Inverter device and its applications

Abstract

In the present invention, an inverter device and its application are disclosed. The inverter device includes an n-phase bridge inverter circuit (where n=2k+1, k is an integer equal to or greater than 2) and n sets of iron core winding coil combinations. The n-phase bridge inverter circuit is composed of n sets of two unidirectional conductive electronic switch devices connected in series. Due to the existence of a determined electromagnetic induction relationship between the iron core winding coils, an n-phase AC voltage source is generated from a predetermined DC power source at n connection points of the n sets of iron core winding coil combinations and n series connection points of the n sets of two unidirectional conductive electronic switch devices connected in series. The n-phase AC voltage source is n sinusoidal voltage sources with equal amplitudes and phases spaced 360° / n in sequence. The present invention further employs a multi-phase bridge inverter method to generate a rotating magnetic field, completely abandoning the operating principle of a DC motor and realizing DC power drive.

Description

[Technical field]

[0001] The present invention relates to the fields of power supply technology, power technology, motor and power drive technology, and electrical technology in general, in particular to multi-phase bridge inverters, DC transformation and DC power drives, and applications thereof. [Background technology]

[0002] AC and DC have their own characteristics. In electrical engineering, power sources need to be converted between DC and AC, but the problems in this conversion have not yet been completely solved. Rectifier circuits can convert alternating positive and negative voltages and currents into unidirectional voltages and currents, but they cannot be converted into flat DC. Capacitive filtering can smooth out voltages, but this causes more problems with higher harmonics on the AC side, and power factor calibration to remove higher harmonics in the current. In many cases, this is impossible to achieve in practice. Converting DC to AC is more complicated. Electronic switches in inverter circuits can convert DC into alternating positive and negative voltages and currents, but the resulting voltages and currents are not sinusoidal, but have a large amount of higher harmonics, which causes more problems.

[0003] How to obtain flat DC voltage or current with an extremely low ripple rate directly from sinusoidal AC voltage or current, and how to obtain AC voltage or current with extremely low higher harmonics and close to a sine wave directly from DC voltage or current are major obstacles to conversion between DC and AC, and are problems that must be solved in the field of electrical technology. Summary of the Invention

[0004] In order to solve the above problems, the technical solution of the present invention starts from the concept of multi-phase AC power supply, and provides an inverter device and its application.

[0005] According to a first aspect of the technical solution of the present invention, there is provided an inverter device including a combination of one n-phase bridge inverter circuit (where n=2k+1, k is an integer equal to or greater than 2) and n sets of iron core winding coils.

[0006] The n-phase bridge inverter circuit is configured by n sets of two unidirectional conductive electronic switch devices connected in series, and has a total of 2n unidirectional conductive electronic switch devices, as follows: S1+, S1-; S2+, S2-; S3+, S3-;… …S n-1 +,S n-1 -;S n +,S n -.

[0007] The two unidirectionally conductive electronic switch devices connected in series each have one end connected to the positive pole of a DC power source and the other end connected to the negative pole of the DC power source. At any one time, at most one of the two unidirectionally conductive electronic switch devices connected in series is conductive. This allows the potential at the series connection point to be the positive pole potential or the negative pole potential of the DC power source. It can also be in a high resistance state, i.e., when both of the two unidirectionally conductive electronic switch devices are cut off, the potential can be any value determined by other factors.

[0008] The n sets of iron core winding coil combinations may adopt a star connection method, that is, one end of each of the n sets of iron core winding coil combinations is connected to one point, and the other end is connected to n connection points of two unidirectional conductive electronic switch devices connected in series in the n-phase bridge inverter circuit. Other connection methods may also be adopted. For example, when a polygonal connection method is adopted, the start and end of each of the n sets of iron core winding coil combinations are connected in a predetermined order to form a closed loop. The connection points of the winding coil combinations using the polygonal connection method are connected to the series connection points of two unidirectional conductive electronic switch devices connected in series in the n-phase bridge inverter circuit.

[0009] The 2n unidirectional conductive electronic switch devices perform switching operations according to the determined on / off order. When the switching operation time is not taken into consideration, each operation turns on one switch and simultaneously turns off one switch, ensuring that a pair of switches are always on. When the switching operation time is taken into consideration, the 2n unidirectional conductive electronic switch devices have two to three unidirectional conductive electronic switch devices turned on at any given moment, that is, at the moment when the unidirectional conductive electronic switch devices switch, the unidirectional conductive electronic switch devices that are on and off are turned on simultaneously. The order in which the unidirectional conductive electronic switch devices are turned on is as follows: (S1+,S k+1 -), (S1+,S2+,S k+1 -), (S2+,S k+1 -), (S2+,S k+1 -,S k+2 -), (S2+,S k+2 -), (S2+, S3+, S k+2 -), (S3+,S k+2 -), (S3+,S k+2 -,S k+3 -), (S3+,S k+3 -), … … (S 2k +,S k-1 -,S k -), (S 2k +,S k -), (S 2k +,S 2k+1 +,S k -), (S 2k+1 +,S k -), (S 2k+1 +,S k -,S k+1 -), (S 2k+1 +,S k+1 -), (S 2k+1 +,S1+,S k+1 -), A continuous cycle → (S1+,Sk + 1-)…… Due to the existence of a determined electromagnetic induction relationship between the iron core winding coils, an n-phase AC voltage source is generated from a predetermined DC power source at n connection points of the n combinations of the iron core winding coils and n series connection points of the n sets of two unidirectional conductive electronic switch devices connected in series of the n-phase bridge inverter circuit, or an n-phase step wave AC voltage source approximating the n n-phase AC power sources is generated.

[0010] The n-phase AC voltage source is a set of n sinusoidal voltage sources having equal amplitudes and sequential phases spaced at intervals of 360° / n.The n-phase step wave AC voltage source is a set of n step wave AC voltage sources having equal amplitudes and sequential fundamental wave phases spaced at intervals of 360° / n.

[0011] Here, the concept of the multi-phase AC power supply is the core and starting point of the technology of the present invention. The n-phase AC voltage source is a number of n sinusoidal voltage sources with equal amplitudes and phases spaced apart by 360° / n in sequence.

