High fault-tolerant current source type inverter topology for driving open winding

Abstract

The invention discloses a high fault-tolerant current source type inverter topology for driving an open winding, belongs to the field of motor control, and aims to solve the problems that the short-circuit fault-tolerant capability of the traditional current source type inverter topology is insufficient and the open-circuit voltage spike is difficult to restrain. The inverter comprises a direct current source, a bus inductor and an inverter unit, wherein the direct current source and the bus inductor are connected in series to provide stable and controllable direct current for the inverter unit; the inverter unit comprises two groups of parallel branches formed by switching devices and diodes, n output ports are formed to supply power to each phase winding, a single and continuous bus current path can be continuously maintained after the switching devices are short-circuited, and short-circuit fault-tolerant control is further realized. The positions of the switching devices and the diodes in the two groups of parallel branches are arranged in a mutually crossed manner, and the n + 1 flying capacitors are connected between the upper branch and the lower branch of the inversion unit, so that the flying capacitors and the two adjacent diodes can form a continuous current path in the transient process after the switching devices are open-circuited, and the overvoltage problem is prevented.

Description

Technical Field

[0001] The invention relates to a high fault-tolerant current source inverter topology for driving an open winding, and belongs to the field of motor control. Background Art

[0002] Motor systems occupy an important position in modern industry and are widely used in many industries such as aerospace, transportation, industrial robots, and household appliances. Motor drivers drive motors through electrical energy conversion and are key components of motor systems. As the application field continues to expand, the complex and changeable operating environment has increasingly stringent requirements on the reliability of motor systems. During operation, they often face complex working conditions such as variable loads, variable temperatures, and instantaneous high overloads, which will cause frequent and severe electrical and thermal stresses on the switching devices of the motor driver, easily causing short circuits or open circuit failures in the switching devices, posing a serious threat to the safety and stability of the motor system. As a driver topology with high reliability, the current source inverter topology has attracted widespread attention from scholars at home and abroad in recent years. The current source inverter uses an inductor as an energy storage device and directly outputs AC current to the load through a pulse width modulation process. It has stronger short-circuit fault resistance and higher current regulation accuracy, and has significant advantages in reliability, environmental adaptability, and torque output quality. For the traditional half-bridge three-phase or multi-phase current source inverter topology, although it has the ability to suppress transient short-circuit current spikes, due to the parallel relationship between the bridge arms of each phase in the half-bridge topology, the low-impedance path formed by the short-circuited bridge arm will have a shunt effect on the remaining healthy bridge arm, resulting in uncontrolled output current, and it is difficult to achieve short-circuit fault tolerance. On the other hand, in the case of an open-circuit failure of the switching device, the bus current will be intermittent, causing overvoltage problems, seriously affecting system safety. Summary of the invention

[0003] In order to solve the problems of insufficient short-circuit fault tolerance and difficulty in suppressing open-circuit voltage spikes in conventional current source inverter topologies, the present invention provides a high-fault-tolerant current source inverter topology for driving open windings.

[0004] The invention discloses a high fault-tolerant current source inverter topology for driving an open winding, comprising a DC current source I p , bus inductance L dc and inverter unit, DC current source I p and bus inductance L dc The series connection provides a stable and controllable DC current to the inverter unit;

[0005] The inverter unit includes a switching device S 1 To S 2n+2 、Diode D 1 To D 2n+2 、Flying capacitor C f1 To Cfn+1 And filter capacitor C s1 To C sn ; Where n is greater than or equal to 2; The inverter unit is divided into two groups of parallel odd-even parallel branches, upper and lower;

[0006] From left to right on the upper branch, follow D 1 ,S 1 ,D 3 ,S 3 ,D 5 ,S 5 ,…,D 2n+1 ,S 2n+1 The lower branch is connected in series from left to right in the order of S 2 ,D 2 ,S 4 ,D 4 ,S 6 ,D 6 ,…,S 2n+2 ,D 2n+2 The conduction direction of the diode is opposite to the conduction direction of the anti-parallel diode of the switching device; S 2i-1 The negative electrode and S 2i+2 The positive pole of the inverter is the i-th output port, i = 1, 2, ..., n, and the 1st to nth output ports of the inverter are respectively connected to the motor phase winding w s1 tow sn The two ends are connected;

