JP2005168171A - Power conversion apparatus and automobile equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion device for reducing electromagnetic wave noise accompanying switching operation and improving a reception state of a wireless receiver, and an automobile equipped with the same.
A gate driving circuit GD of a switching element Q selectively uses one of driving units 302 and 312 in accordance with a switching control signal SDC set corresponding to the operation / stop of a radio receiver. The gate Ng is driven to the on voltage Vc or the off voltage Vs in response to the control signal GS. When the radio receiver is stopped, the drive unit 312 is used, and the gate resistance (resistor 316) is reduced. On the other hand, when the wireless receiver is in operation, the driving unit 302 is used, and the gate resistance (resistor 306) is increased. Therefore, the switching speed is reduced and the generation of surge voltage is suppressed, and switching noise that affects the wireless receiver. Is also reduced.
[Selection] Figure 7

Description

  The present invention relates to a power conversion device, and more specifically to a power conversion device disposed in the vicinity of a radio reception device such as a radio and a vehicle including the same.

  In a power converter, it is known that electromagnetic wave noise is generated when a switching element is opened and closed. For this reason, in a system in which a radio receiver such as a radio and a power conversion device serving as a noise source are provided close to each other, a technique for improving the reception state of the radio receiver is required.

For example, a technique for changing a switching frequency according to a tuning frequency of an in-vehicle radio (radio receiver) for a DC-DC converter mounted on an automobile is disclosed (Patent Document 1).
JP 2002-335672 A JP 2003-18829 A JP 2003-88101 A Japanese Patent Laid-Open No. 11-146641

  However, in the configuration disclosed in Patent Document 1, since the switching frequency is switched every time the radio channel is switched, a problem of switching noise may newly occur.

  The present invention has been made in order to solve such problems, and an object of the present invention is to reduce the electromagnetic wave noise associated with the switching operation and improve the reception situation in the wireless receiver and It is to provide a car equipped with it.

  A power conversion device according to the present invention is a power conversion device arranged in the vicinity of a wireless receiver, and includes a switching element, a control device, and a drive circuit. The plurality of switching elements perform power conversion. The control device has a function of detecting whether or not the wireless receiver is in operation, and controls the opening and closing of the plurality of switching elements. The drive circuit is provided corresponding to each of the plurality of switching elements, opens and closes the corresponding switching element in response to a control signal from the control device, and opens and closes the corresponding switching element during operation of the wireless receiver. The speed can be controlled to be slower than when the radio receiver is stopped.

  Preferably, the driving circuit switches an electric resistance electrically connected between the driving power source of the corresponding switching element and the control electrode of the corresponding switching element between the operation and the stop of the radio receiver. .

  Preferably, the drive circuit determines, to the extent that the switching speed of the corresponding switching element during operation is slower than when the radio receiver is stopped, according to the frequency band of the radio wave received by the radio receiver.

  Alternatively, preferably, the driving circuit determines whether or not the switching speed of the corresponding switching element is made slower during operation than when the wireless receiver is stopped, according to the received radio wave intensity of the wireless receiver.

  Preferably, whether the switching speed of the corresponding switching element in the drive circuit is slower than when the wireless receiver is stopped is determined in advance by evaluating the noise level exerted on the wireless receiver by each switching element. Based on the noise evaluation data, it is determined for each of the plurality of switching elements according to the received radio wave intensity at the wireless receiver.

  An automobile according to the present invention includes the power conversion device according to any one of claims 1 to 5 and an in-vehicle tuner provided as a wireless receiver.

  An automobile according to another configuration of the present invention includes the power conversion device according to claim 3, an in-vehicle tuner provided as a wireless receiver, and a car navigation system capable of specifying the position of the own car, The system has map data indicating the radio field intensity of the broadcast at each point, and the radio field intensity received by the previous wireless receiver is determined based on the map data.

  The power conversion device according to the present invention can reduce the switching speed of the switching element (switching speed) during operation of the wireless receiver, so that the surge voltage during switching can be suppressed and the generated noise level can be reduced. The reception status of the receiver can be improved. Further, since the switching speed is not slowed while the wireless receiver is stopped, it is possible to prevent an increase in power loss.

  Further, by switching the resistance connected to the control electrode of the switching element according to the operation of the wireless receiver, the switching speed when the wireless receiver is activated can be slowed down by a simple drive circuit. .

