Space vector pulse width modulation method for two-phase four-leg inverter and related device

Abstract

The application provides a space vector pulse width modulation method of a two-phase four-bridge-arm inverter and a related device, and belongs to the technical field of power electronics. According to the sector where a reference output voltage vector is located, the application determines the selected switch tube state, switch tube switching sequence and switch tube state duration by judging the action time of the adjacent voltage vector and the action time of the zero voltage vector of the sector where the reference voltage vector after equal proportion shortening is located. According to the selected switch tube state, switch tube switching sequence and switch tube state duration, the driving signal for controlling the switch tube state switching is generated to control the on-off of each switch tube of the two-phase four-bridge-arm inverter. The application solves the problems of the prior art, such as complex calculation process, frequent switch tube state switching and too small utilization rate of the direct current voltage.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology, specifically relating to a space vector pulse width modulation method and related devices for a two-phase four-arm inverter. Background Technology

[0002] Compared to sinusoidal pulse width modulation (SPWM), space vector pulse width modulation (SVPWM) has advantages in terms of output voltage fundamental amplitude and output current harmonic content, but its calculation process is relatively complex. However, with the continuous development and application of digital signal processing technology, the problem of insufficient computing power has been solved, and SVPWM has become more popular than other pulse width modulation methods.

[0003] Among the many space vector pulse width modulation (SVM) technologies, most are designed for three-phase output applications, with only a few focusing on two-phase. However, two-phase inverters are not uncommon, used in applications such as small and medium-power induction motors, including household appliances like fans, hair dryers, and refrigerators. Furthermore, small-power bearingless permanent magnet synchronous wafer motors also tend to use two-phase inverters. Two-phase inverters offer several advantages over three-phase inverters: First, they eliminate the need for three-phase to two-phase coordinate conversion, reducing computational complexity. Second, most household applications do not require three-phase power. Third, two-phase windings require less volume and are less complex to wind than three-phase windings.

[0004] SVPWM technology in two-phase inverters focuses on two-arm or three-arm topologies. Two-arm SVPWM, lacking zero-voltage vector action, requires four voltage vectors to act alternately to achieve a single reference voltage, resulting in complex calculations and high output voltage and current harmonics. Furthermore, this topology requires a center-tapped voltage source or capacitor, increasing manufacturing costs and limiting DC voltage utilization to only 50%. Three-arm SVPWM improves performance in various aspects; however, it requires a common arm to form a loop, where the current amplitude is greater than that of the other two arms. The efficiency is twice that of the DC voltage, and its DC voltage utilization rate is only 70.7%. At the same time, the switching state of these two SVPWM algorithms changes frequently, and each switching transistor needs to switch its state once within a single sampling period. Summary of the Invention

[0005] The purpose of this invention is to provide a space vector pulse width modulation method and related device for a two-phase four-arm inverter, which solves the problems of complex calculation process, frequent switching of switching transistors, and low utilization of DC voltage in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a space vector pulse width modulation method for a two-phase four-arm inverter, comprising the following steps:

[0008] Based on the topology of a two-phase four-arm inverter, the basic output voltage vector of the two-phase four-arm inverter is defined, and the space voltage vector diagram of the two-phase four-arm inverter is drawn.

[0009] The space voltage vector diagram of the two-phase four-arm inverter is divided into several sectors, and the sector where the reference voltage vector is located is determined according to the reference voltage vector angle or the reference output voltage value.

[0010] The duration of action of the adjacent voltage vectors and the zero voltage vector in the sector where the reference voltage vector is located is calculated based on the volt-second equivalence principle. Based on the duration of action of the adjacent voltage vectors in the sector where the reference voltage vector is located, it is determined whether the reference output voltage value is in the linear modulation region.

[0011] Based on whether the reference output voltage value is in the linear modulation region, determine whether to proportionally shorten the duration of the voltage vectors adjacent to the sector where the reference voltage vector is located.

[0012] Based on the sector where the reference output voltage vector is located, the duration of action of the adjacent voltage vectors in the sector where the reference voltage vector is located after proportional shortening, and the duration of action of the zero voltage vector, determine the selected switching state, the switching sequence of the switching transistors, and the duration of the switching state.

[0013] Based on the selected switch state, switch sequence, and switch state duration, a drive signal is generated to control the switching of the switch state, thereby controlling the on / off state of each switch in the two-phase four-arm inverter.

[0014] A further improvement of the present invention is that the basic output voltage vector includes 8 non-zero voltage vectors and 1 zero voltage vector.

