A current source inverter topology with energy feedback loop and control method

Abstract

The application is a current source type inverter topology structure with energy feedback loop and a control method. The application relates to the technical field of power electronics and motor control, and a switching tube and a diode are used to provide stable DC side current, so that the controllable operation of the motor is ensured, and on this basis, only a switching tube and a resistor are used to realize the discharge of motor feedback energy, so that the safety and reliability of the motor four-quadrant operation are ensured under the condition of the simplest topology and low cost. Compared with the existing current source inverter system with DCDC front stage, only two switching tubes and a diode are used in the realization of the function, the system is simplified, the reliability of the system is increased, and the cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of power electronics and motor control technology, and is a current source inverter topology with an energy feedback loop and its control method. Background Technology

[0002] Currently, inverters that convert DC to AC energy can be divided into two types: voltage source inverters (VSI) and current source inverters (CSI). Each arm of a VSI bridge has an upper switch and a lower switch, and each switch has an anti-parallel diode to provide a path for reverse current. CSI uses a DC voltage source on the DC side. The DC bus voltage is typically obtained by uncontrolled rectification from a preceding diode converter, followed by filtering and regulation by an electrolytic capacitor on the DC bus to reduce system cost. On the AC side, a modulation strategy generates an AC voltage with variable amplitude and frequency. VSI has a simple structure and is easy to control. Furthermore, due to the mature technology of fully controlled power devices such as IGBTs and MOSFETs, VSI dominates in automotive motor drive systems. However, it suffers from problems such as high switching harmonics in the output voltage, low fault tolerance under short-circuit faults, and limited operating temperature applicability. Unlike VSI, CSI has an energy storage inductor on the DC side, which, together with the voltage source, provides a constant current to the load. Although the topology of CSI is more complex than that of VSI, it still has advantages such as effectively expanding the constant power operating range of high-speed PMSM, eliminating the need to consider short-circuit protection, being able to withstand higher temperatures, and having a long lifespan, which can make up for some of the shortcomings of VSI.

[0003] However, due to limitations in efficiency and cost of DC energy storage and the availability of suitable power switching devices, current source converter solutions still have a lower market share and application rate in industrial applications compared to voltage source inverters. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention improves and simplifies the topology and introduces an energy feedback loop. This provides a high-quality constant current to the current source inverter while also providing an energy feedback channel for the motor, enabling timely processing of the feedback energy and making it possible for the motor to achieve safe and reliable four-quadrant operation.

[0005] This invention provides a current source inverter topology with an energy feedback loop and a control method thereof. The invention provides the following technical solutions:

[0006] A current-source inverter topology with an energy feedback loop, the topology including a DC adjustable power supply U dc Switch S7, diodes VD1, VD2, VD3, VD4, VD5, VD6, VD7, DC-side inductor Ldc Switch S1, Switch S2, Switch S3, Switch S4, Switch S5, Switch S6, Switch S7, Switch S8, Resistor R, Capacitor C fa Capacitor C fb Capacitor C fc and PMSM motor;

[0007] DC adjustable power supply U dc The positive terminal of transistor S7 is connected in series with the collector of transistor S7; the base of transistor S7 is connected in series with the drive signal; the emitter of transistor S7 is connected in series with the cathode of diode VD7; the anode of diode VD7 is connected in series with the emitter of transistor S8; the base of transistor S8 is connected in series with the drive signal; the collector of transistor S8 is connected in series with the DC adjustable power supply U. dc The negative extreme.

[0008] Preferably, the anode of diode VD7 is connected in series with a resistor R and a DC adjustable power supply U. dc The negative extreme;

[0009] The emitter of the switching transistor S7 is connected in series with an inductor L. dc The collector of switch S1 is connected in series with the base of switch S1, which is connected to the drive signal. The emitter of switch S1 is connected in series with the anode of diode VD1. The cathode of diode VD1 is connected in series with the collector of switch S4. The base of switch S4 is connected to the drive signal. The emitter of switch S4 is connected in series with the anode of diode VD4. The cathode of diode VD4 is connected in series with the DC adjustable power supply U. dc The negative extreme.

