Two-phase permanent magnet motor and household appliance

Abstract

The disclosure provides a two-phase permanent magnet motor and a household appliance, wherein the two-phase permanent magnet motor comprises a stator, a rectified rotor and a phase compensation capacitor; the first winding and the second winding are orthogonally arranged on the stator teeth of the stator, the phase of the no-load back electromotive force of the first winding is ahead of the phase of the no-load back electromotive force of the second winding, and the power supply voltage is adapted to the second winding; the phase compensation capacitor is connected in series with the first winding, the phase compensation capacitor is used for adapting the power supply voltage to the first winding, and the ratio of the current amplitude of the first winding to the current amplitude of the second winding is a preset ratio; the rectified rotor is used for making the waveform of the no-load back electromotive force of the first winding and the second winding a preset waveform. Through the phase compensation capacitor and the rectified rotor, the fluctuations of the electromagnetic torques of the first winding and the second winding can be offset, the pulsation of the two-phase permanent magnet motor is reduced, when operating in parallel, the loss caused by the controller is eliminated, and the noise caused by the pulsation is reduced.

Description

Technical Field

[0001] This disclosure relates to the field of motor technology, specifically to a two-phase permanent magnet motor and a household appliance. Background Technology

[0002] In recent years, with the improvement of people's living standards, people have increasingly higher requirements for the high efficiency, lightweight design, low noise, and comfort of household appliances, such as refrigerators, air conditioners, air purifiers, and dehumidifiers. Taking the compressor drive system of refrigerators and air conditioners as an example, the compressor drive system of a high-efficiency refrigerator or air conditioner currently mainly includes a drive controller, a variable frequency three-phase permanent magnet drive motor, and a compressor cooling structure. In actual operation of a refrigerator or air conditioner, when the cooling effect reaches the set temperature, the system will enter a light-load, low-speed operating condition, which is also the long-term operating condition.

[0003] Since everyday household appliances typically use 220V, 50Hz single-phase AC power, neither three-phase nor two-phase permanent magnet motors can be directly connected to the grid. Only through a controller that converts the single-phase AC power to three-phase or two-phase AC power can the motor operate normally. However, under long-term operating conditions, the controller consumes a significant amount of energy. If the low-speed motor could be directly connected to the grid, it would further reduce controller losses and improve compressor efficiency under these conditions.

[0004] Although single-phase permanent magnet motors can be directly connected to the grid, they suffer from excessive torque pulsation, resulting in noise pollution. Furthermore, single-phase permanent magnet motors cannot self-start. Therefore, current technology lacks motors that can be directly connected to the grid and operate with low noise. Summary of the Invention

[0005] The technical problem to be solved by this disclosure is to overcome the deficiency of existing technology in the lack of motors that can be directly connected to the grid and have low noise, and to provide a two-phase permanent magnet motor and a household appliance.

[0006] This disclosure solves the above-mentioned technical problems through the following technical solution:

[0007] This disclosure provides a two-phase permanent magnet motor, which is used to operate in parallel with the grid when the single-phase power supply is in a preset phase;

[0008] The two-phase permanent magnet motor includes a stator, a rectifier rotor, and a phase compensation capacitor.

[0009] The stator has a first winding and a second winding orthogonally arranged on the stator teeth. The phase of the no-load back EMF of the first winding leads the phase of the no-load back EMF of the second winding. The supply voltage is adapted to the second winding.

[0010] The phase compensation capacitor is connected in series with the first winding. The phase compensation capacitor is used to adapt the supply voltage to the first winding and make the ratio of the current amplitude of the first winding to the current amplitude of the second winding a preset ratio. The preset ratio is used to match the amplitude of the electromagnetic torque of the first winding with the amplitude of the electromagnetic torque of the second winding.

[0011] The rectifier rotor is used to make the waveform of the no-load back EMF of the first winding and the second winding a preset waveform, and the preset waveform is used to match the peak of the electromagnetic torque of the first winding with the trough of the electromagnetic torque of the second winding.