[0015] A further improvement of the present invention is that, in the step of dividing the drawn space voltage vector diagram of the two-phase four-arm inverter into several sectors and determining the sector where the reference voltage vector is located based on the reference voltage vector angle or the reference output voltage value, the specific determination process is as follows: if the angle information of the reference voltage vector is known and the driving load is a two-phase symmetrical load, the determination is made directly by the reference voltage vector angle; otherwise, the determination is made based on the reference output voltage value.

[0016] A further improvement of this invention is that, in the step of calculating the action time of the adjacent voltage vectors and the zero voltage vector in the sector where the reference voltage vector is located according to the volt-second equivalence principle, and determining whether the reference output voltage value is in the linear modulation region based on the action time of the adjacent voltage vectors in the sector where the reference voltage vector is located, the specific process for determining whether the reference output voltage value is in the linear modulation region is as follows: when the sum of the action times of the adjacent voltage vectors is greater than the sampling time, the reference output voltage value is not in the linear modulation region; when the sum of the action times of the adjacent voltage vectors is less than or equal to the sampling time, the reference output voltage value is in the linear modulation region.

[0017] A further improvement of the present invention is that, in the step of determining whether to proportionally shorten the duration of voltage vectors adjacent to the sector where the reference voltage vector is located based on whether the reference output voltage value is in the linear modulation region, the specific determination process is as follows: if the reference output voltage value is not in the linear modulation region, then the duration of voltage vectors adjacent to the sector where the reference voltage vector is located is proportionally shortened; if the reference output voltage value is in the linear modulation region, then the duration of voltage vectors adjacent to the sector where the reference voltage vector is located is not proportionally shortened.

[0018] A further improvement of the present invention is that the calculation formula for the proportional shortening is:

[0019]

[0020] in, and The basic voltage vector after proportional shortening , Duration of action and The basic voltage vector before proportional shortening , Duration of action Sampling time, and These are two adjacent basic voltage vectors of the sector where the reference voltage vector is located.

[0021] A further improvement of the present invention is that the switching transistor is an IGBT or a MOSFET.

[0022] In a second aspect, the present invention provides a space vector pulse width modulation system for a two-phase four-arm inverter, including a space voltage vector partitioning module, a sector judgment module, an action time calculation module, a proportional shortening judgment module, a switching sequence determination module, and a switching tube on / off control module.

[0023] The space voltage vector partitioning module is used to define the basic output voltage vector of the two-phase four-arm inverter based on the topology of the two-phase four-arm inverter, and to draw the space voltage vector diagram of the two-phase four-arm inverter.

[0024] The sector determination module is used to divide the drawn space voltage vector diagram of the two-phase four-arm inverter into several sectors, and determine the sector where the reference voltage vector is located based on the reference voltage vector angle or the reference output voltage value.

[0025] The action time calculation module is used to calculate the action time of the adjacent voltage vectors and zero voltage vector in the sector where the reference voltage vector is located according to the volt-second equivalence principle, and to determine whether the reference output voltage value is in the linear modulation region based on the action time of the adjacent voltage vectors in the sector where the reference voltage vector is located.

[0026] The proportional shortening judgment module is used to determine whether to proportionally shorten the duration of the voltage vectors adjacent to the sector where the reference voltage vector is located, based on whether the reference output voltage value is in the linear modulation region.

[0027] The switching sequence determination module is used to determine the selected switch state, the switching sequence of the switch state, and the duration of the switch state based on the sector where the reference output voltage vector is located, the duration of the adjacent voltage vectors of the sector where the reference voltage vector is located after proportional shortening, and the duration of the zero voltage vector.

[0028] The switching transistor on / off control module is used to generate drive signals to control the switching transistor state switching based on the selected switching transistor state, switching transistor switching sequence and switching transistor state duration, thereby controlling the on / off of each switching transistor of the two-phase four-bridge arm inverter.

[0029] Thirdly, the present invention provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the space vector pulse width modulation method for a two-phase four-arm inverter described above.

[0030] Fourthly, the present invention provides a storage medium storing a computer program thereon, wherein the computer program, when executed by a processor, implements the steps of the space vector pulse width modulation method for a two-phase four-arm inverter described above.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] This invention is an improved version. Compared with existing space vector pulse width modulation methods for two-phase inverters, this invention, based on a two-phase four-arm inverter topology, increases the number of basic voltage vectors, expands the linear operating range, and improves the utilization rate of the DC bus voltage. Furthermore, this invention adds selectable switching states, which, through careful selection of switching states and switching sequences, significantly reduces the number of switching state transitions, load current ripple, and switching losses caused by switching, thereby improving the efficiency of power electronic equipment. This effectively solves the problems of complex calculations, frequent switching state transitions, and insufficient DC voltage utilization in existing technologies. Moreover, this invention readjusts the action time of the reference voltage vector in the nonlinear modulation region, ensuring that the output voltage is not distorted in phase, thus improving the stability of the two-phase four-arm inverter system. Attached Figure Description

