A shunt wound topology for field energy recovery of a separately excited pulsed generator

Abstract

This invention provides a shunt-type series-collection topology for recovering excitation energy from a separately excited pulse generator. This topology has significant advantages over separately excited power supplies composed of multiple single-module pulse capacitors. The main features of this topology are: utilizing the characteristics of an underdamped second-order oscillating circuit to induce a reverse voltage in the pulse capacitor, thereby achieving state switching of the excitation current; the shunt-type series-collection method reduces the system withstand voltage level while enabling rapid recovery of residual excitation energy, increasing the repetitive discharge frequency, reducing excitation winding heating, and improving recovery efficiency; each pulse capacitor module is equipped with three thyristors, two of which are excitation switches connected to its positive and negative terminals respectively, and one is a recovery switch, which also acts as an isolation switch during excitation; a thyristor is connected in series between the negative terminal of the last capacitor and the positive terminal of the excitation winding as a freewheeling switch, and the excitation switch connected to the negative terminal of the last capacitor forms a freewheeling circuit with it.

Description

Technical Field

[0001] This invention belongs to the field of energy storage motor and pulse power technology, specifically relating to a shunt-excited series topology for recovering excitation energy from a separately excited pulse generator. Background Technology

[0002] Pulsed power technology, with its characteristics of short-duration, high-power output, has been widely used in many fields such as plasma physics and controlled nuclear fusion research, nuclear explosion simulation, high-power lasers, and electromagnetic propulsion. High-power pulsed power supplies, as the core component of pulsed power technology, hold an undeniable position and importance. Higher power and energy density have always been the development direction of high-power pulsed power supplies. Capacitor energy storage, with its simple structure and high power density, has been widely used and researched in high-power pulsed power supplies, and is also the most mature form. However, its relatively low energy density has always been a bottleneck for further development. To increase power capacity, it is necessary to increase size and weight, which undoubtedly limits the portability and flexibility of the system. To overcome this bottleneck, energy storage forms with higher energy density have been continuously explored.

[0003] Pulse generators utilize rotating machinery for energy storage, offering advantages such as long storage time, high energy density, high power density, compact structure, and low cost, making them ideal energy storage carriers for high-pulse power supplies. Electrical excitation is typically used to establish a sufficiently strong magnetic field, while external excitation offers advantages such as fast excitation speed, simple structure, system stability, and good controllability.

[0004] Over 40 years of development, pulse generators have gradually evolved into rotary, hollow-core structures. For high-speed rotary pulse generators, avoiding unnecessary heat generation not only reduces motor temperature rise but also improves efficiency. Rotor heating has always been a major challenge in motor thermal management, and heat generation in the excitation winding makes this challenge even more severe. After the pulse generator has finished discharging, the residual magnetic energy in the excitation winding is very high. If not handled properly, it will slowly be converted into heat and dissipated in the excitation winding and freewheeling circuit. This not only wastes energy and reduces system efficiency but also causes severe heating in the excitation winding and freewheeling circuit, seriously affecting the continuous discharge performance and lifespan of the pulse generator. Therefore, it is necessary to recover the residual excitation energy. Summary of the Invention

[0005] The purpose of this invention is to propose a shunt-type series-type topology for excitation energy recovery of separately excited pulse generators, which solves the problem of excitation energy recovery after the discharge of separately excited pulse generators. By connecting in parallel, the excitation current is increased without increasing the system withstand voltage, and by connecting in series, the excitation energy is recovered quickly, reducing excitation winding heating and shortening the discharge interval.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A shunt-excitation series-excitation topology for excitation energy recovery of a separately excited pulse generator includes a pulse capacitor, a thyristor for parallel excitation, a thyristor for series excitation energy recovery, and a freewheeling thyristor for causing the pulse capacitor to be in reverse voltage. The load is the excitation winding of the pulse generator. The underdamped second-order oscillating circuit characteristics are used to cause the pulse capacitor to have a reverse voltage, and the reverse voltage of the pulse capacitor is used to realize the state switching of the excitation current.

