Hybrid-level five phase inverter for common mode voltage mitigation

Abstract

A system can include a direct current (DC) voltage source (104) and a hybrid-level five phase voltage source inverter. The hybrid-level five phase voltage source inverter can include an input side, an output side, and a DC link. The input side can be coupled to the voltage source (104) and configured to store a charge (106a, 106b). The output side can be configured to provide a five-phase alternating current (AC) output. The DC link can couple the input side and a first AC phase output of the five-phase AC output. The DC link can include a bidirectional switch (112a, 112b) between the input side and the first AC phase.

Description

HYBRID-LEVEL FIVE PHASE INVERTER FOR COMMON MODE VOLTAGE MITIGATIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U. S. Provisional Patent Application No. 63 / 713,210, filed October 29, 2024, the entire contents of which are hereby incorporated by reference for all purposes in its entirety.BACKGROUND

[0002] Multi-phase systems can be applied to, or otherwise used within, various industrial applications such as electric vehicles, aerospace, hospital pumps, military applications, and other suitable applications. Multi-phase systems may provide several advantages over traditional three-phase alternatives. Application of space vector pulse width modulation schemes for multi-phase systems can become increasingly challenging due to the enormous number of voltage vectors associated with the multi-phase systems, which can exponentially increase a computation complexity of the multi-phase systems. Additionally, limiting common mode voltage, which, if high enough, may cause wear or damage, in a multi-phase system can be difficult.BRIEF SUMMARY

[0003] In certain embodiments, a system can include a direct current (DC) voltage source and a two-level five phase voltage source inverter. The two-level five phase voltage source inverter can include an input side, an output side, and a DC link. The input side can be coupled to the voltage source and can be configured to store a charge. The output side can be configured to provide a five-phase alternating current (AC) output. The DC link can couple the input side and a first AC phase output of the five-phase AC output. The DC link can include a bidirectional switch between the input side and the first AC phase.

[0004] In other embodiments, another system can include a direct current (DC) voltage source and a two-level five phase voltage source inverter. The two-level five phase voltage source inverter can include a load output, an input side, an output side, and a DC link. Theinput side can be coupled to the voltage source and can be configured to store a charge. The output side can be coupled with the load output and can be configured to provide a five-phase alternating current (AC) output. The DC link can couple the input side and a first AC phase output of the five-phase AC output. The DC link can include a bidirectional switch between the input side and the first AC phase.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 is a simplified diagram of a hybrid-level five phase voltage source inverter according to certain aspects of the present disclosure.

[0006] FIG. 2 is a set of space vector diagrams representing vectors of a hybrid-level five phase voltage source inverter according to certain aspects of the present disclosure.

[0007] FIG. 3 is a simplified space vector diagram representing vectors of a hybrid-level five phase voltage source inverter according to certain aspects of the present disclosure.

[0008] FIG. 4 is a diagram of an example of a switching sequence of a hybrid-level five phase voltage source inverter according to certain aspects of the present disclosure.

[0009] FIG. 5 is a simplified block diagram of a system that includes a hybrid-level five phase voltage source inverter according to certain aspects of the present disclosure.DETAILED DESCRIPTION

[0010] Certain aspects and features of the present disclosure relate to a hybrid-level five phase voltage source inverter that can be used to mitigate common mode voltage. The hybridlevel five phase voltage source inverter may include five phases that can have two or more levels. For example, the hybrid-level five phase voltage source inverter may include four two-level phases and one three-level phase, though other suitable examples of different levels for different phases may be possible. The hybrid-level five phase voltage source inverter may have an increased number of potential switching states compared to other voltage source inverters such as a two-level five phase voltage source inverter. The increased number of switching states may allow the common mode voltage to be mitigated. For example, while other voltage source inverters may experience a peak-to-peak common mode voltage of approximately a voltage of a voltage source of the other voltage source inverters, the hybrid-level five phase voltage source inverter may experience a peak-to-peak common mode voltage of approximately 20% of a voltage source of the hybrid-level five phase voltage source inverter. Additionally oralternatively, the increased number of switching states may allow a rate of change of the common mode voltage for the hybrid-level five phase voltage source inverter to be approximately half of the rate of change of the common mode voltage for the other voltage source inverters.

[0011] In some embodiments, the hybrid-level five phase voltage source inverter can include a direct current (DC) voltage source and a voltage source inverter. The voltage source inverter may include an input side, an output side, and a DC link, though the voltage source inverter may include any additional or alternative components. In some examples, the input side can be coupled with the DC voltage source to store a charge, and the output side may provide a five-phase alternating current (AC) output. The DC link can couple the input side and a first AC phase output of the five-phase AC output. For example, the DC link, or the first AC phase output, can include a bidirectional switch positioned between the input side and the first AC phase. In some embodiments, the hybrid-level five phase voltage source inverter can additionally include a load output that can be coupled with each phase of the five-phase AC output. Additionally, or alternatively, the DC link can include two or more capacitors. In examples in which the DC link includes two capacitors, each capacitor of the two capacitors can be configured to have or otherwise store a voltage that is approximately half of a voltage of the DC voltage source. As used herein, approximately may indicate that a recited value is within a range below and above the recited value, and the range may be 1%, 2%, 3%, 4%, 5%, 5%-10%, or 10%-20% of the recited value.