[0012] Optionally, the preset ratio is the ratio of the effective values ​​of the no-load back EMF of the second winding and the first winding.

[0013] Optionally, the preset waveform is a sine wave.

[0014] Optionally, the formula for calculating the preset phase is:

[0015] ;

[0016] in, The preset phase is U, and the effective value of the supply voltage is U. , These are the first winding and the second winding, respectively. , These are the effective values ​​of the no-load back EMF of the first winding and the second winding, respectively. The initial phase of the no-load back EMF of the second winding is given, and the impedance value of the second winding is given. , The phase angle of the second winding. The phase resistance of the first winding;

[0017] The formula for calculating the capacitance value of the phase compensation capacitor is as follows:

[0018] ;

[0019] in, The capacitance value of the phase compensation capacitor is given.

[0020] Optionally, the wave rotor includes an even number of magnetic poles, and each magnetic pole includes at least two components made of different materials;

[0021] The at least two components made of different materials are fixedly connected according to a preset combination method.

[0022] Optionally, the wave rotor includes an even number of magnetic poles;

[0023] The outer surface of each magnetic pole is a first preset arc shape.

[0024] Optionally, the wave rotor includes several pairs of magnetic poles;

[0025] Each pair of magnetic poles includes two magnetic poles made of the same material, and each magnetic pole includes the same number of magnets, the thickness of which is matched.

[0026] The magnetization direction of several magnets in each pair of magnetic poles is a preset direction.

[0027] Optionally, the wave rotor includes an even number of magnetic poles;

[0028] The even number of magnetic poles are connected to each other to form a circular magnetic ring, and the magnetic field strength of the magnetic ring varies along the circumference according to a preset trend.

[0029] Optionally, the wave rotor includes several pairs of magnetic poles;

[0030] Each pair of magnetic poles includes two magnetic poles made of different materials, and each magnetic pole is a second predetermined arc shape.

[0031] This disclosure also provides a household appliance, which includes the aforementioned two-phase permanent magnet motor.

[0032] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of this disclosure.

[0033] The positive and progressive effect of this disclosure is that by directly connecting the two-phase permanent magnet motor to the single-phase power grid when the single-phase power supply voltage is in a preset phase, the power supply voltage can be directly adapted to the second winding.

[0034] The phase compensation capacitor is connected in series with the first winding. When single-phase power supplies power to the first winding, it needs to pass through the phase compensation capacitor. Since the capacitor can change the phase of the voltage, even if the phase of the no-load back EMF of the first winding is different from the phase of the no-load back EMF of the second winding, the supply voltage can still be adapted to the first winding.

[0035] Since the power supply voltage is adapted to both the first and second windings, the two-phase permanent magnet motor can be connected to the grid at this time. However, the phase of the electromagnetic torque of the first winding is different from the phase of the electromagnetic torque of the second winding during operation.

[0036] Since the ratio of the current amplitude of the first winding to the current amplitude of the second winding is a preset ratio, the amplitude of the electromagnetic torque of the first winding matches the amplitude of the electromagnetic torque of the second winding.

[0037] Since the waveforms of the no-load back EMF generated by the first and second windings are preset waveforms, and the peak of the electromagnetic torque of the first winding matches the trough of the electromagnetic torque of the second winding, when the electromagnetic torque of the first winding approaches the peak, the electromagnetic torque of the second winding approaches the trough, and the amplitude of the electromagnetic torque of the first winding matches the amplitude of the electromagnetic torque of the second winding, the fluctuations of the electromagnetic torque of the first and second windings can cancel each other out, reducing the pulsation of the two-phase permanent magnet motor. When operating directly in grid connection, it eliminates the losses caused by the controller and reduces the noise caused by pulsation. Attached Figure Description

[0038] Figure 1 A schematic diagram of the structure of a two-phase permanent magnet motor provided as an exemplary embodiment of this disclosure;