[0012] Regarding rectification, The DC voltage output by the three-phase bridge rectifier is the potential difference between the upper and lower envelopes of the three-phase AC voltage, and it is clear that the value of the upper and lower envelopes should be near the extreme values. Since the rate of change of the extreme values ​​of any continuously differentiable function is 0, as the number of phases increases, the upper and lower envelopes become flatter rapidly, and the ripple rate of the DC voltage output by the multi-phase bridge rectifier also decreases rapidly. Calculations show that when the number of phases of the multi-phase AC power supply is sufficiently large and odd, the ripple rate of the DC voltage output by the multi-phase bridge rectifier is almost inversely proportional to the square of the number of phases and decreases rapidly. For example, a 9-phase bridge rectifier circuit has Sin80°=Sin100°=0.984819, so the DC pulse voltage output at this time changes between the extreme values ​​and the extreme value of 0.984819, and its ripple rate is less than 1%. With such a low ripple rate, filtering is not required.

[0013] The same is true for a multi-phase bridge inverter. By replacing the diodes in the multi-phase bridge rectifier circuit with switch devices, it is possible to configure a multi-phase bridge inverter circuit and generate a multi-phase AC power supply from a DC power supply by ensuring that only the voltage of the phase with the highest voltage is slightly higher than the maximum positive voltage and that only the voltage of the phase with the lowest voltage is slightly lower than the minimum negative voltage.

[0014] Here, during rectification, the DC power supply is only electrically related to the flat upper and lower envelope voltages of the multi-phase AC power supply through the multi-phase bridge rectifier circuit, and only a very low ripple rate (for example, less than 1%) needs to be processed from AC to DC, and the three-phase AC current on the AC side is also a step wave that is very close to a sine wave. Conversely, the same is true for the DC to AC inverter, where the DC side and the AC side are directly connected by the multi-phase inverter circuit, and the DC power supply is also only electrically related to the flat upper and lower envelope voltages of the multi-phase AC power supply, and only a very small deviation needs to be processed. If the DC side is connected to a small inductance capacitor, the problem can be perfectly solved.

[0015] This polyphase AC power source can be obtained by combining the three phase windings of a three-phase AC transformer. SinαSinωt+Sin(α+120°)Sin(ωt+120°) +Sin(α+240°)Sin(ωt+240°) =(1 / 2)[cos(ωt-α)-cos(ωt+α) +cos(ωt-α)-cos(ωt+α+240°) +cos(ωt-α)-cos(ωt+α+480°)] =(3 / 2)cos(ωt-α) By [cos(ωt+α)+cos(ωt+α+240°)+cos(ωt+α+480°)]=0 Therefore, cos(ωt-α)=(2 / 3)·[SinαSinωt+Sin(α+120°)Sin(ωt+120°)+Sin(α+240°)Sin(ωt+240°)]. moreover, U m cos(ωt-α)=(2 / 3)·U m [SinαSinωt+Sin(α+120°)Sin(ωt+120°)+Sin(α+240°)Sin(ωt+240°)] As shown in the figure, by making the three phases of a three-phase transformer belong to each of the three phases and adding up the voltages in the windings with a given ratio of turns, a sine quantity of any phase α can be obtained.

[0016] α n =n (360° / N) (where N is an integer greater than 5, n=0,1,2,……N-1) And, N sine quantities u n (ωt-α n ) is obtained. u n =U m cos(ωt-α n )=U m cos[ωt-n (360° / N)] (where n=0,1,2,…N-1).

[0017] This is a so-called N-phase AC power source, which is a source of N evenly distributed sinusoidal voltages with equal amplitudes and phases spaced apart by 360° / N in sequence.

[0018] Here, U m Sinωt, U m Sin(ωt+120°), U m Considering Sin(ωt+240°) as a three-phase voltage, Sinα, Sin(α+120°), and Sin(α+240°) are three coefficients, which correspond to the ratio of the number of turns of different windings in a three-phase transformer. By connecting three such windings in series as one winding combination and superimposing the voltages, the required N-phase AC power can be obtained from the combination of N windings. These are N sinusoidal voltage sources with equal amplitudes and phases spaced 360° / N apart in sequence and evenly distributed.

[0019] From the ripple rate of the output DC voltage of three-phase rectification, multi-phase bridge rectification is related, and multi-phase AC power supply is related. From a single trigonometric function relational equation, actual physical meaning is given to each function and coefficient constituting the relational equation, thereby obtaining a method for generating an N-phase AC power supply required for multi-phase bridge rectification by utilizing a combination of windings of a three-phase AC transformer, and further verifying the corresponding relationship between the voltage and current on the primary and secondary sides of the transformer, confirming the multi-phase bridge rectification, and making it possible to directly obtain a DC voltage with an extremely low ripple rate without performing capacitor filtering, and the current on the AC side of the transformer is a step wave that is very close to a sine wave, and there is a small amount of high-order harmonics.

[0020] The multi-phase bridge inverter is completely similar. By replacing the diodes of the multi-phase bridge rectifier circuit with switch devices, it is possible to ensure that only the voltage of the highest phase in each phase of the multi-phase AC power supply is slightly higher than the maximum positive voltage, and only the voltage of the lowest phase in each phase of the multi-phase AC power supply is slightly lower than the minimum negative voltage, thereby forming a multi-phase bridge inverter circuit and generating a multi-phase AC power supply from a DC power supply. Here, the process in which the multi-phase bridge inverter uses a combination of three-phase AC transformer windings to generate a multi-phase AC power supply is actually a process of generating a three-phase AC magnetic field in the three iron cores of the three-phase transformer. This AC magnetic field is superimposed with the voltages induced in each winding of the combination of transformer windings to generate a multi-phase AC power supply.

[0021] Furthermore, here, n=2k+1. That is, n here is an odd number, and the reason is as follows. First, when n is an even number (n=2k and k is an odd number greater than 2), the ripple rate of the DC voltage obtained by the rectifier element is the same as that of a multi-phase rectifier element with n=2k (k is an odd number greater than 2). However, the number of winding combinations and the number of rectifier diodes used to generate a multi-phase AC power supply must both be doubled, which is obviously undesirable compared to the case where n is an odd number. When k is an even number greater than 2, it is also undesirable compared to the case where n is an odd number. The case of the multi-phase inverter is completely similar, and in order to achieve the same effect, the number of winding combinations and the number of unidirectional conductive electronic switch devices must both be doubled. Therefore, in the multi-phase bridge rectification, the electromagnetic induction relationship between the conductive winding coils in the conductive iron core is utilized to generate an n-phase AC power supply from a given AC power supply, and after passing through an n-phase bridge rectifier circuit, the DC voltage and current are directly output as a DC voltage source with a low ripple rate. Here, n is an odd number equal to or greater than 5. In contrast, in the present application, the inverter device includes a combination of one n-phase bridge inverter circuit (where n=2k+1, k is an integer equal to or greater than 2) and n sets of iron core winding coils.

