal of the control circuit.

[0009] In one embodiment, the alternating voltage changes periodically, and the waveform of the alternating voltage changes from zero to a preset peak value and then back to zero within a single cycle.

[0010] In one embodiment, the waveform of the alternating voltage within a single cycle is a quasi-sine wave.

[0011] In one embodiment, the multi-channel independent inverter further includes a power supply circuit, which includes a rectifier module, a first voltage conversion module, and a second voltage conversion module connected in sequence. The input terminal of the rectifier module is used to connect to an external AC power source and to convert the external AC power source into DC power source for output. The power supply terminals of the N inverter circuits are connected to the output terminal of the rectifier module. The input terminal of the first voltage conversion module is connected to the output terminal of the rectifier module, and is used to step down the DC power output by the rectifier module to a first voltage DC power supply and output it. The power supply terminals of the N pre-drive circuits are connected to the output terminal of the first voltage conversion module. The input terminal of the second voltage conversion module is connected to the output terminal of the first voltage conversion module, and is used to step down the first voltage DC power supply output by the first voltage conversion module to the second voltage DC power supply and output it. The power supply terminal of the control circuit is connected to the output terminal of the second voltage conversion module.

[0012] In one embodiment, the control circuit is configured to adjust the duty cycle and / or frequency of the generated N sets of pulse width modulation signals according to the target load, so as to change the torque of the DC asynchronous motor to adapt to the target load. The duty cycle and / or frequency of the pulse width modulation signal are positively correlated with the torque of the DC asynchronous motor.

[0013] This application also provides a motor drive device, which includes a multi-channel independent inverter as described above.

[0014] This application also provides a DC asynchronous motor, the DC asynchronous motor comprising: Poleless rotor; The stator includes a stator core and N independently configured stator windings, where N is greater than 1; The motor drive device described above.

[0015] In one embodiment, the poleless rotor includes a rotor core and a conductor disposed on the rotor core; The conductor includes a conductive bar embedded in the rotor core, or a conductive coil wound around the rotor core.

[0016] In one embodiment, N is specifically 3, and the three inverter circuits are used to convert the connected DC power supply into three independent alternating voltages according to three sets of power drive signals, and the phase difference between two adjacent alternating voltages is 60 degrees.

[0017] In summary, the multi-channel independent inverter, motor drive device, and DC asynchronous motor provided in this application generate independent alternating voltages through N inverter circuits to drive independently configured stator windings. This achieves physical decoupling of the electrical circuits between each phase winding, effectively avoiding electromagnetic coupling and mutual interference between phase windings in traditional star or delta connection architectures. This allows the current or voltage regulation of each phase winding to be performed independently without affecting each other, without relying on complex mathematical decoupling models or control algorithms, ultimately simplifying the drive control of the motor. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 A schematic diagram of an embodiment of the multi-channel independent inverter provided in this application; Figure 2 A waveform diagram of the alternating voltage output of a multi-channel independent inverter provided in this application; Figure 3 A waveform diagram of the alternating voltage output of the multi-channel independent inverter provided in this application; Figure 4 A waveform diagram of a power drive signal in an embodiment of the multi-channel independent inverter provided in this application; Figure 5 A waveform diagram of an embodiment of the third or fourth drive signal in the multi-channel independent inverter provided in this application; Figure 6 A circuit diagram of an embodiment of the inverter circuit provided in this application; Figure 7 A circuit diagram of another embodiment of the inverter circuit provided in this application; Figure 8 A circuit diagram of an embodiment of the pre-driving circuit provided in this application; Figure 9 This is a structural diagram of an embodiment of the DC asynchronous motor provided in this application.

[0020] Explanation of icon numbers: 10. Multi-channel independent inverter; 100. Control circuit; 200. Inverter circuit; 300. Pre-drive circuit; 400. Stator winding.

[0021] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0023] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0024] In existing technologies, the stator windings of DC asynchronous motors generally adopt a star (Y-type) or delta connection architecture. This results in inherent physical coupling between the three-phase windings in the electrical circuit. For example, in a star connection, the sum of the three-phase currents is constrained by Kirchhoff's laws to be zero, meaning that adjusting the current in any one phase will inevitably cause a coordinated change in the currents of the other phases. This strong electrical coupling between the phase windings means that the control system cannot directly and independently adjust the current or voltage of a single phase, leading to complex characteristics of the motor drive system: multivariable, strongly coupled, and nonlinear.

[0025] Therefore, in order to simplify the drive control of the motor, the multi-channel independent inverter 10 proposed in this application is applied to a DC asynchronous motor. The DC asynchronous motor includes a stator and a poleless rotor. The stator includes a stator core and N independently set stator windings 400, where N is greater than 1.

[0026] Understandably, this DC asynchronous motor breaks the traditional boundary of separating the motor and driver, realizing an integrated design of drive control and electromechanical energy conversion. Regarding the stator structure, the stator core is embedded with N independently configured stator windings 400. Unlike traditional motor windings which use star or delta connections, the N stator windings 400 in this application are electrically isolated from each other, do not share a common ground, and have no common neutral point.

[0027] In terms of rotor structure, the poleless rotor does not contain rare-earth permanent magnets or DC excitation windings, but rather a salient pole structure or squirrel-cage structure made of soft magnetic materials with high permeability (such as laminated silicon steel sheets). This poleless rotor does not possess a constant magnetic polarity.

[0028] In one embodiment, such as Figure 1As shown, the multi-channel independent inverter 10 includes a control circuit 100, N pre-drive circuits 300, and N inverter circuits 200. The control circuit 100 generates N sets of pulse width modulation signals. The N pre-drive circuits 300, connected to the control circuit 100, receive the N sets of pulse width modulation signals and output corresponding N sets of power drive signals. The N inverter circuits 200 have power supply terminals for connecting to a DC power source, output terminals for connecting to N stator windings 400 one-to-one, and controlled terminals for connecting to the signal output terminals of the N pre-drive circuits 300 one-to-one. The N inverter circuits 200 convert the connected DC power source into N independent alternating voltages according to the N sets of power drive signals. Each alternating voltage drives one stator winding 400. There is a certain phase difference between any two adjacent alternating voltages.