[0039] Figure 2 A schematic diagram of the structure of a rectifier rotor of a two-phase permanent magnet motor provided as an exemplary embodiment of this disclosure;

[0040] Figure 3 A schematic diagram of the structure of a rectifier rotor of a two-phase permanent magnet motor provided as an exemplary embodiment of this disclosure;

[0041] Figure 4 A schematic diagram of the structure of a rectifier rotor of a two-phase permanent magnet motor provided as an exemplary embodiment of this disclosure;

[0042] Figure 5 A schematic diagram of the structure of a rectifier rotor of a two-phase permanent magnet motor provided as an exemplary embodiment of this disclosure;

[0043] Figure 6 A schematic diagram of the structure of a rectifier rotor of a two-phase permanent magnet motor provided as an exemplary embodiment of this disclosure;

[0044] Figure 7 A schematic diagram of the torque waveform of a two-phase permanent magnet motor provided as an exemplary embodiment of this disclosure;

[0045] Figure 8 This is a schematic diagram of a traditional single-phase permanent magnet motor. Detailed Implementation

[0046] The present disclosure is further illustrated below by way of embodiments, but the present disclosure is not limited to the scope of the embodiments described herein.

[0047] The prefixes such as "first" and "second" used in this disclosure are merely for distinguishing different descriptive objects and do not limit the position, order, priority, quantity, or content of the described objects. The use of ordinal numbers and other prefixes used to distinguish descriptive objects in this disclosure does not constitute a limitation on the described objects. The description of the described objects is given in the claims or the context of the embodiments, and should not be construed as an unnecessary limitation. Furthermore, in the description of this embodiment, unless otherwise stated, "multiple" means two or more.

[0048] Example 1

[0049] Figure 1 This is a schematic diagram of the structure of a two-phase permanent magnet motor provided as an exemplary embodiment of the present disclosure. The two-phase permanent magnet motor is used to operate in parallel with the grid when the single-phase power supply voltage is at a preset phase.

[0050] The two-phase permanent magnet motor includes a stator 1, a rectifier rotor 2, and a phase compensation capacitor.

[0051] The stator has a first winding 11 and a second winding 12 orthogonally arranged on the stator teeth. The phase of the no-load back EMF of the first winding leads the phase of the no-load back EMF of the second winding, and the supply voltage is adapted to the second winding.

[0052] The phase compensation capacitor is connected in series with the first winding. The phase compensation capacitor is used to adapt the supply voltage to the first winding and make the ratio of the current amplitude of the first winding to the current amplitude of the second winding a preset ratio. The preset ratio is used to match the amplitude of the electromagnetic torque of the first winding with the amplitude of the electromagnetic torque of the second winding.

[0053] The rectifier rotor is used to make the waveform of the no-load back EMF of the first winding and the second winding the preset waveform. The preset waveform is used to match the peak of the electromagnetic torque of the first winding with the trough of the electromagnetic torque of the second winding.

[0054] In this solution, "adaptation" or "matching" does not mean a complete correspondence. Those skilled in the art can make adaptive settings according to actual needs. For example, a preset ratio can make the amplitude of the electromagnetic torque of the first winding differ from that of the second winding. A preset waveform can also make the peak of the electromagnetic torque of the first winding differ from the trough of the electromagnetic torque of the second winding. Since the purpose of this solution is to reduce torque pulsation, it is not necessary to completely eliminate torque pulsation. As long as the peak of the electromagnetic torque of the first winding is close to the trough of the electromagnetic torque of the second winding, torque pulsation can be reduced, thereby reducing noise. Similarly, the preset phase of the power supply voltage and the phase compensation capacitor are sufficient to enable the two-phase permanent magnet motor to operate in parallel with the grid. Even if the two-phase permanent magnet motor does not operate in its optimal state, it is still within the scope of this solution.

