A high fault-tolerant current source inverter topology with open winding

Abstract

This invention discloses a high-fault-tolerant current source inverter topology for driving open windings, belonging to the field of motor control. It addresses the problems of insufficient short-circuit fault tolerance and difficulty in suppressing open-circuit voltage spikes in traditional current source inverter topologies. The invention includes a DC current source, a bus inductor, and an inverter unit. The DC current source and bus inductor are connected in series to provide 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. It can maintain a single continuous bus current path even after a short circuit in a switching device, further realizing short-circuit fault-tolerant control. The switching devices and diodes in the two sets of parallel branches are arranged in a staggered manner. By connecting n+1 flying capacitors between the upper and lower branches of the inverter unit, during the transient process after an open circuit in a switching device, the flying capacitors can form a continuous current path with two adjacent diodes, preventing overvoltage problems.

Description

Technical Field

[0001] This invention relates to a high fault-tolerant current source inverter topology for driving open windings, belonging to the field of motor control. Background Technology

[0002] Motor systems play a vital role in modern industry, finding widespread application in aerospace, transportation, industrial robotics, and home appliances. The motor driver, which converts electrical energy to drive the motor, is a key component of the motor system. As application areas expand, the increasingly complex and variable operating environments place increasingly stringent reliability requirements on motor systems. During operation, they often face complex conditions such as varying loads, varying temperatures, and instantaneous high overloads, which subject the switching devices of the motor driver to frequent and severe electrical and thermal stresses. This can easily lead to short circuits or open circuits in the switching devices, seriously threatening the safety and stability of the motor system. Current-source inverter topologies, as a highly reliable driver topology, have received widespread attention from scholars both domestically and internationally in recent years. Current-source inverters use inductors as energy storage devices and directly output AC current to the load through pulse width modulation, exhibiting stronger short-circuit fault resistance and higher current regulation accuracy. They also demonstrate significant advantages in reliability, environmental adaptability, and torque output quality. Traditional half-bridge three-phase or multi-phase current source inverter topologies, while capable of suppressing transient short-circuit current spikes, suffer from several drawbacks. The parallel connection of the phase arms in a half-bridge topology means that the low-impedance path formed by the short-circuited arm can shunt the remaining healthy arms, leading to uncontrolled output current and making short-circuit fault tolerance difficult to achieve. Furthermore, open-circuit faults in switching devices can cause discontinuous bus current, resulting in overvoltage and severely impacting system safety. Summary of the Invention

[0003] To address the issues of insufficient short-circuit fault tolerance and difficulty in suppressing open-circuit voltage spikes in traditional current-source inverter topologies, this invention provides a high-fault-tolerant current-source inverter topology that drives open windings.

[0004] The present invention discloses a high fault-tolerant current source inverter topology with an open-winding drive, comprising a DC current source I. p Bus inductance L dc And inverter unit, DC current source I p With bus inductance L dc A stable and controllable DC current is provided to the inverter unit in series;

[0005] The inverter unit includes switching devices S1 to S2. 2n+2 Diodes D1 to D 2n+2 Flying capacitor C f1 To C fn+1 and filter capacitor C s1To C sn Where n is greater than or equal to 2; the inverter unit is divided into two sets of parallel odd-even branches, upper and lower;

[0006] The upper branch road is arranged from left to right as D1, S1, D3, S3, D5, S5, ..., D 2n+1 ,S 2n+1 The numbers are connected alternately in sequence, with the lower branches from left to right in the order S2, D2, S4, D4, S6, D6, ..., S 2n+2 D 2n+2 The diodes are connected in series alternately in sequence, and the conduction direction of the diodes is opposite to that of the anti-parallel diodes of the switching devices; S 2i-1 negative electrode and S 2i+2 The positive terminals are connected to the i-th output port of the inverter, i = 1, 2, ..., n, and the first to n output ports of the inverter are respectively connected to the windings of each phase of the motor. s1 to w sn The two ends are connected;

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

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

[0009] When a certain switching device S k When a short circuit fault occurs, the original switch state includes S. k The switching effect of a state with a value of 1 is unaffected, including S. k The effect of the switch state with a value of 0 changes, k = 1, 2, ..., 2n+2;

[0010] When a certain switching device S k When an open-circuit fault occurs, under transient conditions, it is related to S. k The connected flying capacitor and two adjacent diodes form a continuous current path to suppress voltage spikes. Under steady-state conditions, this will be related to S... k The operating mode of the health switching device connected to the same flying capacitor is adjusted to the normally-on state to ensure continuous bus current.

[0011] Preferably, the switching device types 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 or semi-controlled semiconductor devices.

[0012] Preferably, DC current source I pIt can be achieved using batteries or through DC-DC or AC-DC power electronic converters.