[0029] The inverter circuit 200 converts the input DC power supply into an alternating voltage. The inverter circuit 200 can be constructed from a bridge structure composed of switching transistors, such as an H-bridge full-bridge topology composed of four power switching devices, such as MOSFETs, IGBTs and transistors.

[0030] The pulse width modulation signal refers to a logic level signal generated by the control circuit 100, whose duty cycle changes regularly with time. This pulse width modulation signal is usually a low-voltage (such as 3.3V or 5V) and low-current weak signal. It carries modulation information such as frequency, phase and amplitude used to control the inverter output waveform, but its driving capability is insufficient to directly drive high-power switching transistors.

[0031] The power drive signal refers to the high-voltage control signal output by the pre-drive circuit 300 after amplifying the voltage, enhancing the current, and shifting the level of the aforementioned pulse width modulation signal. This power drive signal has a high voltage amplitude (e.g., 10V-15V) and a strong instantaneous current output capability, which can overcome the gate capacitance effect of the power switch and ensure that the power switch can quickly enter the fully on or off state.

[0032] In this embodiment, the alternating voltage is the form of electrical energy output after conversion by the inverter circuit 200, used to drive the load.

[0033] In one feasible implementation, the control circuit 100 is configured to output N sets of pulse width modulation (PWM) signals. The N sets of PWM signals can be generated by a microcontroller with multiple PWM output channels, and the output timing and waveform of each channel can be programmed. Alternatively, multiple independent oscillators and phase-shifting circuits can be used to generate logic control signals with specific phase relationships.

[0034] The power supply terminals of the N inverter circuits 200 are used to connect to a DC power source. This DC power source can be directly generated by connecting an external AC power source through the rectifier circuit built into the multi-channel independent inverter 10, or it can be a DC power source input after being rectified and filtered by an external rectifier circuit (such as an external power adapter or switching power supply module) connected to an AC power source. Furthermore, the DC power source can also be a pure DC power source directly provided by a battery pack, lithium battery pack, supercapacitor, or photovoltaic power generation unit. In this way, the multi-channel independent inverter 10 can flexibly adapt to various application scenarios such as mains power supply, industrial DC bus power supply, and mobile battery power supply.

[0035] In this system, N pre-drive circuits 300 are connected between the control circuit 100 and the N inverter circuits 200. The controlled terminals of the N inverter circuits 200 are connected one-to-one with the signal output terminals of the N pre-drive circuits 300, while the input terminals of the N pre-drive circuits 300 are connected one-to-one with the multiple signal output terminals of the control circuit 100. Each inverter circuit 200 converts the DC power supply into an alternating voltage based on the power drive signal it receives from the corresponding pre-drive circuit 300. For example, each inverter circuit 200 can be configured as an H-bridge with four switching transistors. In this architecture, the control circuit 100 first outputs N sets of pulse width modulation signals containing complementary logic. After level shifting and power amplification by the corresponding pre-drive circuits 300, the N sets of pulse width modulation signals form N sets of power drive signals that can drive the gates of the switching transistors, thereby periodically turning the switching transistors on and off, and generating an alternating voltage at the output terminal.

[0036] It should be noted that each pre-drive circuit 300 is used to receive a set of pulse width modulation signals and output a corresponding set of power drive signals. Accordingly, the pre-drive circuit 300 may have multiple independent units to receive multiple pulse width modulation signals from a set of pulse width modulation signals respectively.

[0037] There is a certain phase difference between each pair of alternating voltages, which can be achieved by the clock management unit or timer module inside the control circuit 100. By precisely delaying the start time of each pulse width modulation signal, the relative phase of each power drive signal after being amplified by the pre-drive circuit 300 is indirectly controlled. For example, a specific delay value can be set for each pulse width modulation signal through software programming to ensure that the final output alternating voltage meets the preset phase relationship.

[0038] Optionally, the specific number of pulse width modulation signals in each group depends on the number of switching transistors to be controlled in each inverter circuit 200. For example, if the inverter circuit 200 is a half-bridge structure and needs to control two switching transistors, then each group of pulse width modulation signals includes two pulse width modulation signals, which are processed by the pre-drive circuit 300 to output two power drive signals to control the on / off state of the two bridge arm switching transistors respectively; if the inverter circuit 200 is a full-bridge (H-bridge) structure and needs to control four switching transistors, then each group of pulse width modulation signals includes four pulse width modulation signals, which are converted by the pre-drive circuit 300 into four power drive signals to control the on / off state of the four bridge arm switching transistors respectively.

[0039] Understandably, this multi-channel independent inverter 10 can be matched according to the number of phases of the DC asynchronous motor. For example, if the DC asynchronous motor has two phases, the control circuit 100 outputs two sets of pulse width modulation signals, which are amplified by two pre-drive circuits 300 and then output as two sets of power drive signals to drive two inverter circuits 200. These two inverter circuits 200 generate two alternating voltages with a certain phase difference to control the energization of two independent windings of the motor stator. Similarly, if the motor has N phases, N inverter circuits 200 (and their corresponding pre-drive circuits 300) are configured for one-to-one independent driving.

[0040] Optionally, the phase difference between the first and Xth paths of the N alternating voltages is within a preset phase difference interval, and the minimum value of the preset phase difference interval is: The maximum value of the preset phase difference interval is: The phase difference between path 1 and path X is greater than the phase difference between path 1 and path (X-1), where X is greater than 1 and not greater than N. For example, assuming N is 3, this can be applied to a scenario driving a three-phase DC asynchronous motor. When X=2, that is, the phase difference between the first and second alternating voltages: Its minimum value is: Spend; Its maximum value is: Spend; That is, the phase difference range between the second path and the first path is... Within this range, as a preferred implementation, the second channel can be set to lag the first channel by 60 degrees.