[0007] D 2j-1 The cathode and D 2j The anodes are connected through a flying capacitor, j = 1, 2, ..., n + 1;

[0008] Under normal working conditions, S 2i-1 With S 2i Complementary conduction;

[0009] When a switching device S k When a short circuit occurs, the original switch state includes S k = 1, the switch status effect is not affected, including S k = 0, the effect of some switch states changes, k = 1, 2, ..., 2n + 2;

[0010] When a switching device S k When an open circuit fault occurs, the transient condition is with S k The connected flying capacitor and the two adjacent diodes form a continuous current path to suppress the voltage spike. Under steady-state conditions, it will be connected to S k The working mode of the healthy switch device connected to the same flying capacitor is adjusted to a normally-on state to ensure the continuity of the bus current.

[0011] Preferably, the types of switching devices include but are not limited to insulated gate bipolar transistors IGBTs, metal-oxide semiconductor field effect transistors MOSFETs, gate turn-off thyristors GTOs, integrated gate-commutated thyristors IGCTs, thyristors and other fully controlled or semi-controlled semiconductor devices.

[0012] Preferably, the DC current source I p It is realized by using batteries, or through DC-DC, AC-DC power electronic conversion devices.

[0013] Preferably, the winding w s1 tow sn Arranged from left to right in phase sequence, the phases of the winding back electromotive force differ by 2π / n.

[0014] Preferably, each phase winding is connected in parallel with a filter capacitor.

[0015] Beneficial effects of the present invention: A high-fault-tolerant current source inverter topology for driving an open winding of the present invention has both short-circuit and open-circuit fault tolerance capabilities for switching devices. For short-circuit faults of switching devices, by adjusting the working modes of the remaining switching devices, a single continuous bus current path can continue to be guaranteed, thereby realizing short-circuit fault-tolerant control; for open-circuit faults of switching devices, at the moment of open circuit, the continuous current path formed by the flying capacitor and the adjacent diode solves the overvoltage problem caused by the discontinuous bus current, and by adjusting the working modes of the remaining switching devices, open-circuit fault-tolerant control is realized. When the number of motor phases is the same, the number of switching devices and diodes required by the present invention is 2 more than the number required by the traditional half-bridge topology, which significantly improves the fault-tolerant capability of the topology on the basis of increasing the number of devices. Therefore, the present invention is very suitable for high-reliability application fields such as aerospace, ship propulsion, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a high fault-tolerant current source inverter topology structure for driving an open winding according to the present invention;

[0017] Figure 2 It is a high fault-tolerant current source inverter topology structure driving an open winding corresponding to the n=3 example;

[0018] Figure 3 It is a circuit diagram of the inverter of the present invention when a short circuit fault occurs;

[0019] Figure 4 is a transient circuit diagram of an inverter of the present invention having an open circuit fault;

[0020] Figure 5 This is a steady-state circuit diagram of the inverter of the present invention when an open circuit fault occurs.

[0021] In the figure, S1 ,S 2 ,S 3 ,S 4 ,S 5 ,S 6 ,…S 2n+1 ,S 2n+2 is the switching device, D 1 ,D 2 ,D 3 ,D 4 ,D 5 ,D 6 ,…,D 2n+1 ,D 2n+2 For diode, C f1 ,C f2 ,C f3 ,…,C fn+1 is the flying capacitor, C s1 ,C s2 ,C s3 ,…,C sn is the filter capacitor, w s1 ,w s2 ,…,w sn For the motor winding. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0024] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0025] Specific implementation method 1: The following is combined Figures 1 to 5 The present embodiment is described. The present embodiment describes a high fault-tolerant current source inverter topology for driving an open winding, including a DC current source I p , bus inductance L dc and inverter unit, DC current source I p and bus inductance L dcThe series connection provides a stable and controllable DC current to the inverter unit; the inverter unit contains two sets of parallel branches composed of switching devices and diodes, forming n output ports to supply power to each phase winding, which can continue to ensure a single continuous bus current path after the switching device is short-circuited, further realizing short-circuit fault-tolerant control, and at the same time, parallel filter capacitors at both ends of the winding absorb switching harmonic current to ensure high-quality current output. The switching devices and diodes in the two sets of parallel branches are arranged crosswise with each other, and by connecting n+1 flying capacitors between the upper and lower branches of the inverter unit, in the transient process after the switching device is open-circuited, the flying capacitor can form a continuous current path with the two adjacent diodes to prevent overvoltage problems.