  Further, by determining the degree of slowing down the switching speed according to the frequency band of the received radio wave, while reducing the degree of slowing down the switching speed when receiving a frequency band with relatively good reception conditions (for example, FM broadcasting), When receiving a frequency band (for example, AM broadcast) in which the reception condition is not so good, a control method that increases the degree of slowing down the switching speed can be used. Thereby, it is possible to improve the reception status of the tuner while suppressing power loss in the switching element according to the reception frequency band.

  In addition, by deciding whether or not to control switching speed reduction according to the received radio wave intensity at the radio receiver, the radio wave intensity is so large that it is not affected by noise, or even if the noise is reduced, the reception status If the improvement is so small that it cannot be expected, the switching speed reduction control can be stopped. Therefore, the reception state of the tuner can be improved while suppressing the power loss at the switching element according to the reception condition.

  Furthermore, by performing switching speed reduction control for each switching element, reduction control for slowing down the switching speed with only the necessary switching elements is performed for each switching element, so that the reception status of the tuner can be improved while suppressing power loss. Can do.

  In the automobile of the present invention, the reception state of the in-vehicle tuner can be improved by taking into consideration that the power loss in the power conversion device does not increase unnecessarily by the switching speed reduction control in the power conversion device.

  Furthermore, from the map data of the car navigation system, by obtaining the received radio wave intensity corresponding to the own vehicle position, without installing a radio wave intensity measurement system, while suppressing the power loss in the switching element according to the reception conditions, The tuner reception status can be improved.

  Embodiments of the present invention will be described in detail with reference to the drawings. In addition, about the same or equivalent part in a figure, the same code | symbol is attached | subjected and the description is not repeated.

  The power conversion device according to the present invention is premised on being placed in the same system as the wireless receiver. Therefore, in the following embodiments, a configuration example in which the power conversion device according to the present invention is mounted on an automobile equipped with an in-vehicle radio as a radio receiver will be representatively described. However, as will be apparent from the following description, the present invention has its characteristics in the drive circuit configuration of the switching element, and thus becomes an electromagnetic wave noise source for the wireless receiver without limiting the devices and systems to be mounted. Applicable to the obtained power changing device.

  FIG. 1 is a schematic block diagram showing the configuration of a hybrid vehicle equipped with a power converter according to the present invention.

  Referring to FIG. 1, a hybrid vehicle 100 according to an embodiment of the present invention includes a battery 10, a PCU (Power Control Unit) 20, a power output device 30, a differential gear (DG) 40, a front wheel. 50L, 50R, rear wheels 60L, 60R, front seats 70L, 70R, and a rear seat 80 are provided.

  The battery 10 is formed of a secondary battery such as nickel hydride or lithium ion, for example, and supplies a DC voltage to the PCU 20 and is charged by the DC voltage from the PCU 20. The battery 10 is disposed at the rear portion of the rear seat 80.

  The power output device 30 is disposed in the engine room in front of the dashboard 90. The PCU 20 is electrically connected to the power output device 30. The power output device 30 is connected to the DG 40.

  PCU 20 boosts the DC voltage from battery 10, converts the boosted DC voltage to an AC voltage, and drives and controls motor MT included in power output device 30. Further, the PCU 20 charges the battery 10 by converting the AC voltage generated by the generator GT included in the power output device 30 into a DC voltage. That is, PCU 20 corresponds to a “power converter” that performs power conversion between DC power supplied by battery 10, AC power for driving and controlling motor MT, and AC power generated by generator GT.

  The power output device 30 transmits power from the engine and / or the motor MT to the front wheels 50L and 50R via the DG 40 to drive the front wheels 50L and 50R. Further, the power output device 30 generates power by the rotational force of the generator GT by the front wheels 50L and 50R, and supplies the generated power to the PCU 20. Alternatively, a motor generator having both functions of the motor MT and the generator GT can be provided in the power output device 30.

  The DG 40 transmits the power from the power output device 30 to the front wheels 50L and 50R, and transmits the rotational force of the front wheels 50L and 50R to the power output device 30.

  FIG. 2 is a diagram for explaining the arrangement of the audio system in the automobile 100.

  Referring to FIG. 2, the audio system in automobile 100 includes a multi-display 110, an electronic tuner (hereinafter simply referred to as “tuner”) 120, an antenna 130, and speakers 141 to 144.

  The multi display 110 and the tuner 120 are provided in front of the front seats 70R and 70L (FIG. 1) in order to receive operation inputs from the driver.

  The antenna 130 is disposed outside the vehicle and receives radio waves typified by AM broadcast waves and FM broadcast waves. In FIG. 2, a pole antenna disposed outside the vehicle is representatively shown. However, the type and location of the antenna 130 are not particularly limited.