[0012] In some embodiments, the hybrid-level five phase voltage source inverter may have a set of two-level legs and a three-level leg, which in combination form the output side of the hybrid-level five phase voltage source inverter. The set of two-level legs may be coupled with the DC link, and each two-level leg of the set of two-level legs may include a different set of two switches and a different terminal. The three-level leg may be coupled with the DC link, and the three-level leg may include two switches. In some examples, the three-level leg may additionally include the bidirectional switch, or the bidirectional switch may be shared between the three-level leg and the DC link. The bidirectional switch may extend from the DC link to a point along the second terminal between the two switches of the three-level leg. In some examples, the point to wdiich the bidirectional switch extends may be between, such as at a midpoint or other suitable location, the two capacitors of the DC link.

[0013] In some embodiments, the DC voltage source may have or may be configured to provide a first voltage V. Each two-level leg of the set of two-level legs of the hybrid-level five phase voltage source inverter may have two possible voltage levels based on the DC voltage source. For example, each two-level leg of the set of two-level legs of the hybrid-level five phase voltage source inverter may be set to 0 Volts or V Volts, depending on which switch is engaged. Additionally or alternatively, the three-level leg may have three possible voltage levels: 0 Volts, half of V Volts, and V Volts, depending on which switch, including the bidirectional switch, is engaged. For example, if a bottom switch of any of the two-level legs or of the three-level leg is engaged, then the corresponding leg may be set to 0 Volts. In some embodiments, the bottom switch can be or include a ground switch that can be used to set a corresponding leg to 0 Volts. While the bottom switch is illustrated throughout the present disclosure as being physically at a bottom of the hybrid-level five phase voltage source inverter, the bottom switch need not always be physically at the bottom and may be located in other suitable locations of the hybrid-level five phase voltage source inverter. Additionally, or alternatively, if a top switch of any of the two-level legs or of the three-level leg is engaged, then the corresponding leg may be set to V Volts. In some embodiments, the top switch can be or include a hot switch or a live switch that can be used to set a corresponding leg to V Volts. While the top switch is illustrated throughout the present disclosure as being physically at a top of the hybrid-level five phase voltage source inverter, the top switch need not always be physically at the top and may be located in other suitable locations of the hybrid-level five phase voltage source inverter. Additionally, or alternatively, if the bidirectional switch is engaged, then the three-level leg may be set to half of V Volts.

[0014] In some embodiments, the hybrid-level five phase voltage source inverter may be capable of switching into approximately 48 different potential switching states. That is, there may be approximately 48 different and unique combinations of switch orientations within the hybrid-level five phase voltage source inverter. Additionally, or alternatively, a peak-to-peak value of a common mode voltage that the hybrid-level five phase inverter produces is less than or equals 20% of V, and a rate-of-change value of a common mode voltage that the hybridlevel five phase inverter produces is less than or equals 10% of V.

[0015] These illustrative examples are given to introduce the reader to the general subject matter discussed here and are not intended to limit the scope of the disclosed concepts. The following sections describe various additional features and examples with reference to thedrawings in which like numerals indicate like elements but, like the illustrative examples, should not be used to limit the present disclosure.

[0016] FIG. 1 is a simplified diagram of a hybrid-level five phase voltage source inverter 100 according to certain aspects of the present disclosure. As illustrated in FIG. 1, the hybridlevel five phase voltage source inverter 100 can include five terminals, eleven semiconductor switches, a load output 102, a DC voltage source 104, and a DC link, though the hybrid-level five phase voltage source inverter 100 can include any additional, alternative, or fewer components to provide functionality for the hybrid-level five phase voltage source inverter 100. The five terminals can include a first terminal VA, a second terminal VB, a third terminal Vc, a fourth terminal VD, and a fifth terminal VE, though other examples of terminals are possible. The semiconductor switches can include a set of top switches (e.g., a first top switch SA1, a second top switch SB!, a third top switch SC1, a fourth top switch SD1, and a fifth top switch SE1), a set of bottom switches (e.g., a first bottom switch SA2, a second bottom switch SB2, a third bottom switch SC2, a fourth bottom switch SD2, and a fifth bottom switch SE2), and a bidirectional switch SA3, though other examples of switches are possible. The load output 102 may be coupled with the terminals to receive inverted voltage based on an arrangement or an engagement of the semiconductor switches. The DC voltage source 104 may be configured to provide a voltage VDCthat may be an input voltage to the hybrid-level five phase voltage source inverter 100. The DC link may include two or more capacitors such as a first capacitor 106a and a second capacitor 106b. While the hybrid-level five phase voltage source inverter 100 is illustrated in FIG. 1 as including a DC link with two capacitors, other suitable numbers (e.g., two or more than two) of capacitors are possible.