[0055] In one optional implementation, the preset phase of the power supply voltage can be monitored, and the two-phase permanent magnet motor can be directly connected to the grid when the power supply voltage is at the preset phase. Since the first winding, the second winding, and the single-phase compensation capacitor all correspond to the preset phase of the power supply voltage, the two-phase permanent magnet motor can only be connected to the grid when the power supply voltage is at the preset phase.

[0056] In one optional embodiment, the stator comprises an outer yoke and 4M stator teeth (M being the number of pole pairs of the rotor, with each pole pair consisting of two poles). The stator teeth extend radially inward from the yoke. Symmetrical toothed shoes extend circumferentially to both sides of the stator teeth away from the yoke along the tooth body centerline, with slot intervals between adjacent toothed shoes. The inner surfaces of the multiple toothed shoes and the slots enclose an internal space in which the rotor is placed. The space enclosed by adjacent stator teeth, the yoke, and the toothed shoes forms 4M stator slots, in which 4M coils are placed.

[0057] In one alternative implementation, the coils are wound around the stator teeth, and the 4M coils form two sets of windings, namely the first winding. With the second winding Each coil of the first winding is The second winding has 10 turns, and each coil of the second winding is 10 turns. The coils that make up the first and second windings are alternately wound on adjacent stator teeth, and all coils belonging to the same set of windings are connected in series.

[0058] In one optional implementation, the preset waveform is a sine wave. Since the first winding and the second winding are orthogonally arranged, the phase of the no-load back EMF of the first winding leads the phase of the no-load back EMF of the second winding by 90 electrical degrees. Because the phase of the no-load back EMF of the first winding leads the phase of the no-load back EMF of the second winding by 90 electrical degrees, and the phase compensation capacitor adapts the supply voltage to the first winding, the current passing through the first winding also leads the phase of the second winding by 90 electrical degrees. Since the no-load back EMF and current of the first winding lead the second winding by 90 electrical degrees, the electromagnetic torque of the first winding will lead the electromagnetic torque of the second winding by 180 electrical degrees. Since the preset waveform is a sine wave, the waveforms of the electromagnetic torques of the first and second windings are also sine waves. When the electromagnetic torque of the first winding is at its peak, the electromagnetic torque of the second winding is at its trough, and vice versa. Since the amplitudes of the electromagnetic torques of the first and second windings are the same, the fluctuations of the two electromagnetic torques can cancel each other out, keeping the total electromagnetic torque of the two-phase permanent magnet motor in a constant state, thus achieving noise reduction.

[0059] In one optional implementation, the preset ratio is the ratio of the effective values ​​of the no-load back EMF of the first winding and the second winding. By making the ratio of the current amplitude of the first winding to the current amplitude of the second winding equal to the ratio of the effective values ​​of the no-load back EMF of the second winding and the first winding, the amplitude of the electromagnetic torque of the first winding will be equal to the amplitude of the electromagnetic torque of the second winding.

[0060] In an optional implementation, when the first winding and the second winding are orthogonally arranged and the preset waveform is a sine wave, the formula for calculating the preset phase is:

[0061] ;

[0062] in, The preset phase is U, where U is the effective value of the supply voltage. , The first winding Second winding The effective value of the no-load back EMF, The initial phase of the no-load back EMF of the second winding is given, and the impedance of the second winding is given. , This is the phase angle of the second winding. The phase resistance of the first winding;

[0063] The formula for calculating the capacitance value of the phase compensation capacitor is:

[0064] ;

[0065] in, This is the capacitance value of the phase compensation capacitor.

[0066] The derivation steps of the formulas for calculating the preset phase and capacitance values ​​specifically include:

[0067] S1, Define the power supply voltage In the formula, j is the imaginary unit; U is the effective value of the supply voltage in V; and f is the frequency of the single-phase electricity in Hz. Preset phase, unit °.