[0041] When X=3, the phase difference between the first and third alternating voltages is calculated: Its minimum value is: Spend; Its maximum value is: Spend; That is, the phase difference range between the third path and the first path is... Within this range, as a preferred implementation, the third channel can be set to lag the first channel by 120 degrees.

[0042] By analogy, the phase of each alternating voltage is distributed in an orderly manner within a preset range.

[0043] In its working principle, the multi-channel independent inverter 10 modulates the DC power supply into N independent alternating voltages with specific phase differences (e.g., 180 / N degrees), which are then applied to N stator windings 400. Since the phase windings are physically completely decoupled, the control circuit 100 can individually adjust the voltage amplitude and waveform of each winding without causing forced electrical interference to other windings. The magnetic fields generated by each phase combine to form a rotating magnetic field in the air gap, traction or driving the poleless rotor, simplifying the control algorithm.

[0044] like Figure 2 and Figure 3 As shown, the output voltage waveform timing diagrams of this multi-channel independent inverter 10 under different drive configurations are displayed intuitively. Figure 2 For applications with N=2 (i.e., two-phase drive), it can be seen that "A-path alternating voltage" and "B-path alternating voltage" are two independent paths with a specific phase difference (e.g., 90 degrees, reflected in...). The sequentially lagging sinusoidal waves, together drive the synthesis of a rotating magnetic field; Figure 3 The embodiment corresponding to N=3 (i.e., three-phase drive) shows that the three alternating voltages A, B, and C exhibit a uniform phase change relationship on the time axis, and a preset phase difference (e.g., 60 degrees) is maintained between adjacent voltages, thereby driving three independent stator windings 400 to generate a continuous and smooth rotating magnetic field. Figure 2 and Figure 3 This clearly verifies the logic of this application to independently and accurately modulate multiple alternating voltages through the timing of control signals.

[0045] Optionally, the voltage value corresponding to each set of power drive signals can be 12V, 24V, 42V, or even higher values ​​such as 310V and 400V. The specific value depends on the actual application scenario and is not limited here.

[0046] In summary, the multi-channel independent inverter 10 in this embodiment effectively avoids the electrical coupling problem of each phase winding in traditional DC asynchronous motor drives by providing N independent alternating voltages and precisely controlling the phase difference between each voltage. This enables independent and precise adjustment of the current in each phase, significantly reducing the complexity of the control algorithm and improving the system's fault tolerance. Simultaneously, the optimized phase modulation strategy effectively suppresses the distortion of the motor's air gap magnetic field, thereby reducing torque ripple and electromagnetic noise, improving energy conversion efficiency, and fully leveraging the advantages of low cost and high reliability of the poleless rotor motor.

[0047] In one embodiment, the phase difference between any two adjacent alternating voltages in the N alternating voltage paths is 180 / N degrees. For example, if the phase of the first alternating voltage path is set to 0 degrees, then the phase of the second alternating voltage path should be 180 / N degrees, the third should be 2(180 / N) degrees, and so on, with the phase of the k-th alternating voltage path being (k-1)(180 / N) degrees. This can be achieved by using a control unit such as a digital signal processor, microcontroller, or application-specific integrated circuit to accurately calculate and generate N sets of power drive signals with specific phase differences. The N inverter circuits 200 then convert the DC power output from the rectifier circuit into alternating voltages of corresponding phases based on these power drive signals with precise phase differences.

[0048] By employing a 180 / N degree phase difference setting, the N stator windings 400 driven by N alternating voltages exhibit a high-density interleaved conduction state in their operating sequence. Compared to the traditional 360 / N degree phase distribution, this scheme significantly increases the overlap of torque synthesis within a unit electrical cycle. In a multiphase DC asynchronous motor, when the torque generated by one phase winding begins to decrease (the waveform returns from its peak to zero), the winding of the adjacent phase is precisely in the torque rising stage (the waveform rises from zero to its peak) and intervenes in time, smoothing the total electromagnetic torque synthesized by each phase and effectively suppressing torque pulsation during motor operation.

[0049] Since the phase difference between any two adjacent alternating voltages is 180 / N degrees, the rotating magnetic field generated by the stator winding 400 has a more continuous and uniform distribution in space and time. This effectively reduces the harmonic components of the air gap magnetic flux density of the motor, thereby weakening the radial electromagnetic force waves caused by sudden magnetic field changes or commutation impacts from the source. It also reduces the electromagnetic excitation force between the stator and rotor of the motor, which greatly reduces the electromagnetic noise and mechanical vibration of the motor during operation (especially at low speed and heavy load), and improves the quietness performance and mechanical life of the equipment.

[0050] In one embodiment, the inverter circuit 200 includes a first bridge arm and a second bridge arm. The first bridge arm of the inverter circuit 200 includes a first switch Q1 and a second switch Q2, and the second bridge arm includes a third switch Q3 and a fourth switch Q4. The first terminal of the first switch Q1 is connected to a DC power supply, and the second terminal of the first switch Q1 is connected to the first terminal of the second switch Q2. The second terminal of the second switch Q2 is grounded. The first terminal of the third switch Q3 is connected to a DC power supply, and the second terminal of the third switch Q3 is connected to the first terminal of the fourth switch Q4. The second terminal of the fourth switch Q4 is grounded. The connection point between the first switch Q1 and the second switch Q2 is the midpoint of the first bridge arm, and the connection point between the third switch Q3 and the fourth switch Q4 is the midpoint of the second bridge arm. The midpoints of the first and second bridge arms are connected one-to-one to the two ends of the same stator winding 400.

[0051] The midpoint of the first bridge arm and the midpoint of the second bridge arm are used to output one alternating voltage.