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

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

[0015] The beneficial effects of this invention are as follows: This invention provides a high-fault-tolerant current source inverter topology with an open-winding drive, possessing fault tolerance capabilities for both short-circuit and open-circuit switching devices. For short-circuit faults in the switching devices, by adjusting the operating mode of the remaining switching devices, a single continuous bus current path can be maintained, achieving short-circuit fault-tolerant control. For open-circuit faults in the switching devices, the overvoltage problem caused by discontinuous bus current is solved at the moment of open-circuit by the continuous current path formed by the flying capacitor and adjacent diodes. Open-circuit fault-tolerant control is achieved by adjusting the operating mode of the remaining switching devices. With the same number of motor phases, this invention requires two more switching devices and diodes than the traditional half-bridge topology, significantly improving the fault tolerance capability of the topology with a smaller increase in the number of devices. Therefore, this invention is highly suitable for high-reliability applications such as aerospace and marine propulsion. Attached Figure Description

[0016] Figure 1 This invention describes a high-fault-tolerant current source inverter topology with an open-winding drive.

[0017] Figure 2 This is the high fault-tolerant current source inverter topology with open drive winding corresponding to the n=3 instance;

[0018] Figure 3 This is a circuit diagram of the inverter of this invention when a short-circuit fault occurs;

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

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

[0021] In the diagram, S1, S2, S3, S4, S5, S6, ... S 2n+1 ,S 2n+2 For switching devices, D1, D2, D3, D4, D5, D6, ..., D 2n+1 D 2n+2 For diodes, C f1 C f2 C f3 ,…,Cfn+1 For the flying capacitor, C s1 C s2 C s3 ,…,C sn For filter capacitors, w s1 ,w s2 ,…,w sn This refers to the motor windings. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0025] Specific Implementation Method 1: The following is combined with... Figures 1 to 5 This embodiment describes a high-fault-tolerant current source inverter topology with an open-winding drive, including a DC current source I. p Bus inductance L dc And inverter unit, DC current source I p With bus inductance L dc The inverter unit receives a stable and controllable DC current from a series connection. The inverter unit comprises two parallel branches consisting of switching devices and diodes, forming n output ports to supply power to each phase winding. This ensures a single, continuous bus current path even after a short circuit in the switching devices, further enabling short-circuit fault-tolerant control. Simultaneously, parallel filter capacitors across the windings absorb harmonic currents from the switches, guaranteeing high-quality current output. The switching devices and diodes in the two parallel branches are arranged in a staggered pattern. By connecting n+1 flying capacitors between the upper and lower branches of the inverter unit, during the transient process following an open circuit in the switching devices, the flying capacitors can form a continuous current path with two adjacent diodes, preventing overvoltage issues.

[0026] Specifically, the inverter unit includes switching devices S1 to S2. 2n+2 Diodes D1 to D 2n+2 Flying capacitor C f1 To C fn+1 and filter capacitor C s1 To C snWhere n is greater than or equal to 2; the inverter unit is divided into two parallel odd-even branches, upper and lower. The number of switching devices and diodes in each branch is n+1. Switching devices and diodes with odd subscript numbers are located in the upper branch, and switching devices and diodes with even subscript numbers are located in the lower branch.

[0027] The anode of D1 and the collector (or drain) of S2 are connected to the left end of the inverter unit. 2n+1 The emitter (or source) and D 2n+2 The cathode is connected to the right end of the inverter unit.

[0028] The upper branch road is arranged from left to right as D1, S1, D3, S3, D5, S5, ..., D 2n+1 ,S 2n+1 The numbers are connected alternately in sequence, with the lower branches from left to right in the order S2, D2, S4, D4, S6, D6, ..., S 2n+2 D 2n+2 The diodes are connected in series alternately in sequence, and the conduction direction of the diodes is opposite to that of the anti-parallel diodes of the switching devices; S 2i-1 negative electrode and S 2i+2 The positive terminals of S1 and S4 are connected to form the i-th output port of the inverter, where i = 1, 2, ..., n. Specifically, the output port is between the emitter (or source) of S1 and the collector (or drain) of S4, the output port is between the emitter (or source) of S3 and the collector (or drain) of S6, and so on to the right. 2n-1 The emitter (or source) and S 2n+2 The nth output port is located between the collector (or drain) of the nth output port.

[0029] The inverter's first to nth output ports are respectively connected to the motor's phase windings w s1 to w sn The two ends are connected; a filter capacitor is connected in parallel to each phase winding. This is used to absorb switching harmonic current and ensure high-quality current output.

