Vehicle auxiliary electric-power-supplying system

A vehicle auxiliary electric-power-supplying system can normally stop an electric power inverter by the frequency in use for an electric power supplier being suppressed as low as possible, and electric power being immediately started to be supplied from the power supplier to a controller in a case in which normal electric power has become unable to be obtained from power-outputting of the electric power inverter. The system includes: the electric power inverter for converting a first type of dc power received through an overhead wire to a second type of dc power, and supplying the second type of dc power to a dc load; the power supplier for converting the first type of dc power received through the overhead wire to a third type of dc power; a power-outputting unit, connected to both the electric power inverter and the electric power supplier, for outputting either the second type of dc power or the third type of dc power; and the controller for receiving power from the power-outputting unit, and controlling the electric power inverter.

This disclosure is based up on International Application No. PCT/JP2004/000829, filed Jan. 29, 2004, the contents of which are incorporated by reference.

TECHNICAL FIELD

The present invention relates to vehicle auxiliary electric-power-supplying systems that supply low-voltage power, which is converted from high-voltage power, to loads such as an air conditioner and lighting fixtures installed in an electric vehicle.

BACKGROUND ART

Generally, an electric vehicle has a back-up battery therein. Moreover, a vehicle is provided therein with a vehicle auxiliary electric-power-supplying system that converts high-voltage power supplied from an overhead wire, to low-voltage power, and supplies the low-voltage power to a load installed in the vehicle. Only when electric power has been supplied from the back-up battery voltage to a controller of the vehicle auxiliary electric-power-supplying system, and the controller has operated, the entire vehicle auxiliary electric-power-supplying system has become ready to start. However, when voltage of the back-up battery decreases and does not reach enough voltage to operate the controller, the controller does not start to operate, resultantly the entire vehicle-auxiliary-electric-power-supplying- system does not operate.

Therefore, as disclosed, for example, inFIG. 1andFIG. 2of Japanese Laid-Open Patent Publication 259,704/1989, an electric power supplier (converter) has been provided for converting the high-voltage power, which is supplied from the overhead wire, to the low-voltage power, and supplying the electric power (electric power source) to the controller (control circuit), when the vehicle auxiliary electric-power-supplying system starts to operate. In response to the operation of the power supplier, when the vehicle starts to operate, even though the voltage of the back-up battery has decreased, the controller in the vehicle auxiliary electric-power-supplying system normally operates with electric power being supplied from the power supplier.

However, in the above described vehicle auxiliary electric-power-supplying system, there has been the following problem. The power supplier, in order to reduce its frequency in use, operates only when the vehicle auxiliary electric-power-supplying system starts to operate, then the operation is stopped after electric power has been obtained from output of an electric power inverter. If any short-circuit malfunction occurs during the starter stop, due to an affect such as a dielectric breakdown on the low-voltage side between the electric power inverter and the load, in order to stop the output from the electric power inverter, the controller needs to command the electric power inverter to stop operation. However, because normal electric power from the electric power inverter cannot be obtained due to short-circuit, and in addition, the power supplier is also stopped, the power for the controller is stopped; consequently, a normally stopping operation of the electric power inverter based on the command from the controller has been impossible.

An objective of the present invention, which has been made to solve the foregoing problem, is to obtain a vehicle auxiliary electric-power-supplying system that can suppress the frequency in use for a power supplier as low as possible, and can normally stop an electric power inverter by the power supplier being immediately started to supply electric power to a controller, even in a case in which normal electric power has become unable to be obtained from the output of the electric power inverter.

DISCLOSURE OF THE INVENTION

A vehicle auxiliary electric-power-supplying system according to the present invention includes: an electric power inverter for converting a first type of dc power received through an overhead wire to a second type of dc power, and supplying the second type of dc power to a dc load; an electric power supplier for converting the first type of dc power received through the overhead wire to a third type of dc power; a power-outputting unit, connected to both the electric power inverter and the electric power supplier, for outputting either the second type of dc power or the third type of dc power; and a controller for receiving power from the power-outputting unit, and controlling the electric power inverter; therefore, the system can suppress the frequency in use for the power supplier as low as possible, and can normally stop-the electric power inverter by the power supplier being immediately started to supply electric power to a controller, even in a case in which normal electric power has become unable to be obtained from the output of the electric power inverter.

