阅读说明：本技术 一种永磁磁阻级联发电机控制系统及其控制方法 (Permanent magnet reluctance cascade generator control system and control method thereof ) 是由 王千龙 景鑫 蒋伟 于照 蒋步军 于 2020-08-05 设计创作，主要内容包括：本发明公开了一种永磁磁阻级联发电机控制系统,包括同轴串联的PMG和SRG,还包括：整流电路,选用三相不可控整流电路,连接在PMG上,用以将PMG输出变为直流电,并输出给功率变换器；功率变换器,选用他励式不对称半桥结构,连接在SRG上,用以控制SRG工作,同时还能输出电能；DSP控制器,连接整流电路、功率变换器,用以采集相应电压、电流信号,通过驱动电路输出驱动信号控制功率变换器工作,本发明提高了系统整体的可靠性,提高了安全系数,控制方式简单,易于操作。(The invention discloses a permanent magnet reluctance cascade generator control system, which comprises a PMG and an SRG which are coaxially connected in series, and also comprises: the rectification circuit is connected to the PMG, is used for converting the PMG output into direct current and outputting the direct current to the power converter; the power converter selects a separately excited asymmetric half-bridge structure, is connected to the SRG, is used for controlling the SRG to work and can output electric energy; the DSP controller is connected with the rectifying circuit and the power converter and used for collecting corresponding voltage and current signals, and the driving circuit outputs driving signals to control the power converter to work.)

1. A permanent magnet reluctance cascade generator control system is characterized by comprising the PMG and the SRG which are coaxially connected in series, and further comprising:

the rectification circuit is connected to the PMG, is used for converting the PMG output into direct current and outputting the direct current to the power converter;

the power converter selects a separately excited asymmetric half-bridge structure, is connected to the SRG, is used for controlling the SRG to work and can output electric energy;

the DSP controller is connected with the rectification circuit and the power converter and used for collecting corresponding voltage and current signals and outputting a driving signal through the driving circuit to control the power converter to work, and the DSP controller specifically comprises:

when the rotating speed is low, the direct current is boosted through a BOOST circuit formed by the SRG winding and the power converter to output electric energy; when the rotating speed is high, the direct current is subjected to voltage reduction through a BUCK circuit formed by the SRG winding and the power converter to output electric energy; in a normal rotating speed range, the PMG is firstly used as an excitation motor of the SRG, the SRG adopts a position-sensor-free control method, and the PMG and the SRG realize the common power generation by controlling the on-off of a switching tube of a power converter.

2. A PMMR cascaded generator control system according to claim 1, wherein the three-phase uncontrollable rectifying circuit and the separately excited asymmetric half-bridge structure are cascaded to form a main circuit topology, the separately excited asymmetric half-bridge structure is also a three-phase structure, wherein,

the A phase structure comprises two switching tubes S1 and S2 and two freewheeling diodes D7 and D8, wherein the collector of the switching tube S1 is connected with the anode of the main circuit, the emitter of the switching tube S1 is connected with the cathode of the current diode D7 and one end of the SRG A phase coil, the collector of the switching tube S2 is connected with the other end of the SRGA phase coil and the anode of the freewheeling diode D8, and the emitter of the switching tube S2 and the anode of the freewheeling diode D7 are connected with the cathode of the main circuit;

the B phase structure comprises two switching tubes S3 and S4 and two freewheeling diodes D9 and D10, wherein the collector of the switching tube S3 is connected with the anode of the main circuit, the emitter of the switching tube S3 is connected with the cathode of the current diode D9 and one end of the SRG B phase coil, the collector of the switching tube S4 is connected with the other end of the SRG B phase coil and the anode of the freewheeling diode D10, and the emitter of the switching tube S4 and the anode of the freewheeling diode D9 are connected with the cathode of the main circuit;

the C-phase structure comprises two switching tubes S5 and S6 and two freewheeling diodes D11 and D12, wherein the collector of the switching tube S5 is connected with the anode of the main circuit, the emitter of the switching tube S5 is connected with the cathode of the current diode D11 and one end of the SRG C-phase coil, the collector of the switching tube S6 is connected with the other end of the SRG coil and the anode of the freewheeling diode D12, and the emitter of the switching tube S6 and the anode of the freewheeling diode D11 are connected with the cathode of the main circuit;

the cathode of the freewheel diode D8, the cathode of the freewheel diode D10, and the cathode of the freewheel diode D12 are connected in parallel and serve as output terminals.