  The speakers 141 to 144 are respectively attached to the left and right front door panels and the left and right upper back panels.

  FIG. 3 is a block diagram illustrating a configuration of an audio system in the automobile 100.

  Referring to FIG. 3, an operation input from a driver or a passenger is given to multi-display 110 and tuner 120, and tuner 120 selects a response in response to the operation input from radio waves received by antenna 130. The station frequency signal is extracted and amplified, and the obtained sound is output from the speakers 141, 143, 144, and the like.

  The audio system further includes a navigation computer 150 for specifying the vehicle position of the automobile 100, and can output information based on the specified vehicle position from the multi-display 110 and the speaker 142. An operation input to the navigation computer 150 is given by the multi-display 110 and other switches (not shown).

  FIG. 4 is a circuit diagram illustrating the configuration of PCU 20 shown in FIG.

  Referring to FIG. 4, PCU 20 includes a smoothing capacitor 205, a boosting converter 210, an inverter 220, a DC-DC converter 230, and an air conditioner inverter 240.

  Smoothing capacitor 205 is connected between power supply lines 201 and 202 from battery 10.

  Boost converter 210 includes a reactor 215, switching elements Q1, Q2, and antiparallel diodes D1, D2. Switching elements Q1 and Q2 are connected in series between power supply lines 203 and 202. Reactor 215 is connected between a connection node of switching elements Q 1 and Q 2 and power supply line 201. As the switching element in this embodiment, IGBT (Insulated Gate Bipolar Transistor) or MOS-FET (Metal Oxide Semiconductor-Field Effect Transistor) can be applied.

  Inverter 220 includes an inverter unit 221 provided corresponding to motor MT, an inverter unit 222 provided corresponding to generator GT, and a smoothing capacitor 225.

  Smoothing capacitor 225 is connected between power supply lines 203 and 202 and smoothes the output voltage of boost converter 210, that is, the input voltage of inverter units 221 and 222.

  Inverter unit 221 has a general three-phase inverter configuration, switching elements Q3 and Q4 constituting a U-phase arm, switching elements Q5 and Q6 constituting a V-phase arm, and switching constituting a W-phase arm. Elements Q7 and Q8 are included. Corresponding to each of switching elements Q3 to Q8, antiparallel diodes D3 to D8 are respectively connected so that current flows from the emitter side to the collector side. Each phase arm of inverter unit 221 is connected to a corresponding phase of motor MT.

  Since the configuration of inverter unit 222 is the same as that of inverter unit 221, detailed description will not be repeated. Each phase arm of inverter unit 222 is connected to a corresponding phase of generator GT.

  The controller 250 controls the converter control signal CVS and the inverter unit 221 for controlling the operation of the boost converter 210 according to the output values from various sensors so that the motor MT generates torque, the number of rotations, etc. according to the motor command value. An inverter control signal IVS1 for controlling the operation is generated. Specifically, converter control signal CVS is an on / off control signal for switching elements Q1 and Q2, and inverter control signal IVS1 is an on / off control signal for switching elements Q3 to Q8 in inverter unit 221. Switching elements Q1 to Q8 are opened and closed by gate drive circuits GD1 to GD8 in response to these on / off control signals. The output values from the various sensors include, for example, output values from the position sensor / speed sensor of the motor generator, output values from the current sensor 227, and output from the holding voltage detection sensor of the smoothing capacitor 225.

  The controller 250 corresponding to the “control device” further controls an inverter control signal for controlling the operation of the inverter unit 222 in accordance with outputs from various sensors so that the AC voltage generated by the generator GT is converted into a DC voltage. IVS2 is generated. Specifically, inverter control signal IVS2 is an on / off control signal for switching elements Q3 to Q8 in inverter unit 222.

  Boost converter 210 receives the DC voltage supplied from battery 10 between power supply lines 201 and 202, boosts the input voltage by switching operation of switching elements Q1 and Q2, and supplies the boosted voltage to capacitor 225. The step-up ratio in converter 210 is determined according to the ON period ratio (duty ratio) of switching elements Q1 and Q2.

  The inverter unit 221 drives the motor MT by converting the DC voltage from the boost converter 210 smoothed by the capacitor 225 into an AC voltage by a switching operation in response to the inverter control signal IVS1.

  The inverter unit 222 converts the AC voltage generated by the generator GT into a DC voltage and supplies it to the capacitor 225. Capacitor 225 smoothes the DC voltage from inverter unit 222 and supplies it to boost converter 210. Boost converter 210 steps down the DC voltage from capacitor 225 and supplies it to power supply line 201.

