WO2000019590A1

WO2000019590A1 - Power converter

Info

Publication number: WO2000019590A1
Application number: PCT/JP1999/004292
Authority: WO
Inventors: Tetsuo Kojima; Eiichi Toyota; Kiyoshi Nakata; Wataru Miyake; Mutsuhiro Terunuma; Masato Suzuki; Satoru Inarida
Original assignee: Hitachi, Ltd.
Priority date: 1998-09-30
Filing date: 1999-08-09
Publication date: 2000-04-06
Also published as: JP3843422B2; AU5066999A

Abstract

A power converter comprising a main circuit for converting d.c. to a.c. or vice versa, a controller for controlling the main circuit, and a plurality of means for detecting current or voltage in the main circuit, the detected current or voltage being transmitted as control information to the controller, the power converter characterized in that the detecting means include A/D converting means for converting a detected analog signal to a digital signal and means for outputting the converted digital signal serially in time division, the detecting means are serially connected to the controller by a serial transmission cable in such a way that the controller is at the end. A detected signal is digitized by a detecting section and sent from the detecting section to the controller. Therefore, it is unnecessary for the controller to have an A/D converter circuit (analog circuit) for A/D-converting a detected signal, thereby enhancing the noise resistance. By thus enhancing the noise resistance of the controller, the controller can be disposed near the main circuit, which is a noise source, and the size of the entire power converter is reduced.

Description

Specification

Power conversion equipment Technical field

The present invention relates to a power converter for controlling current and voltage in an inverter / converter as control information, and more particularly to a power converter having a high noise level and a high noise level used in railway vehicles. About technology. Background art

The prior art is described, for example, in Japanese Patent Application Laid-Open No. 6-303778. This publication describes the configuration of an inverter device for driving a general-purpose induction motor. Block diagrams of this conventional inverter device are shown in FIGS. 22 and 23 of the publication. Here, the output current and the DC voltage of the inverter are detected by the current sensor and the voltage sensor, and the detected signals are fed-packed to the control board 800 in the form of analog signals. The analog signal thus fed back is converted into a digital signal by an AZD converter built in the microcomputer 801 in the control board, and is used as control information.

However, power converters (inverters or converters) for electric vehicles have a higher main circuit voltage than the general-purpose inverters, and therefore have a greater noise level due to switching. If control information is transferred as an analog signal in such a noisy environment, noise may occur. Also, in a control circuit arranged near the main circuit that is a source of noise, providing an analog circuit such as an AD converter circuit in the control circuit causes noise contamination. In order to prevent such noise contamination, it is conceivable to physically separate the control circuit from the main circuit that is the source of the noise.

However, arranging the main circuit and the control circuit physically apart from each other causes an increase in the overall size of the power converter. For example, electric vehicles have a limited installation space inside the vehicle, so it is not preferable to increase the size of electric power converters for electric vehicles.

Therefore, an object of the present invention is to provide a power conversion device that achieves both noise resistance and downsizing even in an environment where the main circuit voltage is high and the noise level generated by the main circuit is large, such as an electric car. It is in. Disclosure of the invention

The present invention provides a main circuit that converts direct current into alternating current or alternating current, a control device that controls the main circuit, and a plurality of detection units that detect current or voltage in the main circuit. A plurality of detecting means for converting the detected analog signal into a digital signal, and AZD converting means for converting the detected digital signal into a digital signal. Means for serially outputting in a time-division manner, wherein the plurality of detection means and the control device are connected in series by a serial transmission cable such that the control device is located at the end. The detected signal is digitized from the detection unit and transmitted to the control device. Therefore, an AZD converter circuit (analog circuit) for A / D-converting the detected signal is not required in the control device, and the noise resistance can be increased. By increasing the performance, the control device can be arranged near the main circuit, which is a source of noise, and the size of the entire power converter can be reduced. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram of a power conversion device (an inverter device for an electric vehicle) showing a first embodiment of the present invention. FIG. 2 is a detailed configuration diagram of the motor current sensor unit in FIG. FIG. 3 is a specific implementation configuration diagram of FIG. FIG. 4 is a detailed configuration diagram of the control device in FIG. FIG. 5 is a diagram showing the contents of the detection data transmitted in FIG. FIG. 6 is a block diagram of a power converter (an inverter of an electric vehicle) showing a second embodiment of the present invention. FIG. 7 is a block diagram of a power conversion device (an inverter device of an electric vehicle) showing a third embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an outline of a configuration of an inverter device of an electric vehicle that drives DC motor 6 by converting DC power into AC power. The inverter device is connected to a main circuit 3 including a switching element (IGBT element) for converting the DC voltage V d into three-phase motor currents iu, iv, and iw, and a DC side of the main circuit 3, A filter capacitor 4 that supplies DC power to the main circuit 3 and smoothes it, and generates a modulation factor based on an operation command from the driver's cab 5, a detected motor current, and a filter capacitor voltage, and generates the modulation factor. It is composed of a control device 1 that converts the PWM information a to the gate drive 2 and outputs it to the gate drive 2, and a gate drive 2 that converts the PWM information a into a gate signal b of the switching element in the main circuit 3. You. The driver's cab 5 outputs operation commands such as power command, regenerative command, notch signal, and brake command. This operation command is transmitted to the control device 1 by the serial transmission cable 9C. The AC motor 6 that drives the electric car is connected to the AC side of the main circuit 3. ing.