[0017] In some embodiments, a combination of a particular terminal and a particular set of semiconductor switches may form a particular leg. For example, a combination of the second terminal VB, the second top switch S’gl, and the second bottom switch SB2may form a two-level leg since the leg includes two semiconductor switches. Additionally or alternatively, a combination of the first terminal VA, the first top switchthe first bottom switch SA2, and the bidirectional switch SA3may form a three-level leg. As illustrated in FIG. 1, the hybridlevel five phase voltage source inverter 100 includes four two-level legs and one three-level leg, though other numbers of two-level legs and three-level legs are possible for the hybridlevel five phase voltage source inverter 100. The four two-level legs, which can include a first two-level leg 108a, a second tw’o-level leg 108b, a third two-level leg 108c, and a fourth two-level leg 108d, can be positioned adjacent to one another such that the corresponding terminals,such as the second terminal VB, the third terminal Vc, the fourth terminal VD, and the fifth terminal VE, can be approximately parallel with respect to one another. Additionally, or alternatively, the three-level leg 110 can be positioned adjacent to a particular two-level leg such as the first two-level leg 108a that may be furthest from the load output 102 compared to the other two-level legs. In some embodiments, the first terminal VAof the three-level leg 110 may be approximately parallel with respect to the other terminals of the two-level legs, and the first terminal VAmay be coupled with the bidirectional switch SA3and the load output 102.

[0018] In some embodiments, the hybrid-level five phase voltage source inverter 100 may include a two-level five phase voltage source inverter with a bidirectional switch such as the bidirectional switch SA3. The bidirectional switch SA3may extend from the first terminal to a point along the DC link. For example, the bidirectional switch SA3may extend from the first terminal VAto a midpoint along the DC link. The midpoint may be or include a middle point between the first capacitor 106a and the second capacitor 106b. In other examples, the point along the DC link to which the bidirectional switch SA3may extend may be between, but not at the midpoint between, the first capacitor 106a and the second capacitor 106b.

[0019] In some embodiments, the hybrid-level five phase voltage source inverter 100 may include two additional semiconductor switches (or other suitable numbers of additional semiconductor switches) compared with other voltage source inverters such as the two-level five phase voltage source inverter. Additionally, or alternatively, the voltage ratings of the semiconductor switches of the hybrid-level five phase voltage source inverter 100 may be less than those of the two-level five phase voltage source inverter. In some embodiments, tire two additional semiconductor switches may form the bidirectional switch S\13. For example, the bidirectional switchmay include a first semiconductor switch 112a and a second semiconductor switch 112b that, in combination, can form the bidirectional switch SA3.

[0020] In some embodiments, the arrangement or engagement of the semiconductor switches of the four two-level legs and the three-level leg may cause pole voltages of the terminals included in the hybrid-level five phase voltage source inverter 100 to change. The terminals can have different possible voltage levels based at least in part on the arrangement or engagement of the semiconductor switches. For example, the second terminal ’ / B, the third terminal VC, the fourth terminal VD, and the fifth terminalcan each have possible pole voltages of 0 Volts or of VDCVolts depending on whether a corresponding bottom switch or a corresponding top switch is engaged. In particular, and with reference to the second terminalVB, if the second top switch SB1is engaged, then the pole voltage for the second terminal VBmay be VDCVolts, and if the second bottom switch SB2is engaged, then the pole voltage for the second terminal VBmay be 0 Volts. In another example, first terminal VAmay have possible pole voltages of 0 Volts, of VDC / 2 Volts, or ofVolts depending on whether the first bottom switch SA2, the bidirectional switch SA3, or the first top switch SA1are engaged, respectively.[0021 j Determining whether to engage a top switch, a bottom switch, or the bidirectional switch SA3may be controlled or informed by various conditions. For example, prior to engaging a top switch, a bottom switch, or the bidirectional switch SA3, a determination can be made whether doing so would cause the DC link to short circuit. To prevent short circuiting the hybrid-level five phase voltage source inverter 100, switches may be engaged only if no other switches on a common terminal are also engaged. That is, if a top switch is engaged, then the bottom switch may not be engaged, etc. In another example, prior to engaging a top switch, a bottom switch, or the bidirectional switch SA3, a determination can be made whether doing so would cause overvoltage caused by energy stored in inductive loads. That is, for a particular leg, if a top switch is engaged and the bottom switch is disengaged, the top switch may only be disengaged if the bottom switch is engaged at approximately the same time, or vice versa.

[0022] In some embodiments, the hybrid-level five phase voltage source inverter 100 may have approximately 48 potential switching states, which may be more than (e.g,, 16 states more than) the potential switching states of the two-level five phase voltage source inverter. The additional switching states provided by the hybrid-level five phase voltage source inverter 100 may come from the bidirectional switch SA3and the characteristics of the three-level leg.

[0023] FIG. 2 is a set of space vector diagrams, such as space vector diagrams 200a and space vector diagrams 200b, representing vectors of a hybrid-level five phase voltage source inverter 100 according to certain aspects of the present disclosure. Additionally, FIG. 2 includes a legend that maps each vector included in the space vector diagrams 200a and the space vector diagrams 200b to various colors. As discussed above, the hybrid-level five phase voltage source inverter 100 can provide 48 potential switching states due to the combination of two-level legs and the three-level leg. The space vector diagrams 200a may illustrate vectors representing each of the 48 potential switching states, and the space vector diagrams 200b maybe a simplified version of the space vector diagrams 200a. For example, the space vector diagrams 200b may illustrate fewer than 48 potential switching states for the hybrid-level five phase voltage source inverter 100.