[0052] In one feasible embodiment, each set of power drive signals may include a first drive signal and a second drive signal to drive the first switch Q1 of the first bridge arm and the third switch Q3 of the second bridge arm, respectively. At this time, the second switch Q2 of the first bridge arm and the fourth switch Q4 of the second bridge arm can be connected to external control signals as the third and fourth drive signals. These signals can be the third and fourth drive signals output from a control module outside the multi-channel independent inverter 10; alternatively, the control circuit 100 within the multi-channel independent inverter 10 can be configured to output the third and fourth drive signals (skipping the pre-drive step). In this case, the first drive signal drives the first switch Q1 of the first bridge arm, the third drive signal drives the second switch Q2 of the first bridge arm, the second drive signal drives the third switch Q3 of the second bridge arm, and the fourth drive signal drives the fourth switch Q4 of the second bridge arm, thereby achieving complete takeover and integrated control of the entire H-bridge inverter circuit 200. In other words, the inverter circuit 200 requires a first drive signal, a second drive signal, a third drive signal, and a fourth drive signal for driving. The first and second drive signals are two signals output by a pre-drive circuit 300 after a set of pulse width modulation signals output by the control circuit 100 are processed. The third and fourth drive signals can be directly output by the control circuit 100 without pre-drive (because the transistors do not need pre-drive), or they can be connected by an external circuit. The third and fourth drive signals can be drive signals with a high level of 1 and a low level of 0, which are only used to drive the normally open and normally closed second switch Q2 and fourth switch Q4. Therefore, their generation is relatively simple, as explained below.

[0053] The first and second drive signals are configured as high-frequency modulated signals, operating alternately in time. Each operating cycle includes a high-level period (operating period) and a low-level period (off-end period). During the high-level period, the duty cycle increases progressively from zero to a preset peak value, then gradually decreases back to zero. The frequency of the duty cycle variation is not limited and can be adjusted according to actual accuracy requirements. For example, a high-level period may contain 256 discrete duty cycle changes, 1024 changes, or any other arbitrary number of modulations. The magnitude of the preset peak value is also not limited and depends on the rated voltage or power requirement of the target load. It should be noted that one operating cycle is defined as the time it takes for either the first or second drive signal to complete one full electrical cycle, which includes a high-level period and a low-level period in time.

[0054] The third and fourth drive signals are configured as power frequency commutation signals (or normally-on signals). During the period when the first drive signal is at a high level, the fourth drive signal, which is diagonally opposite to it, remains at a constant high level (duty cycle of 1). The first switch Q1 and the fourth switch Q4 are turned on, and the current flows from the power input terminal into the load through the first switch Q1 and back to ground through the fourth switch Q4, making the midpoint voltage of the first bridge arm higher than the midpoint voltage of the second bridge arm, thus forming a positive output voltage. Similarly, during the period when the second drive signal is at a high level, the third drive signal, which is diagonally opposite to it, remains at a constant high level, and the third switch Q3 and the second switch Q2 are turned on. The current flows from the power input terminal into the load through the third switch Q3 and back to ground through the second switch Q2, making the midpoint voltage of the second bridge arm higher than the midpoint voltage of the first bridge arm, thus forming a reverse output voltage. Thus, through the above hybrid driving strategy, the potential difference between the midpoints of the two bridge arms periodically reverses between positive and negative polarities as the timing changes, thereby achieving precise generation and modulation of the AC output waveform (i.e., alternating voltage).

[0055] In this embodiment, the midpoint of the first bridge arm can be connected to one end of a stator winding 400, and the midpoint of the second bridge arm can be connected to the other end of the stator winding 400; the midpoint of the first bridge arm and the midpoint of the second bridge arm are used to output an alternating voltage.

[0056] It should be noted that the above describes the power drive signal, which is actually mapped and executed by the pulse width modulation signal output by the control circuit 100. Specifically, the control circuit 100 first generates a pulse width modulation signal that is completely consistent with the power drive signal in terms of timing, frequency, and duty cycle variation. These pulse width modulation signals are then processed by the aforementioned pre-drive circuit 300 and finally converted into a power drive signal with driving capability, thereby driving the first to fourth switching transistors Q4 to turn on or off according to a preset strategy, synthesizing the required alternating voltage waveform across the stator winding 400.

[0057] like Figure 4 and Figure 5 As shown, Figure 4 The envelopes of the drive signals acting on the first switch Q1 and the second switch Q2 are shown. It can be seen that the first drive signal a and the second drive signal a in the set of power drive signals labeled "a", and the first drive signal b and the second drive signal b in the set of power drive signals labeled "b" appear alternately in time, and there is a 90-degree phase difference between the two sets of power drive signals (that is, "first drive signal b" lags behind "first drive signal a" by 1 / 4 cycle), which are used to generate the alternating voltage of phase A and phase B, respectively. Figure 5 The middle section shows the power frequency commutation signal acting on the third switch Q3 or the fourth switch Q4, which is a square wave-shaped normally-on signal, and its high-level duration strictly corresponds to... Figure 4 The operating range of each half-wave. The control logic of both is as follows: when the upper arm is based on... Figure 4 When outputting a high-frequency chopper signal, the lower bridge arm at the diagonal position synchronizes according to... Figure 5 By maintaining a constant high level of conduction, a complete current loop is constructed in concert, ultimately synthesizing a rotating magnetic field in the motor stator.

[0058] In one embodiment, such as Figure 7 As shown, the first switch Q1 and the third switch Q3 are MOSFETs or IGBTs, the second switch Q2 and the fourth switch Q4 are transistors, and the control circuit 100 includes N signal output ports. Each signal output port is used to output a set of pulse width modulation signals. The signal output ports include: a first output terminal, a second output terminal, a third output terminal, and a fourth output terminal. The pre-drive circuit 300 includes a first pre-drive unit and a second drive unit. The input terminal of the first pre-drive unit is connected to the first output terminal of the control circuit 100, and the output terminal of the first pre-drive unit is connected to the controlled terminal of the first switch Q1. The input terminal of the second pre-drive unit is connected to the second output terminal of the control circuit 100, and the output terminal of the second pre-drive unit is connected to the controlled terminal of the third switch Q3. The controlled terminal of the second switch Q2 is connected to the third output terminal of the control circuit 100, and the controlled terminal of the fourth switch Q4 is connected to the fourth output terminal of the control circuit 100.