Although not explicitly shown in FIG. 1, the main circuit 3 contains six IGBT elements, ie, two poles on each of the three phases XP and Ν of UVW, ie, two poles. Therefore, six gate signals b are sent from the gate drive 2 to the main circuit 3, and similarly, PWM pulse information a sent from the control device 1 to the gate drive 2 is sent via six signal lines.

On the DC side of the main circuit 3, a DC voltage sensor (PT) 7 for detecting the terminal voltage Vd of the filter capacitor 4 is provided, and on the AC side, the instantaneous values of the motor currents iu, iv, iw are detected. A motor current sensor unit 8 is provided. Each sensor 7, 8 is provided with input and output terminals as connection terminals for serial signal transmission. As a result, the output connection terminal of the DC voltage sensor (PT) 7 and the input connection terminal of the motor current sensor unit 8 are connected by the serial transmission cable 9 A, and the output connection terminal of the sensor unit 8 is connected to the control device. 1 input connection terminal is connected by serial transmission cable 9B. Thus, the sensors 7, 8 and the control device 1 are connected in series via the serial transmission cables 9A to 9B.

The cab 5 and the DC voltage sensor (PT) 7 may be connected by a serial transmission cable.

Each sensor 7 and 8 has a function of converting the detected analog signal to a digital signal by the built-in A / D conversion function (because all sensors are connected by a continuous serial transmission cable). It has a serial interface function that arbitrates the access right of the serial signal line so that the sensor output does not collide, and time-divisionally serializes the AZD-converted digital signal and outputs it serially. The arbitration method for the access right of the serial signal line and an operation example of the serial interface will be described with reference to FIG. FIG. 2 is a detailed configuration diagram of the motor current sensor unit 8 in FIG.

The motor current sensor unit 8 includes current detection devices 81a to 811, which detect the instantaneous values of the motor currents iu, iv, and iw, respectively, and a frequency band for limiting the frequency band as pre-processing when performing AZD conversion. Filter devices 82a to 82c, AZD converters 83a to 83c for converting analog signals to digital signals, and serial interface for AZD-converted data sequentially

Buffers 84a to 84c to temporarily wait for data to be sent to 85, and serial output by serially dividing the motor current value converted to a digital signal into time signals while arbitrating access rights to the serial signal line It consists of a serial interface 85 with the function of Although not shown, the serial interface 23 has a buffer for temporarily waiting a signal from the A / D converter 22.

The current detectors 8 1 a to 8 1 c make use of the Hall effect and are measured by passing the currents 11 11, i V, and i w detected in the rings 81 1 & to 81 1 (respectively. The filter devices 82a to 82c are provided to limit the frequency band of the detected signal to less than half the sampling frequency of the AZD converters 83a to 83c.

The serial transmission cables 9A and 9B are connected to the power line 91 and the ground line.

9 and 3 signal lines. The serial transmission cables 9A and 9B are connected to the motor current sensor unit 8 to supply necessary power in addition to signal wiring. The power is supplied from the control device 1.

The motor current sensor unit 8 not only converts the instantaneous value of the detected motor current into an AZD and sends it, but also performs a predetermined calculation (for example, an overcurrent detection operation). The data after applying the effective value calculation etc. may be sent.

Although the detailed configuration of the DC voltage sensor (PT) 7 is not shown, the current detectors 8 1 a to 81 c in FIG. 2 are replaced with voltage detectors, and the voltage detector, filter, and AZD It is assumed that there is only one converter and one buffer, and the other configurations remain the same.

FIG. 3 shows a specific mounting configuration diagram (exploded perspective view) of the circuit configuration of FIG.

The control device 1, gate drive 2, and main circuit module 30 (including the main circuit 3) are housed in a case where the projected figure from above is almost the same. The module 30 (including the main circuit 3), the cable drive 2, the controller 1, and the cover 10 of the controller 1 are arranged in this order.

Further, concave portions are provided on the side surfaces of these devices, and these concave portions are combined with the convex portions of the filter capacitor 4 and the motor current sensor unit 8. In the drawings, the control device 1, the gate drive 2, the main circuit module 30, and the sensors 7, 8 are shown separately, but they are integrated.

Inside the control device 1, a printed board 11 mounted with a microcomputer for performing an inverter control device described in detail in FIG. 4 and an electro-optical conversion element for outputting a PWM pulse is mounted. It is fixed in a state of being floated by a holder 12 from above. Ventilation holes 13 are provided on both sides of the control device 1 to cool the printing plate 11, and the printing plate 11 is placed near the center of the height of the ventilation port 13. ing. Two serial transmission cable connection terminals 14a and 14b are provided on the front of control unit 1. Although not shown, the PWM pulse information a is transmitted to the gate drive 2 on the bottom of the control device 1. An electro-optic conversion element (EZO) is installed.

Inside the gate drive 2, a printed circuit board 21 on which the gate circuit is mounted is fixed to the case of the gate drive 2 in a state of being lifted from the case of the gate drive 2 by the holder 22 similarly to the control device 1. I have. Also, an optical-electrical conversion element (OZE) 23 is installed to receive the PWM pulse information a. Although not shown, a gate signal connector for transmitting a gate signal b to the main circuit module 30 is attached to the bottom of the gate drive 2.

