WO2022062103A1 - 一种高压永磁变频一体机 - Google Patents

一种高压永磁变频一体机 Download PDF

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Publication number
WO2022062103A1
WO2022062103A1 PCT/CN2020/127879 CN2020127879W WO2022062103A1 WO 2022062103 A1 WO2022062103 A1 WO 2022062103A1 CN 2020127879 W CN2020127879 W CN 2020127879W WO 2022062103 A1 WO2022062103 A1 WO 2022062103A1
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Prior art keywords
voltage
frequency conversion
alternating current
output
permanent magnet
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PCT/CN2020/127879
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English (en)
French (fr)
Inventor
宋承林
张鸿波
刘锡安
杨绪峰
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青岛中加特电气股份有限公司
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Priority to US17/796,344 priority Critical patent/US20230065347A1/en
Publication of WO2022062103A1 publication Critical patent/WO2022062103A1/zh

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/30—Structural association with control circuits or drive circuits
    • H02K11/33—Drive circuits, e.g. power electronics
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/30—Structural association with control circuits or drive circuits
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0009—Devices or circuits for detecting current in a converter
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/0074—Plural converter units whose inputs are connected in series
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
    • H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
    • H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
    • H02M5/453—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M5/458—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/003—Constructional details, e.g. physical layout, assembly, wiring or busbar connections
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
    • H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P2207/00—Indexing scheme relating to controlling arrangements characterised by the type of motor
    • H02P2207/05—Synchronous machines, e.g. with permanent magnets or DC excitation

Definitions

  • the present invention generally relates to the field of motor applications. More specifically, the present invention relates to a high-voltage permanent magnet variable frequency integrated machine.
  • a high-voltage permanent magnet motor of 6 kV to 10 kV is often used as the power source.
  • the existing frequency converter cannot directly drive the high-voltage permanent magnet motor, so the working mode of 10kV high-voltage asynchronous motor + controllable start transmission device (“CST”)_ is mostly used.
  • CST controllable start transmission device
  • the motor in this working mode has problems such as difficult maintenance, high maintenance cost, low starting torque under heavy load, and large impact on the power grid.
  • the topology structure of the existing frequency converter mostly adopts the way of direct series connection of power devices and multi-level output.
  • This topology has low reliability, easily damaged power devices and high output harmonics.
  • the multi-level output method avoids many shortcomings of the direct series connection of power devices, as the number of levels increases, the number of clamping diodes increases exponentially, which undoubtedly increases the cost and reduces the reliability of equipment operation.
  • the inverter Take the simplest topology of six-pulse rectification and two-level inverter as an example. Although this topology is simple, its output harmonics are relatively high, so the impact on the power grid is relatively large. In order to reduce the influence of harmonics on the power grid, more advanced inverters are designed with twelve pulses, twenty-four pulses or even forty-eight pulses rectification. However, such a rectifying and phase-shifting transformer is large in size and high in cost, and at the same time has high requirements on the withstand voltage of the driven motor, which is likely to cause the motor to burn out. In order to make the current output by the inverter smoother, the inverter can be designed as a three-level, five-level or even multi-level inverter. However, the current topologies of such inverters are all single-output structures, and the more advanced the topology requires, the more power devices are required, which results in an excessively large inverter, high cost, and complicated control methods.
  • the present invention provides a frequency conversion integrated machine that uses a high-voltage permanent magnet direct-drive synchronous motor and a high-voltage frequency converter in combination.
  • the frequency conversion integrated machine controls the inverter unit of the frequency converter through the controller, so as to convert the frequency of the high-voltage three-phase alternating current, so as to change the speed of the permanent magnet direct drive synchronous motor.
  • the permanent magnet motor stator winding of the frequency conversion integrated machine of the present invention is connected to the multiple output ends of the inverter unit of the frequency converter through a special winding method, so as to cooperate with the turn-off sequence of the IGBT of the inverter unit. Thereby driving the high-voltage permanent magnet motor to run.
  • the present invention discloses a high-voltage permanent magnet frequency conversion integrated machine.
  • the frequency conversion all-in-one machine includes: a frequency converter, which is used for frequency conversion and output of high-voltage alternating current, and the output alternating current is at least three channels; a permanent magnet motor, which is used for receiving the frequency converted and outputted by the frequency converter. , so as to drive the motor to run; and a controller configured to control the frequency converter to perform frequency conversion of the high-voltage alternating current, and to control the operating state of the permanent magnet motor.
  • the frequency converter includes a rectifier unit, a DC circuit, and an inverter unit, wherein the rectifier unit is used to convert the high-voltage alternating current into direct current;
  • the direct current circuit includes a DC bus and an energy storage capacitor, and for buffering and storing the DC power output by the rectifier unit; and the inverter unit for converting the DC power processed by the DC circuit into at least three-way AC power, so as to supply the permanent magnet motor to the permanent magnet motor output.
  • the voltage range of the high-voltage alternating current is 6 kV to 10 kV.
  • the frequency conversion integrated machine further includes a Hall current transformer, which is used to collect the at least three-way alternating current, and output the collected signals to the controller, so as to control the permanent magnet motor operating status.
  • the frequency conversion all-in-one machine further includes a pre-charging circuit, which is arranged at the input end of the rectifier unit and is used to pre-charge the energy storage capacitor in the DC circuit by the high-voltage alternating current.
  • the frequency conversion integrated machine further includes a bus voltage sampling circuit, which is connected in parallel with the DC bus and is used for sampling the voltage value on the DC bus, and outputting the sampling result to the controller , so as to control the frequency converter to perform frequency conversion of the high-voltage alternating current.
  • the frequency conversion integrated machine further includes a reactor, which is connected to the input end of the frequency converter and is used for stabilizing the high-voltage alternating current and suppressing interference.
  • the energy storage capacitor adopts a package type without a case and a plug-in connection manner, so as to increase the withstand voltage value and electrical interval of the pole case and reduce the volume of the frequency converter.
  • stator winding of the permanent magnet motor is connected to the multiple output ends of the inverter unit in a multi-winding star connection manner.
  • the frequency conversion integrated machine further includes a static voltage equalization circuit, which is connected between the DC bus bars and is used for performing voltage equalization processing on the inverter unit and when the inverter is switched off. When on, the voltage on the DC bus is discharged.
  • the frequency conversion integrated machine of the invention has the advantages of simple structure, small size of the whole machine, stable and reliable operation and the like.
  • the energy storage capacitor of the frequency converter adopts a package type without a casing, and the top of the energy storage capacitor is encapsulated with a metal fixing ear, so as to effectively ensure the energy storage capacitor under the premise of satisfying the withstand voltage, creepage distance and electrical clearance of the pole casing. fixed strength.
  • the frequency conversion all-in-one machine of the present invention adopts a special precharging circuit, so that the energy storage capacitor can be directly precharged by high-voltage electricity, thereby reducing the volume of the frequency conversion all-in-one machine.