3. The system as claimed in claim 2, wherein the main circuit further includes a filter circuit disposed in the post-excited asymmetric half-bridge structure.

4. The system of claim 2, wherein the DSP controller controls the power converter to operate by:

judging the output voltage of the PMG, if the output voltage is lower than a set first threshold voltage, adopting an SRG winding and a power converter in a main circuit to form a BOOST circuit to BOOST the output voltage, closing switch tubes S1, S3 and S5, controlling duty ratios of the switch tubes S2, S4 and S6 by a controller, and boosting the output voltage under closed-loop control;

if the output voltage of the PMG is higher than the set first threshold voltage and lower than the second threshold voltage, an asymmetric half-bridge circuit is formed by an SRG winding and a power converter in a main circuit to realize the common power generation of the PMG and the SRG, switching tubes S1, S2, S3, S4, S5 and S6 are closed, the output voltage of the PMG excites the SRG, when the SRG generates power, the switching tubes S1, S3 and S5 are kept closed, only the switching tubes S2, S4 and S6 are opened, the voltage of an output terminal is measured in real time, and the magnitude of a current chopping value of the SRG under the full-on control is controlled in a closed-loop mode to maintain the output voltage at the charging voltage;

if the PMG output voltage is higher than the second threshold voltage, the output voltage is reduced by using a BUCK circuit formed by an SRG winding and a power converter in the main circuit, the switching tubes S2, S4 and S6 are closed, the duty ratios of the switching tubes S1, S3 and S5 are controlled by the controller, and the output voltage is reduced to the second threshold voltage under closed-loop control.

5. A control method of a permanent magnet reluctance cascade generator, which adopts the control system of the permanent magnet reluctance cascade generator according to any one of claims 1 to 3, characterized by comprising the following steps:

step 1) detecting the output voltage of the PMG;

step 2) controlling the power converter to work through the DSP controller, specifically:

step 2-1) if the output voltage is lower than the set first threshold voltage, adopting a BOOST circuit formed by an SRG winding and a power converter in a main circuit to BOOST the output voltage, closing switch tubes S1, S3 and S5, controlling duty ratios of the switch tubes S2, S4 and S6 by a controller, and boosting the output voltage under closed-loop control;

step 2-2) if the output voltage of the PMG is higher than the set first threshold voltage and lower than the second threshold voltage, at the moment, an asymmetric half-bridge circuit formed by an SRG winding and a power converter in a main circuit is adopted to realize the common power generation of the PMG and the SRG, switching tubes S1, S2, S3, S4, S5 and S6 are closed, the output voltage of the PMG excites the SRG, when the SRG generates power, the switching tubes S1, S3 and S5 are kept closed, only the switching tubes S2, S4 and S6 are opened, the voltage of an output terminal is measured in real time, and the magnitude of a current chopping value of the SRG under the full-on control is controlled in a closed-loop mode to maintain the output voltage at a charging voltage;

and 2-3) if the PMG output voltage is higher than the set second threshold voltage, reducing the output voltage by adopting a BUCK circuit formed by an SRG winding and a power converter in the main circuit, closing the switching tubes S2, S4 and S6, controlling the duty ratios of the switching tubes S1, S3 and S5 by the controller, and reducing the output voltage to the second threshold voltage under closed-loop control.

Technical Field

The invention relates to a generator, in particular to a permanent magnet reluctance cascade generator.

Background

At present, a single motor is used for generating power in a vehicle power generation system, and most of generators adopt electric excitation generators, so that the excitation voltage of the generators can only be obtained from a storage battery, and the normal operation of the storage battery under the conditions of no electricity and damage of the storage battery cannot be ensured. The magnetic field of the electrically excited generator is generated by energizing the winding coil, resulting in low efficiency of the generator and reduced power density. The Permanent Magnet Generator (PMG) has high efficiency and high power density, but the inherent characteristics of the permanent magnet cause that the magnetic field intensity is not adjustable, and the output voltage is required to be adjusted through a corresponding controllable rectifier.