[0024] In some embodiments, the space vector diagrams 200a may illustrate each vector representing each switching state of the 48 potential switching states of the hybrid-level five phase voltage source inverter 100. The vectors illustrated in the space vector diagrams 200a can include two zero vectors, ten blue vectors, ten red vectors, ten black vectors, and 16 green vectors, as indicated by the legend provided in FIG. 2. The two zero vectors, the ten blue vectors, the ten red vectors, and the ten black vectors may represent switching states that can be provided by the hybrid -level five phase voltage source inverter 100 and the two-level five phase voltage source inverter. The 16 green vectors may represent switching states that can be provided by the hybrid-level five phase voltage source inverter 100 but that cannot be provided by the two-level five phase voltage source inverter. The 16 green vectors may be enabled to be provided by the hybrid-level five phase voltage source inverter 100 based at least in part on the bidirectional switchIn some embodiments, the green vectors may aid in reducing the rate of change of the common mode voltage of the hybrid-level five phase voltage source inverter 100.

[0025] In some embodiments, the vectors illustrated in FIG. 2 may represent engagement, or disengagement, of each semiconductor switch included in the hybrid-level five phase voltage source inverter 100. For example, the switching state (12000) may indicate, in order from left-to-right, that the bidirectional switch SA3is engaged for the three-level leg 110, that the second top switch SB1is engaged for the first two-level leg 108a, that the third bottom switch SC2is engaged for tire second two-level leg 108b, that the fourth bottom switch SD2is engaged for the third two-level leg 108c, and that the fifth bottom switch SE2is engaged for the fourth two-level leg 108d. The remaining semiconductor switches not mentioned may all be disengaged in the switching state (12000). In the switching state (12000), the pole voltages for the first terminal VA, the second terminal VB, the third terminal Vc, the fourth terminal VD, and the fifth terminal may be VDC / 2 Volts, VDCVolts, 0 Volts, 0 Volts, and 0 Volts, respectively. The common mode voltage for the hybrid-level five phase voltage source inverter 100 can be determined based on the pole voltages. For example. Equation 1, produced below, can be usedto determine that the common mode voltage for the switching state (12000) is 3VDC / 10 Additionally, or alternatively, the common mode voltage index, k, can be determined by summing the individual values of the switching state to arrive at k = 1 + 2 + 0 + 0 + 0 = 3.

[0026] In some embodiments, the space vector diagrams 200b may be a simplification of vectors in a α − β subspace representing the possible switching states of hybrid-level five phase voltage source inverter 100. Additionally, or alternatively, the state of each leg included in the hybrid-level five phase voltage source inverter 100 can determine five-phase voltages: Vfy.,VBn, which may be represented as switching vectors Vs1and Vs3in the α − β and x − y vector spaces, respectively, as Equation 2 and Equation 3 in which a = e−j2π / 5

[0027] In some embodiments, the secondary subspace x — y may exhibit similarities with respect to the primary subspace a — P. An x − y, ACEBD phase-order system can replace the α − β ABCDE phase order. A distortion voltage represented by the x — y vector space voltage can produce an x − y to eliminate the x − y voltage distortion by eliminating the x − y voltage vector to obtain sinusoidal voltages. In some embodiments, combinations of zero vectors, the red vectors, and the blue vectors in a two-level five phase voltage source inverter may provide the output reference voltage for the five-phase system and nullify the x — y voltage component. The black vectors may be left unutilized since doing so may distort the outputs and raise the inverter's switching loss. Thus, not all the vectors in the space vector diagrams 200a may be used in order to obtain the desired output voltage for the hybrid-level five phase voltage source inverter 100.

[0028] In order to minimize the number of voltage vectors and, consequently, the challenge of determining appropriate switching sequences to generate the required output reference voltage, the unnecessary vectors may be removed, as is illustrated in the space vector diagrams 200b, The transformation from the decoupled reference frame to the phase voltage reference frame can be given as follows:

[0029] In Equation 4, T represents the transpose of the matrix, a = 2π / 5 and the components of the reference output voltage in a — p subspace are Vα= Vrefcos(θ), Vβ= Vrefsin(θ). Thecomponent of the reference output voltage in x − y subspace are Vx= Vy= 0. Thus, the five-phase voltages can be written as:In some embodiments, and given that 0 ≤ θ ≤ π / 5 in sector 1 and using Equation 5 as a substitute, the pole voltages of the hybrid-level five phase voltage source inverter 100 may follow VAO≥ VBO≥ VCO≥ VDO≥ VEO. For the switching state (22002), the magnitude of the pole voltage may be (VDC, VDC, 0,0, VDC), which satisfies the above relationship between pole voltages. Thus, the switching state (22002) may be a potential inverter state that can be used to create a reference voltage. For the switching state (12002), the magnitude of the pole voltage may be (0,5VDC, VDC, 0,0, VDC). This may not fulfill the above relationship between pole voltages, and, thus, the switching state (12002) may not be a potential inverter state and may not be used to create the reference voltage. By applying the above conditions to the extra switching states of the hybrid-level five phase voltage source inverter 100, the switching states (12002), (12202), (12020), (10200), (10220), (10020), (10202), (12022) may not be obvious candidates to formulate the reference voltage. The above, non-obvious switching states may be removed from the space vector diagram 200a to generate the space vector diagram 200b that includes simplified α − β space vectors.[0031 In some embodiments, the hybrid-level five phase voltage source inverter 100 can produce a sinusoidal excitation of tire multiphase system when it applies voltage vectors in the α − β subspace and controls the voltage vector in the x — y subspace to zero. To achieve this, five or more vectors may be included in each switching cycle. The control approach of the hybrid-level five phase voltage source inverter 100 can be governed by a set of rules, which may include:• Space vectors used to construct the vector in the α − β subspace may be chosen in such a manner that the combination of these vectors in the x — y subspace results in cancellation over the switching cycle.® For each sector, the space vectors may be chosen to reduce the peak-to peak value of the common mode voltage toand to reduce the “ of the common mode voltage to taking dt = 1 per unit time.® The switching sequence may be optimized to minimize the switching loss as much as possible.