[0033] Figure 1 This is a flowchart of the space vector pulse width modulation method for the two-phase four-arm inverter of the present invention;

[0034] Figure 2 This is a schematic diagram of the space vector pulse width modulation system of the two-phase four-arm inverter of the present invention;

[0035] Figure 3 This is the main circuit topology diagram of the two-phase four-arm inverter provided in Embodiment 3 of the present invention;

[0036] Figure 4 This is a space voltage vector diagram of the two-phase four-arm inverter of the present invention;

[0037] Figure 5 This is a schematic diagram of the operating time of the two-phase four-arm inverter in Embodiment 3 of the present invention;

[0038] Figure 6 This is a schematic diagram illustrating the function of the basic voltage vector when the reference voltage vector of the present invention is located in sector I;

[0039] Figure 7 The switching sequence of the reference voltage vector in this invention is located in different sectors;

[0040] Figure 8 This is a diagram of the ideal two-phase output voltage waveform of Embodiment 3 of the present invention;

[0041] Figure 9 for Figure 8 Waveform of the magnified area;

[0042] Figure 10 This is a topology diagram of the main circuit of a two-phase four-arm inverter provided in Embodiment 4 of the present invention;

[0043] Figure 11 This is the ideal two-phase output voltage waveform of Embodiment 4 of the present invention;

[0044] Figure 12 for Figure 11 Waveform of the magnified area;

[0045] Figure 13 This is a schematic diagram of the structure of the electronic device of the present invention. Detailed Implementation

[0046] To further understand the content of this invention, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0047] The space vector pulse width modulation method for two-phase four-arm inverters proposed in this invention generates drive signals to control the switching of switch states based on the selected switch states, switching sequence, and duration of switch states, thereby controlling the on / off state of each switch in the two-phase four-arm inverter. Compared with existing technologies, this invention effectively solves the problems of complex calculation processes, frequent switch state switching, and low utilization of DC voltage in existing technologies.

[0048] Example 1:

[0049] The flowchart of the space vector pulse width modulation method for the two-phase four-arm inverter of the present invention is as follows: Figure 1 As shown, the space vector pulse width modulation method for a two-phase four-arm inverter of the present invention includes the following steps:

[0050] S1. Based on the topology of the two-phase four-arm inverter, define the basic output voltage vector of the two-phase four-arm inverter and draw the space voltage vector diagram of the two-phase four-arm inverter.

[0051] S2. Divide the space voltage vector diagram of the two-phase four-arm inverter into several sectors, and determine the sector where the reference voltage vector is located based on the reference voltage vector angle or the reference output voltage value.

[0052] S3. Calculate the duration of action of the adjacent voltage vectors and zero voltage vector in the sector where the reference voltage vector is located based on the volt-second equivalence principle, and determine whether the reference output voltage value is in the linear modulation region based on the duration of action of the adjacent voltage vectors in the sector where the reference voltage vector is located.

[0053] S4. Based on whether the reference output voltage value is in the linear modulation region, determine whether to proportionally shorten the duration of the voltage vectors adjacent to the sector where the reference voltage vector is located.

[0054] S5. Based on the sector where the reference output voltage vector is located, the duration of action of the adjacent voltage vectors and the duration of action of the zero voltage vector in the sector where the reference voltage vector is located after proportional shortening, determine the selected switching state, the switching sequence of the switching transistors, and the duration of the switching state.

[0055] S6. Based on the selected switch state, switch sequence, and switch state duration, generate drive signals to control the switching of switch states, thereby controlling the on / off state of each switch in the two-phase four-arm inverter.

[0056] Example 2:

[0057] A schematic diagram of the space vector pulse width modulation system of the two-phase four-arm inverter of the present invention is shown below. Figure 2 As shown, the space vector pulse width modulation system of the two-phase four-arm inverter of the present invention includes a space voltage vector partitioning module, a sector judgment module, an action time calculation module, a proportional shortening judgment module, a switching sequence determination module, and a switching tube on / off control module.

[0058] The space voltage vector partitioning module is used to define the basic output voltage vector of a two-phase four-arm inverter based on its topology and to draw the space voltage vector diagram of the two-phase four-arm inverter.

[0059] The sector determination module is used to divide the drawn space voltage vector diagram of the two-phase four-arm inverter into several sectors, and determine the sector where the reference voltage vector is located based on the reference voltage vector angle or the reference output voltage value.