  The DC-DC converter 230 converts the level of the DC voltage between the power supply lines 201 and 202 to drive and control an auxiliary machine (not shown). The DC-DC converter 230 is configured by an inverter bridge configured by switching elements, a transformer, and a rectifier, although the detailed configuration is not shown.

  The air conditioner inverter 240 converts the DC voltage between the power supply lines 201 and 202 into an AC voltage, and drives and controls the air conditioner. That is, the air conditioner inverter 240 also includes a plurality of switching elements constituting an inverter bridge.

  As shown in FIG. 4, a large number of switching elements that are opened and closed at a predetermined frequency during the operation of the hybrid vehicle 100 are provided in the PCU 20. As in the arrangement examples shown in FIGS. 1 and 2, the PCU 20 corresponding to the “power converter” and the tuner 120 corresponding to the “wireless receiver” are arranged close to each other in the overall layout of the automobile 100. Then, electromagnetic wave noise accompanying switching operation in the PCU 20 may adversely affect reception in the tuner 120. That is, the plurality of switching elements in the PCU 20 are noise sources.

  Next, the relationship between the switching operation and generation of electromagnetic noise will be described.

  FIG. 5 is a diagram illustrating the switching operation when the switching speed is high.

  Referring to FIG. 5, gate control signal GS for controlling on / off of the switching element is set to a logic high level (H level) during the on period of the switching element, and set to a logic roll (L bell) during the off period. Is done.

  Before time t1, since the gate control signal GS = L bell, the collector-emitter switching voltage Vsw ≠ 0, while the switching current Isw = 0.

  When the gate control signal GS changes from the L level to the H level at time t1, the switching current Isw starts to flow and the switching voltage Vsw decreases according to the change in the gate potential in response to the gate control signal GS. In the fully turned-on state, the switching voltage Vsw is an L level voltage determined by the characteristics of the element.

  On the other hand, when the gate control signal GS changes from the H level to the L level at time t2, the switching current Isw starts to decrease and the switching voltage Vsw increases in accordance with the change in the gate potential in response to the gate control signal GS. In a completely turned off state, the switching current Isw = 0.

  During actual switching operation, the switching current Isw and the switching voltage Vsw change according to a constant rate corresponding to the change rate of the gate potential by the gate drive circuit. This inevitably generates a loss power P1 during switching corresponding to the product of the switching current Isw and the switching voltage Vsw. The constant rate corresponding to the change rate of the gate potential by the gate drive circuit corresponds to the switching speed of the switching element, and is also referred to as “switching speed”.

  In order to suppress the power loss P1, it is preferable to increase the switching speed. However, if the switching speed is increased, so-called surge voltage is likely to be generated, and electromagnetic noise is increased.

  On the other hand, FIG. 6 is a diagram illustrating the switching operation when the switching speed is low.

  Referring to FIG. 6, by reducing the switching speed, the rate at which switching current Isw and switching voltage Vsw change is reduced, and the generation of surge voltage is suppressed. As a result, the generation of electromagnetic wave noise is suppressed, so that the reception situation at the wireless receiver (tuner 120 in FIG. 2) is improved as compared with the switching operation shown in FIG.

  However, the loss power P2 at the time of switching corresponding to the product of the switching current Isw and the switching voltage Vsw becomes larger than the loss power P2 in FIG.

  Thus, the switching speed has an influence on the generation amount of electromagnetic noise and the power loss. Therefore, in the power conversion device according to the present invention, the gate drive circuit arranged corresponding to each switching element has a configuration in which the switching speed is variable in accordance with the operation / non-operation of the wireless receiver and the reception status during operation. It will be given to.

  Next, a configuration example of a gate drive circuit for switching speed control in the power conversion device according to the present invention will be described.

  FIG. 7 is a circuit diagram showing a configuration example of the gate drive circuit according to the present invention.

  Referring to FIG. 7, gate drive circuit GD according to the present invention includes AND circuits 300, 301, 310, 311, drive units 302, 312, and resistors 306 and 316. The gate drive circuit GD generally shows the gate drive circuits GD1 to GD8 shown in FIG. 4 and the gate drive circuits provided corresponding to the switching elements (not shown).

  The AND circuit 300 outputs a logical product (AND) operation result of the gate control signal GS and the switching speed control signal SDC. The AND circuit 301 outputs a logical product (AND) operation result of the inverted signal of the gate control signal GS and the switching speed control signal SDC.

