JP2014117017A - Power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a large ripple current flowing into a battery in a power supply device.SOLUTION: An inverter control unit 152 calculates an average duty Dave of an inverter output pulse from the feedback control of a battery charging power instruction and output power detected by a voltage sensor and a current sensor. The inverter control unit 152 also corrects the average duty Dave on the basis of an average DC power voltage value (PFC average voltage Vpfc0) input to the inverter and a voltage value (PFC output voltage Vpfc) detected by the voltage sensor, to control the inverter on the basis of a corrected duty Dcmp.

Description

  The present invention relates to a power feeding system.

  Conventionally, as a power feeding system, a non-contact power feeding system that supplies power in a non-contact manner by magnetic coupling of a pair of coils is known (see, for example, Patent Documents 1 and 2). This non-contact power supply system is being applied to an electric vehicle such as an electric vehicle, for example. One coil connected to an AC power source is installed in a parking space such as a power supply stand, and the electric vehicle is connected to a battery. The other coil is installed. Then, by using the coil on the parking space side as the primary coil and the coil on the electric vehicle side as the secondary coil, the electric power is supplied from the parking space side AC power source to the vehicle side battery by the magnetic coupling of the pair of coils. Can be supplied.

JP-A-6-133476 JP 2011-142663 A

  However, the input current input to the primary coil has a waveform obtained by rectifying the AC current from the AC power supply, and has a waveform mainly composed of twice the frequency of the AC power supply. For this reason, even if it smooths with a capacitor | condenser, the frequency component of twice that of an alternating current power supply will be contained also in the voltage. This frequency component is also received by the secondary coil, and a ripple current having a frequency twice that of the AC power supply is generated in the battery. The ripple current not only causes unnecessary loss, but also has a problem of affecting current detection. Such a problem is not limited to the method of supplying power in a non-contact manner by magnetic coupling of coils, and can occur in the same manner even when this is performed by wire.

  This invention is made | formed in view of this situation, The objective is to suppress that a big ripple current flows into a battery in an electric power feeding system.

  In order to solve such a problem, a power supply system according to the present invention includes a first power converter that converts a direct current into a high-frequency alternating current and outputs the first power, and converts the alternating current from the alternating current power source into a direct current. Are connected. The charging device converts the high-frequency alternating current output from the second power conversion means into a direct current and outputs the direct current, and charges the battery with the output power. In this case, the control means calculates the average duty of the output pulse of the second power conversion means from the feedback control of the charging power command for charging the battery and the output power of the charging device detected by the power detection means. To do. The control means corrects the average duty based on the average value of the input voltage input to the second power conversion means and the input voltage detected by the voltage detection means, and based on the corrected average duty. The second power conversion means is controlled.

According to the present invention, the ripple current contained in the output current of the charging device can be suppressed by adjusting the output pulse of the second power conversion means through the correction of the average duty. Thereby, it can suppress that a big ripple current flows into a battery.

Block diagram schematically showing the configuration of the non-contact power supply system Explanatory drawing which shows typically the circuit structure of a non-contact electric power feeding system, and the structure of a control system Illustration of duty Explanatory diagram schematically showing the function of the inverter controller Explanatory drawing explaining the magnitude of ripple current

(First embodiment)
FIG. 1 is a block diagram schematically showing a configuration of a non-contact power feeding system according to the present embodiment, and FIG. 2 is an explanatory diagram schematically showing a circuit configuration of the non-contact power feeding system and a configuration of a control system. . The non-contact power supply system includes a power supply device 100 that is a ground-side unit and an electric vehicle (hereinafter simply referred to as “vehicle”) 200 including a vehicle-side unit, and supplies power from the power supply device 100 in a non-contact manner. It is the electric power feeding system which charges the battery 28 provided in.

  The power supply apparatus 100 is installed in a charging stand or the like provided with a parking space for the vehicle 200 and supplies power to the vehicle 200. The power supply apparatus 100 is mainly configured by a power control unit 11, a power transmission coil 12, a wireless communication unit 14, and a control unit 15.

The power control unit 11 has a function for converting AC power transmitted from the AC power source 300 into high-frequency AC power and transmitting the power to the power transmission coil 12. The power control unit 11 includes a rectification unit 111, a PFC (Power Factor Correction) circuit 112, and an inverter 113.

  The rectifying unit 111 is electrically connected to the AC power source 300 and rectifies the output AC current from the AC power source. That is, the rectification unit 111 functions as a first power conversion unit that converts an alternating current from the alternating current power supply 300 into a direct current and outputs the direct current.