[0032] FIG. 3 is a set of simplified space vector diagrams 300 representing vectors of a hybrid-level five phase voltage source inverter 100 according to certain aspects of the present disclosure. FIG. 3 additionally provides a legend that maps each of the vectors to corresponding colors as described herein. Considering the above-mentioned conditions with respect to the description of FIG. 2, the blue vectors in the space vector diagrams 200b may be used in order to minimize peak-to-peak common mode voltage. The common mode voltage index of the blue vectors may be 4 or 6. Thus, among the additional switching states, which may include the green vectors, of the hybrid-level five phase voltage source inverter 100, the switching states (12200) and (10022) may be taken into consideration in order to reduce the rate of change of the common mode voltage. The switching states may have a common mode voltage index of 5, which can ensure that the common mode voltage index vanes by one between two switching events and by two between the highest and minimum values of the common mode voltage index. As a result, the peak-to peak value of the common mode voltage may be reduced towhile the rate of change of the common mode voltage may be reduced toAccordingly, the simplified space vector diagrams 300 can be generated to represent the hybrid-level five phase voltage source inverter 100 in a further simplified a — p subspace.

[0033] To calculate the dwell times and select the switching sequence, sector 1 can be used as example. Sector 1 is highlighted in the top portion of the simplified space vector diagrams 300 as illustrated in FIG. 3. Five vectors, such as V1, V2, V3, V10, and the zero vectors Vo, may be considered to calculate the dwell times. The resulting space vector volt-seconds in the a — p and x — y vector subspaces may be defined as:(7)

[0034] In some embodiments, and with reference to Equation 6 and Equation 7, Tsmay be the switching time, and the vectors V1, V2, V3, V10, and V0may have dwell time durations of T1, T2, T3, T10, and T0, respectively. Additionally, or alternatively, Val, Va2, Va3, Valo and Ipi’ ^>2, Vp3, Vgio may be the a — / ? components associated with the switching vectors, while the x — y components may be Vx1, Vx2,Vx10and Vy1, Vy2, Vy3, Vy10. The a —components and the x — y components of the zero vectors may be zero.

[0035] In some embodiments, a — components of the reference output voltage (4’4 / / y) can be determined using the below equations: Equation 8 and Equation 9. In Equation 8 and Equation 9, 3 may range from 0 to 2?r and may be an angle formed by the reference output voltage vectors and a positive x-axis. Equation 10, which is produced below Equation 8 and Equation 9, can be used to determine the number of sectors s. In Equation 10, the ceil function may round numbers to the nearest integer when approaching positive infinity.

[0036] By solving Equation 6, Equation 7, Equation 8, Equation 9, and / or Equation 10, the dwell times may be given as the following, in which #0= 5, g1= 4 sin(2π / 5), and g2= 4 sin(π / 5).

[0037] In some embodiments, and to reduce the rate of change of the common mode voltage, switching states Vml------ (12200) and Vm2:::(10022) may be used to replace the zero vectors 70. As a result, the dwell time Tmlof Vmiand the dwell time Tm2of Vm2can be determined based on Equation 16, which is produced below'.

[0038] FIG. 4 is a diagram of an example of a switching sequence 400 of a hybrid-level five phase voltage source inverter 100 according to certain aspects of the present disclosure. FIG.4 additionally provides a legend that maps portions of the switching sequence 400 to various colors. With reference to the switching sequence, there may be four possible switching sequences in sector 1 that can ensure the minimum value of a rate of change of the common mode voltage and a minimum value of the peak-to-peak of the common mode voltage. As illustrated in FIG. 5, a first switching sequence, which is illustrated in blue, is described in Sequence A, a second switching sequence, which is illustrated in red, is described in Sequence B, a third switching sequence, which is illustrated in green, as indicated by the legend provided in FIG. 4, is described in Sequence C, and a fourth switching sequence, which is illustrated in yellow, is described in Sequence D.0.5T2- Tml- T3- T. - Tm2- T10- 0.5T2(A) 0.5T2− Tm1− T1− T3− Tm2− T10− 0.5T2(B)

[0039] In some embodiments, in sector 1, sequence A may demonstrate a minimum number of switching transitions, which may be 12 per switching cycle. Additionally, or alternatively, sequence C may demonstrate a maximum number of switching transitions per switching cycle, which may be 20. As a result, switching sequence A may be the best sequence to employ in sector 1 with the hybrid-level five phase voltage source inverter. In some embodiments, the hybrid-level five phase voltage source inverter 100 may have two more switching transitions per switching cycle than the two-level five phase voltage source inverter. However, four of the twelve switching transitions in the hybrid-level five phase voltage source inverter 100 may belong to the bidirectional switch SA3, which may have a lower voltage rating than the otherswitches. Additionally, the number of switching transitions and the configuration of semiconductor switches in the hybrid-level five-phase inverter results in lower inverter losses compared to a three-level five-phase inverter and other topologies, such as the three-level sparse five-phase inverter. Moreover, it offers reduced voltage stress in motor winding. As produced below. Table I displays the switching vectors, optimal switching sequence, and number of switching transitions for the sectors.TABLE THE SWITCHING VECTORS FOR THE HLSPHVSI AND THE OPTIMAL S ITCHING SEQUENCE WITH NUMBE OF SWITCHING E VENTS FOR

[0040] The pole voltages and the common mode voltages can be calculated from Equation 17 and Equation 18, respectively. The phase voltage can be determined from Equation 19, which, along with Equation 17 and Equation 18, is produced below. In Equation 17 and Equation 18,may represent a switching variable, which is 1 when the switch number / for phase i is turned on and is 0 when the switch is turned off.