  The drive unit 302 includes a pull-up n-type transistor 303 and a pull-down n-type transistor 304. N-type transistor 303 is connected between ON voltage Vc of corresponding switching element Q and node N0. N-type transistor 304 is connected between off voltage Vs of corresponding switching element Q and node N0. The output signal of the AND circuit 300 is supplied to the gate of the n-type transistor 303, and the output signal of the AND circuit 301 is supplied to the gate of the n-type transistor 304. The resistor 306 is connected between the node N0 and the gate Ng of the switching element Q.

  Similarly, the AND circuit 310 outputs a logical product (AND) operation result of the inverted signal of the gate control signal GS and the switching speed control signal SDC. The AND circuit 311 outputs a logical product (AND) operation result of the inverted signal of the gate control signal GS and the inverted signal of the switching speed control signal SDC.

  The drive unit 312 includes an n-type transistor 313 for pull-up and an n-type transistor 314 for pull-down. N-type transistor 313 is connected between ON voltage Vc and node N1. N-type transistor 314 is connected between off-voltage Vs and node N1. The output signal of the AND circuit 310 is supplied to the gate of the n-type transistor 313, and the output signal of the AND circuit 311 is supplied to the gate of the n-type transistor 314. Resistor 316 is connected between node N1 and gate Ng. The resistance value R2 of the resistor 316 is smaller than the resistance value R1 of the resistor 306. That is, R1> R2.

  When switching speed control signal SDC = L level, the output signals of AND circuits 300 and 301 are fixed to L level regardless of gate control signal GS, so that each of n-type transistors 303 and 304 is turned off. . Thereby, the node N0 is not connected to either the on voltage Vc or the off voltage Vs.

  On the other hand, one of the output signals of AND circuits 300 and 301 becomes H level and the other becomes L level in accordance with gate control signal GS. When gate control signal GS = H level, n-type transistor 313 is turned on while n-type transistor 314 is turned off, so that node N1 is connected to on-voltage Vc. Conversely, when the gate control signal GS = L level, the n-type transistor 314 is turned on while the n-type transistor 313 is turned off, so that the node N1 is connected to the off voltage Vs.

  Therefore, when the switching speed control signal SDC = L level, the gate resistance connected between the drive voltage of the switching element Q (collectively referring to the ON voltage Vc and the OFF voltage Vs) and the gate Ng is R2. .

  On the other hand, when the switching speed control signal SDC = H level, the output signals of the AND circuits 310 and 311 are fixed to the L level regardless of the gate control signal GS. Each is turned off. Thereby, the node N1 is not connected to either the on-voltage Vc or the off-voltage Vs.

  On the other hand, one of the output signals of AND circuits 310 and 311 becomes H level and the other becomes L level in accordance with gate control signal GS. When gate control signal GS = H level, n-type transistor 303 is turned on while n-type transistor 304 is turned off, so that node N0 is connected to on-voltage Vc. Conversely, when the gate control signal GS = L level, the n-type transistor 304 is turned on while the n-type transistor 303 is turned off, so that the node N0 is connected to the off voltage Vs.

  As a result, when the switching speed control signal SDC = H level, the gate resistance connected between the drive voltage of the switching element Q and the gate Ng is R1.

  Since the gate potential changing speed by the gate driving circuit GD, that is, the switching speed depends on the gate resistance, the switching speed depends on the switching speed control signal SDC = L level when the switching speed control signal SDC = H level. Will also be late.

  Therefore, in the normal state, in order to suppress the power loss, the switching speed control signal SDC = L level and the switching operation as shown in FIG. 5 is performed. On the other hand, when priority is given to suppression of electromagnetic noise, the switching speed control signal SDC = By setting it to the H level, a configuration for performing a switching operation as shown in FIG. 6 can be achieved.

  FIG. 8 is a circuit diagram showing another configuration example of the gate drive circuit according to the present invention.

  Referring to FIG. 8, the gate drive circuit GD includes a drive unit 330, resistors 340, 342, 344, and bypass switches 350, 355.

  The drive unit 330 includes a p-type transistor 331 for pull-up and an n-type transistor 332 for pull-down. N-type transistor 331 is connected between ON voltage Vc and node N2. N-type transistor 332 is connected between off-voltage Vs and node N2. An inverted signal of the gate control signal GS is commonly supplied to the gates of the p-type transistor 331 and the n-type transistor 332.