Disclosure of Invention

The invention aims to provide a permanent magnet reluctance cascade generator control system and a control method thereof, which are used for solving the problems that the existing vehicle power generation control system has poor low-speed power generation performance, a storage battery is damaged and cannot be started, the electric excitation efficiency is low, and the excitation of a permanent magnet generator is uncontrollable, and improving the wide rotating speed range power generation performance of the vehicle generator.

The purpose of the invention is realized as follows: a permanent magnet reluctance cascade generator control system comprising the PMG and SRG in coaxial series, further comprising:

the rectification circuit is connected to the PMG, is used for converting the PMG output into direct current and outputting the direct current to the power converter;

the power converter selects a separately excited asymmetric half-bridge structure, is connected to the SRG, is used for controlling the SRG to work and can output electric energy;

the DSP controller is connected with the rectification circuit and the power converter and used for collecting corresponding voltage and current signals and outputting a driving signal through the driving circuit to control the power converter to work, and the DSP controller specifically comprises:

when the rotating speed is low, the direct current is boosted through a BOOST circuit formed by the SRG winding and the power converter to output electric energy; when the rotating speed is high, the direct current is subjected to voltage reduction through a BUCK circuit formed by the SRG winding and the power converter to output electric energy; in a normal rotating speed range, the PMG is firstly used as an excitation motor of the SRG, the SRG adopts a position-sensor-free control method, and the PMG and the SRG realize the common power generation by controlling the on-off of a switching tube of a power converter.

As a further limitation of the present invention, the three-phase uncontrollable rectifying circuit and the separately excited asymmetric half-bridge structure are cascaded to form a main circuit topology, the separately excited asymmetric half-bridge structure is also a three-phase structure, wherein,

the A phase structure comprises two switching tubes S1 and S2 and two freewheeling diodes D7 and D8, wherein the collector of the switching tube S1 is connected with the anode of the main circuit, the emitter of the switching tube S1 is connected with the cathode of the current diode D7 and one end of the SRG A phase coil, the collector of the switching tube S2 is connected with the other end of the SRGA phase coil and the anode of the freewheeling diode D8, and the emitter of the switching tube S2 and the anode of the freewheeling diode D7 are connected with the cathode of the main circuit;

the B phase structure comprises two switching tubes S3 and S4 and two freewheeling diodes D9 and D10, wherein the collector of the switching tube S3 is connected with the anode of the main circuit, the emitter of the switching tube S3 is connected with the cathode of the current diode D9 and one end of the SRG B phase coil, the collector of the switching tube S4 is connected with the other end of the SRG B phase coil and the anode of the freewheeling diode D10, and the emitter of the switching tube S4 and the anode of the freewheeling diode D9 are connected with the cathode of the main circuit;

the C-phase structure comprises two switching tubes S5 and S6 and two freewheeling diodes D11 and D12, wherein the collector of the switching tube S5 is connected with the anode of the main circuit, the emitter of the switching tube S5 is connected with the cathode of the current diode D11 and one end of the SRG C-phase coil, the collector of the switching tube S6 is connected with the other end of the SRG coil and the anode of the freewheeling diode D12, and the emitter of the switching tube S6 and the anode of the freewheeling diode D11 are connected with the cathode of the main circuit;

the cathode of the freewheel diode D8, the cathode of the freewheel diode D10, and the cathode of the freewheel diode D12 are connected in parallel and serve as output terminals.

As a further limitation of the present invention, the main circuit further comprises a filter circuit disposed in the post-excited asymmetric half-bridge structure.

As a further limitation of the present invention, the method for controlling the power converter to operate by the DSP controller specifically includes:

judging the output voltage of the PMG, if the output voltage is lower than a set first threshold voltage, adopting an SRG winding and a power converter in a main circuit to form a BOOST circuit to BOOST the output voltage, closing switch tubes S1, S3 and S5, controlling duty ratios of the switch tubes S2, S4 and S6 by a controller, and boosting the output voltage under closed-loop control;