  • the frequency conversion integrated machine of the present invention adopts the 4-way electromagnetic coupling technology of the frequency converter combined with the permanent magnet motor, thereby solving the technical problems of difficult low-speed control, difficult high-voltage driving, low starting torque, and difficulty in IGBT voltage equalization.
  • FIG. 1 is a block diagram showing the composition of a frequency conversion integrated machine according to an embodiment of the present invention
  • FIG. 2 is a block diagram showing the composition of a frequency converter according to an embodiment of the present invention.
  • FIG. 3 is a circuit schematic diagram illustrating an all-in-one frequency conversion machine according to an embodiment of the present invention
  • FIG. 4 is a diagram illustrating a stator winding connection diagram of a permanent magnet motor according to an embodiment of the present invention.
  • FIG. 5 is a connection diagram illustrating a storage capacitor according to an embodiment of the present invention.
  • FIG. 1 is a block diagram showing the composition of a frequency conversion integrated machine 100 according to an embodiment of the present invention.
  • a high-voltage alternating current is also drawn in FIG. 1 .
  • the high-voltage alternating current can be, for example, a 10 kV three-phase high-voltage alternating current, which is used to supply power to the frequency conversion integrated machine.
  • the frequency conversion integrated machine 100 of the present invention may include: a controller 101 , a frequency converter 102 and a permanent magnet motor 103 .
  • the frequency converter is used for frequency conversion and output of high-voltage alternating current, and the output alternating current is at least three channels.
  • the permanent magnet motor is used for receiving the alternating current which has been frequency-converted and output by the frequency converter, so as to drive the motor to run.
  • the controller is configured to control the frequency converter to perform frequency conversion of the high voltage alternating current and to control the operating state of the permanent magnet motor.
  • the high-voltage alternating current may be high-voltage three-phase alternating current, wherein the phases of the voltages of each phase are 120 degrees different from each other, and the voltage range may be 6 kV to 10 kV.
  • the frequency conversion integrated machine of the present invention may include a transformer, and the output of the transformer is the high-voltage three-phase alternating current.
  • the transformer may include an iron core (or a magnetic core) and a coil, and the coil has two or more windings, wherein the winding connected to the high-voltage power grid is the primary coil, and the winding connected to the input end of the frequency converter is the primary coil.
  • the winding is the secondary coil.
  • the transformer can transform AC voltage, current and impedance.
  • the voltage of the high-voltage three-phase alternating current transmitted from the high-voltage power grid is as high as 100 kV or more, which is not suitable for the use of electric motors and other equipment. Therefore, it needs to be depressurized through a transformer, so as to output a high-voltage three-phase alternating current of 6 kV to 10 kV to the inverter, so that the matching between the AC input voltage and the DC output voltage can be achieved, as well as the high-voltage grid and the frequency conversion. high-voltage electrical isolation between the rectifier units of the rectifier.
  • FIG. 2 is a block diagram showing the composition of a frequency converter 200 according to an embodiment of the present invention.
  • the frequency converter 200 of the present invention may include a precharge circuit 101 , a rectifier unit 102 , a DC circuit 103 and an inverter unit 104 .
  • the rectifier unit may include a rectifier device and a filter, wherein the rectifier utilizes a component with unidirectional conduction characteristics, and can convert the alternating current with high voltage output by the transformer and with changing direction and magnitude into a single rectifier. to pulsating direct current.
  • the filter is used for filtering out the AC component in the pulsating DC voltage.
  • the DC circuit may include DC busbars DC+, DC- and a storage capacitor C, and is used for buffering and storing the DC power output by the rectifier unit.
  • the inverter unit is used for converting the DC power processed by the DC circuit into at least three-way AC power so as to be output to the permanent magnet motor.
  • the alternating current output by the inverter unit may be, for example, four channels.
  • the pre-charging circuit is arranged at the input end of the rectifier unit, and is used to pre-charge the energy storage capacitor C in the DC circuit by the high-voltage alternating current.
  • the DC circuit may include a circuit composed of energy storage elements such as a plurality of capacitors and inductors, and may be located between the rectifier unit and the inverter unit, wherein the capacitor may be, for example, an electrolytic capacitor.
  • the electrolytic capacitor in the DC circuit of the frequency converter is in a short-circuit state when it is charged instantaneously before the voltage is established.
  • the charging current is very large, which may damage the rectifier diodes, electrolytic capacitors on the DC bus, and other inverter components. For this reason, in order to limit the excessive charging current, the electrolytic capacitors in the DC link must be pre-charged.
  • the rectifier unit can output direct current to the inverter unit through the direct current loop. Since the motor is an inductive load, no matter what operating state the motor is in, its power factor is always not 1. Therefore, there is always an exchange of reactive power between the DC circuit and the motor. This reactive power needs the energy storage element in the DC circuit to buffer, so that the DC voltage output by the rectifier unit is always stable. Based on the above principles, the DC circuit is used for receiving and storing the DC power sent by the rectifier unit, and performing processing such as suppressing interference on the DC power.
  • the high-voltage alternating current output by the transformer is processed by the pre-charging circuit, and then converted into low-current alternating current.
  • the rectifier unit converts the small current alternating current into small current direct current, and pre-charges the energy storage capacitor C in the direct current loop through the small current direct current.
  • the pre-charging circuit is disconnected.
  • the high-voltage alternating current output by the transformer is rectified by the rectifier unit, and then the high-voltage direct current is output.
  • the high-voltage direct current flows to the inverter unit after being processed by energy storage and interference suppression in the direct current circuit.
  • the inverter unit inverts the high-voltage direct current, so as to perform frequency conversion, and outputs to the permanent magnet motor through multiple channels, so as to drive the permanent magnet motor to run.
  • FIG. 3 is a schematic circuit diagram illustrating an integrated frequency conversion machine 300 according to an embodiment of the present invention.
  • the frequency conversion integrated machine 300 of the present invention may include: a controller 301, a reactor 302, a precharge circuit 303, a rectifier circuit 304, a bus voltage sampling circuit 305, a static voltage equalizing circuit 306, a DC circuit, an inverter Circuit 307 , Hall current transformer circuit 308 , interface circuit 309 and 10KV four-way permanent magnet synchronous motor 310 .
  • the reactor is arranged at the input end of the frequency conversion integrated machine, and is used to stabilize and filter the 10KV high-voltage three-phase (R, S and T phase) alternating current input to the frequency conversion integrated machine And suppress the interference, so as to prevent the harmonic interference of the rectifier unit to the power grid.
  • the reactor can also be used to suppress short-circuit energy, so as to prevent excessive energy loss of the preceding stage due to excessive short-circuit energy of the subsequent stage.
  • the reactor may be composed of three inductors L1 , L2 and L3 , which are respectively connected to the R-phase, S-phase and T-phase output terminals of the 10KV high-voltage three-phase alternating current.