BEST MODE FOR CARRYING OUT THE INVENTION

This invention will be described in further detail with reference to the accompanying drawings.

FIG. 1is a view illustrating a configuration of a vehicle auxiliary electric-power-supplying system according to Embodiment 1 of the present invention. In this figure, numeral1denotes an overhead wire, and numeral2denotes a pantograph; here, high-voltage power from the overhead wire1is supplied to the vehicle auxiliary electric-power-supplying system through the pantograph2. As the overhead wire1, a wire placed above ground or in a third rail of subway systems is quoted as the example.

The configuration in the vehicle auxiliary electric-power-supplying system is explained. Numeral3denotes an automatic starter, which is composed of a fuse4, an electromagnetic contactor5, and an input filter reactor6. In the electromagnetic contactor5, a coil, a switch, and a resistor for decreasing voltage are represented. In addition, a contactor, which is not illustrated, is provided between the resistor and the coil. A controller described later detects any excessive voltage inputted through the pantograph2, and opens the contactor; as a result, current will not flow through the coil, enabling the switch to open. Because the contactor is normally closed, the starter automatically starts to operate; the coil is excited; the switch is closed; and then, the high-voltage power is applied to the vehicle auxiliary electric-power-supplying system. In response to excessive current through the overhead wire1, by the fuse4breaking up, the connection between the overhead wire1and the circuits in the vehicle auxiliary electric-power-supplying system is disconnected.

Numeral7denotes an electric power inverter, which is composed of a charging switch8, an input filter capacitor9, an inverter10, a transformer11, a rectifier12, and a smoothing filter13. The electric power inverter7converts to low-voltage dc power high-voltage dc power inputted from the automatic starter3, and supplies the low-voltage power to a load and the vehicle auxiliary electric-power-supplying system. A smoothing operation for the voltage obtained through the overhead wire1is performed using the input filter reactor6and the input filter capacitor9. The charging switch8controls, for the purpose of protecting the input filter capacitor9when the vehicle starts to operate, the electric charging based on the controller described later. The inverter10is used for converting dc electric power into ac. The transformer11transforms to low-voltage power the high-voltage ac power obtained through the inverter10. The rectifier12rectifies into dc power the low-voltage ac power obtained through the transformer11. The smoothing filter13smoothes the low-voltage dc power obtained through the rectifier12so as to enable the power to be supplied to a load in the following stage.

Numeral14denotes a controller, which normally controls the electric power inverter7. The controller14, in order to protect the input filter capacitor9, detects the electric charging state thereof (not illustrated in the figure), and outputs control signals to the charging switch8. After the charging has been performed, the controller indicates to the inverter10a converting operation.

Numeral15is an electric power supplier, which is composed of an inverter16, a transformer17, and a rectifier18. The power supplier15converts to low-voltage dc power the high-voltage dc power obtained through the automatic starter3. The voltage outputted from the power supplier15is lower than the voltage outputted from the electric power inverter7. Both the voltages are controlled by the coil configurations of the transformer11and transformer17.

Numeral19is a butt-jointed diode, in which each cathode of a diode20and a diode21is butt-jointed, and connected to the controller14. Anodes of the butt-jointed diode19each are connected to the smoothing filter13and rectifier18, respectively. Due to the butt-jointed diode19, higher voltage power of either the power supplied from the electric power inverter7or power supplier15is supplied to the controller14. Although voltages of the above described electric power supplied to the butt-jointed diode19are different from each other, the electric power inverter7and the power supplier15are configured so that both the voltages fall within an electric power supplying range in which the controller14can normally operate.

Numeral22denotes a dc load such as lighting fixtures, to which the low-voltage dc power is supplied from the smoothing filter13.

Next, an operation of the vehicle auxiliary electric-power-supplying system is explained.