[0059] First, for the first switch Q1 and the third switch Q3, this embodiment adopts a "MOSFET + pre-drive unit" configuration. Since the first switch Q1 and the third switch Q3 are responsible for high-frequency chopping, they have extremely high requirements for switching speed and losses. Therefore, MOSFETs with low on-resistance and fast switching characteristics are selected. However, as high-side switches, the gate drive voltage of MOSFETs usually needs to be higher than the DC bus voltage (for NMOS) or requires high-voltage level shifting (for PMOS), and their gates have large parasitic capacitances. Therefore, the control circuit 100 and the MOSFETs can be connected through the first pre-drive unit and the second pre-drive unit. The pre-drive unit converts the low-voltage logic signal output by the control circuit 100 into a high-voltage signal with sufficient driving capability, ensuring that the MOSFETs can be quickly and completely turned on and off, thereby guaranteeing the waveform quality and efficiency of high-frequency modulation.

[0060] Secondly, for the second switch Q2 and the fourth switch Q4, this embodiment adopts a low-cost configuration of "transistor + direct connection control". Since the second switch Q2 and the fourth switch Q4 mainly undertake the task of power frequency commutation (low frequency constant on) in the control strategy of this application, the requirement for switching speed is relatively low, so a cheaper transistor is selected. More importantly, the emitter of the lower bridge arm switch is directly grounded, which is a low-side switch. As a current-controlled device, the transistor has a low base conduction threshold voltage (about 0.7V), and the reference potential is the ground potential. This means that the normal logic level (such as 3.3V or 5V) output by the third and fourth output terminals of the control circuit 100 is sufficient to drive the transistor to saturation conduction. Therefore, this embodiment creatively eliminates the pre-drive circuit 300 of the lower bridge arm and directly connects the control port to the controlled terminal of the transistor, simplifying the circuit structure.

[0061] It is understood that each set of pulse width modulation signals specifically includes an independent first pulse width modulation signal and a second pulse width modulation signal. The first pre-drive unit is configured to receive the first pulse width modulation signal to drive and control the first switch Q1; the second pre-drive unit is configured to receive the second pulse width modulation signal to drive and control the second switch Q2. In terms of waveform characteristics, the first or second pulse width modulation signal presents as a high-frequency pulse sequence within one working cycle, exhibiting alternating high-level and low-level periods. Specifically, during the high-level period, its pulse duty cycle discretely changes according to the rule of "gradually increasing from zero to a preset peak value, and then gradually decreasing from the preset peak value back to zero." Based on this, the first pre-drive unit can analyze the received first pulse width modulation signal to output complementary high-side and low-side drive signals to control the on / off state of the first switch Q1; similarly, the second pre-drive unit can perform the same processing on the received second pulse width modulation signal to output a corresponding drive signal to control the on / off state of the third switch Q3.

[0062] When the second switch Q2 and the fourth switch Q4 are transistors, circuit costs can be saved.

[0063] In one embodiment, such as Figure 6 As shown, the first switching transistors Q1 to the fourth switching transistors Q4 are all MOSFETs or IGBTs. Accordingly, the first pre-drive unit of the pre-drive circuit 300 can output a first drive signal based on one pulse width modulation signal from a set of pulse width modulation signals, and the second pre-drive unit of the pre-drive circuit 300 can output a second drive signal based on another pulse width modulation signal from the same set of pulse width modulation signals. In this case, the control circuit 100 can also generate another N sets of pulse width modulation signals (here referred to as N sets of lower-transistor pulse width modulation signals). The first pre-drive unit of the pre-drive circuit 300 can also output a third drive signal based on one lower-transistor pulse width modulation signal from a set of lower-transistor pulse width modulation signals, and the second pre-drive unit of the pre-drive circuit 300 can also output a fourth drive signal based on another lower-transistor pulse width modulation signal from the same set of lower-transistor pulse width modulation signals.

[0064] like Figure 8The diagram illustrates an embodiment of the integrated driver chip used in the pre-drive circuit 300. This chip can be an LKS580 / SOP8 or a half-bridge driver chip with the same pin functions. The chip has a power supply pin (Pin1VCC), a ground pin (Pin4COM / GND), a bootstrap voltage pin (Pin8VB) for constructing the bootstrap circuit, and a high-side floating ground pin (Pin6VS). Regarding the specific connection and application logic: First, for a hybrid architecture of "upper MOS + lower transistor": only the high-side drive capability of the chip is utilized. The chip's input (e.g., Pin2HIN) receives the signal from the control circuit 100, while the seventh pin (Pin7HO, i.e., the high-side output) is connected as an output to the gate of the first switching transistor Q1 (the upper transistor). The floating high voltage generated by the external bootstrap diode and capacitor is used to pre-drive the upper transistor; in this case, the fifth pin (Pin5LO) can be left floating or unused. Second, for an "all-MOS" architecture: the chip is fully utilized to drive a complete bridge arm. The chip's two input terminals (Pin2HIN and Pin3LIN) receive complementary PWM signals from control circuit 100; pin 7HO outputs a first drive signal (high-voltage drive) to drive the first switch Q1, and pin 5LO (i.e., low-side output) outputs a third drive signal (low-voltage drive) to drive the second switch Q2. Similarly, another identical chip uses its seventh and fifth pins to output a second and a fourth drive signal, respectively, to drive the third and fourth switches Q4.

[0065] In one embodiment, the alternating voltage changes periodically, and the waveform of the alternating voltage changes from zero to a preset peak value and then back to zero within a single cycle.

[0066] In this embodiment, the waveform of the alternating voltage within a single cycle is a sine wave.