if the output voltage of the PMG is higher than the set first threshold voltage and lower than the second threshold voltage, an asymmetric half-bridge circuit is formed by an SRG winding and a power converter in a main circuit to realize the common power generation of the PMG and the SRG, switching tubes S1, S2, S3, S4, S5 and S6 are closed, the output voltage of the PMG excites the SRG, when the SRG generates power, the switching tubes S1, S3 and S5 are kept closed, only the switching tubes S2, S4 and S6 are opened, the voltage of an output terminal is measured in real time, and the magnitude of a current chopping value of the SRG under the full-on control is controlled in a closed-loop mode to maintain the output voltage at the charging voltage;

if the PMG output voltage is higher than the second threshold voltage, the output voltage is reduced by using a BUCK circuit formed by an SRG winding and a power converter in the main circuit, the switching tubes S2, S4 and S6 are closed, the duty ratios of the switching tubes S1, S3 and S5 are controlled by the controller, and the output voltage is reduced to the second threshold voltage under closed-loop control.

A control method of a permanent magnet reluctance cascade generator adopts the control system of the permanent magnet reluctance cascade generator, and comprises the following steps:

step 1) detecting the output voltage of the PMG;

step 2) controlling the power converter to work through the DSP controller, specifically:

step 2-1) if the output voltage is lower than the set first threshold voltage, adopting a BOOST circuit formed by an SRG winding and a power converter in a main circuit to BOOST the output voltage, closing switch tubes S1, S3 and S5, controlling duty ratios of the switch tubes S2, S4 and S6 by a controller, and boosting the output voltage under closed-loop control;

step 2-2) if the output voltage of the PMG is higher than the set first threshold voltage and lower than the second threshold voltage, at the moment, an asymmetric half-bridge circuit formed by an SRG winding and a power converter in a main circuit is adopted to realize the common power generation of the PMG and the SRG, switching tubes S1, S2, S3, S4, S5 and S6 are closed, the output voltage of the PMG excites the SRG, when the SRG generates power, the switching tubes S1, S3 and S5 are kept closed, only the switching tubes S2, S4 and S6 are opened, the voltage of an output terminal is measured in real time, and the magnitude of a current chopping value of the SRG under the full-on control is controlled in a closed-loop mode to maintain the output voltage at a charging voltage;

and 2-3) if the PMG output voltage is higher than the set second threshold voltage, reducing the output voltage by adopting a BUCK circuit formed by an SRG winding and a power converter in the main circuit, closing the switching tubes S2, S4 and S6, controlling the duty ratios of the switching tubes S1, S3 and S5 by the controller, and reducing the output voltage to the second threshold voltage under closed-loop control.

Compared with the prior art, the invention has the beneficial effects that: the permanent magnet reluctance cascade power generation system is adopted, the excitation voltage of the SRG can be obtained after rectification by the PMG generator, and an additional storage battery is not needed; even if the storage battery is damaged, the storage battery still can be boosted to a charging voltage through a BOOST circuit formed by an SRG winding, a power switching tube and a diode in a main circuit through a manual cart to ignite an automobile; when the rotating speed of the engine is in a normal range, an asymmetric half-bridge circuit formed by an SRG winding, a power switching tube and a diode in a main circuit is adopted to realize the joint power generation of PMG and SRG; when the engine speed is extremely fast (the PMG output voltage is high), the voltage can be reduced to a charging voltage through a BUCK circuit formed by an SRG winding, a power switch tube and a diode in the main circuit to charge the storage battery; in addition, the invention improves the reliability of the whole system, improves the safety factor, and has simple control mode and easy operation.

Drawings

Fig. 1 is a coaxial series structure diagram of a permanent magnet reluctance cascade generator used in the invention.

Fig. 2 is an optimized structure diagram of a permanent magnet reluctance cascade generator used in the invention.

Fig. 3 shows a power converter topology of a permanent magnet reluctance cascade generator used in the present invention.

FIG. 4 is a waveform of the input/output voltage of the BOOST circuit composed of the SRG winding, the power switch tube and the diode in the main circuit under the low speed condition used by the present invention.

FIG. 5 is a flow chart of a control method of a PMreluctance cascaded generator according to the present invention.

FIG. 6 is a test platform of a prototype of a permanent magnet reluctance cascade generator used in the invention.

Fig. 7 is a three-phase generated current waveform of the SRG used in the present invention.

FIG. 8 is the voltage waveform of the permanent magnet reluctance cascade generator used in the present invention when the storage battery is charged at constant voltage at each speed stage.