The vehicle auxiliary electric-power-supplying system is a unit that starts to operate at first in the vehicle, and to the system, the high-voltage dc power is supplied from the overhead wire1through the pantograph2. Because the electric power received through the overhead wire l has high-voltage such as 1,500 V, and the power therefore cannot be used intact in the dc load22of the vehicle, the power must be converted to lower voltage power of such as 100 V, and supplied to the dc load22. The vehicle auxiliary electric-power-supplying system performs this converting.

When the vehicle system starts to operate, the high-voltage power through the pantograph2is supplied to the automatic starter3. The automatic starter3is an input protector for protecting the power inverter7or power supplier15in the following stage against excessive high-voltage power. The high-voltage power having passed through the automatic starter3is supplied to the charging switch8in the electric power inverter7and the inverter16in the power supplier15. At this point of time when the power is supplied to both of the units, because in the electric power inverter7any control signal has not yet outputted from the controller14to the charging switch8, the charging switch8has not operated. In contrast, the power supplier15operates based on the high-voltage power supplied. The high-voltage power is converted from dc into ac by the inverter16, and transformed to low-voltage by the transformer17. The transformed low-voltage ac power is rectified into low-voltage dc power by the rectifier18. The rectified low-voltage power is supplied to the diode21of the butt-jointed diode19. To the diode20connected to the electric power inverter7, the electric power is not supplied from the electric power inverter7, and the voltage of the power supplied to the diode21of the butt-jointed diode19becomes higher than the other; therefore, the electric power is supplied to the controller14as the electric power source.

With electric power being supplied from this source, the controller14operates. The controller14detects a charging state (voltage, etc.) of the input filter capacitor9, and, based on control information (not illustrated) that has been preinstalled in the controller14, outputs to the charging switch8control signals in response to the detection result. The charging switch8controls current, when the system starts to operate, from the input filter reactor6to the input filter capacitor9based on the control signals, and protects the input filter capacitor9from being rapidly charged. The input filter capacitor9is charged up to the same voltage as that of the overhead wire1.

After the input filter capacitor9has been charged up, the controller14outputs control signals to the inverter10. The high-voltage dc power supplied to the inverter10is converted into ac based on the control signals. After having been converted into ac, the electric power is transformed to low-voltage by the transformer11, and rectified into thee low-voltage dc power by the rectifier12. Then, the low-voltage dc power is smoothed by the smoothing filter, and supplied to the dc load22and to the diode20of the butt-jointed diode19.

In the butt-jointed diode19, because the voltage supplied to the diode20becomes higher than that of the diode21, the power from the diode20is prioritized, and supplied to the controller14as an electric power source.

In a case in which power from the electric power inverter7cannot be obtained due to a short-circuit malfunction that has occurred in the low-voltage side from the electric power inverter7to the dc load22, because the electric power voltage having been supplied to the diode20becomes lower than the electric power voltage being supplied to the diode21, the electric power from the diode21, as the electric power source, is immediately supplied to the controller14. The controller14outputs control signals to the charging switch8and inverter10, etc. of the electric power inverter7, and stops the operation of the electric power inverter7.

During the electric power being supplied from the diode20to the controller14, although the electric power from the diode21cannot be supplied due to its low-voltage, the power supplier15does not stop operation and remains in a standby status so as to enable electric power to be supplied at any time. If the high/low voltage relationship between the diode20and diode21is inverted, the electric power is supplied from the rectifier18to the controller14through the diode21.

The butt-jointed diode19has three roles. The first role is to prevent the electric power from being supplied from the power supplier15to the dc load22. The second is, in order to reduce the frequency in use for circuit elements composing the power supplier15, to automatically switch the electric power source, which supplies power to the controller14, from the power supplier15to the electric power inverter7, after the electric power inverter7has started to operate and the power therefrom has been obtained. The last is to automatically switch the electric power source, which supplies power to the controller14, from output, of the electric power inverter7to that of the power supplier15, because the output voltage of the power supplier15becomes higher than that of the electric power inverter7, if power from the electric power inverter7cannot be obtained due to a malfunction, etc.