  • a high-voltage fuse may also be connected to the input end of the reactor, for example, the high-voltage fuses F1 and F2 with a capacity of 125 amperes in FIG. 3 are respectively connected to the R-phase and T-phase output terminals of high-voltage three-phase alternating current.
  • the pre-charging circuit may include a main switch KM1 and charging switches K1, K2 and K3, wherein the charging switches K1, K2 and K3 may be, for example, 35KV high voltage relays so as to be able to withstand high voltage charging .
  • the charging switch can be connected to current-limiting high-voltage resistors R1, R2 and R3 respectively, so as to limit the charging current from being too large, and the current-limiting high-voltage resistors R1, R2 and R3 are respectively connected to the reactors L1, L2 and L3 .
  • the main switch KM1 when the frequency conversion integrated machine is powered on, the main switch KM1 is in an open state under the control of the controller, and the charging switches K1, K2 and K3 are all in a closed state.
  • the R, S and T phase voltages of the 10KV high-voltage three-phase alternating current are respectively limited by the current limiting resistors R1, R2 and R3, and then converted into low-voltage direct current by the rectifier unit.
  • the low-voltage direct current starts to precharge the energy storage capacitor in the direct current circuit.
  • the controller detects that the voltage value on the DC bus reaches the set value, and then controls to close the main switch KM1.
  • the charging switches K1 , K2 and K3 are turned off with a delay.
  • the 10KV high-voltage three-phase alternating current flows to the rectifier unit through the main switch KM1, and is converted into high-voltage direct current by the rectifier unit and then output to the inverter unit.
  • the rectifier unit may be, for example, a rectifier circuit composed of a three-phase rectifier bridge.
  • the input end is used to receive the 10KV high-voltage three-phase alternating current, and the output end is used to output the rectified high-voltage direct current.
  • the three-phase rectifier bridge may be composed of 18 rectifier diodes D1-D18, wherein the R-phase voltage is connected to the first upper bridge (composed of the series-connected D1-D3) and the first lower bridge (composed of the series-connected D1-D3) in series.
  • the output current of the rectifier circuit at any time flows out from the rectifier diode connected to the phase with the highest potential in the three-phase power, and flows to the rectifier diode connected to the phase with the lowest potential through the load, and finally flows back to the power supply.
  • the rectifier diodes D15, D14, D13 and D12, D11, and D10 are always on during this period, while the rest of the The diode is in the off state.
  • the current is output from the T-phase, and flows through D15, D14 and D13 in sequence, then flows through the load, and then flows back to the S-phase from D12, D11 and D10 in sequence.
  • the T-phase output is the output of the rectifier circuit.
  • the rectifier diodes D3, D2, D1 and D12, D11, D10 are always in the conduction state during this period, while the remaining diodes is in the cut-off state. Therefore, at this time, the current is output from the R-phase, and flows through D3, D2 and D1 in sequence, then flows through the load, and then flows back to the S-phase from D12, D11 and D10 in sequence. At this time, the R-phase output is the output of the rectifier circuit.
  • the rectifier diodes D3, D2, D1 and D18, D17, D16 are always in the conduction state during this period, while The remaining diodes are in the off state. Therefore, at this time, the current is output from the R-phase, and flows through D3, D2 and D1 in sequence, then flows through the load, and then flows back to the T-phase from D18, D17 and D16 in sequence. At this time, the R-phase output is the output of the rectifier circuit.
  • the output of the rectifier circuit in the case of 150 degrees to 360 degrees can be obtained.
  • the rectifier circuit converts the 10KV high-voltage three-phase alternating current into high-voltage direct current.
  • the bus voltage sampling circuit may include an isolated power supply and a high voltage sampling circuit.
  • the bus voltage sampling circuit is connected in parallel between the DC+ terminal and the DC- terminal of the DC bus, and is used to sample the high voltage on the DC bus, and convert it into a low voltage through an isolated power supply, and then send it to the DC bus.
  • the controller outputs the sampling signal. After receiving the sampling signal, the controller performs analysis and processing, and then controls the frequency converter to perform frequency conversion of the high-voltage alternating current.
  • the controller can also control the closing and opening of the pre-charging circuit according to the analysis and processing results, or can also perform overvoltage protection on the frequency conversion integrated machine.
  • the bus voltage sampling circuit can communicate with the controller via a fiber optic link.
  • the DC loop may include a circuit formed by a DC bus and an energy storage capacitor.
  • the DC bus is composed of a DC+ terminal and a DC- terminal
  • the energy storage capacitor may include C1 , C2 , C3 and C4 .
  • the energy storage capacitors in the DC circuit in FIG. 3 can also be replaced with other energy storage components such as energy storage inductors according to different application scenarios, and the number of the energy storage capacitors can be multiple.
  • the static voltage equalizing circuit is connected between the DC+ terminal and the DC- terminal of the DC bus, and is used to perform voltage equalization processing on the inverter unit and when the inverter is disconnected , to discharge the DC bus voltage.
  • the static voltage equalization circuit may include a circuit composed of high-voltage resistors R4 to R7 . After the DC bus voltage is divided by the high-voltage resistors R4-R7, it is loaded into each IGBT module in the inverter unit to ensure that the voltage of each IGBT module is balanced during static state, thereby preventing the IGBT module from burning.
  • the frequency conversion integrated machine when the frequency conversion integrated machine is powered off, in order to ensure its operation safety, it is necessary to perform a discharge operation through the high-voltage resistors R4-R7.
  • the storage capacitors C1, C2, C3 and C4 can also be discharged through the loop formed by the high-voltage resistors R4-R7.
  • the inverter unit may include an inverter circuit composed of a plurality of inverter bridges, and the inverter bridges may be composed of a plurality of insulated gate bipolar transistor ("IGBT") modules.
  • the inverter unit may include an inverter bridge, a logic control circuit and a filter circuit, and is configured to convert the direct current output from the direct current loop into alternating current of constant frequency and constant voltage or frequency regulation and voltage regulation, so as to be supplied to the permanent magnet motor for use .
  • the inverter bridge may include an input interface, a voltage startup loop, a power switch element, a DC conversion loop, a feedback loop, and the like;
  • the logic control circuit may include a pulse width modulation controller, a carrier generator, and a modulated wave generator. and it can be arranged in the controller or its function can be performed by the controller.
  • the inverter bridge plays a key role in the process of converting direct current into three-phase alternating current. It controls the conduction or disconnection of the power switching elements located on the upper bridge and the lower bridge through the pulse width modulation signal generated by the logic control circuit, so as to obtain a phase difference of 120° on the three output ends of the inverter bridge. of three-phase alternating current for output to the motor.
  • the power switching element may be, for example, an insulated gate bipolar transistor ("IGBT”), which has the advantages of high input impedance and low turn-on voltage.
  • the inverter unit and the controller are connected through a communication line, for example, they can communicate with the inverter unit through an RS-485 serial bus.