[0010] Preferably, the emitter of the switching transistor S7 is connected in series with an inductor L. dc The collector of switch S3 is connected in series with the base of switch S3; the anode of diode VD3 is connected in series with the emitter of switch S3; the cathode of diode VD3 is connected in series with the collector of switch S6; the base of switch S6 is connected in series with the drive signal; the anode of diode VD6 is connected in series with the emitter of switch S6; the cathode of diode VD6 is connected in series with the DC adjustable power supply U. dc The negative extreme.

[0011] Preferably, the emitter of the switching transistor S7 is connected in series with an inductor L. dc The collector of switch S5 is connected in series with the base of switch S5, which is connected to the drive signal. The emitter of switch S5 is connected in series with the anode of diode VD5. The cathode of diode VD5 is connected in series with the collector of switch S2. The base of switch S2 is connected to the drive signal. The emitter of switch S2 is connected in series with the anode of diode VD2. The cathode of diode VD2 is connected in series with the DC adjustable power supply U. dc The negative extreme.

[0012] Preferably, the cathode of diode VD1 is connected in series with phase A of the PMSM motor; the cathode of diode VD3 is connected in series with phase B of the PMSM motor; and the cathode of diode VD5 is connected in series with phase C of the PMSM motor.

[0013] The cathode series capacitance C of diode VD1 fa One end; the cathode of diode VD3 connected in series with capacitor C. fb One end; the cathode of diode VD5 connected in series with capacitor C. fc One end; capacitor C fa The other end, capacitor C fb The other end and capacitor C fc The other end is connected.

[0014] Preferably, based on the DC bus sampling current i dc and setting the DC bus current i dc *and the safe current value i given during energy feedback. fb * Compare the settings to determine the switching states of transistors S7 and S8;

[0015] Based on the on / off states of switching transistors S7 and S8, the topology is divided into four operating modes: power supply mode, inductor freewheeling mode, and energy feedback mode.

[0016] Preferably, when the topology is in power supply mode, switch S7 is turned on and switch S8 is turned on.

[0017] When the topology is in inductor freewheeling mode, switch S7 is off and switch S8 is on.

[0018] When the topology is in energy feedback mode, switch S7 is turned off and switch S8 is turned off.

[0019] A control method for a current source inverter with an energy feedback loop, the method comprising the following steps:

[0020] Real-time sampling of DC side current i using a current sensor dc When the sampling current i dc Less than a given i dc When * occurs, S7 is open, S8 remains open, entering power supply mode, and the DC side current increases; when the sampling current i dc Greater than a given i dc When S7 is closed and S8 remains open, the system enters inductor freewheeling mode, and the DC-side current decreases slowly. When a large amount of energy is fed back from the motor to the DC side, S7 and S8 close, entering energy feedback mode. Current flows through the resistor, consuming the feedback energy, and the DC-side current is limited to the threshold value i. fb *

[0021] A computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement a current-source inverter control method with an energy feedback loop.

[0022] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement a current source inverter control method with an energy feedback loop.

[0023] The present invention has the following beneficial effects:

[0024] Compared with the prior art, the present invention:

[0025] This invention provides a stable DC current using only one switching transistor and one diode, thereby ensuring the controllable operation of the motor. Furthermore, it uses only one switching transistor and one resistor to discharge the motor's regenerative energy, ensuring the safe and reliable operation of the motor in four quadrants with a simple topology and low cost.

[0026] Compared to existing methods, the novel current source inverter topology with energy feedback loop of this invention can ensure a stable DC current supply on the DC side while effectively handling the large amount of feedback energy transmitted from the motor to the front stage due to operating conditions such as motor braking, thereby improving system performance and ensuring safe system operation. Compared to existing current source inverter systems with DC-DC converters in the front stage, this invention uses only two switching transistors and one diode to achieve the desired functionality, simplifying the system, increasing its reliability, and reducing costs. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a topology diagram of a current source inverter with an energy feedback loop;

[0029] Figure 2 This is a flowchart of the mode switching judgment logic of the present invention;

[0030] Figure 3 The DC-side current simulation waveform is shown when the current source inverter topology with energy feedback loop of the present invention is adopted.