  The PFC circuit 112 is connected between the rectifier 111 and the inverter 113. The PFC circuit 112 includes a boost chopper circuit, for example, and is a circuit for improving the power factor by shaping the waveform of the output current from the rectifying unit 111. The output of the PFC circuit 112 is smoothed by a smoothing capacitor.

  The inverter 113 is a power conversion device (second power conversion means) including a switching element such as a smoothing capacitor and IGBT, and converts a direct current into a high-frequency alternating current based on a drive signal from the control unit 15. The power is supplied to the power transmission coil 12. For example, the inverter 113 generates a PWM pulse from the DC voltage by PWM control, and thereby applies an equivalent sine wave AC voltage to the power transmission coil 12.

  The power transmission coil 12 is a coil for supplying power in a non-contact manner to the power reception coil 22 on the vehicle 200 side. The power transmission coil 12 is configured by connecting a coil and a resonance capacitor in series, but the connection between the coil and the resonance capacitor may be parallel or series-parallel. The power transmission coil 12 has a structure in which a conductive wire made of a conductor such as metal is wound in a spiral shape within a predetermined plane. The power transmission coil 12 is provided at a target location such as a parking space where the vehicle 200 is parked, and faces the lower side of the power receiving coil 22 on the vehicle 200 side when the vehicle 200 is parked at a specified position in the parking space.

The wireless communication unit 14 performs bidirectional communication with the wireless communication unit 24 provided on the vehicle 200 side. Since the communication frequency between the wireless communication unit 14 and the wireless communication unit 24 is set to a frequency higher than the frequency used in the vehicle peripheral device such as an intelligent key, the wireless communication unit 14 and the wireless communication unit 24 Even if it communicates between, vehicle peripheral devices are hard to receive the interference by the said communication. For communication between the wireless communication unit 14 and the wireless communication unit 24, for example, various wireless LAN methods are used, and communication methods suitable for long distances are used.

  The control unit 15 has a function of controlling the power supply apparatus 100. As the control unit 15, a microcomputer mainly composed of a CPU, a ROM, a RAM, and an I / O interface can be used. For example, the control unit 15 controls the power control unit 11, the power transmission coil 12, and the wireless communication unit 14. The control unit 15 transmits a control signal to start power supply to the vehicle 200 side or receives power from the vehicle 200 side through communication between the wireless communication unit 14 and the wireless communication unit 24. Receive control signals. The control unit 15 performs switching control of the inverter 113 and controls power supplied from the power transmission coil 12.

  The vehicle 200 includes a power receiving coil 22, a wireless communication unit 24, a charging control unit 25, a rectifying unit 26, a relay unit 27, a battery 28, an inverter 29, a motor 30, and a notification unit 32. Yes.

  The power receiving coil 22 is a coil for receiving power in a non-contact manner from the power transmitting coil 12 on the power supply apparatus 100 side. The power receiving coil 22 is configured by connecting a coil and a resonance capacitor in series, but the connection between the coil and the resonance capacitor may be parallel or series-parallel. The power receiving coil 22 has a structure in which a conducting wire made of a conductor such as metal is wound in a spiral shape. The power receiving coil 22 is provided at a target location, for example, between the rear wheels on the bottom surface (chassis) or the like of the vehicle 200, and when the vehicle 200 is parked at a specified position in the parking space, It faces the upper side of the power transmission coil 12.

  The wireless communication unit 24 performs bidirectional communication with the wireless communication unit 14 provided on the power supply apparatus 100 side.

  The rectification unit 26 is connected to the power reception coil 22 and is mainly configured by a rectification circuit that rectifies AC power received by the power reception coil 22 into direct current. The rectifying unit 26 converts the output from the power receiving coil 22 into DC power by filtering the output with a rectifying and filtering circuit, and outputs the DC power.

  The relay unit 27 includes a relay switch that is turned on and off under the control of the charging control unit 25. The relay unit 27 can disconnect the high-power system including the battery 28 from the low-power system of the power receiving coil 22 and the rectifying unit 26 serving as a charging circuit unit by turning off the relay switch.

  The battery 28 is a power source of the vehicle 200 and is configured by electrically connecting a plurality of secondary batteries, for example. Here, the power receiving coil 22 and the rectifying unit 26 described above serve as a charging device that converts the high-frequency AC power output from the inverter 113 on the power feeding device 100 side to DC power, outputs the DC power, and charges the battery 28 with the DC power. Responsible for the function.

  The inverter 29 is a power conversion device that includes a switching element such as an IGBT, a PWM control circuit, and the like. The inverter 29 converts the DC power output from the battery 28 into AC power based on the control signal, and converts the AC power to the motor 30. Supply. The motor 30 is composed of, for example, a three-phase AC motor, and is a drive source for driving the vehicle 200.