[0067] Understandably, during the first half of the operating cycle (the positive half-cycle), the first drive signal is at a high level with its duty cycle changing from zero to a peak value and then back to zero. During this time, the upper transistor (first switch Q1) of the first bridge arm performs high-frequency chopping, while the fourth switch Q4 on the diagonal remains constantly on, allowing current to flow forward through the stator winding 400. Since the average voltage across the stator winding 400 depends on the duty cycle of the drive signal, the stator winding 400 exhibits a positive wave (i.e., voltage rises from 0 to a positive peak value and then drops to 0) consistent with the envelope of the first drive signal during this phase. In the second half of the operating cycle (the negative half-cycle), the first drive signal is cut off, and the second drive signal begins to operate. At this time, the second drive signal controls the upper transistor (third switch Q3) of the second bridge arm to perform high-frequency chopping with the same duty cycle pattern, while the second switch Q2 on the diagonal remains constantly on. The key point is that at this time, the current flows through the stator winding 400 in the opposite direction (inflow from the second bridge arm and outflow from the first bridge arm), thus creating voltages of opposite polarity across the stator winding 400. During this stage, the stator winding 400 exhibits a negative peak wave (i.e., the voltage drops from 0 to a negative peak and then rises back to 0). Thus, as the first and second drive signals alternate in timing, the voltage across the stator winding 400 is composed of positive and negative peak waves, forming a complete, periodically changing AC voltage waveform (sine wave-like).

[0068] This type of sinusoidal drive method enables the drive current waveform in the stator winding 400 to remain continuous and smoothly transition in the time domain, reducing the high-order harmonic content in the voltage / current waveform, thereby making the air gap magnetic field distribution inside the motor closer to the ideal circular rotating magnetic field.

[0069] Furthermore, the reason why this quasi-sine wave drive method can effectively reduce motor vibration is fundamentally due to the elimination of commutation shock in traditional square wave drives. Specifically, in traditional square wave or trapezoidal wave drives, the current undergoes a drastic change at the moment of commutation. This discontinuous current step causes huge instantaneous fluctuations in the motor's output torque (i.e., torque pulsation), which in turn causes vibration of the rotor's mechanical structure. In this embodiment, by gradually modulating the duty cycle, the drive voltage and current present a smooth quasi-sine wave, eliminating the drastic current change point. This allows the electromagnetic torque generated by the motor to remain constant or fluctuate slightly on the time axis, achieving flexible commutation and thus improving the smoothness and quietness of motor operation.

[0070] In one embodiment, the multi-channel independent inverter 10 further includes a power supply circuit, which includes a rectifier module, a first voltage conversion module, and a second voltage conversion module connected in sequence. The input terminal of the rectifier module is used to connect to an external AC power supply and to convert the external AC power supply into DC power supply for output. The power supply terminals of the N inverter circuits 200 are connected to the output terminal of the rectifier module. The input terminal of the first voltage conversion module is connected to the output terminal of the rectifier module and is used to step down the DC power supply output by the rectifier module to a first voltage DC power supply and output it. The power supply terminals of the N pre-drive circuits 300 are connected to the output terminal of the first voltage conversion module. The input terminal of the second voltage conversion module is connected to the output terminal of the first voltage conversion module and is used to step down the first voltage DC power supply output by the first voltage conversion module to a second voltage DC power supply and output it. The power supply terminal of the control circuit 100 is connected to the output terminal of the second voltage conversion module.

[0071] The power supply circuit has a rectifier module at its front end, which is directly connected to an external AC power source (such as 220V AC mains) and converts it into a high-voltage DC power supply. This high-voltage DC bus is directly connected to the power supply terminals of N inverter circuits 200, providing the main energy source for the motor drive, i.e., the power loop. The pre-drive circuit 300 (and the power transistor gate) requires a medium-voltage DC power supply of a specific amplitude, such as 12V or 15V, to overcome the gate capacitance and maintain reliable conduction. In this embodiment, a first voltage conversion module is provided, which can be a high-voltage Buck converter or a flyback switching power supply. The input terminal of the first voltage conversion module is connected to the output of the rectifier module, which steps down the DC power output of the rectifier module to the first voltage DC power supply, supplying the N pre-drive circuits 300 and ensuring that the drive signal has sufficient power strength. In addition, the control circuit 100 requires a low-voltage logic power supply, such as 3.3V or 5V. Therefore, a second voltage conversion module is further configured in this power supply circuit, which can be an LDO linear regulator or a low-voltage DC-DC converter. The input of the second voltage conversion module is connected to the output of the first voltage conversion module, which steps down the first voltage DC power supply to the second voltage DC power supply. This avoids the large voltage drop losses that occur when directly stepping down from the high-voltage bus to the low-voltage bus, significantly optimizing power conversion efficiency and thermal management performance.

[0072] In summary, through this integrated power management strategy, the entire multi-channel independent inverter 10 only requires one external AC input to operate independently, without the need for additional auxiliary power adapters, which greatly simplifies the external wiring and installation costs of the system.

[0073] In one embodiment, the control circuit 100 is configured to adjust the duty cycle and / or frequency of the generated N sets of pulse width modulation signals according to the target load, so as to change the torque of the DC asynchronous motor to adapt to the target load; wherein the duty cycle and / or frequency of the pulse width modulation signal is positively correlated with the torque of the DC asynchronous motor.

[0074] This embodiment provides a closed-loop control scheme. In one feasible implementation, the control circuit 100 can dynamically adjust the duty cycle and / or frequency of each pulse width modulation signal in each set of generated pulse width modulation signals according to the real-time operating status parameters of the target load, such as the magnitude of the feedback current in the stator winding 400 or the difference between the real-time speed of the rotor and the target speed. This changes the average voltage amplitude or magnetic field rotation speed applied across the stator winding 400, so that the electromagnetic torque output by the motor can follow and match the torque demand of the load in real time. For example, it can automatically increase torque when the load increases and automatically save energy when the load decreases.