[0031] Figure 4The simulation waveform of the DC-side braking current when using the current source inverter topology with energy feedback loop of the present invention;

[0032] Figure 5 The simulation waveform of the three-phase current of the motor is shown when the current source inverter topology with energy feedback loop of the present invention is adopted. Detailed Implementation

[0033] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] The present invention will be described in detail below with reference to specific embodiments. Specific Implementation Example 1:

[0039] according to Figures 1-5 As shown, the specific optimized technical solution adopted by the present invention to solve the above-mentioned technical problems is: The present invention relates to a current source inverter topology with an energy feedback loop and a control method.

[0040] This invention provides a current-source inverter topology with an energy feedback loop, the topology including a DC adjustable power supply U. dc Switch S7, diodes VD1, VD2, VD3, VD4, VD5, VD6, VD7, DC-side inductor L dc Switch S1, Switch S2, Switch S3, Switch S4, Switch S5, Switch S6, Switch S7, Switch S8, Resistor R, Capacitor C fa Capacitor C fb Capacitor C fc and PMSM motor;

[0041] DC adjustable power supply U dc The positive terminal of transistor S7 is connected in series with the collector of transistor S7; the base of transistor S7 is connected in series with the drive signal; the emitter of transistor S7 is connected in series with the cathode of diode VD7; the anode of diode VD7 is connected in series with the emitter of transistor S8; the base of transistor S8 is connected in series with the drive signal; the collector of transistor S8 is connected in series with the DC adjustable power supply U. dc The negative extreme.

[0042] This invention proposes a current-source inverter topology with an energy feedback loop and its control method. The topology includes a constant voltage source, a constant current source system consisting of a switch (S7), a diode, and a DC-side inductor, a feedback energy discharge loop consisting of a switch (S8) and a resistor, a basic current-source inverter, and a permanent magnet synchronous motor. The DC-side current i is sampled in real time using a current sensor. dc When the sampling current i dc Less than a given i dc When * occurs, S7 is open, S8 remains open, entering power supply mode, and the DC side current increases; when the sampling current i dc Greater than a given i dc When S7 is closed and S8 remains open, the system enters inductor freewheeling mode, and the DC-side current decreases slowly. When a large amount of energy is fed back from the motor to the DC side, S7 and S8 close, entering energy feedback mode. Current flows through the resistor, consuming the feedback energy, and the DC-side current is limited to the threshold value i. fb *

[0043] Compared to existing methods, the novel current source inverter topology with energy feedback loop of this invention can ensure a stable DC current supply on the DC side while effectively handling the large amount of feedback energy transmitted from the motor to the front stage due to operating conditions such as motor braking, thereby improving system performance and ensuring safe system operation. Compared to existing current source inverter systems with DC-DC converters in the front stage, this invention uses only two switching transistors and one diode to achieve the desired functionality, simplifying the system, increasing its reliability, and reducing costs. Specific Implementation Example 2:

[0045] The difference between Embodiment 2 and Embodiment 1 of the present invention lies only in:

[0046] The anode of diode VD7 is connected in series with a resistor R and a DC adjustable power supply U. dc The negative extreme;

[0047] The emitter of the switching transistor S7 is connected in series with an inductor L. dc The collector of switch S1 is connected in series with the base of switch S1, which is connected to the drive signal. The emitter of switch S1 is connected in series with the anode of diode VD1. The cathode of diode VD1 is connected in series with the collector of switch S4. The base of switch S4 is connected to the drive signal. The emitter of switch S4 is connected in series with the anode of diode VD4. The cathode of diode VD4 is connected in series with the DC adjustable power supply U. dc The negative extreme. Specific Implementation Example 3:

[0049] The difference between Embodiment 3 and Embodiment 2 of the present invention lies only in:

[0050] The emitter of the switching transistor S7 is connected in series with an inductor L. dc The collector of switch S3 is connected in series with the base of switch S3; the anode of diode VD3 is connected in series with the emitter of switch S3; the cathode of diode VD3 is connected in series with the collector of switch S6; the base of switch S6 is connected in series with the drive signal; the anode of diode VD6 is connected in series with the emitter of switch S6; the cathode of diode VD6 is connected in series with the DC adjustable power supply U. dc The negative extreme. Specific Implementation Example 4:

[0052] The only difference between Embodiment 4 and Embodiment 3 of the present invention is that:

[0053] The emitter of the switching transistor S7 is connected in series with an inductor L. dc The collector of switch S5 is connected in series with the base of switch S5, which is connected to the drive signal. The emitter of switch S5 is connected in series with the anode of diode VD5. The cathode of diode VD5 is connected in series with the collector of switch S2. The base of switch S2 is connected to the drive signal. The emitter of switch S2 is connected in series with the anode of diode VD2. The cathode of diode VD2 is connected in series with the DC adjustable power supply U.dc The negative extreme. Specific Implementation Example 5:

[0055] The difference between Embodiment 5 and Embodiment 4 of the present invention lies only in:

[0056] The cathode of diode VD1 is connected in series with phase A of the PMSM motor; the cathode of diode VD3 is connected in series with phase B of the PMSM motor; the cathode of diode VD5 is connected in series with phase C of the PMSM motor.

[0057] The cathode series capacitance C of diode VD1 fa One end; the cathode of diode VD3 connected in series with capacitor C. fb One end; the cathode of diode VD5 connected in series with capacitor C. fc One end; capacitor C fa The other end, capacitor C fb The other end and capacitor C fc The other end is connected. Specific Implementation Example Six:

[0059] The difference between Embodiment Six and Embodiment Five of the present invention lies only in:

[0060] Based on the DC bus sampling current i dc and setting the DC bus current i dc *and the safe current value i given during energy feedback. fb * Compare the settings to determine the switching states of transistors S7 and S8;

[0061] Based on the on / off states of switching transistors S7 and S8, the topology is divided into four operating modes: power supply mode, inductor freewheeling mode, and energy feedback mode. Specific Implementation Example 7:

[0063] The difference between Embodiment Seven and Embodiment Six of the present invention lies only in:

[0064] When the topology is in power supply mode, switch S7 is turned on and switch S8 is turned on.

[0065] When the topology is in inductor freewheeling mode, switch S7 is off and switch S8 is on.

[0066] When the topology is in energy feedback mode, switch S7 is turned off and switch S8 is turned off. Specific Implementation Example 8:

[0068] The difference between Embodiment 8 and Embodiment 7 of the present invention lies only in:

[0069] This invention provides a control method for a current source inverter with an energy feedback loop, the method comprising the following steps:

[0070] Real-time sampling of DC side current i using a current sensor dc When the sampling current i dc Less than a given i dc When * occurs, S7 is open, S8 remains open, entering power supply mode, and the DC side current increases; when the sampling current i dc Greater than a given i dc When S7 is closed and S8 remains open, the system enters inductor freewheeling mode, and the DC-side current decreases slowly. When a large amount of energy is fed back from the motor to the DC side, S7 and S8 close, entering energy feedback mode. Current flows through the resistor, consuming the feedback energy, and the DC-side current is limited to the threshold value i. fb * Specific Implementation Example Nine:

[0072] The difference between Embodiment Nine and Embodiment Eight of the present invention lies only in:

[0073] The present invention provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement a current-source inverter control method with an energy feedback loop, for example. Specific Implementation Example 10:

[0075] The only difference between Embodiment 10 and Embodiment 9 of the present invention is that:

[0076] The present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement a current source inverter control method with an energy feedback loop. Specific Implementation Example Eleven:

[0078] The present invention mainly adopts the following technical solution:

[0079] The topology includes a constant voltage source, a constant current source system consisting of a switch (S7), a diode, and a DC-side inductor, a feedback energy discharge circuit consisting of a switch (S8) and a resistor, a basic current source inverter, and a permanent magnet synchronous motor. The DC-side current i is sampled in real time using a current sensor. dc When the sampling current i dc Less than a given i dc When * occurs, S7 is open, S8 remains open, entering power supply mode, and the DC side current increases; when the sampling current i dc Greater than a given i dcWhen S7 is closed and S8 remains open, the system enters inductor freewheeling mode, and the DC-side current decreases slowly. When a large amount of energy is fed back from the motor to the DC side, S7 and S8 close, entering energy feedback mode. Current flows through the resistor, consuming the feedback energy, and the DC-side current is limited to the threshold value i. fb *

[0080] The specific principles and implementation steps are as follows:

[0081] The specific circuit structure is as follows:

[0082] Record the DC adjustable power supply U dc The end with the positive electrode is called end A, and the end with the negative electrode is called end B;

[0083] Terminal A is connected in series with the collector of switch S7; the base of switch S7 is connected to the drive signal; the emitter of switch S7 is connected in series with the cathode of diode VD7; the anode of diode VD7 is connected in series with the emitter of switch S8; the base of switch S8 is connected to the drive signal; the collector of switch S8 is connected in series with terminal B.