[0022] To sum up, when the number of phases is large enough, the upper and lower envelopes of the multi-phase AC power supply become flat and the fluctuation is very small, so that the multi-phase AC power supply can be easily converted between DC and AC by passing it through a multi-phase rectifier or a multi-phase inverter. For example, if a small inductance capacitor is connected in series to the DC power supply, the conversion between DC and AC will not be a problem.

[0023] Here, the diodes used in the multi-phase bridge rectifier circuit are replaced by unidirectional conductive electronic switch devices in the multi-phase bridge inverter. In this way, one of the two converts DC to AC, and the other converts AC to DC. The conduction directions of the two are opposite to each other. If a diode opposite to the conduction direction is connected in parallel to each of the unidirectional conductive electronic switch devices, the following relationship is established between the DC power supply and the AC power supply: power is supplied from the AC power supply to the DC power supply, or power is supplied from the DC power supply to the AC power supply.

[0024] Additionally, each of the unidirectionally conducting electronic switch devices may have a diode connected in parallel opposite to its conduction direction.

[0025] Furthermore, the n-phase bridge inverter circuit is configured by n sets of two unidirectional conductive electronic switch devices connected in series. The 2n unidirectional conductive electronic switch devices may all be thyristors. Each of the 2n unidirectional conductive electronic switch devices may be: VT1+,VT1-;VT2+,VT2-;VT3+,VT3-;… …VT n-1 +,VT n-1 -;VT n +,VT n -,.

[0026] The combination of the primary winding coil of the three-phase AC transformer has n input / output terminals and is connected to the series connection points of n sets of two thyristors connected in series of the n-phase bridge inverter circuit, and n capacitors C1, C2, C3, ... C n-2 ,C n-1 ,C n are connected in parallel.

[0027] At the positive input of the DC voltage, when the thyristor VT1+ conducts, the capacitor C1 is charged. Since the voltage of the transformer winding combination 1 is always the highest when VT1+ conducts, when VT2+ starts to conduct, the voltage at the capacitor C1 causes VT1+ to receive a reverse voltage. The value of the capacitor C1 should ensure that VT1+ is completely cut off at the end of the switching process, so that the conduction of VT1+ becomes the conduction of VT2+, and at this time, for the combination of the transformer windings, combination 1 is connected to the power supply positive pole, and combination 2 is connected to the power supply positive pole. At the negative voltage end, the switching process of the thyristor switches is similar. During the entire process, only 2-3 thyristors are always conducting, i.e., at the moment of switching, 3 thyristors are conducting, and at the rest of the time, 2 thyristors are conducting. The thyristors conduct in a determined order, repeating a cyclic cycle, and an n-phase AC voltage source or an n-phase step wave AC voltage source can be obtained at the n input / output terminals of the combination of the primary winding coil of the three-phase AC transformer and the n connection points of the n-phase bridge inverter circuit.

[0028] Furthermore, the combination of the n sets of iron core winding coils may be a combination of primary winding coils of a three-phase AC transformer, where n=3k, k being an odd number equal to or greater than 3.

[0029] As described above, the inverter device includes one n-phase bridge inverter circuit (where n=3k, k is an integer equal to or greater than 3) and a combination of n sets of iron core winding coils, and the combination of n sets of iron core winding coils may be a combination of primary winding coils of a three-phase AC transformer. The process in which the multi-phase bridge inverter uses the combination of windings of a three-phase AC transformer to generate a multi-phase AC power supply is actually a process in which a three-phase AC magnetic field is generated in three iron cores of the three-phase transformer, so the secondary three-phase windings of the transformer may be externally connected to a three-phase AC load.

[0030] Furthermore, the three secondary windings of the three-phase AC transformer may be externally connected to a three-phase AC load.

[0031] Furthermore, the three secondary windings of the three-phase AC transformer may be externally connected to a three-phase AC power grid.

[0032] The n-phase bridge inverter circuit uses a phase locked loop to ensure that the phases of the three-phase AC voltage output by the three-phase AC transformer and the three-phase AC voltage of the power grid are completely consistent.

[0033] Furthermore, the inverter device may constitute a DC transformer device together with an m-phase bridge rectifier circuit. Here, the secondary winding of the three-phase AC transformer is a combination of m iron core winding coils, where m=3i, and i is an odd number equal to or greater than 3. An m-phase AC voltage source or m-phase step wave AC voltage sources approximating m of the m-phase AC voltage sources are generated from the combination of the m iron core winding coils. The m-phase AC voltage source is m sinusoidal voltage sources having equal amplitudes and initial phases spaced apart by 360° / m in sequence. The m-phase step wave AC voltage source is m step wave AC voltage sources having equal fundamental wave amplitudes and initial phases spaced apart by 360° / m in sequence.

[0034] The output terminal of the m-phase AC voltage source or an m-phase step wave AC voltage source approximating m of the m-phase AC voltage sources is connected to an m-phase bridge rectifier circuit. The n-phase bridge inverter circuit is composed of n sets of two rectifier diodes connected in series. In all of the two rectifier diodes connected in series, the cathode of one diode is connected to the anode of the other diode, and each connection point between the cathode and the anode is connected to the m-phase output terminal of the m-phase AC voltage source. The other cathode of all of the n sets of two rectifier diodes connected in series is connected to be the output positive electrode of the n-phase bridge inverter circuit. The other anode of all of the n sets of two rectifier diodes connected in series is connected to be the output negative electrode of the n-phase bridge inverter circuit.

[0035] The m-phase bridge rectifier circuit outputs DC voltage and current as a DC voltage source with a low ripple rate without performing capacitor filtering, thereby achieving DC transformation.

[0036] The n-phase AC power source and the m-phase AC power source both appear only in the primary and secondary windings of the transformer. The AC frequency is determined by the switching period of the inverter circuit, and does not have to be the commercial frequency of 50 Hz or 60 Hz, but can be any optimal frequency.

[0037] A DC transformer can be obtained by using the above-mentioned multi-phase bridge inverter circuit and adding a multi-phase bridge rectifier circuit. The DC transformer includes one n-phase bridge inverter circuit (where n=3k, k is an integer equal to or greater than 3) and a combination of n iron core winding coils, and the combination of n iron core winding coils is the combination of the primary winding coils of a three-phase AC transformer.

[0038] Furthermore, the number of combinations of m sets of iron core winding coils on the secondary side of the three-phase AC transformer may be the same as the number of combinations of iron core windings on the primary side, that is, m=n.

