Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M1/00—Details of apparatus for conversion
  • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
  • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
  • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
  • H02H7/122—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters
  • H02H7/1225—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters responsive to internal faults, e.g. shoot-through
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M1/00—Details of apparatus for conversion
  • H02M1/32—Means for protecting converters other than automatic disconnection
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
  • H03K17/18—Modifications for indicating state of switch

Definitions

• the present invention relates to the field of gate drivers for power converters in particular to gate drivers for power converters having a plurality of power converter modules.
• the present invention relates to a power converter comprising a gate driver. Furthermore, the present invention relates to a method of operating a gate driver.
• Multi-megawatt power electronic converters typically adopt a modular approach, using multiple inverter modules connected in soft parallel.
• the output of each module is connected via a balancing reactor to the common load.
• the primary purpose of the balancing reactor is to accommodate the inevitable timing and voltage differences between inverter modules and then provides an important part of the facility by which active current balance is achieved between the inverter modules.
• Fig. 1 schematically shows the electrical system of a wind turbine 100.
• the blades 101 of the wind turbine are coupled to a generator 102 which is coupled to the electrical system via a generator circuit breaker (GCB) 103.
• the electrical system comprises a plurality of balancing reactors 104 which are coupled to the GCB and are used to divert the power generated by the generator into a plurality of inverter or power converters modules 105 connected in parallel so that high power outputs, e.g. in the range of several megawatt, can be handled by the electrical system of the wind turbine.
• the power converters are only schematically depicted in
• Fig. 1 each comprise a generator bridge 106, a voltage clamp 107 and a network bridge 108.
• inverters or power converters is coupled to further balancing reactors 109 which are used to perform inevitable timing and handle voltage differences between inverter modules.
• the output of the further balancing reactors is connected to a network circuit breaker (NCB) 110 via an inductivity (LN) 111 and a pulse width modulation filter (PWM) 112.
• the output of the NCB is in turn coupled to a wind turbine transformer 113 and via a further circuit breaker (MVCN) 114, which serves for the self-protection of the network, to a wind farm collector network 115 which serves for conducting of the generated electrical power of the wind farm.
• the electrical system comprises a wind turbine controller 116 and a controller 117 which are both used to control the inverter or power converter modules.
• the IGBT insulated-gate bipolar transistor
• the IGBT gates operate at potentials several hundred volts from ground potential and so the low voltage command signals must be galvanicaly isolated from the IGBT gate. This signal conditioning and isolation is performed by a gate-drive circuit or gate driver.
• the gate-drive circuit board has a "low-side" circuit which transmits signals to and from the "high-side” circuit using a pulse transformer.
• the IGBT turn-off signal from the controller cannot be transmitted via the pulse transformer to the high-side in order to turn-off an IGBT of the balancing reactor. This represents a temporary loss of control of the conduction state of the IGBT which may result in a failure of the power converter or inverter.
• a gate driver for a power converter comprising a low side circuit and a high side circuit coupled to the low side circuit, wherein the high side circuit comprises a detection circuitry which is adapted to provide an error signal which is indicative of a fault condition of the low side circuit.
• the low side circuit and the high side circuit may be coupled to each other by a coupling element which is adapted to transmit signals, e.g. electrical signals or optical signals, and/or AC current but blocks DC current.
• the low side circuit and the high side circuit may be isolated from each other with respect to a DC current.
• the coupling element may be a transformer or a capacitor.
• the coupling element may be an opto-fiber or opto-coupler which both are suitable to transmit signals but to block electrical current.
• gate driver is not
• switching signal to an input terminal of the switching element may be regarded as a gate driver.
• detection circuitry may particular denote any arrangement of electronic circuits which is suitable and/or adapted to detect a faulty condition of the low side circuit and based on this detection provide and/or generate a
• an electronic converter which comprises a gate driver according to an exemplary aspect and a switching element having an input terminal coupled to an output terminal of the gate driver.
• a method of operating a gate driver according to any an exemplary aspect is provided, wherein the method comprises detecting an error condition of the low side circuit at the high side circuit generating an error signal upon detection of the error condition, and providing the error signal to a switching element.
• a computer program is provided which, when being executed by a processor, is adapted for controlling the method according to an exemplary aspect.
• reference to a computer program is intended to be equivalent to a reference to a program element and/or to a computer readable medium containing instructions for controlling a processor or computer system to coordinate the performance of the method of operating a gate driver.
• the computer program element may be implemented as computer readable instruction code in any suitable programming language, such as, for example, JAVA, C++, and may be stored on a computer-readable medium (removable disk, volatile or non-volatile memory, embedded memory/processor, etc.).