Here, in order to ensure safety during vehicle maintenance, the pantograph2and the fuse4may be configured so as to be separable. Moreover, in a case in which the dc load22is a backup battery, in order to prevent battery consumption, a contactor may be provided so as to enable the smoothing filter13and the backup battery to be suitably separated.

As described above, in the vehicle auxiliary electric-power-supplying system according to Embodiment 1 of the present invention, because power from the power supplier15on standby is immediately supplied to the controller14through the butt-jointed diode19, when any short-circuit malfunction occurs in the low-voltage side from the electric power inverter7to the dc load22, not only the operation of the controller14can be maintained without breaking up the power supplier of the controller14, but also the normal stop operational can be performed from the controller14to the electric power inverter7.

Moreover, the system is configured in such a way that the automatic starter3that automatically starts normally without control by the controller14, and the electric power inverter7that needs control by the controller14are separated; therefore, after the operation till the automatic starter3has been performed, and when the operation of the controller14is needed, the power supplier15finally starts to operate. Consequently, the operation of the power supplier15during the time when the controller14does not need to operate, can be prevented.

In a configuration such as that the electric power is selectively supplied to the controller of the vehicle auxiliary electric-power-supplying system by voltages outputted from the backup battery and the power supplier being butted at each other, if the voltage of the backup battery has not reach a suppliable voltage to the controller, even if the entire vehicle auxiliary electric-power-supplying system is in operation, the power supplier has continued to supply electric power to the controller until the voltage of the backup battery is charged up to the suppliable voltage. On the contrary, in cases in which the voltages outputted from the electric power inverter7and the power supplier15are butted at each other as represented in Embodiment 1, because the voltage of the backup battery becomes unnecessary in the vehicle auxiliary electric-power-supplying system, a time for the power supplier15in use, when the system starts to operate, becomes as short as the time until the power output of the electric power inverter7is obtained. Therefore, the frequency for the power supplier15in use for supplying electric power to the controller14can be significantly reduced; resultantly, the lifetimes of circuit elements in the power supplier15can be extended.

Although the vehicle auxiliary electric-power-supplying system in which only the dc electric power is outputted has been explained in Embodiment 1, a vehicle auxiliary electric-power-supplying system in which both ac electric power and dc electric power are outputted is explained in Embodiment 2.

FIG. 2is a view illustrating a configuration of the vehicle auxiliary electric-power-supplying system according to Embodiment 2.

In this figure, numeral23denotes an electric power inverter, numeral24denotes an inverter, numeral25denotes a smoothing filter, numerals26and27denote transformers, and numeral28denotes an ac load. The ac load28includes an air conditioner. Other numerals are the same elements as those represented in Embodiment 1.

Similarly to the case in Embodiment 1, when high-voltage dc power is supplied to the inverter24, the power is converted into high-voltage ac power in the inverter24. Although the inverter24is used for converting dc into ac, single-phase electric power-outputting system as in Embodiment 1 is not used but three-phase one is employed in Embodiment 2. In order to prevent noise generation due to the transformer26, the high-voltage ac power is smoothed by the smoothing filter25. The smoothed power is transformed to low-voltage ac power by the transformer26, and then supplied to the ac load28.

The low-voltage ac power (single-phase electric power-output) from the transformer26is supplied to the transformer27. The supplied electric power is further transformed to low-voltage power by the transformer27, and then rectified by the rectifier12from ac into dc. The low-voltage dc power having been smoothed by the smoothing filter13is supplied to the dc load22and the diode20of the butt-jointed diode19. In this embodiment, although the transformer27and the rectifier12are used, the ac three-phase power outputted from the transformer26may instead be rectified intact using a three-phase bridge-rectifying-circuit.

After the power-output has been obtained from the electric power inverter23, similarly to the case in Embodiment 1, power-output from the diode20of the butt-jointed diode19is supplied as an electric power source to the controller14.