[0039] Furthermore, the secondary winding of the three-phase AC transformer may be a combination of n sets of secondary core winding coils corresponding to all winding coils of the primary winding coil combination, and the ratio of the number of turns between all corresponding winding coils of the primary and secondary sides may be the same.

[0040] Furthermore, a DC transmission and distribution network may be formed from the power generation equipment to the user end by transmission lines, and transformation, rectification, and inverter equipment, and may be capable of directly supplying DC to the user.

[0041] Furthermore, the secondary winding of the three-phase AC transformer is a three-phase AC winding, and is externally connected to a three-phase AC motor. The switching period of the unidirectional conductive electronic switch device is adjustable, and the speed of the motor can be adjusted by adjusting the switching period of the unidirectional conductive electronic switch device.

[0042] In the above-mentioned inverter device, if the secondary winding of the three-phase AC transformer is externally connected to a three-phase AC motor, and the switching period of the unidirectional conductive electronic switch device of the multi-phase bridge inverter circuit is adjustable, the speed of the motor is adjusted by adjusting the switching period of the unidirectional conductive electronic switch device of the multi-phase bridge inverter circuit. Furthermore, the combination of the windings may be the combination of the stator windings of an AC motor.

[0043] If the n sets of iron core winding coil combinations are winding coil combinations whose beginning and end are connected and uniformly fitted into the stator slots, and the switching period of the unidirectional conductive electronic switch devices of the multi-phase bridge inverter circuit is adjustable, the iron core winding coils may generate a rotating magnetic field, and the speed of the motor may be adjusted by adjusting the switching period of the unidirectional conductive electronic switch devices of the multi-phase bridge inverter circuit.

[0044] When a three-phase AC voltage source (with initial phases of 0°, 120°, and 240°) is applied to three coils in the motor stator with angles of 120° (in the XY plane, the angles with the X-axis are α, α+120°, and α+240°, respectively), a rotating magnetic field with constant amplitude and rotating at a uniform speed can be obtained.

[0045] When a single-phase AC voltage is applied to the corresponding coils, the spatial magnetic fields generated by the three coils are respectively as follows: B m [i cosαcosωt+j(Sinαcosωt)], B m [i[cos(α+120°)cos(ωt+120°)]+j[Sin(α+120°)cos(ωt+120°)]], B m [i[cos(α+240°)cos(ωt+240°)]+j[Sin(α+240°)cos(ωt+240°)]]. When a three-phase AC power supply is applied to three coils simultaneously, the magnetic fields are superimposed, where: j Bm [Sinαcosωt+Sin(α+120°)cos(ωt+120°) +Sin(α+240°)cos(ωt+240°)] =(j / 2)B m [Sin(ωt-α)+Sin(ωt+α)+Sin(ωt-α)+Sin(ωt+α+240°)+Sin(ωt-α)+Sin(ωt+α+480°)] =j(3 / 2)B m Sin(ωt-α) Since Sin(ωt+α)+Sin(ωt+α+240°)+Sin(ωt+α+480°)=0, iB m [cosαcosωt+cos(α+120°)cos(ωt+120°) +cos(α+240°)cos(ωt+240°)] =(i / 2)B m [cos(ωt-α)+cos(ωt+α)+cos(ωt-α)+cos(ωt+α+240°)+cos(ωt-α)+cos(ωt+α+480°)] =i(3 / 2)B m cos(ωt-α) Since cos(ωt+α)+cos(ωt+α+240°)+cos(ωt+α+480°)=0, The result of the superposition is a rotating magnetic field. (3 / 2)B m [i cos(ωt-α)+j Sin(ωt-α)] Here, when a three-phase AC voltage source (with initial phases of 0°, 120°, and 240°, respectively) is applied to three coils of a motor stator with angles of 120° (in the XY plane, the angles with the X-axis are α, α+120°, and α+240°, respectively), a rotating magnetic field with constant amplitude and rotating at a uniform speed can be obtained. This is the basic operating principle of three-phase AC motors (including asynchronous motors and synchronous motors).

[0046] To generalize, when an n-phase AC voltage source (with phases (0, β, 2β, ..., (n-2)β, (n-1)β)) is applied to n coils in the motor stator with spatial angles of β = 360° / n (in the XY plane, the angles with the X-axis are (α, α+β, α+2β, ..., α+(n-2)β, α+(n-1)β)), a rotating magnetic field with constant amplitude and that rotates at a uniform speed can be obtained.

[0047] When single-phase AC voltages are applied to the corresponding coils, the spatial magnetic fields generated by the three coils are respectively as follows: B m [i cosαcosωt+j(Sinαcosωt)], B m [i[cos(α+β)cos(ωt+β)]+j[Sin(α+β)cos(ωt+β)]]; B m [i[cos(α+2β)cos(ωt+2β)]+j[Sin(α+2β)cos(ωt+2β)]]; --- --- B m [i[cos(α+(n-2)β)cos(ωt+(n-2)β)] +j[Sin(α+(n-2)β)cos(ωt+(n-)β)]]; B m [i[cos(α+(n-1)β)cos(ωt+(n-1)β)] +j[Sin(α+(n-1)β)cos(ωt+(n-1)β)]]; When an n-phase AC power supply is applied simultaneously to n coils, the magnetic fields are superimposed, where: iB m [cosαcosωt+cos(α+β)cos(ωt+β) +cos(α+2β)cos(ωt+2β)+···+cos[α+(n-2)β]cos[ωt+(n-2)β] +cos[α+(n-1)β]cos[ωt+(n-1)β]]; =i(n / 2)B m cos(ωt-α) By Cos(ωt+α)+Cos(ωt+α+2β)+Cos(ωt+α+4β)+···+Cos[ωt+α+(n-1)β]+Cos s[ωt+α+(n+1)β]+Cos[ωt+α+(n+3)β]+···+Cos[ωt+α+2(n-2)β]+Cos[ωt+α+2(n-1)β], =Cos(ωt+α)+Cos(ωt+α+2β)+Cos(ωt+α+4β)+···+Cos[ωt+α+(n-1)β]+Cos(ωt+α+β)+Cos(ωt+α+3β)+···+Cos[ωt+α+(n-4)β]+Cos[ωt+α+(n-2)β]=0 j B m [(Sinαcosωt)+Sin(α+β)cos(ωt+β)+Sin(α+2β)cos(ωt+2β)+·····+Sin[α+(n-2)β]cos[ωt+(n-2)β]+Sin[α+(n-1)β]cos[ωt+(n-1)β]]; =j(n / 2)B m Sin(ωt-α) Sin(ωt+α)+Sin(ωt+α+2β)+Sin(ωt+α+4β)+···+Sin[ωt+α+(n-1)β]+Sin s[ωt+α+(n+1)β]+Sin[ωt+α+(n+3)β]+···+Sin[ωt+α+2(n-2)β]+Sin[ωt+α+2(n-1)β]], =Sin(ωt+α)+Sin(ωt+α+2β)+Sin(ωt+α+4β)+···+Sin[ωt+α+(n-1)β]+Sin(ωt+α+β)+Sin(ωt+α+3β)+···+Sin[ωt+α+(n-4)β]+Sin[ωt+α+(n-2)β]=0 superimposed result, get the rotation magnetic field. (n / 2)B m [i cos(ωt-α)+j Sin(ωt-α)] This rotating magnetic field is divided into n series-connected winding coils that are uniformly fitted into the stator core of the motor, and an n-phase AC voltage source is obtained at the n series connection points. When n is sufficiently large, the n-phase AC voltage source can be rectified through n-phase bridge rectification to obtain a DC voltage source with little pulsation. For example, when n is an odd number equal to or greater than 9, the pulsation rate of the DC power supply is less than 1%.