The optical / electrical conversion element (EZO) of the control device 1 and the optical / electrical conversion element (OZE) 23 of the gate drive 2 are provided with an optical fiber for electrical insulation between the two devices 1 and 2. They are connected by a fiber cable and transmit the PWM pulse information a by optical signals.

Inside the main circuit module 30, a gate signal connector 31 for receiving the re-gating signal b from the gate drive 2 and a DC signal from the filter capacitor 4 (terminals 41 a and 41 b) DC voltage terminals 32 a and 32 b (for three phases) for receiving voltage V d and DC voltage V d stabilized by filter capacitor 4 are used for three-phase motor currents iu and iv , Iw, and a motor current terminal 33 (for three phases) for supplying motor currents iu, iv, and iw to the AC motor 6. The main circuit 3 is composed of a total of six power semiconductor elements on the three-phase XP side and the ZN side, and connects the terminals of the P-side and N-side power semiconductor elements for each of the three phases (bus bar). According to 4, the motor current terminal 33 and the DC voltage terminals 32a and 32b are connected, and the motor current terminal 33 is connected to the motor current cable 301.

Although not shown, the main circuit 3 for the electric vehicle has a cooling device such as a fin. Holes are drilled in the bottom of the main circuit module 30 to attach them.

A DC voltage sensor (PT) 7 for measuring the terminal voltage Vd of the filter capacitor 4 is mounted on the upper portion of the filter capacitor 4. However, the DC voltage sensor (PT) 7 does not necessarily need to be arranged above the filter capacitor 4, and may be below or beside the filter capacitor 4 as long as it is near the filter capacitor 4. The reason why the filter capacitor 4 is arranged near the main circuit module 30 is to shorten the wiring distance. Further, the DC voltage sensor (PT) 7 may be integrated with the filter capacitor 4 as an integral part, or may be fixed as a separate part by a screw or the like. The DC voltage sensor (PT) 7 has two serial transmission cable terminals 71a and 71b, which are connected to the serial transmission cable connection terminals of another sensor (motor current sensor unit 8). Shall be.

The motor current sensor unit 8 passes through the three holes of the motor current sensor unit 8 through the cables 301 of the motor currents i u, i v, and i w, respectively. The motor current sensor unit 8 has two serial transmission cable connection terminals 81a and 81b, each of which has a serial transmission cable connection terminal 71a of a DC voltage sensor (PT) 7 and a control device 1 Shall be connected to the serial transmission cable connection terminal 14b.

In this embodiment, the DC side and the AC side of the main circuit 3 are provided on the same side of the main circuit module 30.The AC line 301 is provided from the filter capacitor 4 side of the main circuit module 30. Have been. The current sensor unit 8 is arranged near the main circuit 3 (main circuit module 30), that is, near the root of the AC line 301 (main circuit 3 side). It is arranged between the sensor 4 and the main circuit module 30. Also, the gate signal The signal connector 31 is provided in the main circuit module 30 at a position opposite to the AC side of the main circuit 3 with the main circuit 3 interposed therebetween.

FIG. 4 is a detailed configuration diagram of the control device 1 in FIG. (I) The control device 1 includes a serial interface 101a for converting a serial signal operation command and various protection signals transmitted from the cab 5 via the serial transmission cable 9C into parallel signal information. , Serial transmission cable

9 Converts the instantaneous serial signal of filter capacitor voltage Vd and motor current iu, iV, iw sent from various sensors 7 and 8 via B to parallel signal control information. Serial interface 101 b to perform the modulation rate calculation based on these pieces of control information, and a pulse output device 1 that generates PWM pulse information a from the generated modulation rate. 0 and an electrical / optical conversion element (EZO) unit 104 for outputting the PWM pulse information a to the gate drive.

The control unit 102 includes storage devices 105a and 105a in which the control information of the parallel signal converted by the serial interfaces 101a and 101b is written.

It comprises a buffer 105 and a CPU 106 that reads out control information from the storage devices 105 a and 105 b at an arbitrary timing and performs a modulation factor calculation process. The pulse output device 103 is a device that handles digital signals.

The CPU 106 refers to the storage device 105a and generates a torque command or a speed command control command from the power line, regenerative command, notch signal, brake command, etc. sent from the cab 5. Control command generation unit 107, which generates a time series pattern of current command from the generated control command, and current reading which reads current by referring to storage device 105b. Section 109, the current command value generated by the current command generation section 108, and the current reading section 109. The instantaneous current control unit 110 that controls the current based on the current detection value read from the current reading unit, and the speed that estimates the rotational speed of the motor from the current detection value read by the current reading unit 109. The voltage calculated by the estimating unit 1 1 1, the phase calculating unit 1 1 2 that calculates the phase by integrating the motor rotation speed estimated by the speed estimating unit 1 1 1, and the instantaneous current control unit 1 1 0 It is composed of a modulation rate calculator 113 that calculates the remodulation rate from the pattern and the phase calculated by the phase calculator 112 and transmits the calculated modulation rate to the pulse output device 103.

The electro-optical conversion element (E ZO) unit 104 is composed of six electro-optical conversion elements (E ZO). The pulse output device 103 is connected to these six electro-optical conversion elements (EZO).

In FIG. 4, the control unit 102 is composed of a general-purpose CPU 106 and storage devices 105a and 105b, but this is not always necessary. 02 may be configured by a one-chip LSI such as a gate array or ASIC.