  Resistors 340, 342, and 344 are connected in series between gate Ng and node N2. The bypass switch 350 is connected so that both ends of the resistor 342 are short-circuited when the switching speed control signal SDC1 is at the L level and are opened when the switching speed control signal SDC1 is at the H level. Similarly, the bypass switch 355 is connected so that both ends of the resistor 344 are short-circuited when the switching speed control signal SDC2 is at the L level and opened when the switching speed control signal SDC2 is at the H level.

  In response to the gate control signal GS, one of the p-type transistor 331 and the n-type transistor 332 is turned on while the other is turned off. In other words, node N2 is connected to ON voltage Vc when gate control signal GS = H level, and node N2 is connected to OFF voltage Vs when gate control signal GS = L level.

  In the configuration of FIG. 8, the gate resistance connected between the drive voltage (ON voltage Vc or OFF voltage Vs) and the gate Ng is R1, R1 + R2, R1 + R3 depending on the combination of the switching speed control signals SDC1, SDC2. It can be changed in 4 steps of R1 + R2 + R3.

  Accordingly, in order to suppress power loss, the switching speed control signals SDC1 and SDC2 = L level to perform the switching operation as shown in FIG. By setting at least a part of SDC1 and SDC2 to the H level, the switching speed can be decreased stepwise.

  The gate drive circuit GD illustrated in FIGS. 7 and 8 is arranged corresponding to each switching element in the PCU 20. The controller 250 shown in FIG. 4 generates a switching speed control signal SDC (SDC1, SDC2).

  Next, a specific example of the switching speed control method in the power conversion device according to the present invention will be described.

  FIG. 9 is a diagram for explaining a first specific example of the switching speed control according to the present invention.

  Referring to FIG. 9, controller 250 switches switching speed control signal SDC depending on whether tuner 120 is stopped or operating. For example, the controller 250 has a function of detecting whether or not the tuner 120 is operating by transmitting a signal indicating whether the tuner 120 is stopped or operating from the tuner 120 to the controller 250. be able to.

  That is, when the tuner is stopped, the switching speed control signal SDC (SDC1, SDC2) is set to the L level, the gate resistance of the gate drive circuit GD is reduced, and switching with priority given to the reduction in power loss as shown in FIG. Perform the action.

  On the other hand, during the operation of the tuner, the switching speed control signal SDC (SDC1, SDC2) is set to the H level to increase the gate resistance of the gate drive circuit GD, thereby slowing the switching speed in each switching element Q. Then, the switching operation as shown in FIG. 6 is performed. Thereby, electromagnetic wave noise from the switching element in the PCU 20 is suppressed during the tuner operation, so that the reception situation is improved.

  FIG. 10 is a diagram for explaining a second specific example of the switching speed control according to the present invention.

  In FIG. 10, as illustrated in FIG. 8, when the gate resistance in each gate driving circuit can be set stepwise by a combination of a plurality of switching speed control signals SDC1, SDC2,. The degree of slowing down the switching speed during operation is determined in stages according to the frequency band of the received radio wave.

  Referring to FIG. 10, when the tuner is stopped, the switching speed control signals SDC1 and SDC2 are set to the L level to reduce the gate resistance of the gate drive circuit GD, thereby reducing the power loss as shown in FIG. A switching operation that prioritizes lowering is performed.

  While the tuner is operating, when receiving FM broadcasts with relatively good reception conditions, only one switching speed control signal (for example, SDC1) is set to the H level, while switching is performed when receiving AM broadcasts with poor reception conditions. Both speed control signals SDC1 and SDC2 are set to H level.

  As a result, in the gate drive circuit GD, the gate resistance when the tuner is operating is greater than when the tuner is stopped, but the amount of increase differs depending on the frequency band of the received radio wave at the tuner.

  As a result, while the tuner (wireless receiver) is in operation, the frequency band in which the reception condition is not so good is reduced while the degree of slowing down the switching speed is reduced when receiving a frequency band (for example, FM broadcast) in which the reception condition is relatively good. At the time of receiving (for example, AM broadcast), it is possible to adopt a control method that increases the degree of slowing the switching speed. Thereby, it is possible to improve the reception status of the tuner while suppressing power loss in the switching element according to the reception frequency band.

  FIG. 11 is a flowchart for explaining a third specific example of the switching speed control according to the present invention.

  Referring to FIG. 11, when tuner 120 is activated and reception tuning is performed (step S100), reception radio wave intensity Pin at a tuning frequency is obtained (step S110). The received radio field strength may be measured by mounting the electric field strength system on the vehicle, or based on map data set in advance corresponding to each point in the navigation system by the navigation computer 150, It may be determined correspondingly.