[0084] The anode of diode VD7 is connected in series with a resistor and terminal B.

[0085] The emitter of the switching transistor S7 is connected in series with an inductor L. dc The collector of switch S1; the base of switch S1 is connected to the drive signal; the emitter of switch S1 is connected in series with the anode of diode VD1; the cathode of diode VD1 is connected in series with the collector of switch S4; the base of switch S4 is connected to the drive signal; the emitter of switch S4 is connected in series with the anode of diode VD4; the cathode of diode VD4 is connected in series with terminal B.

[0086] The emitter of the switching transistor S7 is connected in series with an inductor L. dc The collector of switch S3; the base of switch S3 is connected to the drive signal; the emitter of switch S3 is connected in series with the anode of diode VD3; the cathode of diode VD3 is connected in series with the collector of switch S6; the base of switch S6 is connected to the drive signal; the emitter of switch S6 is connected in series with the anode of diode VD6; the cathode of diode VD6 is connected in series with terminal B.

[0087] The emitter of the switching transistor S7 is connected in series with an inductor L. dc The collector of switch S5; the base of switch S5 is connected to the drive signal; the emitter of switch S5 is connected in series with the anode of diode VD5; the cathode of diode VD5 is connected in series with the collector of switch S2; the base of switch S2 is connected to the drive signal; the emitter of switch S2 is connected in series with the anode of diode VD2; the cathode of diode VD2 is connected in series with terminal B.

[0088] The cathodes of diode VD1 are connected in series with the motor in phase A; the cathodes of diode VD3 are connected in series with the motor in phase B; the cathodes of diode VD5 are connected in series with the motor in phase C.

[0089] The cathode series capacitance C of diode VD1 fa One end; the cathode of diode VD3 connected in series with capacitor C. fb One end; the cathode of diode VD5 connected in series with capacitor C. fc One end; capacitor C fa The other end, capacitor C fb The other end, capacitor C fc The other end is connected.

[0090] Based on the DC bus sampling current i dc and setting the DC bus current i dc *and the safe current value i given during energy feedback. fb * The switching states of switching transistors S7 and S8 are set by comparison. Based on the on / off states of switching transistors S7 and S8, the new current-source inverter topology with energy feedback loop is divided into four operating modes: power supply mode, inductor freewheeling mode, and energy feedback mode.

[0091] When the new current source inverter topology with energy feedback loop is in power supply mode, switch S7 is turned on and switch S8 is turned on.

[0092] When the new current source inverter topology with energy feedback loop is in inductor freewheeling mode, switch S7 is turned off and switch S8 is turned on.

[0093] When the new current source inverter topology with energy feedback loop is in energy feedback mode, switch S7 is turned off and switch S8 is turned off.

[0094] This invention provides a stable DC current using only one switching transistor and one diode, thereby ensuring the controllable operation of the motor. Furthermore, it uses only one switching transistor and one resistor to discharge the motor's regenerative energy, ensuring the safe and reliable operation of the motor in four quadrants with a simple topology and low cost. Specific Implementation Example Twelve:

[0096] Figure 1 The complete topology of this invention includes a constant voltage source, a constant current source system consisting of a switching transistor (S7), a diode, and a DC-side inductor, a feedback energy discharge circuit consisting of a switching transistor (S8) and a resistor, a basic current source inverter, and a permanent magnet synchronous motor. The DC-side current i is sampled in real time using a current sensor. dc When the sampling current i dc Less than a given i dcWhen * occurs, S7 is open, S8 remains open, entering power supply mode, and the DC side current increases; when the sampling current i dc Greater than a given i dc When * is in operation, S7 is off and S8 remains on, entering inductor freewheeling mode, and the DC-side current decreases slowly; when a large amount of energy is fed back from the motor to the DC side, S7 and S8 are off, entering energy feedback mode, current flows through the resistor to consume the feedback energy, and the DC-side current is limited to the threshold i. fb *

[0097] The specific principles and implementation steps are as follows:

[0098] The specific circuit structure is as follows:

[0099] Record the DC adjustable power supply U dc The end with the positive electrode is called end A, and the end with the negative electrode is called end B;

[0100] Terminal A is connected in series with the collector of switch S7; the base of switch S7 is connected to the drive signal; the emitter of switch S7 is connected in series with the cathode of diode VD7; the anode of diode VD7 is connected in series with the emitter of switch S8; the base of switch S8 is connected to the drive signal; the collector of switch S8 is connected in series with terminal B.