Fig. 5 shows the structure of data transmitted on the serial transmission cable. On the serial transmission cables 9A and 9B, data of a serial bus structure called a frame is transmitted at a constant sampling cycle. The serial transmission cables 9A and 9B are normally pulled up to the "H" level, but can be set to the "L" level for one bit period (this is called the start bit). Start of frame. After the start bit, each sensor outputs data having a fixed data length onto the serial transmission cable 9 according to the order of the ID (identification number). In this way, the data sent to control device 1 has a configuration as shown in FIG. In this figure, ID = 0 to 2 for motor current sensor unit 8 (ID = 0 for U-phase motor current, ID = 1 for V-phase motor current, ID = 2 for W-phase motor current), ID = 3 is assigned to DC voltage sensor 5.

Note that the ID setting may be fixedly provided with a dip switch for each sensor, or automatically detected by detecting the device connected on the serial transmission cable when the power is turned on. You can assign an ID. The sensors 7 and 8 constantly monitor the state on the serial transmission cable 9 and wait for the "L" level (start bit). The write current on the serial transmission cable 9 is given to the U-phase motor current of ID-0 for a certain period immediately after the end of the start bit, during which the A / D converted U-phase Outputs the instantaneous value of the motor current iu in a time-sharing manner. After the start bit, the V-phase motor current with ID = 1 is given a certain right after the write right on the serial transmission cable 9 is given to the U-phase motor current with ID = 0. Since the write right on the serial transmission cable 9 is given only during the period, the instantaneous value of the AZD-converted V-phase motor current i V is output in a time-sharing manner. For the W-phase motor current with ID = 2, after the start bit is completed, the write right on serial transmission cable 9 is given to the current with ID = 0 and 1 for a certain period of time. Only the write right on the serial transmission cable 9 is given, during which the AZD-converted instantaneous value of the W-phase motor current iw is output in a time-sharing manner. The DC voltage sensor 7 with ID == 3 is used only for a certain period after the start bit ends, after the write right to the serial transmission cable is given to the motor current sensor unit 8 with ID = 0 to 2 Since the right to write on the serial transmission cable 9 is given, the instantaneous value of the AZD-converted DC voltage value Vd is output in a time-sharing manner. Then, each sensor continues to wait for the start bit again. The arbitration of writing on the serial transmission cable 9 is performed as described above, but the reading on the serial transmission cable can be freely performed. The device 1 can also obtain control information by continuing to read data in the order of the sensor ID after the start bit.

As described above, according to the first embodiment of the present invention, the detected voltage or current in the main circuit is immediately converted to a digital signal and transmitted to the control device, which is at least a main function of the control device. The control function that uses voltage or current as control information is digitized. Therefore, even if noise is affected during transmission between the sensor and the control device, the influence of noise on the control device can be reduced. Also, the noise resistance of the control device itself can be increased. As described above, by increasing the noise resistance, the control device and the transmission cable between the control device and the sensor can be arranged near the main circuit that is a source of the noise. Therefore, it is possible to reduce the number of wires and downsize the entire power converter. (In the present embodiment, all the control functions in the control device are digitized by transmitting the detected voltage and current as digital signals to the control device.)

In addition, since the control function using voltage or current as control information as described above can be digitized, the control device also has an effect of being resistant to thermal fluctuations (analog circuits are used). Vulnerable to thermal fluctuations).

However, in the case of railway vehicles, since the main circuit voltage of the power converter is high and the noise level due to switching is high, shields are usually provided on the signal line connecting the sensor and the control device and the main circuit. As a result, the installation of the power conversion device was troublesome, and the power conversion device was enlarged. In this embodiment, a sensor for detecting current or voltage has a built-in AZD conversion function for converting a detected analog signal to a digital signal, digital transmission between the sensor and the control device is performed, and the control device is digitized. I have.

Therefore, the influence of noise from the main circuit during transmission between the sensor and the control device The power converter can be reduced without providing shields in the transmission cable connecting the sensor and the controller and the main circuit, since the influence of noise on the controller can be reduced. It also facilitates outfitting.

In the case of railway vehicles, measures against vibration are important. Especially when connecting the equipment with long cables, it is necessary to fix the cables to prevent the cable from vibrating and take measures such as screwing to prevent the cable connectors from dropping off. is there. For this reason, if the distance between the devices is large, the volume of the cables and the supporting structure of the cables cannot be ignored, which leads to an increase in the size of the inverter device (or the converter device) as a whole. In addition, there is a problem that wiring work is troublesome.

In the present embodiment, at least the control function that uses voltage or current as control information, which is a main function of the control device, can be digitized, so that noise resistance can be increased. For this reason, by increasing the noise resistance of the control device, the control device can be arranged near the main circuit, which is a source of noise, and the cable between the devices can be shortened. A solution.

Similarly, in the case of a railway vehicle, the heat generated in the main circuit is larger than that of a general-purpose inverter device, and the inverter device is operated in a cycle such as driving, coasting, and regenerating (in this case, the inverter). Since the equipment is operating at full power only during regenerative operation), large heat fluctuations occur in a relatively short cycle. Analog circuits are vulnerable to thermal fluctuations due to changes in characteristics such as resistance and capacitors depending on temperature.

In the present embodiment, it is possible to digitize at least the control function that uses voltage or current as control information, which is the main function of the control device. Therefore, it is resistant to heat fluctuation.