[0026] Specifically, the inverter unit includes a switching device S 1 To S 2n+2 、Diode D 1 To D 2n+2 、Flying capacitor C f1 To C fn+1 And filter capacitor C s1 To C sn ; Where n is greater than or equal to 2; the inverter unit is divided into two groups of parallel odd-even parallel branches, the number of switching devices and diodes in each branch is n+1, the switching devices and diodes with odd subscript numbers are located in the upper branch, and the switching devices and diodes with even subscript numbers are located in the lower branch.

[0027] D 1 The anode and S 2 The collector (or drain) is connected to the left end of the inverter unit, S 2n+1 The emitter (or source) and D 2n+2 The cathode is connected to the right end of the inverter unit.

[0028] From left to right on the upper branch, follow D 1 ,S 1 ,D 3 ,S 3 ,D 5 ,S 5 ,…,D 2n+1 ,S 2n+1 The lower branch is connected in series from left to right in the order of S 2 ,D 2 ,S 4 ,D 4 ,S 6 ,D 6 ,…,S 2n+2 ,D 2n+2 The conduction direction of the diode is opposite to the conduction direction of the anti-parallel diode of the switching device; S 2i-1 The negative electrode and S 2i+2The positive pole of the inverter is the i-th output port, i = 1, 2, ..., n. Specifically, S 1 The emitter (or source) and S 4 The collector (or drain) is the first output port, S 3 The emitter (or source) and S 6 The collector (or drain) is the second output port, which is connected to S 2n-1 The emitter (or source) and S 2n+2 The collector (or drain) is the nth output port;

[0029] The first to n output ports of the inverter are connected to the motor phase windings w s1 tow sn Each phase winding is connected in parallel with a filter capacitor to absorb the switching harmonic current and ensure high-quality current output.

[0030] D 2j-1 The cathode and D 2j The anodes are connected through a flying capacitor, j = 1, 2, ..., n + 1; specifically, D 1 The cathode and D 2 The first flying capacitor C f1 Connected, D 3 The cathode and D 4 The anode of f2 Connected, right to D 2n+1 The cathode and D 2n+2 The anodes of fn+1 connected.

[0031] Under normal working conditions, S 2i-1 With S 2i Complementary conduction; S 1 With S 2 , S 3 With S 4 , S 5 With S 6 ... to S 2n+1 With S 2n+2 , forming n+1 pairs of switch devices, the two switch devices in each pair are complementary and conductive, ensuring a continuous bus current path, with a total of 2 n+1 A switch state.

[0032] When a switching device S k When a short circuit occurs, the original switch state includes S k = 1 (indicating that the switch device is in the on state) is not affected, including S k= 0 (indicates that the switch device is in the off state) and the effect of some switch states changes, k = 1, 2, ..., 2n + 2. Figure 3 , when 3≤k≤2n, the number of switch states that can continue to ensure a single continuous bus current path and the effect remains unchanged is reduced to 2 n +2 n-2 ; When k = 1, 2, 2n + 1, 2n + 2, the number of switch states that can continue to ensure a single continuous bus current path and the effect remains unchanged is reduced to 2 n +2 n-1 . Further realize short-circuit fault-tolerant control.

