Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/64—Heating using microwaves
  • H05B6/66—Circuits
  • H05B6/664—Aspects related to the power supply of the microwave heating apparatus

Definitions

• a current ('discharge current') is constantly flowing through the discharge resistor, and a power loss is constantly being implemented, typically in a range of several 100 mW. It is the object of the present invention to reduce a power loss of the household appliance with a simultaneous sufficient discharge of the noise filter at a release of the network connection.
• the at least one discharge element comprises at least one consumer, which is turned on during normal operation of the household appliance.
• the consumer need not be constantly turned on during normal operation, but it is sufficient that it can be switched on during a normal operation of the household appliance or can be switched on.
• a discharge current of the noise filter also flows through the consumer, but firstly with an AC voltage applied to the phase and the neutral conductor only periodically and secondly only when the consumer is switched on.
• the power of the capacity (s) flows back into the supply network.
• the method is not limited to energy converters such as motorized components and / or radiators.
• the at least one discharge element may e.g. also a passive device, e.g. a load, such as a dedicated discharge resistor.
• a passive device e.g. a load, such as a dedicated discharge resistor.
• the nature of the discharge element is not limited.
• the at least one discharge element comprises a fan.
• a fan is particularly suitable for rapid discharge, since he or his fan motor has a low resistance, is usually switched on individually and is non-safety critical in operation.
• the at least one discharge element comprises a circulation fan or its circulating air motor. The circulating air blower is present in particular in most ovens, so that only a small adaptation performance in the implementation of the discharge via the circulating air blower needs to be done for different devices.
• any other suitable fan may be used, e.g. a steam ventilator, a cooling fan, etc.).
• a steam ventilator e.g. a fan ventilator, a cooling fan, etc.
• an antenna motor may also be used as a discharge element.
• radiators are basically suitable as discharge elements, depending on the type of oven, e.g. Upper heat radiator, lower heat radiator, H necessarilyluftutz redesign, grill radiator, etc. It is also an embodiment that the discharge is switched on for a predetermined period of time. As a result, a defined operating state of the discharge element can be achieved after a renewed connection to the supply network.
• the household appliance for discharging the at least one capacity provides a minimum duty cycle for the unloading element of less than 1 s.
• the discharge element is capable of discharging the capacities to a non-critical level within this second, e.g. to below 34 volts. This, in turn, causes a user to be very likely to be protected from electric shock by the capacitors at the latest after one second, e.g. when touching the contacts of a pulled power plug.
• the household appliance for discharging the at least one capacity provides a minimum duty cycle for the unloading of less than 100 ms.
• the unloading element is capable of discharging the capacities to a non-critical level within this tenth of a second. This further increases the operational safety for a user.
• the discharge member is capable of reducing the capacity (s) within the predetermined minimum duty cycle to the predetermined amount, e.g. Voltage level, to discharge, a longer discharge time can further reduce the voltage.
• the release of the network connection is detected by a lack of at least one network connection-dependent signal.
• the network connection dependent signal is a signal that can be present or generated when there is a network connection and is missing if the network connection is or is being disconnected.
• the network connection dependent signal may e.g. be a network synchronous signal, in particular a network synchronous square wave signal.
• a network-dependent periodic signal and / or a network-dependent non-periodic signal (eg a DC voltage level generated from the mains voltage) may be used.
• a shutdown routine is performed upon detecting the release of the network connection, wherein the switching on the discharge element for discharging the capacitors of the noise filter is part of the shutdown routine.
• the logic circuit uses an energy store which is present in the domestic appliance and is suitable for a sufficiently long operation of the logic circuit, for example a capacitor.
• the object is also achieved by a household appliance, wherein the household appliance is set up for implementation.
• the household appliance can, for example, have at least one detachable network connection to a supply network, an interference filter with at least one capacitance and at least one discharge element for discharging the at least one capacitance and be adapted to release the network connection toward the at least one discharge element for discharging the at least one to turn on a capacity. Only during this short time the discharge current flows. A constant current through a permanently suspended discharge resistor is avoided. Standby power consumption is significantly reduced.
• the household appliance can be developed analogously to the embodiments of the method.
• the household appliance may have a monitoring unit in one embodiment for detecting the release of the network connection.
• the monitoring unit can be designed as one or with a logic circuit, in particular as part of a central control unit.
• the logic circuit can be set up in particular for detecting the release of the network connection by a lack of at least one network connection-dependent signal, in particular a network-synchronous signal, in particular a network-synchronous square-wave signal.
• the logic circuit a microcontroller, etc.
• the logic circuit is thus detected by means of the network connection-dependent signal, whether the supply or mains voltage, and thus also the network connection, are present or not.
• noise filter and the discharge element are connected in parallel between a phase and a neutral.