As described above, in the vehicle auxiliary electric-power-supplying system according to Embodiment 2, an effect similar to that in the vehicle auxiliary electric-power-supplying system according to Embodiment 1 can be obtained.

Moreover, the vehicle auxiliary electric-power-supplying system can be obtained, in which electric power can be supplied to both the ac load and the dc load.

FIG. 3is a view illustrating a vehicle auxiliary electric-power-supplying system according to Embodiment 3 of the present invention. In this figure, numeral29denotes an automatic starter having a fuse30. Numeral31denotes an electric power inverter, numeral32denotes an electromagnetic contactor, numeral33denotes an input filter reactor, and numeral35denotes a controller. Other numerals are the same as those represented in Embodiment 1.

In the vehicle auxiliary electric-power-supplying system according to Embodiments 1 and 2, the electromagnetic contactor5has been automatically started to operate using a resistor that can decrease the voltage until the system can start to operate; however, in some areas, because the voltage of the overhead wire1is so high that there may be cases in which an electromagnetic contactor having voltage-resistant. characteristics for enabling automatic start is not available, or the vehicle auxiliary electric-power-supplying system becomes upsized due to the upsized resistor needed for decreasing the voltage to a voltage with which the electromagnetic contactor can automatically start to operate.

In the configuration represented inFIG. 3, the automatic starter29in which any command from the controller35is not needed, when the system starts to operate, is composed of only the fuse30. In the electric power inverter31in which a command from the controller35is needed, the electromagnetic contactor32and the input filter reactor33are installed. The fuse30prevents excessive current from flowing from the overhead wire1to the electric power inverter31. The controller35detects the voltage, etc. from the automatic starter29(not illustrated), and controls coils of the electromagnetic contactor32. A switch therein is opened/closed by the action of the coils. The electromagnetic contactor32is configured in such a way that the resistor for decreasing the voltage, in order to automatically start to operate, has been removed, and the controller35controls the contactor accordingly.

When the system starts to operate, the controller35detects the voltage of the electric power from the automatic starter29, owing to the power-outputting from the diode21(not illustrated). In a case in which the voltage is higher than the voltage that the electric power inverter31can permit, by the controller35controlling the coils of the electromagnetic contactor32, the switch is opened; consequently, the electric power inverter31is protected against excessive voltage through the overhead wire1. On the other hand, in a case in which the voltage is within the permissible range, by the controller35controlling the coils of the electromagnetic contactor32, the coils are excited and the switch is closed, and then the input filter reactor33, the charging switch8, and the input filter capacitor9are turned active. The fuse30and the electromagnetic contactor32each are a protector for protecting, against the electric power through the overhead wire1, the power inputting into the electric power inverter31. The electromagnetic contactor32is operated by the controller35controlling.

After the input filter capacitor9has been charged, by the controller35controlling, the inverter10is operated; consequently, the high-voltage dc power is converted into ac. Moreover, by the transformer11, the rectifier12, and the smoothing filter13, the ac power is changed into low-voltage dc power. If any power-output is obtained from the electric power inverter31, power-output from the diode20of the butt-jointed diode19is supplied to the controller35as an electric power source.

Because the vehicle auxiliary electric-power-supplying system according to Embodiment 3 is configured as described above, an effect similar to that in Embodiment 1 can be obtained.

Moreover, even in a case in which the voltage on the overhead wire1is excessively high, the vehicle auxiliary electric-power-supplying system will not be upsized.

As described above, according to the present invention, the vehicle auxiliary electric-power-supplying system can be obtained, in which the frequency in use for the power supplier is prevented as low as possible, and the electric power inverter operation can be normally stopped by electric power being immediately started to be supplied from the power supplier to the controller even in a case in which normal electric power has become unable to be obtained from the output of the electric power inverter.

The present invention is useful in electric vehicles to realize a vehicle auxiliary electric-power-supplying system, in which the frequency in use for the power supplier is prevented as low as possible, and the electric power inverter operation can be normally stopped by electric power being immediately started to be supplied from the power supplier to the controller even in a case in which normal electric power has become unable to be obtained from the output of the electric power inverter.