[0068] S2, No-load back EMF generated by the first winding Leading the no-load back EMF of the second winding Ninety degrees of electrical angle define the no-load back EMF of the first and second windings. , , These are the first winding and the second winding, respectively. , These are the effective values ​​of the no-load back EMF of the first and second windings, respectively, in V; This represents the initial phase of the no-load back EMF of the second winding, in degrees.

[0069] S3, the impedance value of the first winding is... The impedance value of the second winding is , and They respectively satisfy:

[0070] In the formula , These are the phase resistances of the first winding and the second winding, respectively, in Ω; , These are the inductances of the first winding and the second winding, respectively, in H. Since the first winding and the second winding are orthogonal to each other, their mutual inductance can be ignored, and the inductance value is the self-inductance value of each winding. is the series capacitance value of the first winding, in F; j is the imaginary unit.

[0071] S4, according to The current of the first winding and the second winding can be obtained. , They are respectively To minimize torque fluctuation after the electromagnetic torques generated by the first and second windings are superimposed, the current in the first winding... The current should also be ahead of the second winding current. Ninety degrees electrical angle, and its current Amplitude is approximately of Therefore, a constraint relationship exists: .

[0072] S5. Based on the above constraints, the above can be derived. and The calculation formula is used to solve for the preset phase with minimum torque pulsation required under ideal conditions. and the corresponding capacitance value .

[0073] In one alternative implementation, due to certain assumptions made during the calculation process, and considering the nonlinearity and saturation issues of the motor's ferromagnetic material in reality, the capacitance value... and preset phase The relative analytical results may contain some errors, which can be corrected by simulation calculation using finite element software.

[0074] In one alternative implementation, the rectifier rotor includes a rotor core and M pairs of magnetic poles, each pair of magnetic poles including two magnetic poles with opposite polarities. The inner surface arcs of all magnetic poles are located on the outer circle of the rotor. The outer surface of the magnetic poles and the inner surface of the stator tooth shoe form an electromagnetic air gap. By adjusting the material, shape and magnetization method of the magnetic poles, the waveform of the no-load back EMF of the first winding and the second winding can be made as close as possible to a sine wave, thereby improving the torque pulsation under single-phase power supply.

[0075] In one alternative implementation, the wave rotor includes an even number of magnetic poles, each magnetic pole including at least two components of different materials; the at least two components of different materials are fixedly connected according to a preset combination method, which may include the proportion of the two components in the magnetic pole, the shape and position of the components, etc.

[0076] In an optional implementation, refer to Figure 3 The rotor comprises an even number of magnetic poles; the outer surface of each magnetic pole is a first preset arc shape. Each magnetic pole can be made of the same material, such as a permanent magnet. Each magnetic pole is manufactured from an independent magnet, the thickness of which decreases along its own axis towards both sides. The air gap formed between the outer arc of the magnetic pole and the inner circle of the stator gradually increases along the central axis of the magnetic pole towards both sides. By adjusting the degree to which the thickness of each magnetic pole decreases along its own axis towards both sides, the waveform of the no-load back EMF generated by the first and second windings can be made as close as possible to a sine wave. Specifically, the center of the outer arc of the magnetic pole is... The center of the inner arc of the magnetic pole (the outer circle of the iron core) is... . , Located on the central axis of the magnetic poles, The distance is denoted as ,when At that time, the magnetic poles along the rotor circumference are of equal thickness. When the value is greater than 0, the thickness of each magnetic pole decreases towards both sides along its own axis, and the air gap formed between the outer surface arc of the magnetic pole and the inner circle of the stator gradually increases towards both sides along the central axis of the magnetic pole. This is achieved by increasing... The value of can increase the extent to which the magnetic pole thickness decreases along its own axis to both sides; there exists a suitable value. The value can make the waveform of the no-load back EMF generated by the first winding and the second winding as close as possible to a sine wave.