• the discharge element is switched by a relay, alternatively by another switch such as a triac, etc.
• the domestic appliance can be designed as a stove, in particular as a microwave oven (microwave stand-alone appliance, microwave oven / oven combination appliance, etc.).
• microwave oven microwave stand-alone appliance, microwave oven / oven combination appliance, etc.
• the figure shows a section of a circuit diagram of a combined microwave / oven according to the invention.
• the furnace has a phase P and a neutral N, between which several components are mounted.
• a radio interference filter Z10 located between the phase P and the neutral conductor N is a radio interference filter Z10, which has various parallel-connected capacitances (without reference numerals), comprising an X2 capacity and a Y2 capacity.
• the functioning of noise filters is well known.
• a discharge resistor EW of eg 75 kQ has been permanently connected in parallel with the capacitors in the radio interference suppression filter Z10. When releasing the network connection flows through the discharge resistor EW driven by the capacitive discharge current.
• a disadvantage of the use of the discharge resistor EW is that in the presence of the mains voltage via the discharge resistor EW continuously a leakage current of, for example, 700 mW flows. This leakage current flows so even during a standby operation, in which the furnace is connected to the supply network, but is not operated in a mode.
• the introduced food can be treated by microwaves and / or by heat.
• a magnetron E8 is present, and to generate the heat there are a bottom heat radiator E12, a grill radiator E17, a circulating air radiator E19 and a further grill radiator E27, which have respective power radii.
• the radiators E12, E17, E19 and E27 are also connected in series with two temperature limiter R14 and a cooking chamber lock Y3.
• the cooking chamber lock Y3 is also connected to a temperature limiter R36 and also has two limit switches F31 and F32 for detecting a sitting of a cooking chamber door and a locking motor M10 for the cooking chamber door.
• the cooking chamber lock Y3 is further equipped with a switch S13 for power switching.
• the magnetron E8 is preceded by an inverter T20, which in turn is connected to a temperature limiter R7.
• the magnetron E8 and an antenna motor M6 for rotating a microwave antenna are turned on together via a power relay K2.
• the magnetron E8, the antenna motor M6 and the radiators E12, E17, E19 and E27 are also connected in series to a common power relay K51, so that each of these elements is protected by at least two switches.
• a transformer T15 for operating an oven lamp E22 and a plurality of motors are further connected in parallel, namely a cooling fan motor M1, a circulating air motor M3 of a circulating air blower, a motor M4 a Wrasenlüf- ters and a motor M7 of a magnetron fan.
• the transformer T15, the circulating air motor M3, the motor M4 of the fan-type fan and the motor M7 of a magnetron fan can be turned on by a respective relay K24, K15, K37 and K10, respectively, which are not power relays.
• the cooling fan motor M1 can be switched on by means of two relays K36 or K09. All controllable relays K2, K17, K12, K39, K27, K51, K15, K37, K36, K10, K24 and K09 are housed on a common control board K138.
• a switching power supply G1 is further arranged.
• the discharge resistor EW is missing, as a result of which the associated leakage current no longer occurs.
• the capacitances of the interference suppression filter Z10 are deliberately discharged by the circulating air motor M3 of the circulating air fan is switched on via relay K15 for approx. 20 ms. Only for this time, the discharge current flows. Since only a small amount of current is available for operating the domestic appliance after the mains connection has been disconnected, the low-consumption switching of the circulating-air motor M3 by means of only a single relay is advantageous.
• the switching is done by a control circuit, not shown, which is implemented in the form of a microcontroller.
• the control circuit first detects the disconnection of the network connection by using a network connection dependent signal, e.g. A mains-synchronous square-wave signal is missing, or generally changes its value. In this case, the time duration or the number of signals, from the absence of the release of the network connection is determined to be chosen differently depending on the interpretation.
• the network-synchronous signal can also be used, for example, to clock a power supply to the radiators.
• a shutdown routine takes place on the control circuit after or with the detection of the disconnection of the network connection, which as a part envisages the switching on of the circulating air motor M3 by the relay K15.
• the furnace according to the invention has the advantage that no additional components are required for its implementation, but even the hard-wired discharge resistor can be saved. Thus, a permanent power loss is avoided by the discharge resistor in network connection.
• the present invention is not limited to the embodiment shown.
• the discharge may additionally or alternatively be via another of the motors and / or via one or more of the radiators. It is also basically possible to maintain the discharge resistance and to connect in series with a corresponding switch.
• the circuit of the consumer does not need to be done via relays, but can be done via any other suitable switch such as triacs.
• the invention is not limited to an oven, but can be applied to any household appliances, such as refrigerators, washing machines, dishwashers, etc.
• the release of the network connection can be effected for example by pulling a power plug.

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Electric Ovens (AREA)
• Details Of Connecting Devices For Male And Female Coupling (AREA)
• Filters And Equalizers (AREA)

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• 2009
  • 2009-10-01 DE DE200910045242 patent/DE102009045242A1/de not_active Withdrawn
• 2010
  • 2010-09-22 WO PCT/EP2010/063981 patent/WO2011039089A1/de active Application Filing
  • 2010-09-22 EP EP10765593.8A patent/EP2484007B1/de not_active Not-in-force
  • 2010-09-22 CN CN201080043991.1A patent/CN102549921B/zh not_active Expired - Fee Related

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