[0060] The action time calculation module is used to calculate the action time of the adjacent voltage vectors and zero voltage vector in the sector where the reference voltage vector is located based on the volt-second equivalence principle, and to determine whether the reference output voltage value is in the linear modulation region based on the action time of the adjacent voltage vectors in the sector where the reference voltage vector is located.

[0061] The proportional shortening judgment module is used to determine whether to proportionally shorten the duration of voltage vectors adjacent to the sector where the reference voltage vector is located, based on whether the reference output voltage value is in the linear modulation region.

[0062] The switch sequence determination module is used to determine the selected switch state, switch sequence, and switch state duration based on the sector where the reference output voltage vector is located, the duration of the adjacent voltage vectors in the sector where the reference voltage vector is located after proportional shortening, and the duration of the zero voltage vector.

[0063] The switching transistor on / off control module is used to generate drive signals to control the switching transistor state switching based on the selected switching transistor state, switching sequence, and switching transistor state duration, thereby controlling the on / off of each switching transistor in the two-phase four-arm inverter.

[0064] Example 3:

[0065] S1. Based on the topology of the two-phase four-arm inverter, define the basic output voltage vector of the two-phase four-arm inverter and draw the space voltage vector diagram of the two-phase four-arm inverter.

[0066] The main circuit topology of the two-phase four-arm inverter in this embodiment is as follows: Figure 3 As shown, the main circuit of the two-phase four-arm inverter in this embodiment includes parallel connections at voltages of... The DC voltage source has four bridge arms: Bridge Arm A, Bridge Arm B, Bridge Arm C, and Bridge Arm D. Each bridge arm includes two switching devices, for a total of eight switching devices (also called switching transistors; in this embodiment, they are specifically S1, S2, S3, S4, S5, S6, S7, and S8). In this embodiment, the switching devices can be composed of IGBTs and anti-parallel diodes, or they can be composed of MOSFETs. The voltage difference between the midpoints of Bridge Arm A and Bridge Arm B constitutes one phase of the two-phase output voltage. The voltage difference between the midpoints of bridge arms C and D constitutes the other phase of the two-phase output voltage. The two output voltages are respectively connected to a set of series resistors and inductors with the same parameters as loads.

[0067] In a two-phase four-arm inverter, the switching states of the upper switching devices (S1, S3, S5, and S7) and the lower switching devices (S2, S4, S6, and S8) are always opposite when each arm is operating normally. For convenience, the switching states of the entire inverter are represented by the set of switching states of the four upper switching devices, with 0 representing the off state and 1 representing the on state. The eight switches of the four arms can generate 16 different sets of switching states, and the output voltages of these 16 switching states form eight equally spaced voltages. There are four distributed non-zero voltage vectors and one zero voltage vector. The four non-zero voltage vectors lie on the imaginary and real axes of the complex plane, with lengths of... The other four non-zero voltage vectors lie on the diagonal of the complex plane, with a length of... The zero-voltage vector is located at the exact center of the complex plane. These eight non-zero voltage vectors divide the complex plane into eight sectors. Figure 4The space voltage vector diagram for a two-phase four-arm inverter is shown. Each sector is an isosceles right triangle, and the eight sectors form a standard square. The edges of the square represent the maximum voltage trajectory, and the largest inscribed circle of the square represents the largest reference voltage vector trajectory. The 16 switching states are redundant in forming the above voltage vectors; for example, switching states (0000), (1111), (0011), and (1100) can all output a zero voltage vector. Table 1 shows the two-phase output voltages and the overall output voltage vectors corresponding to different switching states. The output voltage vector is represented by phasors.

[0068] Table 1. Basic voltage vectors corresponding to different switching states.

[0069]

[0070] S2. Divide the space voltage vector diagram of the two-phase four-arm inverter into several sectors, and determine the sector where the reference voltage vector is located based on the reference voltage vector angle or the reference output voltage value.

[0071] The space voltage vector diagram of the two-phase four-arm inverter is divided into several sectors (in this embodiment, the space voltage vector diagram of the two-phase four-arm inverter is divided into 8 sectors: sector I, sector II, sector III, sector IV, sector V, sector VI, sector VII and sector VIII).

[0072] The specific process for determining the sector where the reference voltage vector is located is as follows: if the angle information of the reference voltage vector is known, and the driving load is a two-phase symmetrical load, the judgment is made directly by the angle of the reference voltage vector; otherwise, the judgment is made based on the reference output voltage value.