[0075] On the one hand, the duty cycle directly determines the effective value of the output voltage of the inverter circuit 200, i.e., the average voltage. Specifically, when the duty cycle is increased, the average voltage applied to the stator winding 400 increases. According to Ohm's law and the principle of the equivalent circuit of a motor, the increase in input voltage will cause the excitation current flowing through the winding to increase. Since the electromagnetic torque of the motor is proportional to the product of the air gap flux and the stator current, the increase in current directly translates into an increase in electromagnetic driving force, enabling the motor to output greater torque to overcome load resistance.

[0076] On the other hand, frequency directly determines the synchronous speed of the stator rotating magnetic field, which in turn determines the mechanical speed of the rotor. According to the power formula (power = torque × angular velocity), under the premise of maintaining torque, increasing the drive frequency means that the motor speed increases, enabling it to output more mechanical work per unit time, i.e., increasing the output power. Therefore, simultaneously increasing the duty cycle and frequency can comprehensively improve the motor's output torque reserve and work efficiency, thereby achieving effective adaptation to heavy loads or high-power target loads.

[0077] This application also provides a motor drive device. Since the motor drive device includes a multi-channel independent inverter 10, and the multi-channel independent inverter 10 adopts all the technical solutions of all the above embodiments, the motor drive device has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0078] This application also provides a DC asynchronous motor, the DC asynchronous motor comprising: Poleless rotor; The stator consists of a stator core and N independently configured stator windings 400, where N is greater than 1; As mentioned above, the motor drive device.

[0079] It should be noted that since this DC asynchronous motor includes a motor drive device, and the motor drive device adopts all the technical solutions of all the above embodiments, this DC asynchronous motor has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0080] It is understandable that, such as Figure 9 As shown, this DC asynchronous motor breaks the traditional separation between the motor and the driver, achieving an integrated design of drive control and electromechanical energy conversion. Regarding the stator structure, the stator core is embedded with N independently configured stator windings 400. Unlike traditional motor windings which use star or delta connections, the N stator windings 400 in this application are electrically isolated from each other, do not share a common ground, and have no common neutral point. This motor integrates the aforementioned motor drive device, establishing a one-to-one direct drive connection between its internal N inverter circuits 200 and these N independent windings, thereby constructing a multi-parallel independent drive architecture.

[0081] Specifically, such as Figure 9 The diagram shows a schematic cross-sectional structure of the stator and rotor of a DC asynchronous motor according to an embodiment of this application. The stator core has multiple protruding teeth evenly distributed along the circumference, and the stator winding 400 is wound around these teeth. To construct two independent stator windings 400 (N=2), the coils wound around the teeth are electrically divided into two groups: the first group of coils is wound around odd-numbered teeth spaced apart in space (e.g., teeth 1, 3, 5, and 7), and these coils are connected in series or parallel, leading to two independent terminals, thus forming the first independent stator winding 400 (i.e., phase A winding); correspondingly, the second group of coils is wound around the remaining even-numbered teeth (e.g., teeth 2, 4, 6, and 8), and similarly connected in series or parallel, leading to another two independent terminals, thus forming the second independent stator winding 400 (i.e., phase B winding).

[0082] In terms of rotor structure, the poleless rotor does not contain rare-earth permanent magnets or DC excitation windings, but rather a salient pole structure or squirrel-cage structure made of soft magnetic materials with high permeability (such as laminated silicon steel sheets). This poleless rotor does not possess a constant magnetic polarity.

[0083] In its working principle, the motor drive modulates the DC power supply into N independent alternating voltages with specific phase differences (e.g., 180 / N degrees), which are then applied to N stator windings 400. Since the phase windings are physically completely decoupled, the control circuit 100 can individually adjust the voltage amplitude and waveform of each winding without causing forced electrical interference to other windings. The magnetic fields generated by each phase combine to form a rotating magnetic field in the air gap, traction or driving the poleless rotor, simplifying the control algorithm.

[0084] In one embodiment, the poleless rotor includes a rotor core and a conductor disposed on the rotor core; the conductor includes a conductive bar embedded in the rotor core or a conductive coil wound on the rotor core.

[0085] The squirrel-cage structure utilizes conductive bars (such as copper or cast aluminum) embedded in the iron core slots, forming a closed loop through end rings. The wound structure uses insulated wire wound into coils around the iron core. During operation, these conductors act as carriers of induced current. When the rotating magnetic field generated by the stator cuts these closed conductive bars or coils, an induced electromotive force and induced current are generated inside the conductors according to Faraday's law of electromagnetic induction. This current is further subjected to the Ampere force (Lorentz force) in the magnetic field, thereby generating electromagnetic torque to drive the rotor to rotate. This design eliminates expensive rare-earth permanent magnets, reducing manufacturing costs, and also endows the rotor with extremely high high-temperature resistance and mechanical strength.

[0086] In one embodiment, N is specifically 3, and the three inverter circuits 200 are used to convert the input DC power supply into three independent alternating voltages according to the three sets of power drive signals, and the phase difference between two adjacent alternating voltages is 60 degrees.

[0087] From a signal control perspective, the control circuit 100 first generates three time-locked reference modulation waveforms. Specifically, these three reference signals are the corresponding A-phase reference, B-phase reference, and C-phase reference, respectively. The controller compares these three reference waveforms with the high-frequency carrier wave to calculate three independent pulse width modulation signal sequences. During this process, the control logic strictly ensures the timing relationship of each signal group, such that the starting point of the second signal waveform lags behind the first group by 1 / 6 of an electrical cycle (i.e., 60 degrees), and the third signal lags behind the second group by another 1 / 6 of an electrical cycle. This precise timing control forms the mathematical basis for the subsequent generation of the rotating magnetic field in the physical layer.