[0048] This is because the multi-phase AC power generated by the rotating magnetic field is converted to DC through a multi-phase bridge rectifier. Conversely, if the diodes in the multi-phase bridge rectifier are replaced with unidirectional conductive electronic switch devices in a multi-phase bridge inverter, a multi-phase AC power can be obtained from the DC power source, and a rotating magnetic field is generated in the stator core of the motor.

[0049] If the n sets of winding coils are connected at their beginning and end and are uniformly fitted into the stator slots, without taking into account the switching operation time of the switching devices in a multi-phase bridge inverter, the magnetic field Bm generated by each of these winding coils is a rectangular wave that alternates with time and its direction is perpendicular to the coil plane. As described above, a rotating magnetic field is obtained as a result of superposing the fundamental waves of these rectangular waves. (n / 2)B m [i cos(ωt-α)+j Sin(ωt-α)] Since the number of phases in a polyphase inverter is odd, i.e., the number of phases n = 2k + 1 (k is a positive integer), it is clear that the superposition of these higher harmonics results in a series of corresponding rotating magnetic fields (specific proof is omitted). (n / 2)B m調波 [i cos(ω 調波 t-alpha 調波 )+j Sin(ω 調波 t-alpha 調波 )] To sum up, when the number of phases is large enough, the upper and lower envelopes of the multi-phase AC power supply become flat and the fluctuation is very small, so that the multi-phase AC power supply can be easily converted between DC and AC by passing it through a multi-phase rectifier or a multi-phase inverter. For example, if a small inductance capacitor is connected in series to the DC power supply, the conversion between DC and AC will not be a problem.

[0050] In addition, the polyphase AC power supply is associated with a rotating magnetic field, and as described above, the combination of the n iron core winding coils is a combination of n sets of winding coils whose starting ends and endings are connected and evenly fitted into the stator slots. Therefore, when polyphase AC power supply and a rotating magnetic field are generated from the DC power supply by the inverter, the rotor is rotated, and DC power drive is achieved.

[0051] As mentioned above, the multi-phase bridge inverter and the multi-phase bridge rectifier are completely similar. The diodes used in the multi-phase bridge rectifier circuit are replaced by unidirectional conductive electronic switch devices in the multi-phase bridge inverter. Thus, one of them converts DC to AC, and the other converts AC to DC. And the conduction directions of the two are opposite to each other. If a diode opposite to the conduction direction is connected in parallel to each of the unidirectional conductive electronic switch devices, the following relationship is established between the DC power source and the AC power source: the AC power source supplies power to the DC power source, or the DC power source supplies power to the AC power source.

[0052] Therefore, by connecting a diode in parallel with each unidirectional conductive electronic switch device of the n-phase bridge inverter circuit in the opposite direction to the conduction direction of the switch device, a device can be obtained that can realize unidirectional bridge rectification and a multi-phase bridge inverter at the same time. In particular, when used as a DC drive motor, the motor can operate as a motor or a generator depending on the operating conditions of the motor to realize power driving or braking.

[0053] According to a second aspect of the technical solution of the present invention, there is provided an application of any of the above-mentioned inverter devices, the inverter device being applied to a product end and being a part of the product or the product power supply.

[0054] The beneficial effects of the present invention are as follows: Rectification and inverters have been important issues in electrical engineering for a long time. In electrical engineering, power sources need to be repeatedly converted between DC and AC, but this issue has not been adequately solved theoretically. A rectifier circuit can convert alternating positive and negative voltages and currents into unidirectional voltages and currents, but it cannot convert them into flat DC. Capacitive filtering can make the voltage flat, but power factor calibration to remove the higher harmonics of the current generated by capacitor filtering brings more problems. In many cases, it is impossible to actually realize it. For inverters, the conversion from DC to AC is more complicated and brings more problems.

[0055] The concept of multi-phase AC power supply is introduced, and the DC and AC are transmitted by the multi-phase bridge rectifier and the multi-phase bridge inverter, completely solving various difficulties in rectification and inverter. This makes it very easy to realize the conversion between AC and DC. Through the multi-phase bridge rectifier circuit, the DC power supply is only electrically related to the flat upper and lower envelope voltage of the multi-phase AC power supply, and from AC to DC, it is necessary to process a very low ripple rate (for example, lower than 1%), and the three-phase AC current on the AC side is also a step wave that is very close to a sine wave. Conversely, the same is true for the DC to AC inverter, where the DC side and the AC side are directly connected by the multi-phase inverter circuit, and the DC power supply is also only electrically related to the flat upper and lower envelope voltage of the multi-phase AC power supply, and it is necessary to process only a very small deviation. If the DC side is connected to a small inductance capacitor, the problem can be perfectly solved.

[0056] In addition to being able to supply power to an externally connected three-phase AC load or an externally connected three-phase AC power grid, the present invention can also be used together with a multi-phase bridge rectifier circuit to form a DC transformer device. The multi-phase bridge rectifier circuit outputs DC voltage and current as a DC voltage source with a low ripple rate without capacitor filtering, thereby achieving DC transformation. Here, the AC power source appears only in the primary and secondary windings of the transformer and exists only inside the transformer. All other power transmission and power supply equipment are DC, fundamentally eliminating the impact of AC signals on the environment.