[0077] In an optional implementation, refer to Figure 4The rotor consists of several pairs of magnetic poles; each pair of magnetic poles comprises two poles made of the same material, and each pole comprises an equal number of magnets with matching thicknesses; the magnetization direction of the magnets in each pair of magnetic poles is a preset direction. The magnetic poles can be made of permanent magnets, and each pole consists of the same number of K magnets, with 2K magnets of equal thickness. The air gap formed between the outer surface arc of the magnetic pole and the inner circle of the stator is a uniform air gap. By controlling the magnetization direction of each of the 2K magnets, the no-load air gap magnetic flux density under a pair of magnetic poles can be made as sinusoidal as possible, thus making the waveform of the no-load back electromotive force generated by the first and second windings as close to a sine wave as possible. Specifically, in the three pairs of magnetic poles, the two poles in each pair use the same material, such as permanent magnets. Each pole consists of the same number of 3 permanent magnets, with 18 magnets of equal thickness along the rotor circumference, and the air gap formed between the outer surface arc of the magnetic pole and the inner circle of the stator is a uniform air gap. By controlling the magnetization direction of the six magnets in each pair of magnetic poles, the unloaded air gap magnetic flux density under a pair of magnetic poles can be made as sinusoidal as possible, thereby making the waveform of the unloaded back EMF generated by the first winding and the second winding as close to a sine wave as possible.

[0078] In an optional implementation, refer to Figure 5 The rotor comprises an even number of magnetic poles; these even number of magnetic poles are interconnected to form a circular magnetic ring. The magnetic field strength of the ring varies along the circumference according to a preset trend to form a magnetic field strength curve 21. All magnetic poles can be made of the same material, such as permanent magnets. 2M magnetic poles are connected to form an integral circular magnetic pole. Specifically, the radial component of the magnetic field strength varies sinusoidally along the circumference, and the tangential component varies cosineally along the circumference, with a period equal to the central angle corresponding to a pair of magnetic poles. This ensures that the waveform of the no-load back EMF generated by the first and second windings is as close as possible to a sine wave.

[0079] In an optional implementation, refer to Figure 6 The rotor comprises several pairs of magnetic poles; each pair includes two poles made of different materials, and each pole has a second pre-defined arc shape. In each pair, one pole can be a permanent magnet, and the other can be made of magnetically conductive silicon steel, forming an alternating pole structure. Alternatively, one pole can be a rare-earth permanent magnet, and the other a non-rare-earth permanent magnet. The thickness of each pole is controlled to decrease laterally along its own axis, while the air gap formed between the outer surface arc of the pole and the inner circle of the stator gradually increases laterally along the pole's central axis. By adjusting the degree to which the thickness of each pole decreases laterally along its own axis, the waveform of the no-load back EMF generated by the first and second windings can be made as close as possible to a sine wave.

[0080] In one optional implementation, the effective value of the single-phase power supply voltage is 220V, the frequency is 50Hz, and the grid-connected speed of the two-phase permanent magnet motor is 1000rpm. (Refer to...) Figure 1 A two-phase permanent magnet motor includes a stator and a rectifier rotor. The rectifier rotor includes three pairs of magnetic poles, each pair of magnetic poles including two magnetic poles with opposite polarities. All magnetic poles are mounted on the iron core surface of the rectifier rotor and are evenly arranged along the circumference of the iron core. The inner surface arcs of all magnetic poles are located on the outer circle of the rotor. The outer surface arcs of the magnetic poles and the inner surface of the stator tooth shoe form an electromagnetic air gap.

[0081] The stator has 12 stator teeth, and the coils are wound on the stator teeth to form two sets of windings. Each coil in the first winding has 240 turns, and each coil in the second winding has 500 turns. The coils of the first and second windings are wound on adjacent magnets, and the coils belonging to the same set of windings are connected in series. The first winding is connected in series with the phase compensation capacitor.