  When the received radio wave intensity Pin is sufficiently high, reception failure does not occur even if the electromagnetic wave noise due to the switching operation is not suppressed, and the audibility is not significantly deteriorated. In addition, when the received radio wave intensity Pin is considerably low, even if the electromagnetic wave noise due to the switching operation is suppressed, the reception situation is not good in the first place, so the effect of improving the audibility is small.

  Therefore, upper limit side and lower limit side threshold values Pmax and Pmin are provided for the received radio wave intensity Pin, and it is determined whether the received radio wave intensity Pin is out of the upper limit value and the lower limit value (step S120).

  When the received radio wave intensity Pin exceeds the upper limit Pmax or the lower limit Pmin, since the effect of improving the audibility is small even if the electromagnetic wave noise is suppressed, the switching speed reduction control accompanying the increase in power loss is not performed (step S130). On the other hand, when the received radio wave intensity Pin is within the range between the upper limit Pmax and the lower limit Pmin, an effect of improving audibility can be expected by suppressing electromagnetic noise, and therefore switching speed reduction control is executed during operation of the wireless receiver ( Step S140).

  Accordingly, it is possible to improve the reception status of the tuner while suppressing power loss in the switching element according to the reception condition (received radio wave intensity).

  FIG. 12 is a flowchart for explaining a fourth specific example of the switching speed control according to the present invention. FIG. 12 illustrates a control method in which switching speed control can be set for each switching element.

  Referring to FIG. 12, when tuner 120 is activated, steps S100 and S110 similar to those described with reference to FIG. 11 are executed, and the received radio wave intensity Pin at the selected frequency is obtained.

  Next, an allowable switching noise level Nlm from the PCU 20 (power converter) is determined according to the received radio wave intensity Pin (step S200). Specifically, the allowable switching noise level Nlm increases when the received radio wave intensity Pin is high, and the allowable switching noise level Nlm decreases when the received radio wave intensity Pin is low. In the controller 250, it is assumed that a map or an arithmetic expression for associating the received radio wave intensity Pin and the allowable switching noise level Nlm, and a noise map described below are stored in advance.

  FIG. 13 is a conceptual diagram illustrating a configuration example of a noise map.

  Referring to FIG. 13, a map of reception interference noise levels during operation is created in advance for each circuit constituting the power conversion device. For example, in the PCU 20 shown in FIG. 4, the noise level is set for each of the boost converter 210, the inverter unit 221, the inverter unit 222, the DC-DC converter 230, and the air conditioner inverter 240.

  As the noise level in the map, a measured value obtained by experimenting in advance may be used, or a calculated value based on a switching frequency, a switching current, a distance from a tuner, or the like may be used.

The noise level from each circuit is also set in advance for the switching speed reduction control described above. In the example of FIG. 13, the noise level from the inverter is NI0 with respect to the switching speed LV0 at the normal time (when the tuner is stopped), and the noise level becomes NI1 to NI3 as the switching speed decreases to LV1 to LV3. The point of improvement is estimated (NI0>NI1>NI2> NI3). Similarly, regarding the converter, noise levels NC0 to NC3 are estimated in advance corresponding to switching speeds LV0 to LV3 determined according to switching speed control signals SDC1 and SDC2, respectively. Referring again to FIG. When the switching noise level Nlm is determined, next, the total ΣNs of noise levels from the operating circuits in the power conversion device is obtained based on the noise map shown in FIG. 13 (step S210).

  If the obtained ΣNs ≦ Nlm, it is not necessary to perform a control for delaying the switching speed. However, if ΣNs> Nlm, the controller 250 sets a switching speed level that can satisfy ΣNs ≦ Nlm based on the noise map. (Step S220).

  The controller 250 generates switching speed control signals SDC1 and SDC2 for each circuit corresponding to the determined switching speed level (step S230). The switching speed control signals SDC1 and SDC2 generated by the controller 250 are sent to the gate drive circuit corresponding to each switching element. Each gate drive circuit sets the switching speed of the corresponding switching element according to the transmitted switching speed control signals SDC1, SDC2 (step S240).

  As a result, the switching speed reduction control is performed for each switching element in accordance with the reception status (reception radio wave intensity), so that it is possible to improve the reception status of the tuner while suppressing power loss.

  It should be noted that the second to fourth specific examples of the switching speed control described above can be combined as appropriate. For example, in the fourth specific example, when the received radio wave intensity is not within a predetermined range, the switching speed reduction control may not be performed, or the frequency band of the received radio wave may be reflected in the calculation of the allowable switching noise level.