  • the controller is configured to receive and process the signals transmitted from the inverter unit and the bus voltage sampling circuit, and send a control signal to the inverter unit according to the processing result, so as to control the IGBT to be turned on in turn.
  • the frequency of the alternating current output by the inverter unit can be changed, thereby controlling the rotational speed of the motor.
  • the inverter circuit may include 24 IGBT modules VT1 to VT24, and the inverter circuit may include 4 outputs.
  • VT1 ⁇ VT6 form the first three-phase output U1, V1 and W1
  • VT7 ⁇ VT12 form the second three-phase output U2, V2 and W2
  • VT13 ⁇ VT18 form the third three-phase output U3, V3 and W3
  • VT19 ⁇ VT24 constitute the fourth three-phase output U4, V4 and W4.
  • the inverter unit of the present invention can also have more outputs according to the input voltage value and the connection mode of the permanent magnet motor windings. The working principle of the inverter circuit is briefly described below by taking the first three-phase outputs U1, V1 and W1 as examples.
  • one cycle time is divided into t1-t6.
  • U UV between U-phase and V-phase
  • VT1 and VT4 are turned on at the same time
  • the U-phase voltage is "+” and the V-phase voltage is "-”
  • U UV is "+”
  • the magnitude of U UV is the bus voltage value.
  • VT2 and VT3 are turned on at the same time.
  • the U-phase voltage is "-” and the V-phase voltage is "+”
  • U UV is "-”
  • the amplitude of U UV is the bus voltage value .
  • VT3 and VT6 are turned on at the same time from t3 to t4.
  • the V phase voltage is "+” and the W phase voltage is "-”, then U VW is “+”, and the magnitude of U VW is the bus voltage value.
  • VT4 and VT5 are turned on at the same time.
  • the V-phase voltage is "-” and the W-phase voltage is "+”, then U VW is "-”, and the amplitude of U VW is the bus voltage value .
  • the phases between U UV , U VW and U WU are 120 degrees different from each other, and the amplitude values of the three are equal to the DC bus voltage value. It can be seen that as long as the turn-on and turn-off of the 6 IGBTs are controlled according to certain rules, the direct current can be inverted into three-phase alternating current. And the current frequency after the inverter can be adjusted by changing the change period of the control signal through the controller under the premise that the above conduction law remains unchanged.
  • the working principles of the second, third, and fourth output channels of the inverter circuit are the same as the above-mentioned first channel output principles, and will not be repeated here.
  • the frequency conversion integrated machine may further include a Hall current transformer circuit. It may include Hall current transformers and their associated circuits.
  • the Hall current transformer circuit is used to collect the three-phase AC power output by the inverter unit, and output the collected current signal to the controller, so as to control the operation state of the permanent magnet motor.
  • the Hall current transformer may include TA1 , TA2 and TA3 , which are respectively connected to the U-phase, V-phase and W-phase of the three-phase alternating current output by the inverter unit.
  • the current output by the U1 phase and the U2 phase flows through the Hall current transformer TA1; the current output by the V1 phase and the V2 phase flows through the Hall current transformer TA2; the W1 phase and the W2 phase
  • the phase output current flows through the Hall current transformer TA3.
  • the Hall current transformers TA1, TA2 and TA3 are connected with the controller through communication lines, for example, they can communicate with the controller through the RS-485 serial bus.
  • the controller receives and processes the signal sent by the Hall current transformer, and monitors the running state of the motor according to the processing result, and can also perform overcurrent, overload and short circuit protection for the frequency conversion integrated machine.
  • FIG. 4 is a connection diagram showing a stator winding of a permanent magnet motor according to an embodiment of the present invention. The following describes the winding connection mode of the permanent magnet motor of the present invention with reference to FIG. 3 and FIG. 4 .
  • the permanent magnet motor of the present invention may include a stator and a rotor, wherein the stator is wound with coil windings, and the rotor does not need to be provided with coil windings.
  • the permanent magnet motor can be a 10KV four-way permanent magnet synchronous motor, and four sets of windings can be wound around the stator.
  • the four groups of windings have a total of 12 terminals, which are U1, V1, W1; U2, V2, W2; U3, V3, W3 and U4, V4 , W4.
  • the four sets of windings are all connected in a star-shaped manner, in which the other ends of the three-phase terminals U1, V1 and W1 are connected together; the other ends of U2, V2 and W2 are connected together; the other ends of U3, V3 and W3 are connected together. together; the other ends of U4, V4 and W4 are connected together. Further, the 12 connection terminals of the 4 groups of windings are respectively connected with the 12 connection terminals of the interface circuit, so as to output the 4-way high-voltage three-phase alternating current output from the inverter to the permanent magnet. an electric motor to drive the permanent magnet motor to operate.
  • the frequency conversion integrated machine of the present invention adopts the 4-way electromagnetic coupling technology of the frequency converter combined with the permanent magnet motor, thereby solving the technical problems of difficult low-speed control, difficult high-voltage driving, low starting torque and difficulty in IGBT voltage equalization of the frequency conversion integrated machine.
  • FIG. 5 is a connection diagram illustrating a storage capacitor 501 according to an embodiment of the present invention.
  • the energy storage capacitor 501 of the present invention can be potted with epoxy resin, and the use of no The package type of the shell reduces the volume of the energy storage capacitor on the one hand; on the other hand, it increases the withstand voltage and creepage distance of the pole shell.
  • the pole shell withstand voltage can reach 42kV
  • the energy storage capacitor is The clearance between the storage capacitor and other components is larger.
  • the top end of the energy storage capacitor of the present invention is encapsulated with metal fixing ears 502, thereby effectively ensuring that the energy storage capacitor is firmly fixed.
  • the energy storage capacitor of the present invention is connected to the circuit board where the IGBT module 503 is located by means of plugging, thereby facilitating the installation and maintenance of the energy storage capacitor.