[0082] Reference Figure 1 and Figure 2 Each magnetic pole may include two crescent-shaped components, the materials of which can be rare-earth permanent magnets and ferrite, respectively. The rare-earth permanent magnet material is closer to the rotor surface, and the center of the outer arc of the ferrite component is... The center of the circle corresponding to the internal arc of the ferrite core (the external arc of the rare earth permanent magnet) is The rotor center is . , , Located on the central axis of the magnetic poles, The distance is denoted as , The distance is denoted as By controlling and The magnitude of this value can effectively control the waveform of the back electromotive force. and At this time, the no-load back EMF harmonic THD of the winding is the minimum, at 0.8%.

[0083] The effective value of the single-phase power supply voltage is 220V, the power supply frequency is 50Hz, and the initial phase is... The effective value of the no-load back EMF of the first and second windings , The initial phases of the no-load back EMF of the second winding are 101.8V and 212V, respectively. -1.8°; phase resistance of the first and second windings , The inductances are 15.51Ω and 67.32Ω respectively; the inductances of the first winding and the second winding are... , The impedance values ​​of the second winding are 0.1246H and 0.541H, respectively. 182.807Ω; impedance angle The value is 68.4°. Based on the capacitance value... and preset phase The calculation formula can yield reasonable results. and The values ​​are 1.646uF and 90°, respectively.

[0084] Reference Figure 7 When powered by single-phase electricity, traditional single-phase permanent magnet motors ( Figure 8 As shown, the average torque is 0.21 Nm, the peak-to-peak torque is 0.547 Nm, and the torque pulsation rate is 260%; while using the above-mentioned two-phase permanent magnet motor, and and At 1.646uF and 90° respectively, the average torque of the two-phase permanent magnet motor is 0.211Nm, the peak-to-peak torque is 0.03Nm, ​​and the torque pulsation rate is 14.2%. Further correction through finite element simulation will... and Modified to 1.53uF and 90°, the average torque of the two-phase permanent magnet motor is 0.203Nm, ​​the peak-to-peak torque is 0.024Nm, and the torque pulsation ratio is 11.8%, further reducing torque pulsation. It can be seen that, using the two-phase permanent magnet motor proposed in this disclosure, to achieve the same torque output, its torque pulsation is reduced from 260% to 11.8% compared to the traditional single-phase permanent magnet motor, resulting in a significant reduction in torque pulsation.

[0085] This disclosure allows a two-phase permanent magnet motor to be directly connected to a single-phase power grid for parallel operation when the power supply voltage of the single-phase power grid is in a preset phase, so that the power supply voltage can be directly adapted to the second winding.

[0086] The phase compensation capacitor is connected in series with the first winding. When single-phase power supplies power to the first winding, it needs to pass through the phase compensation capacitor. Since the capacitor can change the phase of the voltage, even if the phase of the no-load back EMF of the first winding is different from the phase of the no-load back EMF of the second winding, the supply voltage can still be adapted to the first winding.

[0087] Since the power supply voltage is adapted to both the first and second windings, the two-phase permanent magnet motor can be connected to the grid at this time. However, the phase of the electromagnetic torque of the first winding is different from the phase of the electromagnetic torque of the second winding during operation.

[0088] Since the ratio of the current amplitude of the first winding to the current amplitude of the second winding is a preset ratio, the amplitude of the electromagnetic torque of the first winding matches the amplitude of the electromagnetic torque of the second winding.

[0089] Since the waveforms of the no-load back EMF generated by the first and second windings are preset waveforms, and the peak of the electromagnetic torque of the first winding matches the trough of the electromagnetic torque of the second winding, when the electromagnetic torque of the first winding approaches the peak, the electromagnetic torque of the second winding approaches the trough, and the amplitude of the electromagnetic torque of the first winding matches the amplitude of the electromagnetic torque of the second winding, the fluctuations of the electromagnetic torque of the first and second windings can cancel each other out, reducing the pulsation of the two-phase permanent magnet motor. When operating directly in grid connection, it eliminates the losses caused by the controller and reduces the noise caused by pulsation.