[0008] Furthermore, by adopting a parallel excitation and series recovery method, the system withstand voltage level can be reduced during excitation; during recovery, the remaining excitation energy can be recovered quickly, the frequency of repeated discharge can be increased, the excitation winding heating can be reduced, and the recovery efficiency can be improved.

[0009] Furthermore, the thyristors and pulse capacitors constitute a pulse capacitor module. Each pulse capacitor module is equipped with three thyristors, two of which are parallel excitation switches connected to the positive and negative terminals of the pulse capacitor respectively, and one is a series excitation energy recovery switch. The series excitation energy recovery switch also serves as an isolation function during parallel excitation.

[0010] Furthermore, a thyristor is connected in series between the negative terminal of the last pulse capacitor and the positive terminal of the excitation winding as a freewheeling switch, and the parallel excitation switch connected to the negative terminal of the last pulse capacitor together with it to form a freewheeling circuit.

[0011] Furthermore, the corresponding times for excitation, freewheeling, and excitation energy recovery are calculated separately, and then the corresponding thyristors are triggered to switch between the three states of parallel excitation, excitation current freewheeling, and series excitation energy recovery.

[0012] Furthermore, the excitation circuit adopts a parallel structure, with the positive and negative terminals of the pulse capacitor connected to the thyristor respectively, forming a separate circuit with the excitation winding. Then, the separate circuits are connected in parallel to form a parallel excitation circuit.

[0013] Furthermore, the excitation energy recovery circuit adopts a series structure, with thyristors connected in series between the first pulse capacitor and the excitation winding, between each pulse capacitor, and between the last pulse capacitor and the excitation winding, forming a series excitation energy recovery circuit.

[0014] Beneficial effects:

[0015] This invention proposes a shunt-type series-type topology for excitation energy recovery in separately excited pulse generators. This topology allows for switching between three states: excitation, freewheeling, and excitation energy recovery, with separate trigger switches for each state. The thyristors corresponding to each of the three states are then triggered according to pre-calculated trigger times, while the previous state is automatically cut off. The shunt-type series-type topology helps reduce the system withstand voltage during excitation and enables rapid recovery of remaining excitation energy during recovery, reducing rotor heating and shortening the discharge gap of the pulse generator. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a shunt-type series-type topology for recovering excitation energy from a separately excited pulse generator according to the present invention.

[0017] Figure 2 This is a first working schematic diagram of the topology of the present invention;

[0018] Figure 3 This is a second working schematic diagram of the topology of the present invention;

[0019] Figure 4 This is a third working schematic diagram of the topology of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0021] This invention discloses a shunt-excitation series-collection topology for excitation energy recovery in separately excited pulse generators, which offers significant advantages over separately excited power supplies composed of multiple single-module pulse capacitors. The topology utilizes the characteristics of an underdamped second-order oscillating circuit to induce a reverse voltage in the pulse capacitors, and uses this reverse voltage to switch the state of the excitation current. The shunt-excitation series-collection method helps reduce the system withstand voltage level while enabling rapid recovery of residual excitation energy, increasing the repetitive discharge frequency, reducing excitation winding heating, and improving recovery efficiency. Each pulse capacitor module is equipped with three thyristors: two are excitation switches connected to its positive and negative terminals respectively, and one is an excitation energy recovery switch, which also acts as an isolation switch during parallel excitation. A thyristor is connected in series between the negative terminal of the last pulse capacitor and the positive terminal of the excitation winding as a freewheeling switch, and together with the parallel excitation switch connected to the negative terminal of the last pulse capacitor, forms a freewheeling circuit.