• the instruction code is operable to program a computer or any other programmable device to carry out the intended
• the computer program may be available from a network, such as the World Wide Web, from which it may be downloaded .
• the switching element may be a transistor of the electronic converter.
• the electronic converter may comprise a plurality of converter stages or modules each comprising at least one gate driver and coupled in parallel so that the amount of current and/or power providable by the electronic converter is increased.
• the electronic converter which may be a multi-megawatt power electronic converter, may comprise a balancing reactor adapted to provide a timing and/or voltage adaption or matching for different converter stages of the electronic converter .
• turn-off signals for a switching element may be transmitted fast enough from the controller so that the switching element can be turned-off.
• a temporary loss of control of the conduction state of the switching element may be avoided.
• the low side circuit and the high side circuit are galvanicaly separated from each other.
• the separation or isolation may be performed by providing a transformer, by an opto-fiber or opto-coupler .
• the gate driver further comprises a pulse transformer, wherein the pulse transformer is adapted to couple the low side circuit to the high side circuit .
• a pulse transformer as the means of coupling or isolation may provide for an optimisation of signal latency (and variation of latency) , skew (and variation of skew) , voltage isolation capability, lifetime/performance degradation, and cost.
• the pulse transformer may use a form of voltage pulse, to turn-on and a pulse to turn-off, which is latched by the high-side.
• the gate driver further comprises an output terminal which is adapted to be coupled to a switching element in such a way that the error signal is provided at a switching input terminal of the switching element .
• the switching element may be a transistor, preferably a power transistor, and may be an IGBT, a MOSFET, a BPT, GTO or IGCT.
• the fault condition is a loss of a low side power supply and/or a loss of a clock signal of the low side circuit.
• the loss of the low side power supply may be caused by a short-circuit component.
• the detection circuitry is adapted to provide the error signal in a time span which is lower than a predetermined limit.
• a predetermined limit may be defined as a time span which is sufficient short to protect a switching element when coupled to the gate driver. Examples for the
• predetermined limit may be 1 millisecond, 100 microseconds, 50 microseconds or even 10 microseconds.
• the high side circuit comprises a top part and a bottom part.
• the high side circuit comprises a power supply circuitry and a logic circuitry wherein the high side power supply circuitry is coupled to a low side power supply circuitry.
• the detection circuitry may be a part of the logic circuitry or at least some parts or components of the detection circuitry may be part of the logic circuitry.
• the detection circuitry or at least some parts or components of the detection circuitry may be part of the power supply circuitry.
• the detection circuitry comprises a pair of diodes and an RC filter coupled to each other in such a way that a detection signal is generatable.
• the detection circuitry may be part of the high side power supply circuitry and the pair of diodes and the RC filter are coupled to each other in such a way that the detection signal is supplied to the logic circuitry.
• the detection signal may be used to generate the error signal or may itself be the error signal depending on the specific implementation of the detection circuitry.
• a fast e.g. faster than 1 millisecond or even faster than 100 microseconds
• logic signal suitable for providing an error signal.
• another number of diodes may be used and may thus form at least a part of the detection circuitry.
• a detection circuitry or logic circuitry may be used which is adapted to detect a square wave carrier or square wave signal modulated onto the power supply.
• an edge triggered timer/monostable or phase-locked loop may be used to provide a high speed signal as the detection signal and/or error signal based on the detection of the presence of the square wave carrier, which error signal may then be used to switch- off switching elements of a corresponding balancing reactor.
• the logic signal is supplied to an AND and/or NAND element having an output terminal wherein the AND and/or NAND element is adapted to provide the error signal at an output terminal
• phase current for closed-loop current control, current balancing, and over-current protection
• the detection on the low side may have some disadvantages in specific cases which disadvantages may be avoided when the error signal is generated at the high side.
• the disadvantages that in certain internal component fault conditions (e.g. a sudden loss of power on the "low-side" circuit due to short-circuit component or loss of gate drive clock signal) the transistor (e.g. an IGBT) turn-off signal from the controller cannot be transmitted via the pulse transformer to the high-side in order to turn-off the respective transistor, may be avoided, since the error signal is already generated on the high side.
• the generation of the error signal on the high side may avoid a temporary loss of control of the conduction state of the transistor which loss of control would, if the IGBT is in a turned-on state and conducting current at the instant of the fault, lead to the fact that it will remain turned-on and conducting current until the power supply fails of the "high- side" electronics (held up by high- side local reservoir capacitor) collapses to its undervoltage lockout threshold. At this point in time (possibly several milliseconds after the fault occurred) the transistor gate will be turned off. However, this delay of turn-off of the transistor, which may cause damage to the transistor, may be avoided in case the error signal is already generated on the high side circuit.