According to the first embodiment of the present invention, the main circuit module 30 (including the main circuit 3), the gate drive 2, and the control device 1 are provided with concave portions on their side surfaces. And the projection of the filter capacitor 4 and the motor current sensor unit 8, so that the power converter can be made compact.

Further, according to the first embodiment of the present invention, the three-phase motor current is collectively detected by the motor 鼋 current sensor unit 8 without providing a sensor for detecting each of the three-phase motor currents. This eliminates the need for a transmission cable between the control device and the sensor or a serial transmission cable connecting between the sensor and the sensor.

Further, according to the first embodiment of the present invention, since the transmission between the sensor and the control device is performed serially, the number of signal lines can be reduced. Further, according to the first embodiment of the present invention, the plurality of sensors have an AZD conversion function of converting a detected analog signal into a digital signal and a function of serially outputting the converted digital signal in a time-division manner. (Serial interface), and these multiple sensors and the control device are connected in series by a serial transmission cable. Can be greatly reduced. Also, since serial transmission is used, the number of signal lines can be significantly reduced as compared with parallel transmission. These reductions also have the advantage of facilitating wiring and connecting cables. In addition, since multiple sensors and the control device are connected in series with a serial transmission cable, only one input connection terminal is required for the control device that inputs sensor information, and the control device can be downsized. Can be. Also, by connecting each sensor and control device in series with a serial transmission cable (control device is the end), it is easy to respond during testing. In applications such as observing various types of sensor information such as motor current and DC voltage on a vehicle during a test, there are times when it is desired to transmit sensor information input to a control device to the vehicle. In such a case, in the case of the conventional parallel connection using analog signals, it is necessary to provide a branch in all signal wirings and to wire all the further branched wirings up to the vehicle. However, in the case of the serial connection as in the present embodiment, since the serial transmission cable immediately before input to the control device includes information of all sensors, the device for branching the signal there is used. And only one serial transmission cable needs to be led up to the vehicle.

Also, by connecting each sensor and control device in series with a serial transmission cable (control device is the end), it is easy to add sensors. Although it is not essential information for control, a new sensor may be added during testing to confirm control performance. Examples include vibration sensors for measuring ride comfort, sound level meters, temperature sensors in the main circuit, and air flow meters for cooling air in the control box. When such sensor information is taken into the control unit, it can be added to the end of the chain of serial connection of the existing sensor using a serial transmission cable, or it can be interrupted halfway. There is no need to provide a signal input section (connector) in the system. Also, the information of the above sensors can be easily transmitted on the vehicle using the on-vehicle monitoring function described in the preceding paragraph.

In addition, by connecting each sensor and control device in series with a serial transmission cable (the control device is the end), the distance of the entire transmission cable can be shortened and generated from the main circuit 3. Noise that is picked up by the transmission cable is reduced. Also, according to the first embodiment of the present invention, since the sensor has a built-in filter device, differences in the output and pressure level of various sensors can be dealt with on the sensor side. The hardware does not need to be changed. That is, conventionally, the filter device is built in the control device, and the filter device is converted or adjusted according to the output voltage of the sensor. However, in this embodiment, the filter device is provided with a filter. Since the device is built-in, it can be handled only by converting each sensor.

Further, according to the first embodiment of the present invention, the DC side and the AC side of the main circuit 3 are provided on the same side of the main circuit module 30, and the AC line 301 is connected to the main circuit module 30. It is provided from the filter capacitor 4 side. For this reason, the high-voltage side wiring should be integrated by combining the connector that takes in the DC voltage from the filter capacitor and the connector that takes out the motor current (including the AC line 301) into one side of the main circuit module 30. (It is desirable to separate high-voltage wiring and low-voltage wiring from the viewpoint of insulation measures and noise measures).

Further, according to the first embodiment of the present invention, the current sensor unit 8 is arranged near the main circuit 3 (close to the main circuit module 30 (close to the root of the AC line 301 on the main circuit 3 side). Therefore, there is no need to remove a part of the shield in the middle of the AC line 301. (In the case of high-voltage, large-current AC lines, the AC line is usually passed through a ferrite core. It is necessary to take measures against electromagnetic induction such as winding the shield of the AC line, etc. For this reason, it is necessary to remove some of the shield to mount the sensor on the AC line. It is not preferable to remove the part in order to prevent electromagnetic induction interference).

Further, according to the first embodiment of the present invention, since the current sensor unit 8 is disposed between the filter capacitor 4 and the main circuit module 30, the DC voltage sensor (PT) 7 To connect the current sensor unit 8 to Transmission cable 9 A can be wired short.

Further, according to the first embodiment of the present invention, the gate signal connector 31 is located at a position opposite to the AC side of the main circuit 3 with the main circuit 3 interposed therebetween. The three-phase gate signal and motor current wiring distance is shortened because the arrangement from the gate signal connector 31 to the semiconductor element (IGBT element) and the AC line outlet is arranged in a straight line. As a result, the switching speed of the semiconductor device (IGBT device) can be increased. Furthermore, since the wiring of each phase does not cross each other, it is not affected by the switching of other phases.

In the mounting configuration shown in FIG. 3 of the present embodiment, a fiber cable is used for optical transmission of the PWM signal from the control device 1 to the gate drive 2, but the light emitting part and the light receiving part are opposed to each other. If optical transmission is performed directly, a fiber cable becomes unnecessary, and the inverter device can be made more compact.