[0022] like Figure 1 As shown, a shunt-type series-type topology for excitation energy recovery of a separately excited pulse generator according to the present invention includes a pulse capacitor, a thyristor for excitation, a thyristor for excitation energy recovery, and a freewheeling thyristor for causing the pulse capacitor to be under reverse voltage. Its load is the excitation winding of the pulse generator. The underdamped second-order oscillator circuit characteristics are used to cause a reverse voltage in the pulse capacitor, and the reverse voltage of the pulse capacitor is used to achieve the state switching of the excitation current. That is, the topology includes n (n is a positive integer) pulse capacitors, 2n thyristors for excitation, n thyristors for excitation energy recovery, and 1 freewheeling thyristor for causing the pulse capacitor to be under reverse voltage. Its load is the excitation winding of the pulse generator, requiring a total of 3n+1 thyristors.

[0023] Specifically, each pulse capacitor is equipped with three thyristors: two are parallel excitation switches connected to its positive and negative terminals respectively, and one is a series excitation energy recovery switch, which also acts as an isolation switch during parallel excitation. A thyristor is connected in series between the negative terminal of the last pulse capacitor and the positive terminal of the excitation winding as a freewheeling switch, forming a freewheeling circuit together with the parallel excitation switch connected to the negative terminal of the last pulse capacitor. According to system requirements, the corresponding times for excitation, freewheeling, and excitation energy recovery are calculated, and then the corresponding thyristors are triggered to switch between the three states: parallel excitation, excitation current freewheeling, and series excitation energy recovery.

[0024] The excitation circuit adopts a parallel structure. The positive and negative terminals of the pulse capacitor are connected to the thyristor respectively, forming a separate circuit with the excitation winding. Then, the separate circuits are connected in parallel to form a parallel excitation circuit.

[0025] The excitation energy recovery circuit adopts a series structure. Thyristors are connected in series between the first pulse capacitor and the excitation winding, between each pulse capacitor, and between the last pulse capacitor and the excitation winding, which together form the excitation energy recovery circuit.

[0026] In the freewheeling circuit, the thyristor used as a freewheeling switch can be used as a thyristor connected in series between the last pulse capacitor and the excitation winding in the excitation energy recovery circuit during the excitation energy recovery stage.

[0027] like Figure 1-4 As shown, the specific working principle and detailed steps of this invention are as follows:

[0028] Step a, the preparatory work before excitation includes towing the pulse generator to its rated speed to store energy; and charging n pulse capacitors to their rated voltage.

[0029] Step b: Trigger timing calculation. Taking the received discharge command as time T0, excitation begins simultaneously. Then, based on the required excitation current value, the reverse voltage value of the pulse capacitor, the remaining excitation current value after the pulse generator discharges, the pulse capacitor parameter values, and the excitation winding parameters of the pulse generator, the freewheeling time T is derived. c and the time T of series excitation energy recovery r .

[0030] Step c, at time T0, 2n thyristors Se1_1~Se1_n and Se2_1~Se2_n for parallel excitation are triggered to start parallel excitation. The excitation current is in the excitation state, and the current direction is as follows: Figure 2 As indicated by the arrow.

[0031] Step d, follow-through time T c The freewheeling thyristor Sc, used to reverse the voltage of the pulse capacitor, is triggered. Since the voltage of the pulse capacitor is negative on the left and positive on the right at this time, after triggering the freewheeling thyristor Sc, the parallel-excited thyristors Se1_1 to Se1_n will turn off under the action of the reverse voltage. The parallel-excited thyristors Se2_1 to Se2_n-1 will also turn off because the discharge circuit is cut off. The parallel-excited thyristor Se2_n and Sc together form a freewheeling circuit, causing the excitation current to change from the excitation state to the freewheeling state. The current direction is as follows. Figure 3 As indicated by the arrow.

[0032] Step e, Series excitation energy recovery time T r Triggering n thyristors used for series recovery, the parallel-excited thyristor Se2_n is turned off under the reverse voltage of n pulse capacitors, causing the excitation current to switch from freewheeling state to series excitation energy recovery state, with the current direction as follows: Figure 4 As indicated by the arrow.