The notification unit 32 includes a warning lamp, a display of a navigation system, a speaker, and the like, and is arranged on an instrument panel or the like in the vehicle interior. The notification unit 32 outputs light, an image, sound, or the like to the user based on the control by the charging control unit 25.

  The charging control unit 25 has a function of controlling charging of the battery 28. As the charging control unit 25, a microcomputer mainly composed of a CPU, a ROM, a RAM, and an I / O interface can be used. For example, the charging control unit 25 receives a control signal for starting power supply from the power supply apparatus 100 side or supplies a control signal for receiving power through communication between the wireless communication unit 24 and the wireless communication unit 14. Or transmitted to the device 100 side.

  Although not shown, the charging control unit 25 is connected to a controller that controls the entire vehicle 200 via a CAN communication network. The controller manages the switching control of the inverter 29 and the state of charge (SOC) of the battery 28. When the charging control unit 25 determines full charging based on the SOC of the battery 28 obtained from the controller, the charging control unit 25 transmits a control signal to the power supply apparatus 100 to end charging.

  In the non-contact power feeding system according to the present embodiment, high-frequency power is transmitted between the power transmission coil 12 and the power receiving coil 22 in a non-contact state by electromagnetic induction. That is, when a voltage is applied to the power transmission coil 12 that is the primary coil, magnetic coupling occurs between the power transmission coil 12 and the power reception coil 22 that is the secondary coil, and power is supplied from the power transmission coil 12 to the power reception coil 22. The

  Hereinafter, a specific power feeding control method by the non-contact power feeding system will be described. As shown in FIG. 2, the charging control unit 25 on the vehicle 200 side is a ground side unit based on a charging power command output from a controller (not shown) according to the charging state of the battery 28 of the vehicle 200. The power supply apparatus 100 is controlled. Specifically, the charging control unit 25 detects the output voltage and output current of the power receiving coil 22 with the voltage sensor 261 and the current sensor 262, respectively, and uses the charging power command, the output voltage and output current of the power receiving coil 22 for wireless communication. Convert to data. The converted data is transmitted by the wireless communication unit 24 on the vehicle 200 side, received by the wireless communication unit 14 on the power supply device 100 side, and output to the control unit 15 on the power supply device 100 side. Here, the voltage sensor 261 and the current sensor 262 function as a power detection unit that detects output power (output voltage and output voltage) of the power receiving coil 22 and the rectifying unit 26 that are charging devices.

  As illustrated in FIG. 2, the control unit 15 on the power supply apparatus 100 side includes a PFC control unit 151 and an inverter control unit 152 when this is functionally grasped.

  The PFC control unit 151 includes an input voltage of the PFC circuit 112 detected by the voltage sensor 114, an input current of the PFC circuit 112 detected by the current sensor 115, and an output voltage of the PFC circuit 112 detected by the voltage sensor 116. (Hereinafter referred to as “PFC output voltage”). Based on these pieces of information, the PFC control unit 151 controls the input current and the PFC output voltage by operating the boost chopper circuit.

The inverter control unit 152 includes an input voltage input to the inverter 113, that is, a PFC output voltage detected by the voltage sensor 116, a charging power command acquired from the vehicle 200 side, and a charging device (the receiving coil 22 and the rectifying unit). The output voltage and output current of (26) are input. Based on these pieces of information, inverter control unit 152 calculates the frequency of the output pulse of inverter 113 and its duty, and generates a drive signal for each switching element forming inverter 113 based on the calculation result. Here, as shown in FIG. 3, the duty D of the output pulse of the inverter 113 is defined as a ratio of the positive voltage output time Tpon with respect to the output voltage waveform to the PWM cycle Ts of one positive / negative cycle.

Hereinafter, the control concept by the inverter control unit 152 will be described. The amplitude Va of the fundamental wave component of the output pulse of the inverter 113 can be expressed as follows using the PFC output voltage Vpfc that is the pulse height and the duty D of the output pulse.

Here, since the PFC output voltage Vpfc is rectified by the rectifier 111 and includes a ripple having a frequency twice that of the AC power supply 300, the amplitude of the output pulse also includes a ripple component. Therefore, the target amplitude Va * of the output pulse that is in an ideal state is set to a PFC output voltage that does not include a ripple, that is, an average value of the PFC output voltage Vpfc (hereinafter referred to as “PFC average voltage”) Vpfc0 and a preset average duty. When determined from Dave, it is expressed by the following equation.