[0041] FIG. 5 is a simplified block diagram of a system 500 that includes a hybrid-level five phase voltage source inverter 100 according to certain aspects of the present disclosure. As illustrated in FIG. 5, the system can include a power source 502, the hybrid-level five phase voltage source inverter 100, and a set of loads 504a~e, which includes load A 504a, load B 504b, load C 504c, load D 504d, and load E 504e.

[0042] In some embodiments, the power source 502 may be or include a DC power source that can provide a DC voltage. For example, the power source 502 may be or include a battery or other suitable energy storage device that can provide DC power or photovoltaic system. The hybrid-level five phase voltage source inverter 100 may be similar or identical to the hybridlevel five phase voltage source inverter 100 as described above with respect to at least FIG. 1. For example, die hybrid-level five phase voltage source inverter 100 may include a set of two-level legs and a three-level leg that can include a bidirectional switch. The hybrid-level five phase voltage source inverter 100 may be configured to provide five phase voltage source inversion to provide output to the set of loads 504a-e. In some embodiments, load A 504a, load B 504b, load C 504c, load D 504d, and load E 504e may each, or a subset thereof, be or include a five phase load output and may be connected with five phases of the hybrid-level five phase voltage source inverter 100.

[0043] In some aspects, the embodiments described herein can be provided according to one or more of the following examples. As used below, any reference to a series of examples is to be understood as a reference to each of those examples disjunctively (e.g., "Examples 1-4" is to be understood as "Examples 1, 2, 3, or 4").

[0044] Example 1: a system comprising: a direct current (DC) voltage source; and a two-level five phase voltage source inverter comprising: an input side coupled to the voltage source and configured to store a charge; an output side configured to provide a five-phase alternating current (AC) output; and a DC link that couples the input side and a first AC phase output of the five-phase AC output and that includes a bidirectional switch between the input side and the first AC phase.

[0045] Example 2: the system of example 1, wherein the DC link comprises two capacitors, and wherein each capacitor of the two capacitors has a voltage that is half of a voltage of the DC voltage source.

[0046] Example 3: the system of example 2, wherein the output side comprises: a plurality' of two-level legs coupled with the DC link, each two-level leg of the plurality of two-level legs comprising a different set of two switches and a different terminal; and a three-level leg coupled with the DC link, the three-level leg comprising two switches, the bidirectional switch, and a second terminal, wherein the bidirectional switch extends from the DC link to a point along the second terminal between the two switches.

[0047] Example 4: the system of example 3, wherein the bidirectional switch extends from the point along the second terminal between the two switches to a second point along the DC link that is between the two capacitors.[004§] Example 5: the system of example 3, wherein the DC voltage source is configured to provide a first voltage, wfierein each two-level leg of the plurality of two-le vel legs has two possible voltage levels of 0 Volts and the first voltage, and wherein the three-level leg has three possible voltage levels of 0 Volts, half of the first voltage, and the first voltage.

[0049] Example 6: the system of example 5, herein each two-lev el leg of the plurality of two-level legs comprises (i) a different bottom switch for seting a voltage of a corresponding two-level leg to 0 Volts and (ii) a different top switch for seting the voltage of the corresponding two-level leg to the first voltage, wherein a bottom switch of the two switches of the three-level leg is u sable to set a voltage of the three-level leg to 0 Volts, wherein a top switch of the two switches of the three-level leg is usable to set the voltage of the three-level leg to the first voltage, and wherein the bidirectional switch is usable to set the voltage of the three-level leg to half of the first voltage.

[0050] Example 7: the system of example 3, wherein switches of the plurality of two-level legs, the two switches, and the bidirectional switch are usable to set the hybrid-level five phase inverter to one of 48 potential switching states.

[0051] Example 8: the system of example 3, wherein the plurality of two-level legs includes four two-level legs, wherein the four two-level legs are positioned adjacent to one another such that four terminals corresponding to the four two-level legs are parallel with one another, wherein the four terminals are each coupled with a load by four electrical connectors that extend from the load to the four terminals.

[0052] Example 9: the system of example 8, wherein the three-level leg is positioned adjacent to a particular two-level leg that is furthest from the load compared with other two-level legs of the four two-level legs, wherein the second terminal is parallel with the four terminals, and wherein the second terminal is coupled with the load and with the bidirectional switch,

[0053] Example 10: the system of example 1, wherein a peak-to-peak value of a common mode voltage that the hybrid-level five phase inverter is capable of producing is less than or equals 20% of a voltage of the DC voltage source, wherein a rate-of-change value of a commonmode voltage that a hybrid-level five phase inverter is capable of producing is less than 10% of a voltage of the DC voltage source which is 50% lower than the two-level five-phase inverter, wherein the hybrid-level five phase inverter is configured to provide fewer switching transitions and a lower dv / dt than the two-level five-phase inverter, and wherein the system is configured to balance a self-DC-link capacitor voltage.