FIG. 9 shows the input/output voltage waveforms of the BUCK circuit composed of SRG winding, power switch tube and diode in the main circuit used in the present invention.

FIG. 10 shows the SRG phase current chopping waveforms (a chopping value of 2A, (b) chopping value of 4A, and (c) chopping value of 6A) used in the present invention.

Detailed Description

The present invention is further illustrated by the following specific examples.

As shown in fig. 1, a permanent magnet reluctance cascade generator control system includes a permanent magnet generator (a permanent magnet synchronous generator or a brushless dc generator, abbreviated as PMG) and a Switched Reluctance Generator (SRG) which are coaxially connected in series, in order to reduce the size of the motor, as shown in fig. 2, a coupler can be removed from the two generators, the two generators are processed in a housing by using a shaft, rotating shafts of the PMG and the SRG are connected with a prime mover through a dynamic torque sensor, and the prime mover outputs power given by a simulation engine to drive the PMG and the SRG to work, this embodiment further includes:

the rectification circuit is connected to the PMG, is used for converting the PMG output into direct current and outputting the direct current to the power converter;

the power converter selects a separately excited asymmetric half-bridge structure, is connected to the SRG and is used for controlling the SRG to work and outputting electric energy to a load or a storage battery;

the DSP controller is connected with the rectifying circuit and the power converter and used for collecting corresponding voltage and current signals and outputting a driving signal through the driving circuit to control the power converter to work, and the DSP controller specifically comprises:

when the rotating speed is low, the direct current is boosted through a BOOST circuit formed by the SRG winding and the power converter to output electric energy to a load or a storage battery; when the rotating speed is high, the direct current is subjected to voltage reduction through a BUCK circuit formed by the SRG winding and the power converter to output electric energy to a load or a storage battery; in a normal rotating speed range, the PMG is firstly used as an excitation motor of the SRG, the SRG adopts a position-sensor-free control method, and the PMG and the SRG realize the common power generation by controlling the on-off of a switching tube of a power converter.

As shown in fig. 3, the three-phase uncontrollable rectifying circuit, the separately excited asymmetric half-bridge structure are cascaded and the filter circuit arranged in the separately excited asymmetric half-bridge structure forms a main circuit topology structure, the low-pass filter circuit is arranged at the rear, the voltage ripple when the storage battery is charged can be reduced, and the separately excited asymmetric half-bridge structure is a three-phase structure, and specifically is:

the A phase structure comprises two switching tubes S1 and S2 and two freewheeling diodes D7 and D8, wherein the collector of the switching tube S1 is connected with the anode of the main circuit, the emitter of the switching tube S1 is connected with the cathode of the current diode D7 and one end of the SRG A phase coil, the collector of the switching tube S2 is connected with the other end of the SRGA phase coil and the anode of the freewheeling diode D8, and the emitter of the switching tube S2 and the anode of the freewheeling diode D7 are connected with the cathode of the main circuit;

the B phase structure comprises two switching tubes S3 and S4 and two freewheeling diodes D9 and D10, wherein the collector of the switching tube S3 is connected with the anode of the main circuit, the emitter of the switching tube S3 is connected with the cathode of the current diode D9 and one end of the SRG B phase coil, the collector of the switching tube S4 is connected with the other end of the SRG B phase coil and the anode of the freewheeling diode D10, and the emitter of the switching tube S4 and the anode of the freewheeling diode D9 are connected with the cathode of the main circuit;

the C-phase structure comprises two switching tubes S5 and S6 and two freewheeling diodes D11 and D12, wherein the collector of the switching tube S5 is connected with the anode of the main circuit, the emitter of the switching tube S5 is connected with the cathode of the current diode D11 and one end of the SRG C-phase coil, the collector of the switching tube S6 is connected with the other end of the SRG coil and the anode of the freewheeling diode D12, and the emitter of the switching tube S6 and the anode of the freewheeling diode D11 are connected with the cathode of the main circuit;

the cathode of the freewheel diode D8, the cathode of the freewheel diode D10, and the cathode of the freewheel diode D12 are connected in parallel and serve as output terminals.