FIG. 6 shows a second embodiment of the present invention, in which a single control device and a main circuit convert DC power into AC power and drive the plurality of motors in an inverter device of an electric vehicle. An outline of the configuration is shown in the block diagram.

The inverter device according to the present embodiment has the same configuration as that of the first embodiment.

The difference from the first embodiment is that two motors 6a and 6b are driven by the main circuit 3 to detect the motor currents iul, ivl, iwl and iu2, iv2, iw2. This means that the motor current sensor units 8a and 8b are installed. The DC voltage sensor (PT) 7, the sensor unit 8b, the sensor unit 8a, and the control device 1 are connected in series by serial transmission cables 9D to 9F.

In Fig. 6, two motors are driven by one controller and main circuit. Although an example of operation is shown, in a normal electric vehicle, four or eight motors are often driven by one controller and main circuit. In the case of driving a plurality of motors in this way, a normal electric vehicle does not have a current sensor for each motor, and for example, the U-phase is connected to the main circuit 3 side from the point where the U-phase motor currents iu1 and iu2 are branched. In most cases, the same number of current sensors as in the case of a single motor can be used by arranging the same motor current sensors and using the same arrangement for the V and W phase motor currents. In such a case, the value detected by the motor current sensor is the sum of the motor currents of the plurality of motors. Even when estimating the rotation speed of the motor from the motor current, the value of the rotation speed of the plurality of motors is calculated. You can only get the average value. At this point, the rotation speed of the motor actually varies depending on the radius of the wheels connected to the motors and the road surface conditions, etc. Sometimes you want to get the maximum or minimum value. For this purpose, it is necessary to provide a current sensor for each motor. However, if a current sensor is provided for each motor, the number of motors X three-phase current sensors are required, and the same number of And the same number of transmission cables as the number of connection terminals and sensors. In addition, shields will be provided in the transmission cable and main circuit for noise immunity. In other words, the outfitting of the power conversion device becomes complicated. Therefore, conventionally, the number of sensors has been reduced as described above. In this embodiment, as in the first embodiment, the DC voltage sensor 7 and the motor current sensor units 8a and 8b include an AZD converter and a serial interface. Since the device 1 is connected in series by serial transmission cables 9D to 9F, the number of input terminals on the control device side is not increased, and the outfitting of the power conversion device is not complicated. Fine spin control is possible. In this embodiment, the three-phase motor Since a motor current sensor unit that detects current collectively is used, fine-grained sliding control can be performed simply by adding this motor current sensor according to the number of motors.

Instead of using a motor current sensor unit as in the present embodiment, a sensor having a built-in A / D converter may be provided for each phase, and these sensors may be connected in series with a serial transmission cable. In addition, there is no need to shield the main circuit and transmission cable due to the improvement of noise immunity, and the effect of reducing transmission cables and signal lines by serial transmission is achieved. Outfitting becomes easier. Therefore, a sensor can be added relatively easily as compared with a conventional power converter, and fine-grained spin control can be performed.

Next, a third embodiment of the present invention will be described.

Fig. 7 is a block diagram showing the outline of the configuration of an electric vehicle converter that converts AC power into DC power by a converter and supplies DC power to the inverter of an electric vehicle that drives the AC motor. It is shown in the figure.

The converter device in the present embodiment includes a main circuit 3C including a switching element (IGBT element) for rectifying the AC voltage V of the AC power supply 70 and converting it into a DC voltage Vd, and an AC voltage of the AC power supply. v, the AC current i, and the terminal voltage V d of the filter capacitor 4 as control information, generate an AC voltage command, convert it into PWM pulse information c, and output it to the gate drive 2C. And a gate drive 2C that converts the PWM pulse information c output from the control device IC into a gate signal d of a switching element in the main circuit 3C.

On the AC side of the main circuit 3 C, a single-phase AC power supply 70 and a reactor 71 for holding the AC voltage V of the AC power supply 70 are provided. Is provided with a filter capacitor 4 for holding the DC voltage Vd converted by the main circuit 3C.

Although not shown, it is assumed that four IGBT elements having two poles on the XP and N sides for two phases are incorporated in the main circuit 3C. Therefore, four gate signals d are sent from the gate drive 2C to the main circuit 3C, and four PWM pulse information c are sent from the controller 1C to the gate drive 2C. Sent by line.

On the AC side of the main circuit 3C, there are an AC voltage sensor (PT) 72 that detects the (instantaneous value) of the AC voltage of the AC power supply 70, and an AC current that flows into the main circuit 3C from the reactor 71. An AC current sensor (CT) 73 is provided to detect the instantaneous value of the current. A DC voltage sensor (PT) 7 for detecting the terminal voltage Vd of the filter capacitor 4 is provided on the DC side. AC voltage sensor (PT) 72, AC current sensor (CT) 73, AC current sensor (CT) 73, DC voltage sensor (PT) 7, and DC voltage sensor (PT) 7 and control device 1 C are connected in series via serial transmission cables 9G to 10I, respectively.

The sensors 72 and 73 have the same structure as that of FIG. 2 described in the first embodiment.

Further, the specific configuration of the converter device shown in FIG. 7 is the same as that shown in FIG.

In addition, the timing of the output from each sensor to the serial transmission cable 9 (9G to 9I) and the configuration of the data transmitted on the serial are also the first embodiment (Fig. 5). This is the same as that described in.