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Abstract

一种高压永磁变频一体机（100），该变频一体机（100）包括：变频器（102），其用于将高压交流电进行频率转换并输出，并且其输出的交流电至少为三路；永磁电动机（103），其用于接收经过变频器（102）频率转换并输出的交流电，以便驱动电动机（103）运转；以及控制器（101），其配置用于控制所述变频器（102）将高压交流电进行频率转换，并且用于控制永磁电动机（103）的运行状态。该变频器（102）拓扑结构采用多路输出，使得每路输出的电压相对减小，从而减少了对功率器件额定电压的要求。其次，该变频一体机（100）采用特殊的储能电容（501）插接方式，从而使得变频器（102）的体积减小；该永磁电动机（103）采用特殊的绕组缠绕方式，以便连接所述变频器（102）的多路输出。

Description

一种高压永磁变频一体机
相关申请的交叉引用
本申请要求于2020年9月22日向中国国家知识产权局提交的、申请号为2020110040693、发明名称为“一种高压永磁变频一体机”的中国发明专利申请的优先权,其全部内容通过引用结合在本申请中。
技术领域
本发明一般地涉及电动机应用领域。更具体地，本发明涉及一种高压永磁变频一体机。
背景技术
目前，煤矿井下利用主运皮带等进行运输的场合，经常使用6千伏～10千伏的高压永磁电动机作为动力源。而在对高压永磁电动机的使用过程中，现有的变频器并不能直接驱动高压永磁电动机，因此多采用10kV高压异步电动机+可控启动传输装置(“CST”)_的工作方式。但是这种工作方式的电动机存在维护困难、维护成本高、重载启动转矩小以及对电网冲击大等问题。
其次，现有的变频器的拓扑结构多采用功率器件直接串联和多电平输出的方式。这种拓扑结构可靠性低，功率器件易损坏并且输出谐波高。多电平输出的方式虽然规避了功率器件直接串联方式的诸多缺点，但随着电平数增多，导致钳位二极管的数量成倍数增加，这无疑增加了成本，降低了设备运行的可靠性。
以最简单的六脉冲整流配合两电平逆变的拓扑结构为例。这种拓扑结构虽然简单，但是其输出谐波较高，因此对电网的冲击较大。为了减弱谐波对电网的影响，较高级的变频器设计有十二脉冲、二十四脉冲或者还有四十八脉冲整流。但是这样的整流移相变压器尺寸较大且成本较高，同时对所驱动的电动机的耐压要求较高，易造成电动机烧毁。为了使得逆变器输出的电流更加平滑，可以将逆变器设计成三电平、五电平甚至多电平逆变。但是，目前此类逆变部分的拓扑结构都是单输出结构，而且越高级的拓扑结构所需的功率器件越多，从而导致变频器的体积过大、成本较高以及控制方式复杂。
另外，在对变频器进行预充电的过程中，现有技术并不能直接采用高压交流电对储能电容进行充电，通常是单独设计低压充电电路进行预充电，这样导致变频器电路复杂且成本较高。同时，由于储能电容体积较大，且要满足高压充电以及爬电距离和电气间隔的要求，不但使得变频器的体积较大而且容易造成储能电容烧毁。
发明内容
为了解决上述背景技术中的一个或多个问题，本发明提供了一种将高压永磁直驱同步电动机和高压变频器配合使用的变频一体机。该变频一体机通过控制器控制变频器的逆变单元，从而将高压三相交流电进行频率转换，以便改变永磁直驱同步电动机的转速。另外，本发明的变频一体机的永磁电动机定子绕组通过特殊的缠绕方式，与变频器的逆变单元的多路输出端连接，以便与所述逆变单元的IGBT的关断顺序进行配合，从而驱动高压永磁电动机运转。
具体地，本发明公开了一种高压永磁变频一体机。该变频一体机包括：变频器，其用于将高压交流电进行频率转换并输出，并且其输出的交流电至少为三路；永磁电动机，其用于接收经过所述变频器频率转换并输出的交流电，以便驱动所述电动机运转；以及控制器，其配置用于控制所述变频器将高压交流电进行频率转换，并且用于控制所述永磁电动机的运行状态。
在一个实施例中，所述变频器包括整流单元、直流回路和逆变单元，其中所述整流单元用于将所述高压交流电转换成直流电；所述直流回路包括直流母线和储能电容，并且用于将所述整流单元输出的直流电进行缓冲和储能；以及所述逆变单元用于将经过所述直流回路处理后的所述直流电转变为至少三路交流电，以便向所述永磁电动机输出。
在另一个实施例中，所述高压交流电的电压范围为6千伏～10千伏。
在又一个实施例中，所述变频一体机还包括霍尔电流互感器，其用于采集所述至少三路交流电，并将采集的信号向所述控制器输出，以便控制所述永磁电动机的运行状态。
在一个实施例中，所述变频一体机还包括预充电电路，其布置于所述整流单元的输入端，并 且用于通过所述高压交流电对所述直流回路中的储能电容进行预充电。
在另一个实施例中，所述变频一体机还包括母线电压取样电路，其与所述直流母线并联，并且用于对直流母线上的电压值进行取样，并将取样结果向所述控制器输出，以便控制所述变频器将所述高压交流电进行频率转换。
在又一个实施例中，所述变频一体机还包括电抗器，其连接于所述变频器的输入端，并且用于对所述高压交流电进行稳压和抑制干扰。
在一个实施例中，所述储能电容采用无外壳的封装型式和插接的连接方式，以便增大极壳耐压值和电气间隔以及减小所述变频器的体积。
在另一个实施例中，所述永磁电动机的定子绕组采用多绕组的星型连接方式与所述逆变单元的多路输出端进行连接。
在又一个实施例中，所述变频一体机，还包括静态均压电路，其连接于所述直流母线之间，并且用于对所述逆变单元进行均压处理以及在所述变频器断开时，对所述直流母线上的电压进行放电。
本发明的变频一体机具有结构简单、整机体积小并且运行稳定可靠等优点。一方面，所述变频器的储能电容采用无外壳的封装型式，其顶端封装金属固定耳，从而在满足极壳耐压、爬电距离和电气间隙的前提下，有效地保证了储能电容的固定强度。另一方面，本发明的变频一体机采用特殊的预充电电路，使得可以通过高压电直接对所述储能电容进行预充电，从而减小了所述变频一体机的体积。另外，本发明的变频一体机采用变频器结合永磁电动机的4路电磁耦合技术，从而解决了变频一体机的难以低速控制、难以高压驱动、启动转矩小以及IGBT均压困难等技术难题。
附图说明
通过参考附图阅读下文的详细描述，可以更好地理解本发明的上述特征，并且其众多目的、特征和优点对于本领域技术人员而言是显而易见的。下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可根据这些附图获得其他的附图，其中:
图1是示出根据本发明实施例的变频一体机的组成框图；
图2是示出根据本发明实施例的变频器的组成框图；
图3是示出根据本发明实施例的变频一体机的电路原理图；
图4是示出根据本发明实施例的永磁电动机的定子绕组连接图；以及
图5是示出根据本发明实施例的储能电容的连接图。