[0073] The following is a detailed explanation of the specific process for determining the sector where the reference voltage vector is located:

[0074] If the angle of the reference voltage vector is known, and the driving load is a two-phase symmetrical load, the angle can be directly determined using the reference voltage vector. Specifically, in sector I, In sector II, In sector III, In sector IV, In sector V, In sector VI, In sector VII, In sector VIII, .

[0075] Otherwise, based on the reference output voltage value and The sector is determined based on the following four criteria: Criterion 1: Criterion 2: Criterion 3: And Criterion 4: .

[0076] Specifically, in sector I, criteria 1, 2, and 3 are satisfied. In sector II, criteria 1 and 2 are satisfied, but criterion 3 is not satisfied. In sector III, criteria 2 and 4 are satisfied, but criterion 1 is not satisfied. In sector IV, criterion 2 is satisfied, but criteria 1 and 4 are not satisfied. In sector V, criteria 1, 2, and 3 are not satisfied. In sector VI, criterion 3 is satisfied, but criteria 1 and 2 are not satisfied. In sector VII, criterion 1 is satisfied, but criteria 2 and 4 are not satisfied. In sector VIII, criteria 1 and 4 are satisfied, but criterion 2 is not satisfied.

[0077] The angle intervals of the eight sectors and the satisfaction of the criteria are shown in Table 2.

[0078] Table 2. Angle intervals of the eight sectors and satisfaction of the criteria.

[0079]

[0080] In Table 2, 1 indicates that the condition is met, 0 indicates that the condition is not met, and * indicates that the criterion is not considered during the judgment.

[0081] S3. Calculate the duration of action of the adjacent voltage vectors and zero voltage vector in the sector where the reference voltage vector is located based on the volt-second equivalence principle, and determine whether the reference output voltage value is in the linear modulation region based on the duration of action of the adjacent voltage vectors in the sector where the reference voltage vector is located.

[0082] The duration of action of the adjacent voltage vectors and the zero voltage vector in the sector containing the reference voltage vector is calculated using the volt-second equivalence principle. The formula is as follows:

[0083]

[0084] in, As a reference output voltage vector, , These are two adjacent basic voltage vectors of the sector where the reference voltage vector is located. For the basic voltage vector Duration of action For the basic voltage vector Duration of action Zero fundamental voltage vector Duration of action Sampling time, The sector number where the reference output voltage vector is located ( When, define ).

[0085] This step also introduces intermediate variables X, Y, Z, and W to simplify the application time of adjacent voltage vectors and zero voltage vectors in the sector where the reference voltage vector is located. The calculation formulas for intermediate variables X, Y, Z, and W are as follows:

[0086]

[0087] in, This is called the inverter modulation ratio. When this value is between 0 and 1, the inverter is in the linear operating region. Introducing this intermediate variable simplifies the representation of the operating time. Taking sector I as an example... , The calculated results are -Z and X, respectively. When the reference voltage falls in sector II, the results are Y and Z, respectively. Table 3 shows the duration of action for all sectors. Figure 5 The duration of action for each sector ( , , In this embodiment, the basic sampling period is 50 ms, the modulation wave period is 0.02 s, and the inverter modulation ratio is set to 1. The duration of the zero-voltage vector in all sectors is calculated using the following formula:

[0088]

[0089] The duration of action of the eight sectors is summarized in Table 3.

[0090] Table 3 Summary of the operating time of the eight sectors

[0091]

[0092] The specific process for determining whether the reference output voltage value is within the linear modulation region is as follows: when the sum of the action times of adjacent voltage vectors is greater than the sampling time, the reference output voltage value is not within the linear modulation region; when the sum of the action times of adjacent voltage vectors is less than or equal to the sampling time, the reference output voltage value is within the linear modulation region.

[0093] S4. Based on whether the reference output voltage value is in the linear modulation region, determine whether to proportionally shorten the duration of the voltage vectors adjacent to the sector where the reference voltage vector is located.

[0094] The specific determination process for whether to proportionally shorten the duration of voltage vectors adjacent to the sector where the reference voltage vector is located is as follows: if the reference output voltage value is not within the linear modulation region, then the duration of voltage vectors adjacent to the sector where the reference voltage vector is located is proportionally shortened; if the reference output voltage value is within the linear modulation region, then the duration of voltage vectors adjacent to the sector where the reference voltage vector is located is not proportionally shortened.

[0095] The formula for calculating proportional shortening is:

[0096]

[0097] in, and The basic voltage vector after proportional shortening , Duration of action and The basic voltage vector before proportional shortening , Duration of action Sampling time, and These are two adjacent basic voltage vectors of the sector where the reference voltage vector is located.