Although a single-phase converter is shown in the present embodiment, the present invention is applicable to a three-phase converter. AC power supply Since the number of power supply lines increases to three, it is advisable to arrange AC voltage sensors and AC current sensors as necessary.

As described above, also in the converter device, by adopting the configuration as in the third embodiment of the present invention, the same effects as in the first embodiment of the present invention can be obtained.

In other words, it is noise-resistant, reduces the number of signal lines, and reduces the number of signal lines. (For example, when transmitting digital signals in parallel, three signals of AC voltage V + AC current i + DC voltage V d = For example, when quantizing at 8 bits each, three types of X8 bits = 24 four signal lines are required, but when transmitting serially, AC voltage v + AC current i + DC voltage V d = A total of three signal lines is sufficient.), Easy to handle during testing, Easy to add sensors, Output voltage levels of various sensors can be handled on the sensor side, No shield on signal lines and main circuit It is possible to achieve effects such as good and easy outfitting.

Comparing FIG. 1 with FIG. 7, the configuration of the control device does not change except for the type and number of sensors, that is, the control device for the inverter device and the converter device can be shared.

In the above embodiment, each of the inverter device and the converter device has been described. However, in an electric vehicle in which AC power is supplied from an overhead line, the inverter shown in FIG. 1 (or FIG. 6) and the inverter shown in FIG. 7 It is conceivable to connect the converter shown in the figure and use it. In this configuration, the main circuit 3 and the main circuit 3 C are connected on the DC side to each other via a filter capacitor 4. At this time, the DC voltage sensor (PT) 7 for detecting the filter capacitor voltage has two input connection terminals and two output connection terminals. In both the inverter device and the converter device, the sensor and the It forms part of a series body consisting of a controller and a serial transmission cable. In addition, DC Two pressure sensors (PT) 7 for the converter and for the inverter may be provided, and in each of the inverter and the converter, the sensor and the control device may be connected in series by a serial transmission cable.

In this specification, the terms motor current (AC current) and instantaneous value of AC voltage are used. Sending an instantaneous value means sampling and transmitting at a time interval sufficient to reproduce the waveform (at least 10 times the frequency of the original waveform). For example, in the case of AC voltage, the fundamental frequency is 50 to 60 Hz, so sampling is performed at 500 to 600 Hz or more, which is a time interval sufficient to reproduce the AC voltage waveform. Will be transferred.

However, the DC voltage Vd of the filter capacitor has a small time change compared to the motor currents iu, iv, iw of the inverter device, the AC current i of the AC power supply, and the AC voltage ν. Therefore, it is not necessary to transfer the DC voltage V d of the filter capacitor at the same sampling period as the motor currents i u, i V, i w.

In addition, the DC amount with a small time change, such as the DC voltage V d of the filter capacitor, is changed to the AC amount with a large time change, such as the motor currents iu, iV, iw, the AC current i of the AC power supply, and the AC voltage V. The importance of control is lower than that, and the AC amount is more susceptible to noise than the DC amount. Therefore, the AC amount such as the motor currents iu, iv, iw, etc. is taken in as a digital signal, but the DC voltage Vd is set to the AZD conversion function in the control device 1 as in the past, and the DC voltage Vd is A hybrid configuration, such as taking in analog signals as they are, is also possible. In this case, the control device 1 includes an analog circuit, but the main function of the control device 1 has little effect. Industrial applicability According to the present invention, it is possible to provide a power converter that is resistant to noise and that can be miniaturized in an environment where the main circuit voltage is high, such as a railway vehicle, and the noise level generated by the main circuit is large. Most suitable for conversion equipment. However, if noise resistance is required, it can be used in a wide range of fields other than railway vehicles (general-purpose inverters, electric vehicles, etc.).

Claims

The scope of the claims

1. A main circuit that converts DC to AC or vice versa, a control device that controls the main circuit, and a plurality of detection units that detect current or voltage in the main circuit, and the detected voltage. Alternatively, in the power conversion device transmitting current as control information to the control device, the plurality of detection units include an AZD conversion unit configured to convert a detected analog signal into a digital signal, and the converted digital signal. A plurality of detection means and the control device are connected in series by a serial transmission cable such that the control device is located at an end. Conversion device.

2. It has a main circuit for converting DC to AC or vice versa, a plurality of detecting means for detecting a current or a voltage in the main circuit, and an input connection terminal, which is detected by the detecting means. A voltage or current is input as control information via the connection terminal, and based on the input control information, a power converter including a control device for controlling the main circuit includes:

The plurality of detection units each include an AZD conversion unit that converts a detected analog signal into a digital signal, a unit that serially outputs the converted digital signal in a time-division manner, an input connection terminal, and an output connection terminal. An output connection terminal of the detection means and an input connection terminal of another detection means are connected by a serial transmission cable to form the plurality of detection means in series, and a detection means at one end of the series body. A power transmission device, wherein the output connection terminal of the control device and the input connection terminal of the control device are connected by a serial transmission cable.

3. It has a main circuit for converting DC to AC or vice versa, a plurality of detecting means for detecting a current or a voltage in the main circuit, and an input connection terminal, which is detected by the detecting means. Input the voltage or current as control information And a control device that controls the main circuit based on the input control information.