[0057] The present invention uses a multi-phase bridge inverter method to generate a multi-phase AC power supply, form a rotating magnetic field, and realize DC power drive. This is a brand new DC drive motor, which not only replaces the commutator with an electric switch device, but also completely abandons the working principle of the DC motor and the commutator. Not only greatly simplifies the structure of the DC drive motor, but also realizes the speed regulation of the motor at the same time, and in the process of speed regulation, the automatic conversion of the working state of the two types of motors, the electric motor or the generator, realizes driving or braking. In this way, the kinetic energy consumed in the braking process is not used to generate harmful heat, but is converted into useful electrical energy. [Brief description of the drawings]

[0058] In order to make the technical solution of the present invention clearer, the following briefly introduces the drawings used. The following drawings are part of the embodiments of the present invention, and it is obvious for those skilled in the art that they can obtain other drawings based on these drawings without any creative effort. [Figure 1] This is a diagram showing a combination of n types of windings connected using a star connection method. [Diagram 2] FIG. 1 is a diagram showing waveforms of voltages of a nine-phase AC power supply applied to a combination of nine primary windings of a transformer. [Diagram 3] FIG. 1 is a diagram showing the relationship between magnetomotive forces generated by primary and secondary currents in three iron cores of a three-phase transformer. [Figure 4]FIG. 1 is a block diagram of a DC power drive that includes a combination of winding coils uniformly fitted into stator slots and unidirectional conductive electronic switch devices in a multi-phase bridge inverter circuit. [Diagram 5] FIG. 1 is a block diagram showing the principle of a nine-phase bridge inverter device that uses thyristors as electronic switches. [Figure 6] FIG. 2 is a block diagram of a DC transformer device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0059] Specific embodiments will be described below through several implementations.

[0060] EMBODIMENT 1 This is a specific embodiment of a nine-phase bridge inverter circuit in which the secondary winding of a three-phase AC transformer is connected to a three-phase AC power grid.

[0061] The block diagram of an n-phase bridge inverter circuit is shown in Figure 1, where n=9.

[0062] Here, there are five different numbers of turns in each primary winding of the three-phase AC transformer, and the ratio of the numbers of turns between them is N1:N2:N3:N4:N5 = Sin90°:Sin50°:Sin10°:Sin30°:Sin70°.

[0063] By adding positive and negative polarities to these five types of winding numbers, and connecting them in series in groups of three, we can construct the nine types of transformer primary winding combinations required. They are as follows: Transformer primary winding combination 1: Phase A N1, Phase B N4, Phase C N4, Transformer primary winding combination 2: Phase A - N2 turns, Phase B - N3 turns, Phase C - N5 turns, Transformer primary winding combination 3: Phase A - N3 turns, Phase B - N2 turns, Phase C - N5 turns, Transformer primary winding combination 4: Phase A-N4, Phase B-N1, Phase C-N4, Transformer primary winding combination 5: Phase A - N5 turns, Phase B - N2 turns, Phase C - N3 turns, Transformer primary winding combination 6: Phase A - N5 turns, Phase B - N3 turns, Phase C - N2 turns, Transformer primary winding combination 7: Phase A-N4, Phase B-N4, Phase C-N1, Transformer primary winding combination 8: A phase N3 turns, B phase N5 turns, C phase N2 turns, Transformer primary winding combination 9: Phase A - N2 turns, Phase B - N5 turns, Phase C - N3 turns.

[0064] FIG. 1 shows a combination of n types of windings connected in a star configuration.

[0065] FIG. 2 is a diagram showing the waveforms of voltages of a nine-phase AC power supply applied to a combination of nine primary windings of a transformer.

[0066] Figure 3 shows the relationship between the magnetomotive forces generated by the primary and secondary currents in the three iron cores of a three-phase transformer. (The load power factor on the secondary side of the transformer is 1.0 after power factor compensation.)

[0067] EMBODIMENT 2 Another specific embodiment will be described below by taking a DC power drive device constituted by a combination of winding coils uniformly fitted into stator slots and a multi-phase bridge inverter circuit as an example.

[0068] FIG. 4 is a block diagram of a DC power drive that is constructed by connecting a combination of winding coils uniformly fitted into stator slots and unidirectional conductive electronic switch devices in a multi-phase bridge inverter circuit.

[0069] EMBODIMENT 3 FIG. 5 is a block diagram showing the principle of a multi-phase bridge inverter device using thyristors as electronic switches.

[0070] At the positive input of the DC voltage, when the thyristor VT1+ conducts, the capacitor C1 is charged. Since the voltage of the combination 1 of the transformer windings when VT1+ conducts is always the highest, when VT2+ starts to conduct, the voltage at the capacitor C1 causes VT1+ to receive a reverse voltage. The value of the capacitor C1 should ensure that VT1+ is completely blocked, so that the conduction of VT1+ becomes the conduction of VT2+, and at this time, for the combination of the transformer windings, combination 1 is connected to the positive pole of the power supply, and combination 2 is connected to the positive pole of the power supply. At the negative voltage end, the switching process of the thyristors is similar. During the entire process, only 2-3 thyristors are always conducting. That is, at the moment of switching, three thyristors are conducting, and at the rest of the time, two thyristors are conducting. The order of the thyristors' conduction is as follows: (VT1+,VT5-)(VT1+,VT2+,VT5-)(VT2+,VT5-)(VT2+,VT5-,VT6-) (VT2+,VT6-)(VT2+,VT3+,VT6-)(VT3+,VT6-)(VT3+,VT6-,VT7-) (VT3+,VT7-)(VT3+,VT4+,VT7-)(VT4+,VT7-)(VT4+,VT7-,VT8-) (VT4+,VT8-)(VT4+,VT5+,VT8-)(VT5+,VT8-)(VT5+,VT8-,VT9-) (VT5+,VT9-)(VT5+,VT6+,VT9-)(VT6+,VT9-)(VT6+,VT9-,VT1-) (VT6+,VT1-)(VT6+,VT7+,VT1-)(VT7+,VT1-)(VT7+,VT1-,VT2-) (VT7+,VT2-)(VT7+,VT8+,VT2-)(VT8+,VT1-)(VT8+,VT2-,VT3-) (VT8+,VT3-)(VT8+,VT9+,VT3-)(VT9+,VT2-)(VT9+,VT3-,VT4-) (VT9+,VT4-)(VT9+,VT1+,VT4-)(VT1+,VT3-)(VT1+,VT4-,VT5-) Continuous cyclical cycle (VT1+,VT5-)(VT1+,VT2+,VT5-)(VT2+,VT4-)(VT2+,VT5-,VT6-) --- ---

[0071] The thyristors conduct in this order, repeating the cycle, and an 8-phase AC voltage source or a 9-phase step-wave AC voltage source can be obtained at the nine input / output terminals of the combination of the primary winding coil of the three-phase AC transformer and the nine connection points of the nine-phase bridge inverter circuit.

