Power converter and control for microturbine
First Claim
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1. A turbogenerator/motor control arrangement for connection to an AC power grid, comprising:
- at least one AC generator;
at least one turbine operatively connected to the generator;
a first converter operatively connected to the generator;
a second converter operatively connected between the first converter and an electric utility interface; and
a DC bus operatively connected to the first and second converters, wherein power is supplied to the DC bus via the second converter during a first starting mode of the turbogenerator and power is supplied to the DC bus by the first converter during the second “
generating”
mode of the turbogenerator.
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Abstract
An arrangement and method for controlling a microturbine. Back-to-back inverters are provided such that a second inverter provides power to the DC bus prior to achieving self-sustaining operation of the turbine, and a first converter provides power to the DC bus and optionally controls its voltage once the turbine is self-sustaining. The second inverter operates in either AC utility voltage and frequency control mode or output current control mode depending upon the needs of the application.
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Citations
73 Claims
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1. A turbogenerator/motor control arrangement for connection to an AC power grid, comprising:
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at least one AC generator;
at least one turbine operatively connected to the generator;
a first converter operatively connected to the generator;
a second converter operatively connected between the first converter and an electric utility interface; and
a DC bus operatively connected to the first and second converters, wherein power is supplied to the DC bus via the second converter during a first starting mode of the turbogenerator and power is supplied to the DC bus by the first converter during the second “
generating”
mode of the turbogenerator.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A method for controlling a generator, comprising the steps of:
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providing electrical power to the generator through a first converter, a second converter, and a DC bus converter operatively connected to the generator, the first and second converters operating in a first mode to achieve self-sustaining operation of the generator or during a cool down cycle of the turbine;
supplying voltage from the generator to the DC bus and to the second converter through the first converter in a second mode of operation. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48)
providing electrical energy to the first inverter when utility electrical power is unavailable to start the generator and during self-sustained operation when the generator cannot meet an instantaneous load requirement.
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43. The method of claim 41, further comprising the step of providing an energy storage and discharge system for the first and second converters to provide electrical energy to the first converter when utility electrical power is unavailable to start the generator and during self sustained operation when the generator cannot meet an instantaneous load requirement and to otherwise store electrical energy during self-sustained operation.
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44. The method of claim 41, wherein the DC bus voltage is controlled according to a first technique during the first mode of operation.
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45. The method of claim 44, wherein the first technique includes controlling the DC bus voltage based on an AC voltage present on a power grid associated with the generator.
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46. The method of claim 44, wherein the DC bus voltage is controlled by a second technique during the second mode of operation.
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47. The method of claim 46, wherein the second technique includes controlling the bus voltage by generating voltages from one or more switches associated with the first converter, and producing reactive currents in the generator by providing the generated voltages to the generator.
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48. The method of claim 41, further comprising the step of filtering the voltage prior to the step of supplying.
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49. A turbine controller, comprising:
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an AC generator connected to the turbine;
a first converter connected to the generator;
a second converter connected to the first converter and to an AC power grid; and
a DC bus operatively connected to the first and second converters, wherein power is supplied to the DC bus via the second converter during a first starting mode of the generator and power is supplied to the DC bus by the first converter during a second operating mode of the generator. - View Dependent Claims (50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73)
an energy storage and discharge system for the first and second converters to provide electrical energy to the first converter when utility electrical power is unavailable to start the generator and during self sustained operation when the first converter cannot meet an instantaneous load requirement and to otherwise store electrical energy during self-sustained operation.
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52. The controller of claim 49, further comprising an exhaust gas temperature regulator operatively connected to maintain an exhaust gas temperature of the generator at a substantially constant value while supplying power.
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53. The controller of claim 52, wherein the regulator includes a fuel command proportional integral control loop.
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54. The controller of claim 52, wherein the regulator includes a current command proportional integral control loop.
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55. The controller of claim 52, wherein the regulator includes a fuel command proportional integral control loop and a current command proportional integral control loop.
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56. The controller of claim 53, wherein the fuel command proportional integral control loop includes a power proportional integral control.
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57. The controller of claim 53, wherein the fuel command proportional integral control loop includes a speed proportional integral control.
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58. The controller of claim 53, wherein the fuel command proportional integral control loop includes a power proportional integral control and a speed proportional integral control.
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59. The controller of claim 58, wherein the speed proportional integral control has a higher sampling time than the power proportional integral control.
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60. The controller of claim 58, wherein the fuel command proportional integral control loop additionally includes a minimum DC bus voltage proportional integral control and a selector to select the highest signal from said speed proportional integral control and said minimum DC bus voltage proportional integral control.
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61. The controller of claim 54, wherein the current command proportional integral control loop includes an exhaust gas temperature proportional integral control.
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62. The controller of claim 54, wherein the current command proportional integral control loop includes a lower bus voltage proportional integral control.
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63. The controller of claim 54, wherein the current command proportional integral control loop includes an exhaust gas temperature proportional integral control and a lower bus voltage proportional integral control.
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64. The controller of claim 63, wherein said lower bus voltage proportional integral control has a higher sampling time than said exhaust gas temperature proportional integral control.
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65. The controller of claim 52, wherein the regulator includes a fuel command proportional integral control loop having a power proportional integral control and a speed proportional integral control, and a current command proportional integral control loop having an exhaust gas temperature proportional integral control and a lower bus voltage proportional integral control.
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66. The controller of claim 65, wherein the speed proportional integral control has a higher sampling time than said power proportional integral control.
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67. The controller of claim 66, wherein the fuel command proportional integral control loop additionally includes a minimum DC bus voltage proportional integral control and a selector to select the highest signal from said speed proportional integral control and said minimum DC bus voltage proportional integral control.
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68. The controller of claim 65, wherein the lower bus voltage proportional integral control has a higher sampling time than said exhaust gas temperature proportional integral control.
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69. The controller of claim 65, wherein the speed proportional integral control has a higher sampling time than said power proportional integral control, and said lower bus voltage proportional integral control has a higher sampling time than said exhaust gas temperature proportional integral control.
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70. The controller of claim 65, wherein the power proportional integral control has a lower sampling time than said exhaust gas temperature proportional integral control.
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71. The controller of claim 65, wherein the exhaust gas temperature proportional integral control has a lower sampling time than said speed proportional integral control.
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72. The controller of claim 65, wherein the speed proportional integral control has a lower sampling time than said lower bus voltage proportional integral control.
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73. The controller of claim 65, wherein the power proportional integral control has a lower sampling time than said exhaust gas temperature proportional integral control, said exhaust gas temperature proportional integral control has a lower sampling time than said speed proportional integral control, and said speed proportional integral control has a lower sampling time than said lower bus voltage proportional integral control.
Specification