[0030] D 2j-1 Cathode and D 2j The anodes of D1 and D2 are connected by a flying capacitor, j = 1, 2, ..., n+1; specifically, the cathode of D1 and the anode of D2 are connected by the first flying capacitor C. f1 Connected, the cathode of D3 and the anode of D4 are connected by a second flying capacitor C. f2 Connected, sequentially to the right up to D 2n+1 Cathode and D 2n+2 The anodes are connected by the (n+1)th flying capacitor C. fn+1 Connected.

[0031] Under normal operating conditions, S 2i-1 With S 2iComplementary conduction; S1 and S2, S3 and S4, S5 and S6… to S 2n+1 With S 2n+2 This forms n+1 pairs of switching device combinations, with the two switching devices in each pair complementarily conducting to ensure a continuous bus current path. There are a total of 2 n+1 Types of switch states.

[0032] When a certain switching device S k When a short circuit fault occurs, the original switch state includes S. k The switching effect of a state with a value of 1 (indicating the switching device is in the ON state) is unaffected, including S. k The effect of some switching states changes when k = 0 (indicating the switching device is in the off state), k = 1, 2, ..., 2n+2. See also Figure 3 When 3 ≤ k ≤ 2n, the number of switch states that can continue to guarantee a single continuous bus current path and whose 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 guarantee a single continuous bus current path and whose effect remains unchanged is reduced to 2. n +2 n-1 Further improve short-circuit fault-tolerant control.

[0033] When a certain switching device S k When an open circuit fault occurs, see Figure 4 under transient conditions and S k The connected flying capacitor and the two adjacent diodes form a continuous current path to suppress voltage spikes. Taking an open-circuit fault at S4 as an example, at the moment of open circuit, the flying capacitor C connected to S4... f2 It can form a continuous current path with diodes D3 and D4, solving the overvoltage problem caused by discontinuous bus current. See also Figure 5 Under steady-state conditions, the operating mode of the healthy switching device connected to the same flying capacitor as the open-circuit switching device is adjusted to the normally-on state to ensure continuous bus current. Flying capacitor C f2 No more current flows. At this point, S3, connected to the same flying capacitor as S4, is kept in the normally open state to ensure continuous current flow. The other switching devices are unaffected. By adjusting the operating mode, a single, continuous bus current path can be maintained, further achieving open-circuit fault-tolerant control. The number of switching states is reduced to 2. n .

[0034] Switching device types 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), and various other fully or semi-controlled semiconductor devices such as thyristors.

[0035] DC current source I p It can be achieved using batteries or through DC-DC or AC-DC power electronic converters.

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

[0037] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A high-fault-tolerant current source inverter topology for driving open windings, characterized in that, Including DC current source I p Bus inductance L dc And inverter unit, DC current source I p With bus inductance L dc A stable and controllable DC current is provided to the inverter unit in series; The inverter unit includes switching devices S1 to S2. 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 sets of parallel odd-even branches, upper and lower; The upper branch road is arranged from left to right as D1, S1, D3, S3, D5, S5, ..., D 2n+1 ,S 2n+1 The numbers are connected alternately in sequence, with the lower branches from left to right in the order S2, D2, S4, D4, S6, D6, ..., S 2n+2 D 2n+2 The diodes are connected in series alternately in sequence, and the conduction direction of the diodes is opposite to that of the anti-parallel diodes of the switching devices; S 2i-1 negative electrode and S 2i+2 The positive terminals are connected to the i-th output port of the inverter, i = 1, 2, ..., n, and the first to n output ports of the inverter are respectively connected to the windings of each phase of the motor. s1 to w sn The two ends are connected; D 2j-1 Cathode and D 2j The anodes are connected by a flying capacitor, j = 1, 2, ..., n+1; Under normal operating conditions, S 2i-1 With S 2i Complementary conduction; When a certain switching device S k When a short circuit fault occurs, the original switch state includes S. k The switching effect of a state with a value of 1 is unaffected, including S. k The effect of the switch state with a value of 0 changes, k = 1, 2, ..., 2n+2; When a certain switching device S k When an open-circuit fault occurs, under transient conditions, it is related to S. k The connected flying capacitor and two adjacent diodes form a continuous current path to suppress voltage spikes. Under steady-state conditions, this will be related to S... k The operating mode of the health switching device connected to the same flying capacitor is adjusted to the normally-on state to ensure continuous bus current.

2. The high fault-tolerant current source inverter topology with an open-winding drive according to claim 1, characterized in that, Switching device types 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), and various fully or partially controlled semiconductor devices.

3. The high fault-tolerant current source inverter topology with an open-winding drive according to claim 1, characterized in that, DC current source I p It can be achieved using batteries or through DC-DC or AC-DC power electronic converters.

4. The high fault-tolerant current source inverter topology with an open-winding drive according to claim 1, characterized in that, winding w s1 to w sn Arranged sequentially from left to right according to phase sequence, the phases of the back electromotive force of the windings differ by 2π / n.

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

Images