[0033] When a switching device S k In case of an open circuit fault, refer to Figure 4 , under transient conditions with S k The connected flying capacitor and two adjacent diodes form a continuous current path to suppress the voltage spike, with S 4 Take an open circuit fault as an example. At the moment of opening, 4 The connected flying capacitor C f2 Can be connected with diode D 3 and D 4 It forms a continuous current path and solves the overvoltage problem caused by the intermittent bus current. Figure 5 Under steady-state conditions, the working mode of the healthy switch device connected to the same flying capacitor as the open-circuit switch device is adjusted to the normally-on state to ensure the continuity of the bus current. f2 No current flows anymore. Now let S 4 Connected to the same flying capacitor S 3 In the normally on state, the current is guaranteed to be continuous, and the other switch devices are not affected. By adjusting the working mode, a single continuous bus current path can be guaranteed, and open circuit fault tolerance control can be further realized. The number of switch states is reduced to 2 n .

[0034] The types of switching devices include, but are not limited to, insulated gate bipolar transistors IGBTs, metal-oxide semiconductor field effect transistors MOSFETs, gate turn-off thyristors GTOs, integrated gate-commutated thyristors IGCTs, thyristors and other fully controlled or semi-controlled semiconductor devices.

[0035] DC current source I p It is realized by using batteries, or through DC-DC, AC-DC power electronic conversion devices.

[0036] Winding w s1 tow sn Arranged from left to right in phase sequence, the phases of the winding back electromotive force differ by 2π / n.

[0037] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that the features described in conjunction with a single embodiment may be used in other described embodiments.

Claims

1. A high fault-tolerant current source inverter topology for driving an open winding, characterized in that: Including DC current source I p , bus inductance L dc and inverter unit, DC current source I p and bus inductance L dc The series connection provides a stable and controllable DC current to the inverter unit; The inverter unit includes switch devices S1 to S 2n+2 , diodes D1 to D 2n+2 、Flying capacitor C f1 To C fn+1 And filter capacitor C s1 To C sn ; Where n is greater than or equal to 2; The inverter unit is divided into two groups of parallel odd-even parallel branches, upper and lower; The upper branch from left to right follows D1, S1, D3, S3, D5, S5, ..., D 2n+1 ,S 2n+1 The lower branches are connected in series from left to right in the order of S2, D2, S4, D4, S6, D6, ..., S 2n+2 ,D 2n+2 The conduction direction of the diode is opposite to the conduction direction of the anti-parallel diode of the switching device; S 2i-1 The negative electrode and S 2i+2 The positive pole of the inverter is the i-th output port, i = 1, 2, ..., n, and the 1st to nth output ports of the inverter are respectively connected to the phase windings w of the motor. s1 tow sn The two ends are connected; D 2j-1 The cathode and D 2j The anodes are connected through a flying capacitor, j = 1, 2, ..., n + 1; Under normal working conditions, S 2i-1 With S 2i Complementary conduction; When a switching device S k When a short circuit occurs, the original switch state includes S k = 1, the switch status effect is not affected, including S k = 0, the effect of some switch states changes, k = 1, 2, ..., 2n + 2; When a switching device S k When an open circuit fault occurs, the transient condition is with S k The connected flying capacitor and the two adjacent diodes form a continuous current path to suppress the voltage spike. Under steady-state conditions, it will be connected to S k The working mode of the healthy switch device connected to the same flying capacitor is adjusted to a normally-on state to ensure the continuity of the bus current.

2. A high fault-tolerant current source inverter topology for driving an open winding according to claim 1, characterized in that: The types of switching devices include, but are not limited to, insulated gate bipolar transistors IGBTs, metal-oxide semiconductor field effect transistors MOSFETs, gate turn-off thyristors GTOs, integrated gate-commutated thyristors IGCTs, thyristors and other fully controlled or semi-controlled semiconductor devices.

3. A high fault-tolerant current source inverter topology for driving an open winding according to claim 1, characterized in that: DC current source I p It is realized by using batteries, or through DC-DC, AC-DC power electronic conversion devices.

4. A high fault-tolerant current source inverter topology for driving an open winding according to claim 1, characterized in that: Winding w s1 tow sn Arranged from left to right in phase sequence, the phases of the winding back electromotive force differ by 2π / n.

5. A high fault-tolerant current source inverter topology for driving an open winding according to claim 1, characterized in that: Each phase winding is connected in parallel with a filter capacitor.

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