具体实施方式
下面将结合附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
图1是示出根据本发明实施例的变频一体机100的组成框图。为了更好地理解本发明的变频一体机的功能和原理，图1中还绘出了高压交流电。所述高压交流电，例如可以是10千伏的三相高压交流电，以用于对所述变频一体机进行供电。
如图1所示，本发明的变频一体机100可以包括：控制器101、变频器102和永磁电动机103。其中，所述变频器用于将高压交流电进行频率转换并输出，并且其输出的交流电至少为三路。所述永磁电动机用于接收经过所述变频器频率转换并输出的交流电，以便驱动所述电动机运转。所述控制器配置用于控制所述变频器将高压交流电进行频率转换，并且用于控制所述永磁电动机的运行状态。
在一个实施例中，所述高压交流电可以是高压三相交流电，其中每一相电压的相位互差120度，并且其电压范围可以为6千伏～10千伏。在一个应用场景中，本发明的变频一体机可以包括变压器，所述变压器的输出为所述高压三相交流电。具体地，所述变压器可以包括铁芯(或磁芯)和线圈，所 述线圈有两个或两个以上的绕组，其中连接所述高压电网的绕组是初级线圈，连接所述变频器输入端的绕组是次级线圈。所述变压器可以变换交流电压、电流和阻抗。通常所述高压电网输送来的高压三相交流电的电压高达100千伏以上，并不适合于电动机等设备的使用。因此需要通过变压器对其进行降压处理，以便向所述变频器输出6千伏～10千伏的高压三相交流电，从而可以实现交流输入电压与直流输出电压间的匹配，以及高压电网与变频器的整流单元之间的高压电隔离。
图2是示出根据本发明实施例的变频器200的组成框图。
如图2所示，本发明的变频器200可以包括预充电电路101、整流单元102、直流回路103以及逆变单元104。在一个实施例中，所述整流单元可以包括整流器件和滤波器，其中所述整流器利用具有单向导电特性的元器件，可以将变压器输出的电压较高且方向和大小变化的交流电转换成单向脉动性直流电。所述滤波器用于滤除所述脉动直流电压中的交流成分。
在另一个实施例中，所述直流回路可以包括直流母线DC+、DC-和储能电容C，并且用于将所述整流单元输出的直流电进行缓冲和储能。所述逆变单元用于将经过所述直流回路处理后的所述直流电转变为至少三路交流电，以便向所述永磁电动机输出。在一个应用场景中，所述逆变单元输出的交流电例如可以为4路。所述预充电电路布置于所述整流单元的输入端，并且用于通过所述高压交流电对所述直流回路中的储能电容C进行预充电。
进一步，所述直流回路可以包括由多个电容和电感等储能元件组成的电路，并且其可以位于所述整流单元和逆变单元之间，其中所述电容例如可以是电解电容。当所述变频器加电时，变频器的直流回路中的电解电容在没有建立电压之前，其充电瞬间相当于短路状态。此时，由于整流单元输出的直流电压极高，因此充电电流非常大，进而有可能会损害整流二极管、直流母线上的电解电容和其他变频器部件。基于此原因，为了限制充电电流过大，必须对直流回路中的电解电容进行预充电。
当所述电解电容预充电过程完成后，所述整流单元即可以通过直流回路向所述逆变单元输出直流电。由于所述电动机为属于感性负载，因此无论电动机处于何种运行状态，其功率因素总不为1。因此在直流回路和电动机之间总会有无功功率的交换，这种无功功率需要直流回路中的储能元件来进行缓冲，以便使整流单元输出的直流电压始终保持平稳。基于上述原理，所述直流回路用于接收和存储整流单元发送来的直流电，并且将所述直流电进行抑制干扰等处理。
在变频器工作过程中，首先，变压器输出的高压交流电经过预充电电路处理后，将其转变为小电流交流电。随后，整流单元将该小电流交流电转换为小电流直流电，并且通过该小电流直流电对直流回路中的储能电容C进行预充电。当预充电过程完成后，断开预充电电路，此时变压器输出的高压交流电经过整流单元进行整流处理，进而输出高压直流电。接着，该高压直流电经过直流回路的储能和干扰抑制等处理之后，流向逆变单元。最后，逆变单元将所述高压直流电进行逆变处理，以便将其进行频率转换，并且通过多路输出给永磁电动机，从而驱动永磁电动机运转。
图3是示出根据本发明实施例的变频一体机300的电路原理图。
如图3所示，本发明的变频一体机300可以包括：控制器301、电抗器302、预充电电路303、整流电路304、母线电压取样电路305、静态均压电路306、直流回路、逆变电路307、霍尔电流互感器电路308、接口电路309以及10KV四路永磁同步电动机310。
在一个实施例中，所述电抗器布置于所述变频一体机的输入端，并且用于将输入所述变频一体机的10KV高压三相(R、S和T相)交流电进行稳压、滤波和抑制干扰，从而防止整流单元对电网的谐波干扰。另外，所述电抗器还可以用于抑制短路能量，以便防止由于后级的短路能量过大从而造成前级过多的能量损耗。具体地，如图3所示，所述电抗器可以由3个电感L1、L2和L3组成，其分别连接所述10KV高压三相交流电的R相、S相和T相输出端。为了对所述变频一体机进行短路保护，在所述电抗器的输入端还可以连接有高压熔断器，例如图3中的容量为125安培的高压熔断器F1和F2，其分别连接于所述高压三相交流电的R相和T相输出端。
在另一个实施例中，所述预充电电路可以包括主开关KM1和充电开关K1、K2和K3，其中所述充电开关K1、K2和K3例如可以是35KV的高压继电器，以便能承受高电压充电。进一步，所述充电开关可以分别连接有限流高压电阻R1、R2和R3，以便限制充电电流过大，并且所述限流高压电阻R1、R2和R3分别与所述电抗器L1、L2和L3连接。
在一个应用场景中，当所述变频一体机加电时，所述主开关KM1在控制器的控制下处于断开状态，而所述充电开关K1、K2和K3均处于闭合状态。此时，所述10KV高压三相交流电的R、S和T相电压分别经过限流电阻R1、R2和R3限流之后，通过整流单元转换为低压直流电。然后，所述低压直流电开始对直流回路中的储能电容进行预充电。当预充电过程完成后，控制器检测到直流母线上的电压值达到设定值，于是控制闭合所述主开关KM1。接着，延迟断开所述充电开关K1、K2和K3。最后，所述10KV高压三相交流电经过所述主开关KM1流向整流单元，经过整流单元将其转换为高压直流电后向逆变单元输出。
在又一个实施例中，所述整流单元例如可以是由三相整流桥所组成的整流电路。其输入端用于接收所述10KV高压三相交流电，其输出端用于输出经过整流处理之后的直流高压电。具体地，所述三相整流桥可以由18个整流二极管D1～D18组成，其中R相电压连接于串联的第一上桥(由串联的D1～D3组成)和第一下桥(由串联的D4～D6)之间；S相电压连接于串联的第二上桥(由串联的D7～D9组成)和第二下桥(由串联的D10～D12)之间；T相电压连接于串联的第三上桥(由串联的D13～D15组成)和第三下桥(由串联的D16～D18)之间。进一步，整流二极管D1、D7和D13的输出端连接于一点，以作为直流母线的DC+端；整流二极管D6、D12和D18的输入端连接于一点，以作为直流母线的DC-端。下面简要描述整流电路的工作原理。