The plurality of detection units include an AZD conversion unit that converts a detected analog signal into a digital signal, and a unit that serially outputs the converted digital signal in a time-division manner, and an input connection terminal of the control device. The power conversion device, wherein the plurality of detection means and the control device are connected by a serial transmission cable so that the number of the detection devices becomes one.

4. It has a main circuit for converting DC to AC or vice versa, N (N≥2) detecting means for detecting current or voltage in the main circuit, and an input connection terminal, A voltage or current detected by the detection means is input as control information via the input connection terminal, and the control circuit controls the main circuit based on the input control information. In the conversion device, the N (N≥2) detection means includes: an AZD conversion means for converting a detected analog signal into a digital signal; and a means for serially transmitting the converted digital signal; A power conversion system, wherein the plurality of detection means and the control device are connected by a serial transmission cable so that the number of input connection terminals of the device is M (1 ≤ M ≤ N-1). apparatus.

5. It has a main circuit for converting DC to AC, a main circuit module for storing the main circuit, an AC motor connected to the AC side of the main circuit, and a fan connected to the DC side of the main circuit. A power converter including a filter capacitor and a control device for controlling the main circuit;

A power converter, wherein a DC side and an AC side of the main circuit are provided on the same side of the main circuit module.

6. A main circuit module that has a main circuit for converting alternating current to direct current and stores the main circuit; an AC power supply connected to the AC side of the main circuit; A power converter comprising: a filter capacitor connected to a DC side of a road; and a control device for controlling the main circuit.

7. A main circuit module for storing a main circuit for converting DC to AC, an AC motor connected to an AC side of the main circuit via an AC line, and a DC for the main circuit. In the power converter equipped with the filter capacitor connected to the side and the control device for controlling the main circuit,

The power converter according to claim 1, wherein the AC line is provided from a filter capacitor side of the main circuit module.

8. There is a main circuit that stores a main circuit that converts AC into DC, an AC power supply that is connected to an AC side of the main circuit via an AC line, and a DC that is connected to the main circuit. A filter capacitor connected to the side, and a power converter having a control device for controlling the main circuit,

The power conversion device, wherein the AC line is provided from a filter capacitor side of the main circuit module.

9. A main circuit module that has a main circuit that converts DC to AC or vice versa and stores the main circuit, a filter capacitor connected to the DC side of the main circuit, and the main circuit A current detection means for detecting a current on the AC side of the filter, voltage detection means for detecting a voltage of the filter capacitor, and a current detected by the current detection means and a voltage detected by the voltage detection means. In the power converter including a control device which is input as control information and controls the main circuit based on the input control information,

The current detecting means and the voltage detecting means convert the detected analog signal into a digital signal; an AZD converting means; and the converted digital signal. A time-division serial output means, and the current detection means and the voltage detection means are connected in series with a serial transmission cable to form a series body, and the current detection means or the voltage detection means A power converter, wherein the control device is connected by a serial transmission cable, and the current detecting means is provided between the filter capacitor and the main circuit module.

10. A main circuit for converting DC to AC, an AC motor connected to the AC side of the main circuit via an AC line, current detecting means for detecting a current flowing in the AC line, and the current detection A power converter provided with a control device for inputting the current detected by the means as control information and controlling the main circuit based on the input control information;

The power conversion device, wherein the current detection means is arranged near a root of the AC line on the main circuit side.

11. A main circuit for converting AC to DC, an AC power supply connected to an AC side of the main circuit via an AC line, current detecting means for detecting a current flowing in the AC line, and the current In a power converter including a control device that inputs the current detected by the detection means as control information and controls the main circuit based on the input control information,

12. A main circuit module that has a main circuit that converts DC to AC or vice versa, stores the main circuit, a control device that outputs PWM information for controlling the main circuit, In a power converter having a gate drive for inputting PWM pulse information output from a control device, converting the input PWM pulse information into a gate signal, and transmitting the gate signal to the main circuit module, A gate signal connector for receiving a gate signal transmitted from the gate drive is provided in the main circuit module at a position opposite to the AC side of the main circuit with the main circuit interposed therebetween. Power converter.

13. A first circuit that is connected to an AC power supply and converts AC to DC; and a second circuit that is connected to the DC side of the first circuit via a filter capacitor and converts DC to AC. An AC motor for driving an electric vehicle connected to the AC side of the second circuit; a first current detecting means for detecting a current on the AC side of the first main circuit; AC voltage detection means for detecting the voltage on the AC side of the main circuit; filter capacitor voltage detection means for detecting the voltage of the filter capacitor; and current on the AC side of the second main circuit. A second current detecting means for detecting, and a current detected by the first current detecting means. Based on a voltage detected by the AC voltage detecting means and a voltage detected by the filter capacitor voltage detecting means. A first control for controlling the first main circuit; And a second control device for controlling the second main circuit based on the current detected by the second current detection means and the voltage detected by the filter capacitor voltage detection means. In a power converter for electric vehicles,

Each of the detection means includes an analog-to-digital conversion means for converting the detected analog signal into a digital signal, and a means for serially outputting the converted digital signal in a time-division manner. The AC voltage detecting means, the filter capacitor voltage detecting means, and the first control device are connected in series with a serial transmission cable so that the first control device is located at an end, and the second control device is connected to the second control device. An electric vehicle, wherein a current detecting means, the filter capacitor voltage detecting means, and the second control device are connected by a serial transmission cable such that the second detecting means is located at an end. Power converter