  In this embodiment. Although an example has been shown in which the switching speed of each switching element can be set to two or four stages, the number of stages can be any number. For example, in the gate drive circuit shown in FIG. 7, the degree of slowing down the switching speed can be set stepwise by providing a larger number of sets of driving units and resistors and corresponding switching speed control signals. Further, in the gate drive circuit shown in FIG. 8, a new resistor connected in series between the node N2 and the gate Ng, a set of bypass switches of the resistor, and a large number of corresponding switching speed control signals are provided. The degree of slowing down the switching speed can be set in stages.

  In the above embodiment, the configuration example of the gate drive circuit is disclosed on the assumption that the switching element is a voltage driven element such as an IGBT or a MOS-FET. However, a current driven element such as a power transistor is used as the switching element. The present invention can be similarly applied to the provided power conversion device.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic block diagram showing a configuration of a hybrid vehicle equipped with a power conversion device according to the present invention. It is a figure explaining the audio system in the motor vehicle shown in FIG. It is a block diagram which shows the structure of the audio system in the motor vehicle shown in FIG. It is a circuit diagram explaining the structure of PCU (power converter device) shown by FIG. It is a figure explaining switching operation in case switching speed is high. It is a figure explaining switching operation when switching speed is low. It is a circuit diagram showing a configuration example of a gate drive circuit according to the present invention. It is a circuit diagram which shows the other structural example of the gate drive circuit by this invention. It is a figure explaining the 1st specific example of switching speed control by this invention. It is a figure explaining the 2nd specific example of the switching speed control by this invention. It is a flowchart explaining the 3rd specific example of switching speed control by this invention. It is a flowchart explaining the 4th specific example of switching speed control by this invention. It is a conceptual diagram explaining the structural example of a noise map.

Explanation of symbols

  10 battery, 30 power output device, 50L, 50R front wheel, 60L, 60R rear wheel, 70L, 70R front seat, 100 hybrid vehicle, 110 multi-display, 120 electronic tuner, 130 antenna, 141-144 speaker, 150 navigation computer, 201 , 202, 203 Power line, 210 Boost converter, 221, 222 Inverter unit, 230 DC-DC converter, 240 Air conditioner inverter, 250 Controller, 306, 316, 340, 342, 344 Resistance (gate resistance), 350, 355 Bypass Switch, GD, GD1-GD8 gate drive circuit, GS gate control signal, GT generator, Q1-Q8 switching element, SDC, SDC1, SDC2 switch Etching speed control signal, Vc ON voltage (drive voltage), Vs-off voltage (driving voltage).

Claims (7)

A power converter arranged in the vicinity of a wireless receiver,
A plurality of switching elements for performing power conversion;
A control device having a function of detecting whether or not the wireless receiver is in operation, and controlling opening and closing of the plurality of switching elements;
A drive circuit that is provided corresponding to each of the plurality of switching elements, and that opens and closes the corresponding switching elements in response to a control signal from the control device;
The power converter is capable of controlling the drive circuit so that the switching speed of the corresponding switching element during operation of the wireless receiver is slower than when the wireless receiver is stopped.   The drive circuit has an electrical resistance electrically connected between a driving power source of the corresponding switching element and a control electrode of the corresponding switching element between when the radio receiver is operating and when it is stopped. The power converter according to claim 1, wherein the power converter is switched.   The drive circuit determines, during the operation, a degree to which the opening / closing speed of the corresponding switching element is slower than when the radio receiver is stopped according to a frequency band of a radio wave received by the radio receiver. Item 4. The power conversion device according to Item 1.   The drive circuit determines, in the operation, whether to slow down the opening / closing speed of the corresponding switching element as compared to when the wireless receiver is stopped, according to the received radio wave intensity of the wireless receiver. The power converter according to 1.   Whether or not the opening / closing speed of the corresponding switching element in the driving circuit is slower than when the wireless receiver is stopped is determined in advance by evaluating a noise level exerted on the wireless receiver by each of the switching elements. The power conversion device according to claim 1, wherein the power conversion device is determined for each of the plurality of switching elements according to received radio wave intensity at the wireless receiver based on the noise evaluation data. The power conversion device according to any one of claims 1 to 5,
An automobile comprising an on-vehicle tuner provided as the wireless receiver. The power conversion device according to claim 3 or 4,
An in-vehicle tuner provided as the wireless receiver;
With a car navigation system that can identify the vehicle position,
The car navigation system has map data indicating the radio field intensity of the broadcast at each point,
The received radio wave intensity of the previous radio receiver is determined based on the map data.

Images