[0088] At the drive execution level, three pre-drive circuits 200 convert the three sets of pulse width modulation signals into three corresponding power drive signals. These three power drive signals, carrying specific phase information, are then fed into three physically independent inverter circuits 200. The first inverter circuit 200 responds to the first signal by modulating the DC power supply into a first alternating voltage to drive the first stator winding 400. Subsequently, the second and third inverter circuits 200, with a 60-degree phase delay, sequentially modulate the DC power supply into second and third alternating voltages, respectively, driving the second and third stator windings 400. Because these three alternating voltages exhibit a denser stepped distribution on the time axis (compared to the traditional 120-degree interval), when they act on the stator space, they can synthesize a circular rotating magnetic field with lower harmonic content and smoother transitions, thereby effectively driving the poleless rotor to operate smoothly and significantly reducing torque ripple.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no technical conflict, the various technical features mentioned in the various embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A multi-channel independent inverter, characterized in that, This invention is applied to a DC asynchronous motor, which includes a stator and a poleless rotor. The stator includes a stator core and N independently configured stator windings, where N is greater than 1. The multi-channel independent inverter includes: The control circuit is used to generate N sets of pulse width modulation signals; N pre-drive circuits are connected to the control circuit to receive N sets of pulse width modulation signals and output corresponding N sets of power drive signals. N inverter circuits, the power supply terminals of the N inverter circuits are used to connect to a DC power supply, the output terminals of the N inverter circuits are used to be connected to the N stator windings one by one, and the controlled terminals of the N inverter circuits are connected to the signal output terminals of the N pre-drive circuits one by one. The N inverter circuits are used to convert the input DC power supply into N independent alternating voltages according to the N sets of power drive signals, and each alternating voltage is used to drive a stator winding. The phase difference between the first and Xth paths of the N-path alternating voltage is within a preset phase difference range, and the minimum value of the preset phase difference range is: The maximum value of the preset phase difference interval is: The phase difference between the first path and the Xth path is greater than the phase difference between the first path and the (X-1)th path, where X is greater than 1 and not greater than N.

2. The multi-channel independent inverter as described in claim 1, characterized in that, In the N alternating voltages, the phase difference between any two adjacent alternating voltages is 180 / N degrees.

3. The multi-channel independent inverter as described in claim 1, characterized in that, The inverter circuit includes a first bridge arm and a second bridge arm. The first bridge arm includes a first switch and a second switch, and the second bridge arm includes a third switch and a fourth switch. The first terminal of the first switch is connected to a DC power supply, and the second terminal of the first switch is connected to the first terminal of the second switch. The second terminal of the second switch is grounded. The first terminal of the third switch is connected to a DC power supply, and the second terminal of the third switch is connected to the first terminal of the fourth switch. The second terminal of the fourth switch is grounded. The connection point between the first and second switches is the midpoint of the first bridge arm, and the connection point between the third and fourth switches is the midpoint of the second bridge arm. The midpoints of the first bridge arm and the second bridge arm are connected one-to-one to the two ends of the same stator winding.

4. The multi-channel independent inverter as described in claim 3, characterized in that, The first and third switching transistors are MOSFETs or IGBTs, the second and fourth switching transistors are transistors, and the control circuit includes N signal output ports. Each signal output port is used to output a set of pulse width modulation signals. The signal output ports include: a first output terminal, a second output terminal, a third output terminal, and a fourth output terminal. The pre-driving circuit includes: The first pre-drive unit has its input terminal connected to the first output terminal of the control circuit, and its output terminal connected to the controlled terminal of the first switching transistor. The second pre-drive unit has its input terminal connected to the second output terminal of the control circuit, and its output terminal connected to the controlled terminal of the third switching transistor. The controlled terminal of the second switching transistor is connected to the third output terminal of the control circuit, and the controlled terminal of the fourth switching transistor is connected to the fourth output terminal of the control circuit.

5. The multi-channel independent inverter as described in claim 1, characterized in that, The alternating voltage changes periodically, and the waveform of the alternating voltage changes from zero to a preset peak value and then back to zero within a single cycle.

6. The multi-channel independent inverter as described in claim 5, characterized in that, The waveform of the alternating voltage within a single cycle is a sine wave.

7. The multi-channel independent inverter as described in claim 1, characterized in that, The multi-channel independent inverter also includes a power supply circuit, which includes a rectifier module, a first voltage conversion module and a second voltage conversion module connected in sequence. The input terminal of the rectifier module is used to connect to an external AC power source and to convert the external AC power source into DC power source for output. The power supply terminals of the N inverter circuits are connected to the output terminal of the rectifier module. The input terminal of the first voltage conversion module is connected to the output terminal of the rectifier module, and is used to step down the DC power output by the rectifier module to the first voltage DC power and output it. The power supply terminals of the N pre-drive circuits are connected to the output terminal of the first voltage conversion module. The input terminal of the second voltage conversion module is connected to the output terminal of the first voltage conversion module, and is used to step down the first voltage DC power supply output by the first voltage conversion module to the second voltage DC power supply and output it. The power supply terminal of the control circuit is connected to the output terminal of the second voltage conversion module.

8. The multi-channel independent inverter as described in any one of claims 1 to 7, characterized in that, The control circuit is configured to adjust the duty cycle and / or frequency of the generated N sets of pulse width modulation signals according to the target load, so as to change the torque of the DC asynchronous motor to adapt to the target load. The duty cycle and / or frequency of the pulse width modulation signal are positively correlated with the torque of the DC asynchronous motor.

9. A motor drive device, characterized in that, The motor drive device includes a multi-channel independent inverter as described in any one of claims 1 to 8.

10. A DC asynchronous motor, characterized in that, The DC asynchronous motor includes: Poleless rotor; The stator includes a stator core and N independently configured stator windings, where N is greater than 1; The motor drive device as described in claim 9.

11. The DC asynchronous motor as described in claim 10, characterized in that, The non-magnetic pole rotor includes a rotor core and a conductor disposed on the rotor core; The conductor includes a conductive bar embedded in the rotor core, or a conductive coil wound around the rotor core.

12. The DC asynchronous motor as described in claim 10 or 11, characterized in that, N is specifically 3. The three inverter circuits are used to convert the connected DC power supply into three independent alternating voltages according to the three sets of power drive signals, and the phase difference between two adjacent alternating voltages is 60 degrees.

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