[0098] S5. Based on the sector where the reference output voltage vector is located, the duration of action of the adjacent voltage vectors and the duration of action of the zero voltage vector in the sector where the reference voltage vector is located after proportional shortening, determine the selected switching state, the switching sequence of the switching transistors, and the duration of the switching state.

[0099] S6. Based on the selected switch state, switch sequence, and switch state duration, generate drive signals to control the switching of switch states, thereby controlling the on / off state of each switch in the two-phase four-arm inverter.

[0100] The basic voltage vector to be applied is determined based on the sector. The basic voltage vector and the zero vector are applied alternately to generate the target reference voltage vector. Since multiple basic voltage vectors can be implemented through multiple switching states, nine specific switching states out of 16 are selected as the eight required non-zero basic voltage vectors and one zero basic voltage vector, as follows: , , , , , , , and .

[0101] The order of action of the basic voltage vector is determined according to the sector it belongs to, and a five-segment symmetrical modulation strategy is adopted to... and Each segment is divided into two equal parts for symmetrical action, with a zero voltage vector acting in the middle. In this symmetrical action method, within odd-numbered sectors, the order of action of the basic voltage vectors is as follows: In even-numbered sectors, the order of action of the basic voltage vectors is as follows: . Figure 6 The basic voltage vector when the reference voltage vector falls in sector I. and and zero voltage vector The diagram illustrates the sequence of actions. Based on the selected switch state and the symmetrical five-segment switch modulation strategy, switching signals are generated for the switching devices to control the opening and closing of the switches. The drive signals for the upper and lower switches on the same bridge arm are opposite. Specifically, the sequence of action of the basic voltage vector in each sector is as follows: In sector I, the sequence is... In sector II, the sequence is as follows: In sector III, the sequence is as follows: In sector IV, the sequence is as follows: In sector V, the sequence is as follows: In sector VI, the sequence is as follows: In sector VII, the sequence is as follows: In sector VIII, the sequence is as follows: . Figure 7 The switching states of the upper switches of the four bridge arms when the reference voltage is located in different sectors.

[0102] To better illustrate the space vector pulse width modulation (SVM) method for a two-phase four-arm inverter proposed in this invention, this embodiment connects the load after the SVM of the two-phase four-arm inverter is completed. In this embodiment, the driving load is a two-phase symmetrical load, so the two-phase modulation voltages (i.e., the two-phase reference voltages) have equal amplitudes and a phase difference of [missing information]. The sinusoidal quantity can be expressed by the following formula:

[0103]

[0104] in, This is the reference output phase voltage between the midpoints of bridge arms A and B. This is the reference output phase voltage between the midpoints of bridge arms C and D. It is the amplitude of the reference output voltage. It is the angular frequency of the current.

[0105] Figure 8 The image shows the ideal output voltage waveforms for a two-phase four-arm inverter. Figure 9 for Figure 8 Waveform diagram of the magnified region. In this embodiment, the sampling frequency used is 20 kHz, and the current angular frequency is 100°. rad / s (corresponding to a current frequency of 50Hz).

[0106] Example 4:

[0107] The main circuit topology of the two-phase four-arm inverter in this embodiment is as follows: Figure 10 As shown, the main circuit of the two-phase four-arm inverter in this embodiment includes parallel connections at voltages of... The DC voltage source has four bridge arms: Bridge Arm A, Bridge Arm B, Bridge Arm C, and Bridge Arm D. Each bridge arm includes two switching devices, for a total of eight switching devices (also called switching transistors; in this embodiment, they are specifically S1, S2, S3, S4, S5, S6, S7, and S8). In this embodiment, the switching devices can be composed of IGBTs and anti-parallel diodes, or they can be composed of MOSFETs. The voltage difference between the midpoints of Bridge Arm A and Bridge Arm B constitutes one phase of the two-phase output voltage. The voltage difference between the midpoints of bridge arms C and D constitutes the other phase of the two-phase output voltage. The two output voltages are respectively connected to the two-phase windings of the asymmetrical two-phase induction motor.

[0108] Asymmetrical two-phase induction motors are widely used in industrial and domestic applications, especially in low-power applications. An asymmetrical two-phase induction motor has two windings: a main winding and an auxiliary winding. These two windings have different numbers of turns, typically with the auxiliary winding having more turns than the main winding. To drive such a motor, the auxiliary winding requires a higher voltage supply than the main winding, and the phase difference between the two voltages must always be between them. Only then can good performance be obtained. Usually, it is used... The winding turns ratio is represented by the number of turns in the auxiliary winding divided by the number of turns in the main winding. In this embodiment, to drive an asymmetrical two-phase induction motor, the two-phase reference output voltages should satisfy the following:

[0109]

[0110] in, This is the reference output phase voltage between the midpoints of bridge arms A and B. This phase voltage is output to the auxiliary winding of the motor. This is the reference output phase voltage between the midpoints of the C-bridge arm and the D-bridge arm, which is output to the main winding of the motor. For reference, the amplitude of the output voltage, It is the angular frequency of the current.