所述整流电路在任意时刻下的输出电流，是由三相电中最高电位的一相所连接的整流二极管流出，并且经过负载流向电位最低的一相所连接的整流二极管，最终流回电源。例如在0～30度之间的情形下，由于T相电位最高，S相电位最低，故在这段时间内整流二极管D15、D14、D13和D12、D11、D10始终处于导通状态，而其余二极管则处于截止状态。因此，此时电流由T相输出，并顺序流经D15、D14和D13，然后流经负载，再顺序由D12、D11和D10流回S相，此时T相输出即为整流电路的输出。
在30～90度之间的情形下，由于R相电位最高，S相电位最低，故在这段时间内整流二极管D3、D2、D1和D12、D11、D10始终处于导通状态，而其余二极管则处于截止状态。因此，此时电流由R相输出，并顺序流经D3、D2和D1，然后流经负载，再顺序由D12、D11和D10流回S相，此时R相输出即为整流电路的输出。
进一步，在90～150度之间的情形下，由于R相电位最高，T相电位最低，故在这段时间内整流二极管D3、D2、D1和D18、D17、D16始终处于导通状态，而其余二极管则处于截止状态。因此，此时电流由R相输出，并顺序流经D3、D2和D1，然后流经负载，再顺序由D18、D17和D16流回T相，此时R相输出即为整流电路的输出。以此类推，可以得出150度～360度情形下的整流电路的输出。有上述可知，经过三组整流二极管的轮流导通，最终，整流电路将所述10KV高压三相交流电转换为高压直流电。
在一个实施例中，所述母线电压取样电路可以包括隔离电源和高压取样电路。所述母线电压取样电路并联于所述直流母线的DC+端与DC-端之间，并且用于对直流母线上的高电压进行取样，并通过隔离电源将其转换成低电压，进而向所述控制器输出取样信号。所述控制器在接收到取样信号后，进行分析与处理，进而控制所述变频器将所述高压交流电进行频率转换。所述控制器还可以根据分析与处理的结果，控制预充电电路的闭合与断开，或者还可以对所述变频一体机进行过压保护。优选地，所述母线电压取样电路可以通过光纤链路与所述控制器进行通信。
在另一个实施例中，所述直流回路可以包括由直流母线和储能电容所构成的电路。如图3所示，其中所述直流母线由DC+端和DC-端构成，所述储能电容可以包括C1、C2、C3和C4。可以理解的是，图3中的直流回路中的储能电容根据应用场景的不同还可以替换为储能电感等其他储能元器件，并且所述储能电容的数量可以为多个。
在又一个实施例中，所述静态均压电路连接于所述直流母线DC+端和DC-端之间，并且用于对所述逆变单元进行均压处理以及在所述变频器断开时，对所述直流母线电压进行放电。具体地，如图3所示，所述静态均压电路可以包括高压电阻R4～R7所组成的电路。所述直流母线电压通过所述高压电阻R4～R7分压之后，加载到所述逆变单元中的各IGBT模块，以保证在静态时各IGBT模块保持电压均衡，从而防止IGBT模块烧毁。进一步，当所述变频一体机断电时，为保证其操作安全，需要通过 所述高压电阻R4～R7进行放电操作。同时所述储能电容C1、C2、C3和C4也可以通过所述高压电阻R4～R7所组成的回路进行放电操作。
在一个实施例中，所述逆变单元可以包括由多个逆变桥所构成的逆变电路，所述逆变桥可以由多个绝缘栅双极晶体管(“IGBT”)模块构成。具体地，所述逆变单元可以包括逆变桥、逻辑控制电路和滤波电路，并且配置用于将直流回路输出的直流电转换成定频定压或调频调压的交流电，以便供给永磁电动机使用。进一步地，所述逆变桥可以包括输入接口、电压启动回路、功率开关元件、直流变换回路和反馈回路等部分；所述逻辑控制电路可以包括脉宽调制控制器、载波发生器和调制波发生器等部分，并且其可以布置于所述控制器内或者其功能可以由所述控制器完成。
在所述逆变单元工作过程中，所述逆变桥在将直流电转变为三相交流电的过程中起到了关键的作用。其通过逻辑控制电路所产生的脉宽调制信号，控制位于其上桥和下桥上的功率开关元件的导通或者断开，从而在逆变桥的三个输出端上获得相位互差120°的三相交流电，以便向所述电动机进行输出。在一个实施例中，所述功率开关元件例如可以是绝缘栅双极型晶体管(“IGBT”)，其具有的高输入阻抗和低导通电压等优点。
所述逆变单元与所述控制器通过通讯线路连接，例如其可以通过RS-485串行总线与逆变单元进行相互通信。所述控制器配置用于接收并处理所述逆变单元和母线电压取样电路传送来的信号，并且根据处理结果向所述逆变单元发送控制信号，以便控制所述IGBT进行轮流导通。由此，可以对所述逆变单元输出的交流电的频率进行改变，进而控制电动机的转速。
在一个实施例中，所述逆变电路可以包括24个IGBT模块VT1～VT24，并且所述逆变电路可以包括4路输出。其中，VT1～VT6构成第一路三相输出U1、V1和W1，VT7～VT12构成第二路三相输出U2、V2和W2；VT13～VT18构成第三路三相输出U3、V3和W3；VT19～VT24构成第四路三相输出U4、V4和W4。需要说明的是，本发明的逆变单元根据输入电压值和永磁电动机绕组的连接方式的不同，还可以有更多路的输出。下面以第一路三相输出U1、V1和W1为例，简要说明逆变电路的工作原理。
为了描述方便，把一个周期时间分成t1～t6。对于U相和V相之间的电压U UV来说，在t1～t2时间内，VT1和VT4同时导通，此时U相电压为“+”，V相电压为“-”，则U UV为“+”，且U UV的幅值为母线电压值。在t4～t5时间内，VT2和VT3同时导通，此时U相电压为“-”，V相电压为“+”，则U UV为“-”，且U UV的幅值为母线电压值。
对于V相和W相之间的电压U VW来说，在t3～t4时间内，VT3和VT6同时导通，此时V相电压为“+”，W相电压为“-”，则U VW为“+”，且U VW的幅值为母线电压值。在t6～t1时间内，VT4和VT5同时导通，此时V相电压为“-”，W相电压为“+”，则U VW为“-”，且U VW的幅值为母线电压值。
对于W相和U相之间的电压U WU来说，在t5～t6时间内，VT5和VT2同时导通，此时W相电压为“+”，U相电压为“-”，则U WU为“+”，且U WU的幅值为母线电压值。在t2～t3时间内，VT1和VT6同时导通，此时W相电压为“-”，U相电压为“+”，则U WU为“-”，且U WU的幅值为母线电压值。