Therefore, the inverter control unit 152 compensates the ripple component included in the output pulse by controlling the duty so that the target amplitude Va * and the amplitude Va of the fundamental wave component of the actual output pulse coincide with each other. . Here, the duty D for compensating the ripple is set to “duty Dcmp”, and this duty Dcmp is expressed by the following equation.

The duty Dcmp shown in the equation is the PFC average voltage Vpfc0 corresponding to the average value of the input voltage input to the inverter 113, and the PFC output voltage corresponding to the sensor detection value (actual value) of the input voltage input to the inverter 113. This is a value obtained by correcting the average duty Dave based on Vpfc.

FIG. 4 is an explanatory diagram schematically illustrating the function of the inverter control unit 152. In the inverter control unit 152, the PFC average voltage calculation unit 152a filters the detected PFC voltage Vpfc and outputs the PFC average voltage Vpfc0. The duty calculator 152b performs the above correction calculation using the PFC average voltage Vpfc0, the PFC output voltage Vpfc, and the average duty Dave (see Formula 3). The duty calculator 152b may perform the calculation shown in Equation 3 in real time, but may specify the duty Dcmp using a map or the like.
The average duty Dave is preset as a value calculated from feedback control of the output power of the power receiving coil 22 and the charging power command (for example, 0.4).

On the other hand, the integrating unit 152 e calculates output power from the output voltage and output current of the power receiving coil 22. Then, the frequency calculation unit 152f calculates the output frequency fpwm by frequency calculation based on feedback control according to the difference between the output power of the charging device (the receiving coil 22 and the rectification unit 26) calculated by the integration unit 152e and the charging power command. Ask. The output frequency fpwm obtained by the frequency calculator 152f is output to the carrier comparison value converter 152c and the PWM carrier comparator 152d.

Note that the output power of the charging device (the power receiving coil 22 and the rectifying unit 26) is preferably detected as an average value of the sampled values. As a method for obtaining the average value, the charging control unit 25 calculates and outputs the average value for the detection value of the power detection means as a part of the power detection means (voltage sensor 261 and current sensor 262). Alternatively, the voltage sensor 261 and the current sensor 262 themselves may average and output the values sampled. Further, the integration unit 152e may integrate average values for the input output voltage and output current as part of the power detection means. Thereby, since the average tendency can be caught without detecting only a specific portion of the pulsation component, the calculation accuracy can be improved.

  The carrier comparison value conversion unit 152c sets the frequency of the PWM carrier by the output frequency fpwm and standardizes the duty Dcmp to generate a PWM pulse by carrier comparison, and thereby compares the value (comparison value) with the PWM carrier. Calculate.

  The PWM carrier comparison unit 152d compares the comparison value with the PWM carrier, and generates a drive signal for controlling on / off of each switching element forming the inverter 113.

FIG. 5 is an explanatory diagram showing an output current on the vehicle 200 side. Here, (a) in the figure is an explanatory diagram showing the output current on the vehicle 200 side when the control is performed with the average duty Dave, and (b) is the control with the corrected duty Dcmp. It is explanatory drawing which shows the output current by the side of the vehicle 200 at the time of performing. In FIG. 6B, it is understood that the ripple current is suppressed as compared with FIG.

Thus, in the present embodiment, the inverter control unit 152 calculates the average duty Dave of the output pulse of the inverter 113 from the feedback control of the battery charging power command and the output power detected by the voltage sensor 261 and the current sensor 262. To do. And
The inverter control unit 152 determines the average duty Dave based on the PFC average voltage Vpfc0 (average value of the input voltage input to the inverter 113) and the PFC output voltage Vpfc (input voltage of the inverter 113 detected by the voltage sensor 116). And the inverter 113 is controlled based on the corrected duty Dcmp.

According to the present embodiment, it is possible to grasp the overall transition tendency of the PFC output voltage that is in the ideal state from the PFC average voltage Vpfc0, and the instantaneous values of the PFC output voltages Vpfc and Pp
The pulsation component can be grasped from the difference from the FC average voltage Vpfc0. For this reason, by adjusting the output pulse of the inverter 113 through the correction of the average duty Dave, the pulsating component included in the output current of the charging device, that is, the current input to the battery 28 can be suppressed. Thereby, it is possible to suppress a large ripple current from flowing through the battery 28.