[0111] Figure 11 The image shows the ideal output voltage waveforms for a two-phase four-arm inverter. Figure 12 for Figure 11 Waveform diagram of the magnified region. In this embodiment, the sampling frequency used is 5 kHz, and the current angular frequency is 100°. rad / s (corresponding to a current frequency of 50 Hz). .

[0112] Example 5:

[0113] Please see Figure 13 As shown, the present invention also provides an electronic device 100 for a space vector pulse width modulation method for a two-phase four-arm inverter; the electronic device 100 includes a memory 101, at least one processor 102, a computer program 103 stored in the memory 101 and executable on the at least one processor 102, and at least one communication bus 104.

[0114] The memory 101 can be used to store the computer program 103. The processor 102 implements the steps of the space vector pulse width modulation method for the two-phase four-arm inverter described in Embodiment 1 by running or executing the computer program stored in the memory 101 and calling the data stored in the memory 101. The memory 101 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created according to the use of the electronic device 100 (such as audio data), etc. In addition, the memory 101 may include non-volatile memory, such as hard disk, memory, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other non-volatile solid-state storage device.

[0115] The at least one processor 102 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The processor 102 may be a microprocessor or any conventional processor. The processor 102 is the control center of the electronic device 100, connecting various parts of the electronic device 100 via various interfaces and lines.

[0116] The memory 101 in the electronic device 100 stores multiple instructions to implement a space vector pulse width modulation method for a two-phase four-arm inverter, and the processor 102 can execute the multiple instructions to achieve the following:

[0117] Based on the topology of a two-phase four-arm inverter, the basic output voltage vector of the two-phase four-arm inverter is defined, and the space voltage vector diagram of the two-phase four-arm inverter is drawn.

[0118] The space voltage vector diagram of the two-phase four-arm inverter is divided into several sectors, and the sector where the reference voltage vector is located is determined according to the reference voltage vector angle or the reference output voltage value.

[0119] The duration of action of the adjacent voltage vectors and the zero voltage vector in the sector where the reference voltage vector is located is calculated based on the volt-second equivalence principle. Based on the duration of action of the adjacent voltage vectors in the sector where the reference voltage vector is located, it is determined whether the reference output voltage value is in the linear modulation region.

[0120] Based on whether the reference output voltage value is in the linear modulation region, determine whether to proportionally shorten the duration of the voltage vectors adjacent to the sector where the reference voltage vector is located.

[0121] Based on the sector where the reference output voltage vector is located, the duration of action of the adjacent voltage vectors in the sector where the reference voltage vector is located after proportional shortening, and the duration of action of the zero voltage vector, determine the selected switching state, the switching sequence of the switching transistors, and the duration of the switching state.

[0122] Based on the selected switch state, switch sequence, and switch state duration, a drive signal is generated to control the switching of the switch state, thereby controlling the on / off state of each switch in the two-phase four-arm inverter.

[0123] Example 6:

[0124] If the modules / units integrated in the electronic device 100 are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, and a read-only memory (ROM).

[0125] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0126] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0127] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1The function specified in one or more boxes.

[0128] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A space vector pulse width modulation method for a two-phase four-arm inverter, characterized in that, Includes the following steps: Based on the topology of a two-phase four-arm inverter, the basic output voltage vector of the two-phase four-arm inverter is defined, and the space voltage vector diagram of the two-phase four-arm inverter is drawn. The space voltage vector diagram of the two-phase four-arm inverter is divided into several sectors, and the sector where the reference voltage vector is located is determined according to the reference voltage vector angle or the reference output voltage value. The duration of action of the adjacent voltage vectors and the zero voltage vector in the sector where the reference voltage vector is located is calculated based on the volt-second equivalence principle. Based on the duration of action of the adjacent voltage vectors in the sector where the reference voltage vector is located, it is determined whether the reference output voltage value is in the linear modulation region. Based on whether the reference output voltage value is in the linear modulation region, determine whether to proportionally shorten the duration of the voltage vectors adjacent to the sector where the reference voltage vector is located. Based on the sector where the reference output voltage vector is located, the duration of action of the adjacent voltage vectors in the sector where the reference voltage vector is located after proportional shortening, and the duration of action of the zero voltage vector, determine the selected switching state, the switching sequence of the switching transistors, and the duration of the switching state. Based on the selected switch state, switch sequence, and switch state duration, a drive signal is generated to control the switching of the switch state, thereby controlling the on / off state of each switch in the two-phase four-arm inverter.