由上述分析可知，U UV、U VW和U WU之间的相位互差120度，且三者的振幅值都与直流母线电压值相等。可见，只要按照一定的规律来控制6个IGBT的导通与截止，就可以将直流电逆变成三相交流电。而逆变后的电流频率，则可以在上述导通规律不变的前提下，通过控制器改变控制信号的变化周期来进行调节。所述逆变电路的第二、第三、第四路输出的工作原理与上述第一路输出原理相同，此处不再赘述。
在一个实施例中，所述变频一体机还可以包括霍尔电流互感器电路。其可以包括霍尔电流互感器及其附属电路。所述霍尔电流互感器电路用于采集所述逆变单元输出的三相交流电，并将采集到的电流信号向所述控制器输出，以便控制所述永磁电动机的运行状态。具体地，如图3所示，所述霍尔电流互感器可以包括TA1、TA2和TA3，其分别连接所述逆变单元输出的三相交流电的U相、V相和W相。
进一步，所述U1相和U2相输出的电流流经所述霍尔电流互感器TA1；所述V1相和V2相输出 的电流流经所述霍尔电流互感器TA2；所述W1相和W2相输出的电流流经所述霍尔电流互感器TA3。所述霍尔电流互感器TA1、TA2和TA3通过通讯线路与所述控制器连接，例如其可以通过RS-485串行总线与控制器进行相互通信。所述控制器接收并处理所述霍尔电流互感器发送来的信号，并根据处理结果来监控所述电动机的运行状态，同时还可以对所述变频一体机进行过流、过载和短路保护。
图4是示出根据本发明实施例的永磁电动机的定子绕组连接图。下面结合图3和图4来描述本发明的永磁电动机的绕组连接方式。
如图3和图4所示，本发明的永磁电动机可以包括定子和转子，其中所述定子上缠绕有线圈绕组，而所述转子上无需设置线圈绕组。具体地，所述永磁电动机可以为10KV四路永磁同步电动机，其定子上可以缠绕4组绕组。与图3中所示接口电路中的接线端子相对应地，所述4组绕组共有12个接线端子，分别是U1、V1、W1；U2、V2、W2；U3、V3、W3和U4、V4、W4。
所述4组绕组均采用星型连接方式，其中三相端U1、V1和W1的另外一端连接在一起；U2、V2和W2的另外一端连接在一起；U3、V3和W3的另外一端连接在一起；U4、V4和W4的另外一端连接在一起。进一步，所述4组绕组的12个接线端子分别与所述接口电路的12个接线端子对应地连接在一起，从而将所述逆变器输出的4路高压三相交流电输出到所述永磁电动机，以便驱动所述永磁电动机运转。本发明的变频一体机采用变频器结合永磁电动机的4路电磁耦合技术，从而解决了变频一体机的难以低速控制、难以高压驱动、启动转矩小以及IGBT均压困难等技术难题。
图5是示出根据本发明实施例的储能电容501的连接图。
如图5所示，由于本发明的变频一体机在工作过程中，其直流母线电压值为1万伏以上的高压，因此本发明的储能电容501可以经过环氧树脂灌封，并且采用无外壳的封装型式，从而一方面减小了储能电容的体积；另一方面增大了极壳耐压和爬电距离，例如其极壳耐压可以达到42kV，并且使得所述储能电容之间或者储能电容和其他元器件之间的电气间隙更大。其次，本发明的储能电容的顶端封装有金属固定耳502，从而有效保证了对储能电容进行牢固地固定。另外，本发明的储能电容采用插接的方式与所述IGBT模块503所在的电路板进行连接，从而方便了储能电容的安装和维护。
应当理解，本发明的权利要求、说明书及附图中的术语“第一”、“第二”、“第三”和“第四”等是用于区别不同对象，而不是用于描述特定顺序。本公开的说明书和权利要求书中使用的术语“包括”和“包含”指示所描述特征、整体、步骤、操作、元素和/或组件的存在，但并不排除一个或多个其它特征、整体、步骤、操作、元素、组件和/或其集合的存在或添加。
还应当理解，在本发明说明书中所使用的术语仅仅是出于描述特定实施例的目的，而并不意在限定本发明。如在本发明说明书和权利要求书中所使用的那样，除非上下文清楚地指明其它情况，否则单数形式的“一”、“一个”及“该”意在包括复数形式。还应当进一步理解，在本发明说明书和权利要求书中使用的术语“和/或”是指相关联列出的项中的一个或多个的任何组合以及所有可能组合，并且包括这些组合。
虽然本发明所实施的方式如上，但所述内容只是为便于理解本发明而采用的实施例，并非用以限定本发明的范围和应用场景。任何本发明所述技术领域内的技术人员，在不脱离本发明所揭露的精神和范围的前提下，可以在实施的形式上及细节上作任何的修改与变化，但本发明的专利保护范围，仍须以所附的权利要求书所界定的范围为准。

Claims (10)

  1. 一种高压永磁变频一体机，包括：
    变频器，其用于将高压交流电进行频率转换并输出，并且其输出的交流电至少为三路；
    永磁电动机，其用于接收经过所述变频器频率转换并输出的交流电，以便驱动所述电动机运转；以及
    控制器，其配置用于控制所述变频器将高压交流电进行频率转换，并且用于控制所述永磁电动机的运行状态。
  2. 根据权利要求1所述的变频一体机，其中所述变频器包括整流单元、直流回路和逆变单元，其中
    所述整流单元用于将所述高压交流电转换成直流电；
    所述直流回路包括直流母线和储能电容，并且用于将所述整流单元输出的所述直流电进行缓冲和储能；以及
    所述逆变单元用于将经过所述直流回路处理后的所述直流电转变为至少三路交流电，以便向所述永磁电动机输出。
  3. 根据权利要求1所述的变频一体机，其中所述高压交流电的电压范围为6千伏～10千伏。
  4. 根据权利要求1所述的变频一体机，还包括霍尔电流互感器，其用于采集所述至少三路交流电，并将采集到的信号向所述控制器输出，以便控制所述永磁电动机的运行状态。
  5. 根据权利要求2所述的变频一体机，还包括预充电电路，其布置于所述整流单元的输入端，并且用于通过所述高压交流电对所述直流回路中的储能电容进行预充电。
  6. 根据权利要求2所述的变频一体机，还包括母线电压取样电路，其与所述直流母线并联，并且用于对所述直流母线上的电压值进行取样，并将取样结果向所述控制器输出，以便控制所述变频器将所述高压交流电进行频率转换。
  7. 根据权利要求1所述的变频一体机，还包括电抗器，其连接于所述变频器的输入端，并且用于对所述高压交流电进行稳压和抑制干扰。
  8. 根据权利要求2所述的变频一体机，其中所述储能电容采用无外壳的封装型式和插接的连接方式，以便增大极壳耐压值和电气间隔以及减小所述变频器的体积。
  9. 根据权利要求2所述的变频一体机，其中所述永磁电动机的定子绕组采用多绕组的星型连接方式与所述逆变器的多路输出端进行连接。
  10. 根据权利要求2～9中任意一项所述的变频一体机，还包括静态均压电路，其连接于所述直流母线之间，并且用于对所述逆变单元进行均压处理以及在所述变频器断开时，对所述直流母线上的电压进行放电。
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