[0072] EMBODIMENT 4 This is a DC transformer device, and its principle block diagram is shown in Figure 6.

[0073] The secondary winding of a three-phase AC transformer is a combination of all the winding coils of the n sets of iron core winding coils on the primary side and the n sets of iron core winding coils on the secondary side, respectively corresponding to each other, and the ratio of the number of turns between the corresponding winding coils on the primary side and the secondary side is the same.

[0074] Here, the number of turns of all primary windings of the three-phase transformer is five, and the ratio of the number of turns is, N1 一次 :N2 一次 :N3 一次 :N4 一次 :N5 一次 =Sin90°:Sin50°:Sin10°:Sin30°:Sin70°.

[0075] By adding positive and negative polarities to these five types of winding numbers, and connecting them in series in groups of three, we can construct the nine types of transformer primary winding combinations required. They are as follows: Transformer primary winding combination 1: Phase A N1, Phase B N4, Phase C N4, Transformer primary winding combination 2: Phase A - N2 turns, Phase B - N3 turns, Phase C - N5 turns, Transformer primary winding combination 3: Phase A - N3 turns, Phase B - N2 turns, Phase C - N5 turns, Transformer primary winding combination 4: Phase A-N4, Phase B-N1, Phase C-N4, Transformer primary winding combination 5: Phase A - N5 turns, Phase B - N2 turns, Phase C - N3 turns, Transformer primary winding combination 6: Phase A - N5 turns, Phase B - N3 turns, Phase C - N2 turns, Transformer primary winding combination 7: Phase A-N4, Phase B-N4, Phase C-N1, Transformer primary winding combination 8: A phase N3 turns, B phase N5 turns, C phase N2 turns, Transformer primary winding combination 9: Phase A - N2 turns, Phase B - N5 turns, Phase C - N3 turns.

[0076] All the secondary windings of the three-phase transformer also have five different numbers of turns, and the ratio of the number of turns is also the same. N1 二次 :N2 二次 :N3 二次 :N4 二次 :N5 二次 =Sin90°:Sin50°:Sin1°:Sin30°:Sin70°.

[0077] However, the number of turns of the secondary winding is always larger (when stepping up) or k times smaller (when stepping down) than the number of turns of the corresponding primary winding.

[0078] These five different winding numbers are then combined with positive and negative polarities, and three are connected in series to form a set of nine different transformer secondary winding combinations, as follows: Transformer secondary winding combination 1: Phase A - kN 1 turn, Phase B - kN 4 turns, Phase C - kN 4 turns, Transformer secondary winding combination 2: Phase A kN 2 times, Phase B kN 3 times, Phase C kN 4 times, Transformer secondary winding combination 3: Phase A kN 3 times, Phase B kN 2 times, Phase C - kN 5 times, Transformer secondary winding combination 4: Phase A - kN 4 times, Phase B - kN 1 time, Phase C - kN 4 times, Transformer secondary winding combination 5: Phase A - kN 5 times, Phase B - kN 2 times, Phase C - kN 3 times, Transformer secondary winding combination 6: Phase A - kN 5 times, Phase B - kN 3 times, Phase C - kN 2 times, Transformer secondary winding combination 7: Phase A - kN 4 times, Phase B - kN 4 times, Phase C - kN 1 time, Transformer secondary winding combination 8: A phase kN 3 times, B phase - kN 5 times, C phase kN 2 times, Transformer secondary winding combination 9: A phase - kN 2 turns, B phase - kN 5 turns, C phase - kN 3 turns.

[0079] These five different windings are then connected in series to form a set of three, which are then combined to form the nine required combinations of secondary windings for the transformer. Finally, a DC voltage is output by multi-phase bridge rectification, achieving DC transformation.

[0080] Using the above-mentioned DC transformer device, a DC transmission and distribution network is constructed by repeatedly passing the power from the power generation facility to the user end through a transmission line, as well as transformation, rectification, and inverter facilities, and DC can be directly supplied to the user.

[0081] Although the embodiment of the present invention has been described above in conjunction with the drawings, the present invention is not limited to the above specific embodiment. The above specific embodiment is illustrative rather than restrictive. Based on the present invention, a person skilled in the art can create many forms without departing from the spirit of the present invention and the scope of the claims, all of which are included in the protection scope of the present invention.

Claims

1. An inverter device, the inverter device including a combination of one n-phase bridge inverter circuit and n sets of iron core winding coils, where n=2k+1, k being an integer of 2 or more; The n-phase bridge inverter circuit is configured by n sets of two unidirectional conductive electronic switch devices connected in series, and has a total of 2n unidirectional conductive electronic switch devices, which are as follows: S 1 +,S 1 -;S 2 +,S 2 -;S 3 +,S 3 -;… …S n-1 +,S n-1 -;S n +,S n -; The two unidirectionally conductive electronic switch devices connected in series each have one end connected to the positive pole of a DC power source and the other end connected to the negative pole of the DC power source, and at any one time, at most one of the two unidirectionally conductive electronic switch devices connected in series is conductive, so that the potential at the series connection point can be the positive or negative potential of the DC power source, and can also be in a high resistance state, i.e., when both of the two unidirectionally conductive electronic switch devices are cut off, the potential can be any value determined by other factors; The n sets of iron core winding coil combinations adopt a star connection method, that is, one end of each of the n sets of iron core winding coil combinations is connected to one point, and the other end is connected to n connection points of two unidirectional conductive electronic switch devices connected in series of the n-phase bridge inverter circuit; or adopt a polygonal connection method, that is, the start and end of each of the n sets of iron core winding coil combinations are connected in a predetermined order to form a closed loop, and the n connection points of the polygonal connection method are connected to the series connection points of the n sets of two unidirectional conductive electronic switch devices connected in series of the n-phase bridge inverter circuit; The 2n unidirectional conductive electronic switch devices perform switching operations according to a determined on-off sequence. When the switching operation time is not taken into consideration, each operation turns on one switch and simultaneously turns off one switch, ensuring that a pair of switches are always on. When the switching operation time is taken into consideration, the 2n unidirectional conductive electronic switch devices have two or three unidirectional conductive electronic switch devices turned on at any given moment, that is, at the moment when the unidirectional conductive electronic switch devices switch, the unidirectional conductive electronic switch devices that are on and off are turned on at the same time. At this time, the order in which the unidirectional conductive electronic switch devices are turned on is as follows: (S 1 +,S k+1 -)、(S 1 +,S 2 +,S k+1 -)、(S 2 +,S k+1 -)、(S 2 +,S k+1 -,S k+2 -)、(S 2 +,S k+2 -)、(S 2 +,S 3 +,S k+2 -)、(S 3 +,S k+2 -)、(S 3 +,S k+2 -,S k+3 -)、(S 3 +,S k+3 -)、 … … (S 2k +,S k-1 -,S kk -)、(S 2kk +,S k -)、(S 2k +,S 2k+1 +,S k -)、(S 2k+1 +,S k -)、(S 2k+1 +,S kkk -,S k+1 -)、(S 2k+1 +,S k+1 -)、(S 2k+1 +,S 1 +,S k+1 -)、 A continuous cycle → (S 1 +,S k+1 -)… … Since a determined electromagnetic induction relationship exists between the iron core winding coils, an n-phase AC voltage source is generated from a predetermined DC power source at n connection points of the n combinations of the iron core winding coils and n series connection points of the n sets of two unidirectional conductive electronic switch devices connected in series of the n-phase bridge inverter circuit, or an n-phase step wave AC voltage source approximating the n n-phase AC voltage sources is generated; the n-phase AC voltage source includes n sinusoidal voltage sources having equal amplitudes and whose fundamental wave phases are spaced apart by 360° / n in sequence, and the n-phase step-wave AC voltage source includes n step-wave AC voltage sources having equal amplitudes and whose fundamental wave phases are spaced apart by 360° / n in sequence.