2. The space vector pulse width modulation method for a two-phase four-arm inverter according to claim 1, wherein the basic output voltage vector includes eight non-zero voltage vectors and one zero voltage vector.

3. The space vector pulse width modulation method for a two-phase four-arm inverter according to claim 1, characterized in that, The step of dividing the drawn space voltage vector diagram of the two-phase four-arm inverter into several sectors and determining the sector where the reference voltage vector is located based on the reference voltage vector angle or the reference output voltage value is as follows: if the angle information of the reference voltage vector is known and the driving load is a two-phase symmetrical load, the judgment is made directly by the reference voltage vector angle; otherwise, the judgment is made based on the reference output voltage value.

4. The space vector pulse width modulation method for a two-phase four-arm inverter according to claim 1, wherein the step of calculating the action time of the adjacent voltage vectors and the zero voltage vector in the sector where the reference voltage vector is located based on the volt-second equivalent principle, and determining whether the reference output voltage value is in the linear modulation region based on the action time of the adjacent voltage vectors in the sector where the reference voltage vector is located, specifically the process of determining whether the reference output voltage value is in the linear modulation region is as follows: when the sum of the action times of the adjacent voltage vectors is greater than the sampling time, the reference output voltage value is not in the linear modulation region; when the sum of the action times of the adjacent voltage vectors is less than or equal to the sampling time, the reference output voltage value is in the linear modulation region.

5. The space vector pulse width modulation method for a two-phase four-arm inverter according to claim 1, characterized in that, The specific determination process for the step of determining whether to proportionally shorten the duration of voltage vectors adjacent to the sector where the reference voltage vector is located based on whether the reference output voltage value is in the linear modulation region is as follows: if the reference output voltage value is not in the linear modulation region, the duration of voltage vectors adjacent to the sector where the reference voltage vector is located is proportionally shortened; if the reference output voltage value is in the linear modulation region, the duration of voltage vectors adjacent to the sector where the reference voltage vector is located is not proportionally shortened.

6. The space vector pulse width modulation method for a two-phase four-arm inverter according to claim 5, characterized in that, The formula for calculating the proportional shortening is: in, and The basic voltage vector after proportional shortening , Duration of action and The basic voltage vector before proportional shortening , Duration of action Sampling time, and These are two adjacent basic voltage vectors of the sector where the reference voltage vector is located.

7. The space vector pulse width modulation method for a two-phase four-arm inverter according to claim 1, characterized in that, The switching transistor is either an IGBT or a MOSFET.

8. A space vector pulse width modulation system for a two-phase four-arm inverter, characterized in that, It includes a space voltage vector partitioning module, a sector judgment module, an action time calculation module, a proportional shortening judgment module, a switch sequence determination module, and a switch tube on / off control module; The space voltage vector partitioning module is used to define the basic output voltage vector of the two-phase four-arm inverter based on the topology of the two-phase four-arm inverter, and to draw the space voltage vector diagram of the two-phase four-arm inverter. The sector determination module is used to divide the drawn space voltage vector diagram of the two-phase four-arm inverter into several sectors, and determine the sector where the reference voltage vector is located based on the reference voltage vector angle or the reference output voltage value. The action time calculation module is used to calculate the action time of the adjacent voltage vectors and zero voltage vector in the sector where the reference voltage vector is located according to the volt-second equivalence principle, and to determine whether the reference output voltage value is in the linear modulation region based on the action time of the adjacent voltage vectors in the sector where the reference voltage vector is located. The proportional shortening judgment module is used to determine whether to proportionally shorten the duration of the voltage vectors adjacent to the sector where the reference voltage vector is located, based on whether the reference output voltage value is in the linear modulation region. The switching sequence determination module is used to determine the selected switch state, the switching sequence of the switch state, and the duration of the switch state based on the sector where the reference output voltage vector is located, the duration of the adjacent voltage vectors of the sector where the reference voltage vector is located after proportional shortening, and the duration of the zero voltage vector. The switching transistor on / off control module is used to generate drive signals to control the switching transistor state switching based on the selected switching transistor state, switching transistor switching sequence and switching transistor state duration, thereby controlling the on / off of each switching transistor of the two-phase four-bridge arm inverter.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the space vector pulse width modulation method for the two-phase four-arm inverter as described in any one of claims 1 to 7.

10. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the space vector pulse width modulation method for the two-phase four-arm inverter as described in any one of claims 1 to 7.

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