[0054] In some embodiments, the hybrid-level five-phase inverter can have a smaller number of switches compared to three-level five-phase inverter and the three-level sparse five-phase inverter. This can enhance size, cost, and reliability' and can reduce complexity of this converter. Moreover, the hybrid-level inverter can provide lower inverter losses compared to a three-level five-phase inverter and other topologies such as the three-level sparse five-phase inverter. Additionally, the hybrid-level inverter can obtain a self-neutral point voltage balancing without applying any control method, which can further simplify the control system.

[0055] Example 11: a system comprising: a direct current (DC) voltage source; and a two-level five phase voltage source inverter comprising: a load output; an input side coupled to the voltage source and configured to store a charge; an output side coupled with the load output and configured to provide a five-phase alternating current (AC) output; and a DC link that couples the input side and a first AC phase output of the five-phase AC output and that includes a bidirectional switch between the input side and the first AC phase.

[0056] Example 12: the system of example 11, wherein the DC link comprises two capacitors, and wherein each capacitor of the two capacitors has a voltage that is half of a voltage of the DC voltage source.

[0057] Example 13: the system of example 12, wherein the output side comprises: a plurality' of two-level legs coupled with the DC link and the load output, each two-level leg of the plurality of two-level legs comprising a different set of two switches and a different terminal; and a three-level leg coupled with the DC link and the load output, the three-level leg comprising two switches, a bidirectional switch, and a second terminal, wherein the bidirectional switch extends from the DC link to a point along the second terminal between the two switches.

[0058] Example 14: the system of example 13, wherein the bidirectional switch extends from the point along the second terminal between the two switches to a second point along the DC link that is between the two capacitors.

[0059] Example 15: the system of example 13, wherein the DC voltage source is configured to provide a first voltage, wherein each two-level leg of the plurality of two-level legs has two possible voltage levels of 0 Volts and the first voltage, and wherein the three-level leg has three possible voltage levels of 0 Volts, half of the first voltage, and the first voltage.

[0060] Example 16: the system of example 15, wherein each two-level leg of the plurality of two-level legs comprises (i) a different bottom switch for setting a voltage of a corresponding two-level leg to 0 Volts and (ii) a different top switch tor setting the voltage of the corresponding two-level leg to the first voltage, wherein a bottom switch of tire two switches of the three-level leg is usable to set a voltage of the three-level leg to 0 Volts, wherein a top switch of the two switches of the three-level leg is usable to set the voltage of the three-level leg to the first voltage, and wherein the bidirectional switch is usable to set the voltage of the three-level leg to half of the first voltage.

[0061] Example 17: the system of example 13, wherein switches ofthe plurality of two-level legs, the two switches, and the bidirectional switch are usable to set the hybrid-level five phase inverter to one of 48 potential switching states.

[0062] Example 18: the system of example 13, wherein tire plurality of two-level legs includes four two-level legs, wherein the four two-level legs are positioned adjacent to one another such that four terminals corresponding to the four two-level legs are parallel with one another, wherein the four terminals are each coupled with the load by four electrical connectors that extend from the load to the four terminals.

[0063] Example 19: the system of example 18, wherein the three-level leg is positioned adjacent to a particular two-level leg that is furthest from the load compared with other two-level legs of the four two-level legs, wherein the second terminal is parallel with the four terminals, and wherein the second terminal is coupled with the load and with the bidirectional switch.

[0064] Example 20: the system of example 11, wherein a peak-to-peak value of a common mode voltage that the two-level five phase inverter is capable of producing is less than 20% of a voltage of the DC voltage source, and wherein a rate-of-change value of a common mode voltage that the two-level five phase inverter is capable of producing is less than 10% of a voltage ofthe DC voltage source.

[0065] The foregoing description of certain examples, including illustrated examples, has been presented only for the purpose of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Numerous modifications, adaptations, and uses thereof will be apparent to those skilled in the art without departing from the scope of the disclosure. For instance, any examples described herein can be combined with any other examples to yield further examples.

Claims

1 WHAT IS CLAIMED IS:1 1. A system comprising:a direct current (DC) voltage source; anda hybrid-level five phase voltage source inverter comprising:an input side coupled to the voltage source and configured to store a charge;an output side configured to provide a five-phase alternating current (AC) output; anda DC link that couples the input side and a first AC phase output of the five-phase AC output and that includes a bidirectional switch between the input side and the first AC phase.1 2. The system of claim 1, wherein the DC link comprises two capacitors, and wherein each capacitor of the two capacitors has a voltage that is half of a voltage of the DC voltage source.1The system of claim 2, wherein the output side comprises:a plurality of two-level legs coupled with the DC link, each two-level leg of the plurality of two-level legs comprising a different set of two switches and a different terminal; anda three-level leg coupled with the DC link, the three-level leg comprising two switches, the bidirectional switch, and a second terminal, wherein the bidirectional switch / extends from the DC link to a point along the second terminal between the two switches. 1 4. The system of claim 3, wherein the bidirectional switch extends from the point along the second terminal between the two switches to a second point along the DC link that is between the two capacitors.1 5. The system of any of claims 3-4, wherein the DC voltage source is configured to provide a first voltage, wherein each two-level leg of the plurality of two-level legs has two possible voltage levels of 0 Volts and the first voltage, and wherein the three- level leg has three possible voltage levels of 0 Volts, half of the first voltage, and the first voltage,6. The system of claim 5, wherein each two-level leg of the plurality of two-level legs comprises (i) a different bottom switch for setting a voltage of a corresponding two-level leg to 0 Volts and (ii) a different top switch for seting the voltage of the corresponding t ’o-level leg to the first voltage, wherein a bottom switch of the two switches of the three-level leg is usable to set a voltage of the three-level leg to 0 Volts, wherein a top switch of the two switches of the three-level leg is usable to set the voltage of the three-level leg to the first voltage, and wherein the bidirectional switch is usable to set the voltage of the three-level leg to half of the first voltage.