2. 2. The inverter apparatus of claim 1, wherein each of said unidirectionally conductive electronic switch devices has a diode connected in parallel therewith in a direction opposite to the direction of conduction of said unidirectionally conductive electronic switch device.

3. each of said unidirectional conductive electronic switch devices is a thyristor; 3. The inverter device according to claim 1 or 2, wherein the combination of the n sets of iron core-winding coils has n input / output terminals and is connected to a series connection point of the n sets of two thyristors connected in series of the n-phase bridge inverter circuit, and n capacitors are connected in parallel between the n connection points to obtain an n-phase AC voltage source or an n-phase step wave AC voltage source at the n connection points.

4. 2. The inverter device according to claim 1, wherein the n sets of combinations of iron core winding coils are combinations of primary winding coils of a three-phase AC transformer, and n=3k, where k is an odd number equal to or greater than 3.

5. 5. The inverter device according to claim 4, wherein the three secondary windings of the three-phase AC transformer are externally connected to a three-phase AC load.

6. The three secondary windings of the three-phase AC transformer are externally connected to a three-phase AC power grid, and the n-phase bridge inverter circuit uses a phase locking circuit to ensure that the three-phase AC voltage output by the three-phase AC transformer and the three-phase AC voltage of the power grid are completely in phase with each other.

5. The inverter device according to claim 4.

7. The inverter device and the m-phase bridge rectifier circuit constitute a DC transformer device, wherein the secondary winding of the three-phase AC transformer is a combination of m sets of iron core winding coils, where m=3i, i being an odd number equal to or greater than 3; an m-phase AC voltage source or m-phase step wave AC voltage sources approximating m of the m-phase AC voltage sources are generated from the combination of the m sets of iron core winding coils; the m-phase AC voltage source includes m sinusoidal voltage sources having equal amplitudes and phases spaced apart by 360° / m in sequence; and the m-phase step wave AC voltage source includes m step wave AC voltage sources having equal fundamental wave amplitudes and phases spaced apart by 360° / m in sequence; an output terminal of the m-phase AC voltage source or an m-phase step wave AC voltage source approximating m of the m-phase AC voltage sources is connected to an m-phase bridge rectifier circuit, the n-phase bridge inverter circuit is constituted by n sets of two rectifier diodes connected in series, a cathode of one diode of each of the two rectifier diodes connected in series is connected to an anode of the other diode, and each connection point between the cathode and the anode of each of the two rectifier diodes is connected to an m-phase output terminal of the m-phase AC voltage source, the other cathodes of each of the n sets of two rectifier diodes connected in series are connected to each other and serve as an output positive terminal of the n-phase bridge inverter circuit, and the other anodes of each of the n sets of two rectifier diodes connected in series are connected to each other and serve as an output negative terminal of the n-phase bridge inverter circuit, The n-phase bridge inverter circuit serves as a DC voltage source to output DC voltage and current, and realize DC transformation; 5. The inverter device according to claim 4, wherein the n-phase AC voltage source and the m-phase AC voltage source both appear only in a primary winding and a secondary winding of a transformer, and an AC frequency is determined by a switching period of a switch device of an inverter circuit.

8. 8. The inverter device according to claim 7, wherein the number of combinations of m sets of iron core winding coils on the secondary side of the three-phase AC transformer is the same as the number of combinations of iron core windings on the primary side, i.e., m=n.

9. 9. The inverter device according to claim 7 or 8, characterized in that the secondary winding of the three-phase AC transformer is a combination of n sets of secondary-side iron core winding coils corresponding to all winding coils of the combination of primary winding coils, and the ratio of the number of turns between all corresponding winding coils of the primary and secondary sides is the same.

10. 10. The inverter device according to claim 9, wherein a DC transmission and distribution network is formed from a power generation facility to a user end by a power transmission line, and a transformer, rectifier, and inverter facility, and supplies DC directly to the user.

11. 5. The inverter device according to claim 4, wherein the secondary winding of the three-phase AC transformer is a three-phase AC winding, which is externally connected to a three-phase AC motor, the switching period of the unidirectional conductive electronic switch device is adjustable, and the speed of the motor is adjusted by adjusting the switching period of the unidirectional conductive electronic switch device.

12. 3. The inverter device according to claim 1 or 2, wherein the n sets of iron core winding coil combinations are combinations of winding coils whose starting ends and ending ends are connected and fitted into stator slots of a motor, the switching period of the unidirectional conductive electronic switch device is adjustable, and the speed of the motor is adjusted by adjusting the switching period of the unidirectional conductive electronic switch device.

13. 13. The inverter device according to claim 12, wherein k is an integer of 3 or more.

14. The application of the inverter device according to any one of claims 1 to 13, characterized in that the inverter device is applied to a product end and becomes a part of the product or a product power supply.

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