In order to intuitively embody PMG + SRG power generation and optimize relevant parameters of PMG + SRG power generation, a scheme of separately coupling and rotating a permanent magnet reluctance motor is adopted in an experiment, so that the space of the whole system is increased. And then, in order to reduce the waste of space and expand the advantages of the system, the PMG and the SRG are arranged in the same motor, the coupler is removed, and the two generators are processed in one shell by one shaft. Fig. 2 shows an optimized structure schematic diagram of the permanent magnet reluctance cascade generator.

The control method of the permanent magnet reluctance cascade generator control system shown in fig. 5 comprises the following steps: the method comprises the following steps:

step 1) detecting the output voltage of the PMG;

step 2) controlling the power converter to work through the DSP controller, specifically:

step 2-1) if the output voltage is lower than the set first threshold voltage, adopting a BOOST circuit formed by an SRG winding and a power converter in a main circuit to BOOST the output voltage, closing switch tubes S1, S3 and S5, controlling duty ratios of the switch tubes S2, S4 and S6 by a controller, and boosting the output voltage under closed-loop control;

step 2-2) if the output voltage of the PMG is higher than the set first threshold voltage and lower than the charging voltage, at the moment, an asymmetric half-bridge circuit formed by an SRG winding and a power converter in the main circuit is adopted to realize the common power generation of the PMG and the SRG, the switching tubes S1, S2, S3, S4, S5 and S6 are closed, the output voltage of the PMG excites the SRG, the switching tubes S1, S3 and S5 are kept closed during the power generation of the SRG, only the switching tubes S2, S4 and S6 are opened, the voltage at two ends of the storage battery/load is measured in real time, and the current chopping value I of the SRG under the full-on control is controlled by the closed-loop control_refA magnitude to maintain the output voltage at the charging voltage;

and 2-3) if the PMG output voltage is higher than the set charging voltage, adopting a BUCK circuit formed by an SRG winding and a power converter in the main circuit to reduce the output voltage, closing the switching tubes S2, S4 and S6, controlling the duty ratios of the switching tubes S1, S3 and S5 by the controller, and reducing the output voltage to a second threshold voltage under closed-loop control.

FIG. 4 shows the input/output voltage waveform of the BOOST circuit composed of the SRG winding, the power switch tube and the diode in the main circuit. In order to realize the continuous operation of the motor, the system state is determined according to the output voltage of the PMG after the motor is started, and then the processes in different states are determined, and the specific flow is shown in fig. 5.

As shown in fig. 6, in order to verify the effectiveness of the control method provided by the present description, a prototype test platform and a control platform are built, and the PMG and the SRG are coaxially connected in series. DSP TMS320F28335 is selected as the digital signal processor, a driving circuit takes a driving optocoupler HCPL-3120 as a driving chip, and a filtering circuit selects LCL filtering.

The generated voltages of the PMG generator and the SRG are detected by the sampling circuit, and the generated current of each phase of the three-phase switched reluctance generator is detected by the LEM current sensor, and the waveform is shown in fig. 7. Fig. 8 shows voltage waveforms when the permanent magnet reluctance cascade generator performs constant voltage charging on the storage battery at each speed stage, and it can be known from the figure that the current chopping limit value can be effectively adjusted and the output voltage can be maintained at the charging voltage when the speed of the permanent magnet reluctance cascade generator changes through voltage closed-loop control.

Because the rotating speed range of the engine is wider, the engine can run at a higher rotating speed, so that the output voltage of the permanent magnet type direct current generator is greater than the rated voltage, and at the moment, the output voltage is higher than the charging voltage of the storage battery and the rated voltage of the storage battery/load in the vehicle; in order to ensure the normal charging of the storage battery and the normal operation of the storage battery/load in the vehicle, the duty ratio of the switching tube is adjusted by closed-loop control through a BUCK circuit composed of the SRG winding, the power switching tube and the diode in the main circuit, so as to maintain the output voltage to be stabilized at the charging voltage, and fig. 9 shows the input/output voltage waveform of the BUCK circuit composed of the SRG winding, the power switching tube and the diode in the main circuit. Fig. 10 shows current waveforms of the SRG under different current chopping limit values, and it can be seen from the figure that the peak current of the SRG phase current can be effectively controlled by controlling the current chopping limit value, and meanwhile, in the current falling region, the phase current can be effectively controlled by controlling the current chopping limit value.

The present invention is not limited to the above-mentioned embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts according to the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.