7. The system of any of claims 3-4 or 6, wherein switches of the plurality of two-level legs, the two switches, and the bidirection al switch are usable to set the hybridlevel five phase inverter to one of 48 potential switching states.

8. The system of any of claims 3-4 or 6-7, wherein the plurality of two-level legs includes four two-level legs, wherein the four two-level legs are positioned adjacent to one another such that four terminals corresponding to the four two-level legs are parallel with one another, wherein the four terminals are each coupled with a load by four electrical connectors that extend from the load to the four terminals.

9. The system of claim 8, wherein the three-level leg is positioned adjacent to a particular two-level leg that is furthest from the load compared with other two-level legs of the four two-level legs, wherein the second terminal is parallel with the four terminals, and wherein the second terminal is coupled with the load and with the bidirectional switch.

10. The system of any of claims 1-9, wherein a peak-to-peak value of a common mode voltage that the hybrid-level five phase inverter is capable of producing is less than or equals 20% of a voltage of the DC voltage source, wherein a rate-of-change value of a common mode voltage that a two-level five phase inverter is capable of producing is less than 10% of a voltage of the DC voltage source which is 50% lower than the two-level five-phase inverter, wherein the hybrid-level five phase inverter is configured to provide fewer switching transitions and a lower dv / dt than the two-level five-phase inverter, and wherein the system is configured to balance a self-DC-link capacitor voltage.

11. A system comprising:a direct current (DC) voltage source; anda hybrid-level five phase voltage source inverter comprising:a load output;an input side coupled to the voltage source and configured to store a charge;an output side coupled with the load output and configured to provide a five-phase alternating current (AC) output; anda DC link that couples the input side and a first AC phase output of the five-phase AC output and that includes a bidirectional switch between the input side and the first AC phase.

12. The system of claim 11, wherein the DC link comprises two capacitors, and wherein each capacitor of the two capacitors has a voltage that is half of a voltage of the DC voltage source.

13. The system of claim 12, wherein the output side comprises:a plurality of two-level legs coupled with the DC link and the load output, each two-level leg of the plurality of two-level legs comprising a different set of two switches and a different terminal; anda three-level leg coupled with the DC link and the load output, the three-level leg comprising two switches, a bidirectional switch, and a second terminal, wherein the bidirectional switch extends from the DC link to a point along the second terminal between the two switches.

14. The system of claim 13, wherein the bidirectional switch extends from the point along the second terminal between the two switches to a second point along the DC link that is between the two capacitors.

15. The system of any of claims 13-14, wherein the DC voltage source is configured to provide a first voltage, wherein each two-level leg of the plurality of two-level legs has two possible voltage levels of 0 Volts and the first voltage, and wherein the three-level leg has three possible voltage levels of 0 Volts, half of the first voltage, and the first voltage.

16. The system of claim 15, wherein each two-level leg of the plurality of two-level legs comprises (i) a different bottom switch for setting a voltage of a corresponding two-level leg to 0 Volts and (ii) a different top switch for seting the voltage of the corresponding t ’o-ievel leg to the first voltage, wherein a bottom switch of the two switches of the three-level leg is usable to set a voltage of the three-level leg to 0 Volts, wherein a top switch of the two switches of the three-level leg is usable to set the voltage of the three-level leg to the first voltage, and wherein the bidirectional switch is usable to set the voltage of the three-level leg to half of the first voltage.

17. The system of any of claims 13-14 or 16, wherein switches of the plurality of two-level legs, the two switches, and the bidirectional switch are usable to set the two-level five phase inverter to one of 48 potential switching states.

18. The system of any of claims 13-14 or 16-17, wherein the plurality of two-level legs includes four two-level legs, wherein the four two-level legs are positioned adjacent to one another such that four terminals corresponding to the four two-level legs are parallel with one another, wherein the four terminals are each coupled with the load by four electrical connectors that extend from the load to the four terminals.

19. The system of claim 18, wherein the three-level leg is positioned adjacent to a particular two-level leg that is furthest from the load compared with other two-level legs of the four two-level legs, wherein the second terminal is parallel with the four terminals, and wherein the second terminal is coupled with the load and with the bidirectional switch.

20. The system of any of claims 11-19, wherein a peak-to-peak value of a common mode voltage that the two-level five phase inverter is capable of producing is less than 20% of a voltage of the DC voltage source, and wherein a rate-of-change value of a common mode voltage that the two-level five phase inverter is capable of producing is less than 10% of a voltage of the DC voltage source.

Images