[0033] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A shunt wound topology for field energy recovery of a separately excited pulsed generator, characterized by: It includes n pulse capacitors, thyristors for parallel excitation, thyristors for series excitation energy recovery, and freewheeling thyristors for making the pulse capacitors reverse voltage. Its load is the excitation winding of a pulse generator. The characteristics of an underdamped second-order oscillating circuit are used to induce a reverse voltage in the pulse capacitor, and the reverse voltage of the pulse capacitor is used to switch the state of the excitation current. Each pulse capacitor is equipped with three thyristors: two are parallel excitation switches connected to its positive and negative terminals respectively, and one is a series excitation energy recovery switch, which also acts as an isolation switch during parallel excitation. A thyristor is connected in series between the negative terminal of the last pulse capacitor and the positive terminal of the excitation winding as a freewheeling switch, and together with the parallel excitation switch connected to the negative terminal of the last pulse capacitor, they form a freewheeling circuit. According to the system requirements, the corresponding times for excitation, freewheeling, and excitation energy recovery are calculated respectively, and then the corresponding thyristors are triggered to realize the switching between the three states of parallel excitation, excitation current freewheeling, and series excitation energy recovery. The excitation circuit adopts a parallel structure. The positive and negative terminals of the pulse capacitor are connected to the thyristor respectively, forming a separate circuit with the excitation winding. Then, the separate circuits are connected in parallel to form a parallel excitation circuit. The excitation energy recovery circuit adopts a series structure. Thyristors are connected in series between the first pulse capacitor and the excitation winding, between each pulse capacitor, and between the last pulse capacitor and the excitation winding, which together form the excitation energy recovery circuit. In the freewheeling circuit, the thyristor used as a freewheeling switch is used in the excitation energy recovery stage as a thyristor connected in series between the last pulse capacitor and the excitation winding in the excitation energy recovery circuit.

2. A shunt wound topology for field energy recovery of a separately excited pulsed generator according to claim 1, characterized in that: Using a parallel excitation and series recovery method, parallel excitation helps to reduce the system withstand voltage level; series recovery enables rapid recovery of residual excitation energy, increases the frequency of repeated discharge, reduces excitation winding heating, and improves recovery efficiency.

3. A shunt wound topology for field energy recovery of a separately excited pulsed generator according to claim 1, characterized in that: Thyristors and pulse capacitors constitute a pulse capacitor module. Each pulse capacitor module is equipped with three thyristors, two of which are parallel excitation switches connected to the positive and negative terminals of the pulse capacitor respectively, and one is a series excitation energy recovery switch. The series excitation energy recovery switch also serves as an isolation function during parallel excitation.

4. A shunt wound topology for field energy recovery of a separately excited pulsed generator according to claim 1, characterized in that: A thyristor is connected in series between the negative terminal of the last pulse capacitor and the positive terminal of the excitation winding as a freewheeling switch, and the parallel excitation switch connected to the negative terminal of the last pulse capacitor together with it to form a freewheeling circuit.

5. A shunt-type series-type topology for excitation energy recovery of a separately excited pulse generator according to claim 1, characterized in that: The corresponding times for excitation, freewheeling, and excitation energy recovery are calculated separately, and then the corresponding thyristors are triggered to switch between the three states of parallel excitation, excitation current freewheeling, and series excitation energy recovery.

6. The shunt-type series-type topology for excitation energy recovery of a separately excited pulse generator according to claim 1, characterized in that: The excitation circuit adopts a parallel structure. The positive and negative terminals of the pulse capacitor are connected to the thyristor respectively, forming a separate circuit with the excitation winding. Then, the separate circuits are connected in parallel to form a parallel excitation circuit.

7. A shunt-type series-type topology for excitation energy recovery of a separately excited pulse generator according to claim 1, characterized in that: The excitation energy recovery circuit adopts a series structure. Thyristors are connected in series between the first pulse capacitor and the excitation winding, between each pulse capacitor, and between the last pulse capacitor and the excitation winding, forming a series excitation energy recovery circuit.

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