[0101] The anode of diode VD7 is connected in series with a resistor and terminal B.

[0102] The emitter of the switching transistor S7 is connected in series with an inductor L. dc The collector of switch S1; the base of switch S1 is connected to the drive signal; the emitter of switch S1 is connected in series with the anode of diode VD1; the cathode of diode VD1 is connected in series with the collector of switch S4; the base of switch S4 is connected to the drive signal; the emitter of switch S4 is connected in series with the anode of diode VD4; the cathode of diode VD4 is connected in series with terminal B.

[0103] The emitter of the switching transistor S7 is connected in series with an inductor L. dc The collector of switch S3; the base of switch S3 is connected to the drive signal; the emitter of switch S3 is connected in series with the anode of diode VD3; the cathode of diode VD3 is connected in series with the collector of switch S6; the base of switch S6 is connected to the drive signal; the emitter of switch S6 is connected in series with the anode of diode VD6; the cathode of diode VD6 is connected in series with terminal B.

[0104] The emitter of the switching transistor S7 is connected in series with an inductor L. dc The collector of switch S5; the base of switch S5 is connected to the drive signal; the emitter of switch S5 is connected in series with the anode of diode VD5; the cathode of diode VD5 is connected in series with the collector of switch S2; the base of switch S2 is connected to the drive signal; the emitter of switch S2 is connected in series with the anode of diode VD2; the cathode of diode VD2 is connected in series with terminal B.

[0105] The cathodes of diode VD1 are connected in series with the motor in phase A; the cathodes of diode VD3 are connected in series with the motor in phase B; the cathodes of diode VD5 are connected in series with the motor in phase C.

[0106] The cathode series capacitance C of diode VD1 fa One end; the cathode of diode VD3 connected in series with capacitor C. fb One end; the cathode of diode VD5 connected in series with capacitor C. fc One end; capacitor C fa The other end, capacitor C fb The other end, capacitor C fc The other end is connected.

[0107] Figure 2 This is a flowchart of the mode switching judgment logic of the present invention. Based on the DC bus sampling current i... dc and setting the DC bus current i dc *and the safe current value i given during energy feedback. fb * The switching states of switching transistors S7 and S8 are set by comparison. Based on the on / off status of switching transistors S7 and S8, the new current source inverter topology with energy feedback loop is divided into four operating modes: power supply mode, inductor freewheeling mode, and energy feedback mode.

[0108] When the new current source inverter topology with energy feedback loop is in power supply mode, switch S7 is turned on and switch S8 is turned on.

[0109] When the new current source inverter topology with energy feedback loop is in inductor freewheeling mode, switch S7 is turned off and switch S8 is turned on.

[0110] When the new current source inverter topology with energy feedback loop is in energy feedback mode, switch S7 is turned off and switch S8 is turned off.

[0111] Figure 3 The DC-side current simulation waveform is shown when using the novel current-source inverter topology with energy feedback loop of this invention; i is set. dc * is 50A;

[0112] Figure 4 The simulation waveform of the DC-side braking current is shown when using the novel current-source inverter topology with energy feedback loop of this invention; i is set. fb * is 52A;

[0113] Figure 5 The simulation waveform of the three-phase current of the motor is shown when the novel current source inverter topology with energy feedback loop of the present invention is adopted.

[0114] As can be seen from the simulation waveforms above, the novel current-source inverter topology with energy feedback loop of this invention can provide the necessary constant current for the current-source inverter, ensuring the normal operation of the motor. Furthermore, when the motor feeds energy back to the upstream stage, the fed-back energy is promptly released, ensuring that the DC bus current is controlled below a specified value.

[0115] The above description is merely a preferred embodiment of a current-source inverter topology and control method with an energy feedback loop. The scope of protection for this current-source inverter topology and control method with an energy feedback loop is not limited to the above embodiments; all technical solutions falling within this conceptual framework are within the protection scope of this invention. It should be noted that for those skilled in the art, any improvements and variations made without departing from the principles of this invention should also be considered within the protection scope of this invention.