[0090] Example 2

[0091] An exemplary embodiment of this disclosure provides a household appliance, which includes a two-phase permanent magnet motor as described in Embodiment 1. The household appliance may include a refrigerator, an air conditioner, a washing machine, etc.

[0092] This disclosure reduces the energy consumption and noise generated during operation of household appliances by incorporating the two-phase permanent magnet motor of Embodiment 1 or 2 into them.

[0093] While specific embodiments of this disclosure have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this disclosure is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this disclosure, but all such changes and modifications fall within the scope of protection of this disclosure.

Claims

1. A two-phase permanent magnet motor, characterized in that, The two-phase permanent magnet motor is used to operate in parallel with the grid when the single-phase power supply voltage is at a preset phase. The two-phase permanent magnet motor includes a stator, a rectifier rotor, and a phase compensation capacitor. The stator has a first winding and a second winding orthogonally arranged on the stator teeth. The phase of the no-load back EMF of the first winding leads the phase of the no-load back EMF of the second winding. The supply voltage is adapted to the second winding. The phase compensation capacitor is connected in series with the first winding. The phase compensation capacitor is used to adapt the supply voltage to the first winding and make the ratio of the current amplitude of the first winding to the current amplitude of the second winding a preset ratio. The preset ratio is used to match the amplitude of the electromagnetic torque of the first winding with the amplitude of the electromagnetic torque of the second winding. The rectifier rotor is used to make the waveform of the no-load back EMF of the first winding and the second winding a preset waveform, and the preset waveform is used to match the peak of the electromagnetic torque of the first winding with the trough of the electromagnetic torque of the second winding.

2. The two-phase permanent magnet motor as described in claim 1, characterized in that, The preset ratio is the ratio of the effective values ​​of the no-load back EMF of the second winding and the first winding.

3. The two-phase permanent magnet motor as described in claim 1, characterized in that, The preset waveform is a sine wave.

4. The two-phase permanent magnet motor as described in claim 3, characterized in that, The formula for calculating the preset phase is: ； in, The preset phase is U, and the effective value of the supply voltage is U. , These are the first winding and the second winding, respectively. , These are the effective values ​​of the no-load back EMF of the first winding and the second winding, respectively. The initial phase of the no-load back EMF of the second winding is given, and the impedance value of the second winding is given. , The phase angle of the second winding. The phase resistance of the first winding; The formula for calculating the capacitance value of the phase compensation capacitor is as follows: ； in, The capacitance value of the phase compensation capacitor is given.

5. The two-phase permanent magnet motor as described in claim 3, characterized in that, The wave rotor includes an even number of magnetic poles, and each magnetic pole includes at least two components made of different materials; The at least two components made of different materials are fixedly connected according to a preset combination method.

6. The two-phase permanent magnet motor as described in claim 3, characterized in that, The wave rotor includes an even number of magnetic poles; The outer surface of each magnetic pole is a first preset arc shape.

7. The two-phase permanent magnet motor as described in claim 3, characterized in that, The wave-forming rotor includes several pairs of magnetic poles; Each pair of magnetic poles includes two magnetic poles made of the same material, and each magnetic pole includes the same number of magnets, the thickness of which is matched. The magnetization direction of several magnets in each pair of magnetic poles is a preset direction.

8. The two-phase permanent magnet motor as described in claim 3, characterized in that, The wave rotor has an even number of magnetic poles.

9. The even number of magnetic poles are interconnected to form a circular magnetic ring, and the magnetic field strength of the magnetic ring varies along the circumference according to a preset trend.

10. The two-phase permanent magnet motor as described in claim 3, characterized in that, The wave-forming rotor includes several pairs of magnetic poles; Each pair of magnetic poles includes two magnetic poles made of different materials, and each magnetic pole is a second predetermined arc shape.

11. A household appliance, characterized in that, The household appliance includes a two-phase permanent magnet motor as described in any one of claims 1-9.

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