  Further, according to the present embodiment, the power information on the vehicle 200 side is fed back to the power supply apparatus 100 by the wireless communication unit 14 and the wireless communication unit 24. For this reason, since the electric power information on the vehicle 200 side is input to the inverter control unit 152 with a delay, the responsiveness in the feedback control is poor, and it is difficult to improve the suppression of the ripple current by the feedback control. Is included. However, according to the present embodiment, the average duty Dave is corrected based on the PFC average voltage Vpfc0 and the PFC output voltage Vpfc, which are information on the power supply apparatus 100 side, so that the ripple current can be appropriately suppressed. it can.

  In this embodiment, the inverter control unit 152 obtains the frequency fpwm of the output pulse of the inverter 113 from the feedback control of the output power detected by the voltage sensor 261 and the current sensor 262 and the charging power command, and the corrected duty The inverter 113 is controlled based on Dcmp and the frequency fpwm.

  According to such a configuration, the inverter 113 can be appropriately controlled so as to suppress the ripple current.

  In this embodiment, the average duty Dave is obtained by calculating the average value of the PFC output voltage Vpfc. However, the command value of the output voltage of the PFC circuit 112 controlled by the PFC control unit 151 may be used. .

(Second Embodiment)
The non-contact power supply system according to the second embodiment is different from that of the first embodiment in the calculation method of the duty Dcmp by the control unit 15 of the power supply apparatus 100. Note that description of points that are the same as in the first embodiment will be omitted, and hereinafter, differences will be mainly described.

The duty Dcmp for compensating the ripple is a value obtained by correcting the average duty Dave. From the basic equation shown in Equation 3, it is known that this correction amount is very small. Therefore, based on such knowledge, the duty Dcmp is obtained by approximate calculation, and the control unit 1
The calculation load due to 5 is reduced. The duty Dcmp can be expressed by the following equation.

As described above, according to the present embodiment, the calculation formula of the duty Dcmp is derived by the approximate calculation. According to such a configuration, as shown in the first embodiment, it is not necessary to perform an inverse sine function, so that the calculation load can be reduced.

  In addition, according to each embodiment mentioned above, supply of the electric power from the inverter 113 of the electric power feeder 100 to the rectification | straightening part 26 by the side of the vehicle 200 is carried out between the power transmission coil 12 and the power reception coil 22 by magnetic coupling. It is supposed to be done without contact. However, the present invention is not limited to such a form, and the connection from the inverter of the power feeding device to the rectifying unit on the vehicle side may be simply made by wire.

  Further, according to the method shown in the present embodiment, not only the delay in response due to wireless communication but also the cycle of sampling the output power of the charging device is longer than the switching cycle of generating the duty of the output pulse of the inverter. It can be applied as well if the situation.

  The unit on the vehicle 200 side of the non-contact power feeding system is mounted on an electric vehicle, but may be a vehicle such as a hybrid vehicle.

  The contactless charging system to which the contactless charging apparatus of the present invention is applied has been described above, but the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the invention. Needless to say.

DESCRIPTION OF SYMBOLS 100 Power supply apparatus 11 Power control part 111 Rectification part 112 PFC circuit 113 Inverter 114 Voltage sensor 115 Current sensor 12 Power transmission coil 14 Wireless communication part 15 Control part 151 PFC control part 152 Inverter control part 152a PFC average voltage calculating part 152b Duty calculating part 152c Carrier comparison value conversion unit 152d PWM carrier comparison unit 152e integration unit 200 vehicle 22 power receiving coil 24 wireless communication unit 25 charge control unit 26 rectification unit 27 relay unit 28 battery

Claims (3)

First power conversion means for converting an alternating current from an alternating current power source into a direct current and outputting the direct current;
Second power conversion means for converting a direct current output from the first power conversion means into a high-frequency alternating current and outputting;
A charging device for converting the high-frequency alternating current output from the second power conversion means into a direct current and outputting the direct current, and charging the output power to the battery;
Control means for controlling the second power conversion means;
Power detection means for detecting the output power of the charging device;
Voltage detection means for detecting an input voltage input to the second power conversion means,
The control means includes
An average duty of an output pulse of the second power conversion means is calculated from feedback control of a charging power command for charging the battery and output power detected by the power detection means, and the second power conversion means The average duty is corrected based on the average value of the input voltage input to the input voltage and the input voltage detected by the voltage detection means, and the second power conversion means is controlled based on the corrected average duty. A power supply system characterized by that.   The power supply system according to claim 1, wherein the power detection unit detects an average value of the sampled values as output power of the charging device.   The control means calculates the frequency of the output pulse of the second power conversion means from feedback control of the output power detected by the power detection unit and the charging power command, and sets the corrected duty and the frequency to the corrected duty and the frequency. The power supply system according to claim 1 or 2, wherein the second power conversion means is controlled based on the second power conversion means.