Claims

1. A current-source inverter topology with an energy feedback loop, characterized in that: The topology includes a DC adjustable power supply. Switch S7, diodes VD1, VD2, VD3, VD4, VD5, VD6, VD7, DC-side inductor Switch S1, Switch S2, Switch S3, Switch S4, Switch S5, Switch S6, Switch S7, Switch S8, Resistor R, Capacitor ,capacitance ,capacitance and PMSM motor; DC adjustable power supply The positive terminal of transistor S7 is connected in series with the collector of transistor S7; the base of transistor S7 is connected in series with the drive signal; the emitter of transistor S7 is connected in series with the cathode of diode VD7; the anode of diode VD7 is connected in series with the emitter of transistor S8; the base of transistor S8 is connected in series with the drive signal; the collector of transistor S8 is connected in series with a DC adjustable power supply. The negative extreme; The anode of diode VD7 is connected in series with resistor R and a DC adjustable power supply. The negative extreme; The emitter of the switching transistor S7 is connected in series with an inductor. The collector of switch S1 is connected in series with the base of switch S1, which is connected to the drive signal. The emitter of switch S1 is connected in series with the anode of diode VD1. The cathode of diode VD1 is connected in series with the collector of switch S4. The base of switch S4 is connected to the drive signal. The emitter of switch S4 is connected in series with the anode of diode VD4. The cathode of diode VD4 is connected in series with the DC adjustable power supply. The negative extreme; The emitter of the switching transistor S7 is connected in series with an inductor. The collector of switch S3 is connected in series with the base of switch S3; the anode of diode VD3 is connected in series with the emitter of switch S3; the cathode of diode VD3 is connected in series with the collector of switch S6; the base of switch S6 is connected in series with the drive signal; the anode of diode VD6 is connected in series with the emitter of switch S6; the cathode of diode VD6 is connected in series with the DC adjustable power supply. The negative extreme; The emitter of the switching transistor S7 is connected in series with an inductor. The collector of switch S5 is connected in series with the base of switch S5; the anode of diode VD5 is connected in series with the emitter of switch S5; the cathode of diode VD5 is connected in series with the collector of switch S2; the base of switch S2 is connected in series with the drive signal; the anode of diode VD2 is connected in series with the emitter of switch S2; the cathode of diode VD2 is connected in series with the DC adjustable power supply. The negative extreme; Based on DC bus sampling current and setting DC bus current and the safe current value given during energy feedback. The switching states of transistors S7 and S8 are set by comparison; According to the on / off state of switching transistors S7 and S8, the topology is divided into three operating modes: power supply mode, inductor freewheeling mode, and energy feedback mode. When the topology is in power supply mode, switch S7 is turned on and switch S8 is turned on. When the topology is in inductor freewheeling mode, switch S7 is off and switch S8 is on. When the topology is in energy feedback mode, switch S7 is turned off and switch S8 is turned off.

2. The topology according to claim 1, characterized in that: The cathode of diode VD1 is connected in series with phase A of the PMSM motor; the cathode of diode VD3 is connected in series with phase B of the PMSM motor; the cathode of diode VD5 is connected in series with phase C of the PMSM motor. Cathode series capacitance of diode VD1 One end; the cathode of diode VD3 connected in series with the capacitor. One end; the cathode of diode VD5 connected in series with the capacitor. One end; capacitor The other end, capacitor The other end and the capacitor The other end is connected.

3. A control method for a current source inverter with an energy feedback loop, the method being used to control the topology described in claim 1, characterized in that: The method includes the following steps: Real-time sampling of DC-side current using a current sensor When sampling current Less than given When S7 is open and S8 remains open, the system enters power supply mode, and the DC side current increases; when the sampling current... Greater than given When S7 is closed and S8 remains open, the system enters inductor freewheeling mode, and the DC-side current decreases slowly. When a large amount of energy is fed back from the motor to the DC side, S7 and S8 close, and the system enters energy feedback mode. Current flows through the resistor, consuming the feedback energy, and the DC-side current is limited to a threshold value. .

4. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the method as claimed in claim 3.

5. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: The processor implements the method of claim 3 when executing the computer program.

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