• inverter modules or power converter modules operating in parallel e.g. in multi-megawatt inverters
• inverter modules connected to a load that is a voltage source for extended period (e.g. large induction/PM
• a simple facility on the high side of the gate driver or gate drive electronics may be provided that monitors the health of the low side of the gate driver electronics and possibly autonomously turn- off the transistor within a very short time (a few
• microseconds rather than milliseconds
• Figure 1 schematically shows a wind turbine
• Figure 2 schematically shows a principle layout of a gate driver .
• Figure 3 schematically shows a layout of a gate driver according to an exemplary embodiment.
• Figure 4 schematically shows a circuit used to explain a fault condition.
• Figure 5 schematically shows an example of a specific fault.
• FIG. 2 schematically shows a principle layout of a gate driver 200.
• Fig. 2 shows a low side circuit 201 and a high side circuit 202 which comprises a top part 203 and a symmetric bottom part 204.
• the low side circuit and the high side circuit are coupled to each other via a phase transformer or power supply transformer 205 which provides the power supply for the high side circuit.
• additional transformers 206 and 207 are provided which couple the low side circuit with the top part and the bottom part of the high side circuit, respectively.
• the high side circuit comprises a power supply circuitry 208 coupled to the power supply transformer 205 and providing the high side circuit with power.
• the power supply circuitry 208 comprises two parts 209 and 210 forming the power supply for the top part and the bottom part of the high side circuit, respectively.
• Each of the two parts of the power supply circuitry 208 comprises diodes and a capacitor, e.g. a local reservoir capacitor, and is
• the logic part of the top part of the high side circuit 211 comprises a control logic 213 coupled on the one side to a signal conditioning unit 214 which is then coupled to a first terminal 215 of the gate driver.
• the control logic 213 is coupled to one of the additional
• the logic part of the bottom part of the high side circuit 212 comprises a control logic 216 coupled on the one side to a signal conditioning unit 217 which is then coupled to a second terminal 218 of the gate driver.
• the control logic 216 is coupled to the other one of the additional transformers 207.
• a top command signal or top control signal and a bottom command signal or bottom control signal are provided to the top part and the bottom part of the high side circuit, respectively.
• the first terminal 215 and the second terminal 218 are coupled to a phase connection element 219 comprising a first transistor 220 coupled in parallel with a diode 221, wherein the first terminal 215 is connected to the gate of the first transistor 220.
• connection element 219 is coupled to the second terminal 218 and is connected in parallel to a second diode 223.
• a source of the transistor 220 is coupled to a voltage DC+ while the source of the transistor 222 is coupled to a voltage DC-.
• the drains of the transistors each are coupled to a phase
• Figure 3 schematically shows a layout of a gate driver according to an exemplary embodiment.
• the gate driver of Figure 3 is substantial identical to the one depicted in Figure 2 so that only the differences are described in the following.
• the power supply circuitry of the gate driver according to Figure 3 comprises detection
• each of the first and second detection circuitries 330 and 331 comprises a pair of diodes 332 and 333 and 334 and 335, -Ir ⁇ respectively and a RC filter 336 and 337 having a time constant in the range of microseconds, e.g. less than
• the detection circuitries provide a function which is effectively an " IGBT TURN-ON ENABLE" signal.
• the respective signal is ANDed, by AND or NAND elements 338 and 339,
• Alternative solutions include any method of rapidly detecting ( ⁇ 10 microseconds) the loss of the voltage and absence of switching of the power supply, whilst retaining high-side power supply for sufficient time (stored energy in reservoir capacitance) to turn off the IGBT in a controlled manner.
• These alternative solutions include:
• Figure 4 schematically shows a circuit used to explain a fault condition.
• Figure 4 schematically shows a plurality of inverter modules 440, 441 and 442. For clarity reasons for each inverter module only the two transistors connected to the balancing reactors via the phase connection (cf. Figure 2 and 3) are shown.
• the AC current can be considered as a constant negative current source
• a turn-off command is sent to ⁇ , ⁇ ( ⁇ ) to T n , X ( B ), either a) as a result of the fault initiating a trip, or b) a normal turn- off event.
• T liX(B) If immediately prior to the fault, the prevailing total phase current for the n paralleled inverters is greater than the peak current commutation limit of T liX(B) then T liX(B) can no longer turn off without destruction, nor can it remain turned on without destruction.
• Figure 5 schematically shows an example of a specific fault.
• Figure 5 shows one example of a short circuit path (in bold) resulting from a single IGBT (T X , 2 ( B >)
• transistors pairs 550, 551 and 552 connected to the balancing reactor 553 are shown of a given inverter module. The three pairs correspond to the different phases of the AC current. Additionally, Figure 5 shows an AC voltage source 554 to which the balancing reactors are coupled.
• the failure mode of the IGBT may be either:

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Inverter Devices (AREA)
• Power Conversion In General (AREA)

Priority Applications (1)

Applications Claiming Priority (3)

Publications (1)

Family

ID=47748592

Family Applications (1)

Country Status (3)

Families Citing this family (3)

Family Cites Families (6)

• 2013
  • 2013-02-13 CN CN201380026963.2A patent/CN104303405B/zh not_active Expired - Fee Related
  • 2013-02-13 EP EP13705749.3A patent/EP2815491A2/de not_active Withdrawn
  • 2013-02-13 WO PCT/EP2013/052805 patent/WO2013174528A2/en active Application Filing

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events